veedubber what do your ribs weigh?

I applaud your experimental rib building but I wonder how much the
work achieves.

I weighed two of my truss ribs.
one in alaskan yellow cedar and one in queensland hoop pine.
naca23012 aerofoil in 4ft chord with all the gussets but not all the
strengtheners in place. unvarnished.
they are for the druine turbulent, the plans I sent you.

in QHP the rib weighs 134 grams. in AYC the rib weighs 143 grams.
143 grams is 5.044 avoirdupois ounces.

for all your experimental work on ribs you've never mentioned the
resulting weights?
ok what are they? I'm curious.

Stealth Pilot

On Dec 25, 11:38*pm, Stealth Pilot
wrote:

for all your experimental work on ribs you've never mentioned the
resulting weights?
ok what are they? I'm curious.
----------------------------------------------------------------------------------------------------------------

Hi, Stealth,

Yes I did, but you'll have to read everything I wrote to find it. So
here's some current weights:

5 of the BIG ribs,that finish-out to a about a 60 inch chord, weighed
586 grams (for five) or 117.2g each.
4 of the SMALL ribs, the ones that finish out to about a 50" chord,
weighed 454 grams (for 4) or 113.5g each

I'm assuming the small ones I've measured here are the ones you're
interested in. I have some similar ribs which measure 25.25" between
the spar holes, whereas the ones I've measured above are exactly
24.00" and are intended for use with the 'Chugger' project.
----------------------------------------------------------------------------------------------------------------------------

Checking through the shop, I have examples of the Chugger's rib, ribs
for a modified Teenie Two, some old Primary Glider ribs and so
forth.

Using a conversion factor of .03527 to convert grams into ounces, the
big ribs with their paper gussets AND the section aft of the rear
spar, weighs 4.133 ounces per rib, where as the short ribs (113.5g
each) come out as 4.003 ounces... but of course that's without the
trailing edge. That is, there is NO structure aft of the aft spar
(because the entire trailing edge is meant to move. One reason for
the extra weight is that the short ribs use gussets made of 1/8" thick
doorskins (!). (They are what you would call 'sturdy' ribs :-)

-Bob Hoover

PS -- Neither of the ribs shown includes the leading edge structure.
In one version the leading edge detaches and is in fact, a fuel tank.
In another, the leading edge contains a portion of the wing folding &
latching mechanism.

But in most cases the Leading Edge consists of a single piece, routed
from 1/8" plywood, with notches to accept longitudinal stringers. In
most cases the leading edge itself is fabricated from 1/32" or 1/16"
aviation-grade plywood. In another experiment it is urethane foam
covered with fabric or... whatever.

I've posted some pictures of the ribs on my blog.

-Bob

To All:

A couple of private messages commenting on the significant WEIGHT
difference between the big ribs, which weigh less than the little
ribs.

I believe the most significant difference is in the gusseting
material. The little ribs are gusseted with 1/8" doorskin material
whereas the big ribs use 'fiber' gussets... that is, heavy-grade of
CARDBOARD (as has been previously discussed). This rib is meant for a
PRIMARY GLIDER. Very low total weight and not much in the way of
forward speed. Plus, the big ribs are made of REDWOOD, each piece
selected for its light weight. The small ribs are meant for the wing
of a SINGLE-PLACE VW powered parasol. Other than for the methods of
rib construction, there is virtually nothing in common between the two
wings. The small ribs are made from much heavier PINE, and use
heavier wooden gussets.

-Bob

PS -- If you've comments, I'd appreciate you posting them here. It
isn't convenient to copy them from the blog area.

On Fri, 26 Dec 2008 21:12:22 -0800 (PST), "
wrote:

To All:

A couple of private messages commenting on the significant WEIGHT
difference between the big ribs, which weigh less than the little
ribs.

I believe the most significant difference is in the gusseting
material. The little ribs are gusseted with 1/8" doorskin material
whereas the big ribs use 'fiber' gussets... that is, heavy-grade of
CARDBOARD (as has been previously discussed). This rib is meant for a
PRIMARY GLIDER. Very low total weight and not much in the way of
forward speed. Plus, the big ribs are made of REDWOOD, each piece
selected for its light weight. The small ribs are meant for the wing
of a SINGLE-PLACE VW powered parasol. Other than for the methods of
rib construction, there is virtually nothing in common between the two
wings. The small ribs are made from much heavier PINE, and use
heavier wooden gussets.

-Bob

PS -- If you've comments, I'd appreciate you posting them here. It
isn't convenient to copy them from the blog area.

I've been away.
It looks to me as though the experimenting should continue (after the
morning hack up of course) the weights are pretty well on the money.

this all leads to a comment for the impecunious.
(impecunious = as poor as a church mouse )
I saw this commented years ago but never believed it at the time.
most people build the fuselage first because it builds quick. then it
gathers dust as the other bits get worked on and often the project
stops there because life's demands push the boring bits to the
background.

if you build all of your ribs first, and honestly they are a little
tedious, you still have the fuselage to go so the project has an
exciting bit ahead.this helps you get through the tedious bit.
in the case of the druine turbulent there are 20 ribs made from about
2 kilos of 6 x 9mm stripped up wood and ply ( about 4 and a half
pounds of wood) they are trusses made on a building board template.
you make one rib ready for gussets every day. so it amounts to a month
or so's work.
the cost is actually five eighths of stuff all because the techniques
of ignoring the knots and stripping up the wood that veedubber writes
about actually do work. you just cut away any part of a strip with a
knot and dont use it.
but in building your ribs you have actually assembled over half the
joints that will be made in the aircraft.

the benefits of getting on and doing your ribs first are that you
develop all your fine dexterity skills in woodwork that will be hidden
under the wing fabric. when you come to do the woodwork that will be
visible your skills and fluency with the techniques are just so much
more refined and practised.

you wouldnt think that building a rib could be done in too many
different ways but bob and I have totally different approaches to rib
making. bob's is a time honoured traditional method. my approach uses
no nails.

if anyone is actually interested I'll write up a narrative on how I do
them.

btw if anyone wants a copy of the druine turbulent plans I can share
legible photos of the plans gratis via email. I dont know that anyone
actually enforces copyrights on these plans. from australian
experience there is no money to be made from them and the plans
originators are more interested in seeing turbulents being built.
turbulents fly really well behind a converted 1600cc vw engine just
bolted straight to the firewall.
this works because the vw is an unbelievably smooth running engine.
from what I've read of bob's conversions to date he is doing a pretty
good job with them.

Stealth Pilot

(if you need to quantify what 'five eights of stuff all' means try
half of two tenths of a brass razoo's worth. it's a lot less than a
'penny for your thoughts' :-) )

On Dec 28, 3:18*pm, Stealth Pilot
wrote:


if you build all of your ribs first, and honestly they are a little
tedious, you still have the fuselage to go so the project has an
exciting bit ahead.this helps you get through the tedious bit.
-------------------------------------------------------------------------------------------

Dear Stealth,

I hate to pee in your campfire but to build ALL of your ribs first is
to fly in the face of proven wisdom (as opposed to Conventional
Wisdom, which I believe is the package you are trying to tie on your
pony). And just to prove it, if you'll kindly take a seat, I will
showz you how it's SUPPOSED to be done.

See that big balk of timber over there? (Of course you can't, but
work with me here.) You wanna build a plane. So you go looking for
some WOOD, as in Sitka Spruce wood or Western Hemlock Wood or Red Wood
Wood. (Red can't. But he would if he could.)

Sometimes your ideal piece of wood is growing right up outta the
ground! Yeah! Like that tree-thing over there. So before you build
your aeroplane you gotta chop a notch in the side of that three,
making sure the center of the notch is perfectly perpendicular to the
line upon which you wish the tree to FALL. And here is a trick that
will serve you all your life here in the Gulag. See that notch? All
the eggheaded boys sent to the gulag think the notch must proscribe 90
degrees, and they are correct, but their failure as a Forester is in
that seemingly simple supposition, because if you want the tree to
fall where you are hoping it will, which is precisely atop the head of
Mikhail, the trustee and a rotten ******* if ever there was one...

So yes, a 90 degree notch is good. But No! The notch must NOT be 45
degrees below and 45 degrees above. The notch must be only 35 degrees
below and 55 degrees above! Or even more, if the diameter of the tree
is greater than one meter... or if its height is greater than thirty
meters. But you are what, an accountant? To preserve your innocence
you may make it 45/45 if you wish and hope God (or your friend Ivan)
will nudge Mikhail at the proper time.

Look at the earth upon which your tree will fall. Is it flat? Does
it slope up or down? Are there boulders? Does it span a gully? Are
there other trees of substantial size in the way? If so, you must
take those things into account or your tree will contain an unfaithful
heart; it will suffer Compression Fractures when it strikes the
ground. The fall has given your tree a considerable amount of
energy. As the branches touch the ground the truck of your tree will
tend to bend like an archers bow, generating a curve that would hold
water if it could. But since it can't, the end nearest you will TRY
to spring into the air, but if it can't do that, because of improper
notching OR because the trunk represents substantial mass, or because
the terrain upon which Your tree will fall is below the horizontal,
thus pumping more energy into the tree... because it's falling, you
stupid person you! It is accelerating by the SQUARE of the TIME. You
have given it more time, IF the ground is sloping downward.

But enough of that. Odds are you'll forget it anyway by the time you
get to the tree and talk Mikhail into position and find the fellow
with the saw (yes, the SAW. We are Foresters here, not Accountants).
SO IF... IF any of those things are present, you must put the brakes
onto your tree. You must prevent it from falling too fast. How? Yea
gods, man! You're in a forest! How do you think we'll slow it down?
(With... trees? He asks. Of COURSE WITH TREES! [and me with still
forty years to go...]) You must build a cradle for your baby of a
tree. A beautiful bed into which your love may fall with a smile and
extended limbs.

Do all those things and your beautiful tree will NOT suffer the
Compression Fractures to lie hidden in its heart of wood.

Cut the notch. Then take up the saw (and weld two together if one is
not long enough). And just ABOVE the apex of your notch, begin your
cut, keeping it even and true. That is, even meaning each side will
progress at the same rate as the other, and true in that however it
starts out, it continues. Level is good but the ground is often
crooked and your cut may be up or down but whatever it is, keep it
that way for its entire length. Otherwise your tree will think it's a
member of the Bolshoi and spin around and turn you into a bloody pulp
before you can "Jack Robinson." (Don't ask! It could cost you twenty
more years.)

The part of the tree that flys the best begins the height of a tall
man above the ground. NOT above the felling cut, but above the earth
which nurtured your beautiful tree. You may cut the fallen tree
there. The flying portion of the tree will extend to about two meters
BELOW the first limb of substantial size. The resulting stick may be
as long as twenty meters or more but if you have such a tall
candidate, select your flying portion from that nearest the ground.
How LONG that piece may be is determined by which Camp you are in.
See if you can find Mikhail and ask him (the silly ******* seems to
have disappeared again).

-------------------------------------------------------------------------------------------------------

Got your balk of timber? Try to. It works best.

A good balk is a Bridge Timber that is a Quarter-sawn cut. And you
may have to bribe someone to get that. Or go over to the Flybaby
Group and ask around amongst the builders who know Vancouver Island.

Get a balk of timber that has been properly cut then allowed to dry,
well supported, for as many years as it takes. (Stop your
complaining! You'll be here until you die anyway so what's a few
years?)

A Useful size is seven meters in length, 20centimeters in thickness
and 30centimeters in width. Or if you are in a Canadian Gulag, about
22'x 8"x12"

What you want first are your Spars. There will four of them in a Real
airplane. Then comes your Fuselage stringers and finally your smaller
stringers.

Somewhere along the line you will have built jigs for your ribs and
your tail group. As you cut the longer pieces out of your balk of
timber the cuts will yield some Waste. Set your saw to produce Rib
Stock from the waste.

Your ribs will have two long pieces and a myriad of shorter pieces.
Your task is to know the length of all of these pieces and whenever
the opportunity presents its self, to cut your Rib Stock into the
sizes you will need to produce your ribs. Sort the pieces. If you
put them in tin cans, be sure to poke holes in the BOTTOM of the
cans. If you don't, you'll find out why you should.

----------------------------------------------------------------------------------------------------------------------

And now we have finally arrived at Making of the Ribs.

Do NOT tackle this job as a Death Race. (Yeah, I know, but that was
a Varriviggen or whatever so it doesn't count.)

In producing your spars and stringers and diagonals and intercostals
and all the OTHER pieces of wood needed to build your airplane, you
will have AUTOMATICALLY produced enough pieces to fabricate all of the
ribs in your airplane! (In effect, your ribs are free!!) But you
will only produce those ribs as time permits; when you have finished a
More Important task. That's when you will REWARD YOURSELF by making a
rib. One at a time. Each one a perfect example of the wood-workers
art. Building ribs is NOT a chore nor task to be avoided; building a
rib is a REWARD for doing all the millions of other ****ty Little
Details that insist on being done before the airplane can fly. Why is
that so? Because the Secret is in the Wing.

You'll need to ponder on that so I'll leave you to it. Ponder away.
It is because your Life -- and the Life of anyone else who flys in
your machine depends upon your skill and dedication in making a
Perfect Wing, which itself depends upon a whole ****-pot full of
Perfect Ribs, made one at a time.

Why such emphasis? You will answer that question yourself as your
SKILLS accumulate. And because you would not believe me NOW no matter
how skillful you think you are.

-Bob

On Sun, 28 Dec 2008 16:46:19 -0800 (PST), "
wrote:

On Dec 28, 3:18*pm, Stealth Pilot
wrote:


if you build all of your ribs first, and honestly they are a little
tedious, you still have the fuselage to go so the project has an
exciting bit ahead.this helps you get through the tedious bit.
-------------------------------------------------------------------------------------------

Dear Stealth,

I hate to pee in your campfire but to build ALL of your ribs first is
to fly in the face of proven wisdom (as opposed to Conventional
Wisdom, which I believe is the package you are trying to tie on your
pony). And just to prove it, if you'll kindly take a seat, I will
showz you how it's SUPPOSED to be done.

See that big balk of timber over there? (Of course you can't, but
work with me here.) You wanna build a plane. So you go looking for
some WOOD, as in Sitka Spruce wood or Western Hemlock Wood or Red Wood
Wood. (Red can't. But he would if he could.)

Sometimes your ideal piece of wood is growing right up outta the
ground! Yeah! Like that tree-thing over there. So before you build
your aeroplane you gotta chop a notch in the side of that three,
making sure the center of the notch is perfectly perpendicular to the
line upon which you wish the tree to FALL. And here is a trick that
will serve you all your life here in the Gulag. See that notch? All
the eggheaded boys sent to the gulag think the notch must proscribe 90
degrees, and they are correct, but their failure as a Forester is in
that seemingly simple supposition, because if you want the tree to
fall where you are hoping it will, which is precisely atop the head of
Mikhail, the trustee and a rotten ******* if ever there was one...

So yes, a 90 degree notch is good. But No! The notch must NOT be 45
degrees below and 45 degrees above. The notch must be only 35 degrees
below and 55 degrees above! Or even more, if the diameter of the tree
is greater than one meter... or if its height is greater than thirty
meters. But you are what, an accountant? To preserve your innocence
you may make it 45/45 if you wish and hope God (or your friend Ivan)
will nudge Mikhail at the proper time.

Look at the earth upon which your tree will fall. Is it flat? Does
it slope up or down? Are there boulders? Does it span a gully? Are
there other trees of substantial size in the way? If so, you must
take those things into account or your tree will contain an unfaithful
heart; it will suffer Compression Fractures when it strikes the
ground. The fall has given your tree a considerable amount of
energy. As the branches touch the ground the truck of your tree will
tend to bend like an archers bow, generating a curve that would hold
water if it could. But since it can't, the end nearest you will TRY
to spring into the air, but if it can't do that, because of improper
notching OR because the trunk represents substantial mass, or because
the terrain upon which Your tree will fall is below the horizontal,
thus pumping more energy into the tree... because it's falling, you
stupid person you! It is accelerating by the SQUARE of the TIME. You
have given it more time, IF the ground is sloping downward.

But enough of that. Odds are you'll forget it anyway by the time you
get to the tree and talk Mikhail into position and find the fellow
with the saw (yes, the SAW. We are Foresters here, not Accountants).
SO IF... IF any of those things are present, you must put the brakes
onto your tree. You must prevent it from falling too fast. How? Yea
gods, man! You're in a forest! How do you think we'll slow it down?
(With... trees? He asks. Of COURSE WITH TREES! [and me with still
forty years to go...]) You must build a cradle for your baby of a
tree. A beautiful bed into which your love may fall with a smile and
extended limbs.

Do all those things and your beautiful tree will NOT suffer the
Compression Fractures to lie hidden in its heart of wood.

Cut the notch. Then take up the saw (and weld two together if one is
not long enough). And just ABOVE the apex of your notch, begin your
cut, keeping it even and true. That is, even meaning each side will
progress at the same rate as the other, and true in that however it
starts out, it continues. Level is good but the ground is often
crooked and your cut may be up or down but whatever it is, keep it
that way for its entire length. Otherwise your tree will think it's a
member of the Bolshoi and spin around and turn you into a bloody pulp
before you can "Jack Robinson." (Don't ask! It could cost you twenty
more years.)

The part of the tree that flys the best begins the height of a tall
man above the ground. NOT above the felling cut, but above the earth
which nurtured your beautiful tree. You may cut the fallen tree
there. The flying portion of the tree will extend to about two meters
BELOW the first limb of substantial size. The resulting stick may be
as long as twenty meters or more but if you have such a tall
candidate, select your flying portion from that nearest the ground.
How LONG that piece may be is determined by which Camp you are in.
See if you can find Mikhail and ask him (the silly ******* seems to
have disappeared again).

-------------------------------------------------------------------------------------------------------

Got your balk of timber? Try to. It works best.

A good balk is a Bridge Timber that is a Quarter-sawn cut. And you
may have to bribe someone to get that. Or go over to the Flybaby
Group and ask around amongst the builders who know Vancouver Island.

Get a balk of timber that has been properly cut then allowed to dry,
well supported, for as many years as it takes. (Stop your
complaining! You'll be here until you die anyway so what's a few
years?)

A Useful size is seven meters in length, 20centimeters in thickness
and 30centimeters in width. Or if you are in a Canadian Gulag, about
22'x 8"x12"

What you want first are your Spars. There will four of them in a Real
airplane. Then comes your Fuselage stringers and finally your smaller
stringers.

Somewhere along the line you will have built jigs for your ribs and
your tail group. As you cut the longer pieces out of your balk of
timber the cuts will yield some Waste. Set your saw to produce Rib
Stock from the waste.

Your ribs will have two long pieces and a myriad of shorter pieces.
Your task is to know the length of all of these pieces and whenever
the opportunity presents its self, to cut your Rib Stock into the
sizes you will need to produce your ribs. Sort the pieces. If you
put them in tin cans, be sure to poke holes in the BOTTOM of the
cans. If you don't, you'll find out why you should.

----------------------------------------------------------------------------------------------------------------------

And now we have finally arrived at Making of the Ribs.

Do NOT tackle this job as a Death Race. (Yeah, I know, but that was
a Varriviggen or whatever so it doesn't count.)

In producing your spars and stringers and diagonals and intercostals
and all the OTHER pieces of wood needed to build your airplane, you
will have AUTOMATICALLY produced enough pieces to fabricate all of the
ribs in your airplane! (In effect, your ribs are free!!) But you
will only produce those ribs as time permits; when you have finished a
More Important task. That's when you will REWARD YOURSELF by making a
rib. One at a time. Each one a perfect example of the wood-workers
art. Building ribs is NOT a chore nor task to be avoided; building a
rib is a REWARD for doing all the millions of other ****ty Little
Details that insist on being done before the airplane can fly. Why is
that so? Because the Secret is in the Wing.

You'll need to ponder on that so I'll leave you to it. Ponder away.
It is because your Life -- and the Life of anyone else who flys in
your machine depends upon your skill and dedication in making a
Perfect Wing, which itself depends upon a whole ****-pot full of
Perfect Ribs, made one at a time.

Why such emphasis? You will answer that question yourself as your
SKILLS accumulate. And because you would not believe me NOW no matter
how skillful you think you are.

-Bob



you mention glue.
how do you make that?

Stealth Pilot

On Dec 30, 2:11*am, Stealth Pilot
wrote:


you mention glue.
how do you make that?
------------------------------------------------------------------------------------------------------------------------

How you make it depends of what you're trying to glue together.

A good general purpose glue is made from raw hides. This can take a
pretty strong nose.

Go to one of the big Chain Stores that carries Pet supplies. Buy some
pigs ears or dried 'chewables' of rawhide.

Try cutting the rawhide or dried ears into smaller pieces. Depending
on how they were prepared, their size can be as large as 8x10 inches.
For making glue you want the size to be more on the order of 1/4 x
1/4" or in the form of strings. Soak the pieces in water until they
are fully saturated then begin adding heat. To maintain control of
the temperature you'll need to use a double boiler.

If you've never made hide glue, start by BUYING SOME, so you'll know
what it looks like. It is made from rawhide -- the residue of making
leather -- or from hooves and horns. Properly made, the stuff looks
like honey. In use, it may be thinned and heated.

Rawhide itself is rather handy stuff. When saturated with water it
can be stretched but will try to shrink back to its original size
unless restrained. You can make molds of things you wish to protect,
such as some of your precision tools. Soaking the dried rawhide in a
light oil will prevent it from absorbing water and losing it's shape.

For homebuilders the most useful glue is Casein. This is made from
the protein in MILK. Run your milk through a cream separator more
than once, or allow it to stand, giving the cream time to separate.
When making milkglue you want to be damn sure that you do NOT get any
cream in the mix. If you live in an area that does not provide real
milk, visit your local grocery store and see if they carry 'fat-free'
or 'skim' milk.

Starting with skim milk, add an acid such as vinegar to cause the milk
to 'turn'. Stir the milk to ensure the acid reaches all of the milk.
Allow it to stand for about half an hour then pour off the liquid (ie,
the whey) then whisk the curds into a uniform paste and neutralize
them using bicarbonate of soda dissolved in water. Heat this mix in a
double boiler to reduce it to the consistency of heavy cream. If you
are not familiar with this consistency go BUY some heavy cream... or
allow some real ice cream to melt. The basic test is to take it up a
teaspoon at a time and allow it to pour back into the container.
'Heavy Cream' is the point at which it pours back as a single stream
rather than as a series of drops.

The next step is to make sure you have neutralized the acid. The best
way to do this is with Litmus paper, purchased at the drug store or on-
line. If that is not available to you, you can do the test with a
STRONG mixture of bicarbonate of soda in warm water. Add this to
your mix ONE DROP AT A TIME whilst looking for it to generate any
bubbles. If the mix is still acidic you will have to add more
neutralizer, stirring it in good and repeating your tests. The
problem here is that you are trying to achieve a NEUTRAL mix, one that
is neither acidic nor base. The tests make it easy to DETECT acidity
but not the opposite, unless you are using Litmus papers, so you want
to very careful that you do not end up with a mix that contains too
much bicarbonate of Soda because the soda will precipitate out as
crystals within the glue line, reducing its strength.

If you glue is too thick you may dilute it with water; if too thin you
may heat it to drive off some of the water. When you have achieved
what you believe is your best mix, you must test it using the standard
FTC shear-strength test. That is,a coupon two inches wide by four
inches long, with the adhesive applied to a 2x2 area. The adhesive is
applied to both faces and clamped with approximately 70 pounds of
pressure, all this while maintaining a gluing temperature of about 70
degrees on the Fahrenheit scale. The test-coupon is sheared at the
glue-line by clamping the free end in a vise and striking the other
free end with a three pound hammer, using enough force to cause the
sample to fail at the glue line.

Examination of the failure should show that the WOOD failed over at
least 80% of the glued area.

Casein glue is stronger than most of the softwoods used in aircraft
fabrication. Unfortunately, casein glue is subject to biological
attack by bacteria and fungi. For that reason it is important to seal
any glue-line with varnish or paint as quickly as practical, and to
include inspection of that sealing surface, for any aircraft in
service. In a similar vein it is important that you do not allow any
glue to become contaminated before it can be used.

-Bob

-PS -- One of the more important uses of rawhide is 'corners.' (!)
That is, on tool kits and small pieces of luggage, or the cases for
such things as VOM's, binoculars and so forth. It's a fairly simply
chore to make a corner of solid aluminum, or of hardwood well sealed
with varnish, over which you may stretch a piece of saturated rawhide,
tacked or clamped to the back of the form until the rawhide is fully
hardened. It is then trimmed to the required shape and attached using
stitching, glue or rivets.

And of course, we use rawhide for mallets :-) Often times we need a
mallet having a particular shape and the only way to get one is to
sacrifice a new mallet, sawing the rawhide to the desired corner &
curve. But if we have a supply of rawhide (strip is handiest for
this) we can literally 'roll our own,' producing a tool that is far
superior to making the head our of lignum vitae or whatever. - rsh

Thanks for this info. As well, I wanted to see if an ammonia solution
could be used instead of bicarbonate, so I did some googling, and found
a discussion of the chemistry involved. Turns out that various bases or
basic salts can be used resulting in, I suppose, various chemical
properties of the casein glue since it specifically mentions that casein
glue formed using lime has a known assoiation with aviation related wood
gluing. Here is the link
http://www.dotapea.com/english/chap03casein.htm

There's another article on casein linked from that page, but needs
translating from French.

A.L.

On Tue, 30 Dec 2008 21:44:14 -0800 (PST), "
wrote:

On Dec 30, 2:11*am, Stealth Pilot
wrote:

this was just too good to snip out so I didnt :-)



you mention glue.
how do you make that?
------------------------------------------------------------------------------------------------------------------------

How you make it depends of what you're trying to glue together.

A good general purpose glue is made from raw hides. This can take a
pretty strong nose.

Go to one of the big Chain Stores that carries Pet supplies. Buy some
pigs ears or dried 'chewables' of rawhide.

Try cutting the rawhide or dried ears into smaller pieces. Depending
on how they were prepared, their size can be as large as 8x10 inches.
For making glue you want the size to be more on the order of 1/4 x
1/4" or in the form of strings. Soak the pieces in water until they
are fully saturated then begin adding heat. To maintain control of
the temperature you'll need to use a double boiler.

If you've never made hide glue, start by BUYING SOME, so you'll know
what it looks like. It is made from rawhide -- the residue of making
leather -- or from hooves and horns. Properly made, the stuff looks
like honey. In use, it may be thinned and heated.

Rawhide itself is rather handy stuff. When saturated with water it
can be stretched but will try to shrink back to its original size
unless restrained. You can make molds of things you wish to protect,
such as some of your precision tools. Soaking the dried rawhide in a
light oil will prevent it from absorbing water and losing it's shape.

For homebuilders the most useful glue is Casein. This is made from
the protein in MILK. Run your milk through a cream separator more
than once, or allow it to stand, giving the cream time to separate.
When making milkglue you want to be damn sure that you do NOT get any
cream in the mix. If you live in an area that does not provide real
milk, visit your local grocery store and see if they carry 'fat-free'
or 'skim' milk.

Starting with skim milk, add an acid such as vinegar to cause the milk
to 'turn'. Stir the milk to ensure the acid reaches all of the milk.
Allow it to stand for about half an hour then pour off the liquid (ie,
the whey) then whisk the curds into a uniform paste and neutralize
them using bicarbonate of soda dissolved in water. Heat this mix in a
double boiler to reduce it to the consistency of heavy cream. If you
are not familiar with this consistency go BUY some heavy cream... or
allow some real ice cream to melt. The basic test is to take it up a
teaspoon at a time and allow it to pour back into the container.
'Heavy Cream' is the point at which it pours back as a single stream
rather than as a series of drops.

The next step is to make sure you have neutralized the acid. The best
way to do this is with Litmus paper, purchased at the drug store or on-
line. If that is not available to you, you can do the test with a
STRONG mixture of bicarbonate of soda in warm water. Add this to
your mix ONE DROP AT A TIME whilst looking for it to generate any
bubbles. If the mix is still acidic you will have to add more
neutralizer, stirring it in good and repeating your tests. The
problem here is that you are trying to achieve a NEUTRAL mix, one that
is neither acidic nor base. The tests make it easy to DETECT acidity
but not the opposite, unless you are using Litmus papers, so you want
to very careful that you do not end up with a mix that contains too
much bicarbonate of Soda because the soda will precipitate out as
crystals within the glue line, reducing its strength.

If you glue is too thick you may dilute it with water; if too thin you
may heat it to drive off some of the water. When you have achieved
what you believe is your best mix, you must test it using the standard
FTC shear-strength test. That is,a coupon two inches wide by four
inches long, with the adhesive applied to a 2x2 area. The adhesive is
applied to both faces and clamped with approximately 70 pounds of
pressure, all this while maintaining a gluing temperature of about 70
degrees on the Fahrenheit scale. The test-coupon is sheared at the
glue-line by clamping the free end in a vise and striking the other
free end with a three pound hammer, using enough force to cause the
sample to fail at the glue line.

Examination of the failure should show that the WOOD failed over at
least 80% of the glued area.

Casein glue is stronger than most of the softwoods used in aircraft
fabrication. Unfortunately, casein glue is subject to biological
attack by bacteria and fungi. For that reason it is important to seal
any glue-line with varnish or paint as quickly as practical, and to
include inspection of that sealing surface, for any aircraft in
service. In a similar vein it is important that you do not allow any
glue to become contaminated before it can be used.

-Bob

-PS -- One of the more important uses of rawhide is 'corners.' (!)
That is, on tool kits and small pieces of luggage, or the cases for
such things as VOM's, binoculars and so forth. It's a fairly simply
chore to make a corner of solid aluminum, or of hardwood well sealed
with varnish, over which you may stretch a piece of saturated rawhide,
tacked or clamped to the back of the form until the rawhide is fully
hardened. It is then trimmed to the required shape and attached using
stitching, glue or rivets.

And of course, we use rawhide for mallets :-) Often times we need a
mallet having a particular shape and the only way to get one is to
sacrifice a new mallet, sawing the rawhide to the desired corner &
curve. But if we have a supply of rawhide (strip is handiest for
this) we can literally 'roll our own,' producing a tool that is far
superior to making the head our of lignum vitae or whatever. - rsh

talking about hammers reminds me. I needed to tap the vise into
alignment on the mill table. I was chopping up some pretzeled up
pranged aluminium propellers to machine little lengths of them for
flying instructors to trace around when they want to draw an aerofoil
on a white board.
I'm a great fan of 4 ounce ball pein hammers so I reached for my
favourite 4oz.
I was in mid swing with my first tap when I thought ...hang on,
that'll peen the side of the thing, hmmm cant do that.
what I needed was a soft face tapping hammer but I didnt have one.
I went down to the local home depot which we call bunnings.
bloody hell they are expensive!
buying one was outa the question but I still needed one!
so I took a 1 inch diameter bar of mild steel and cut 45mm off the end
in the band saw. I chucked it in the lathe I use to machine up
aircraft replacement bits, faced off each end and bored a 10mm dia
hole in each end.
I'm a great fan of wooden hammer handles so I milled a flat on
opposite faces of the head and drilled through to make a hammer handle
hole. you know the double taper socket style which turned out to be
easy to mill out then file to final shape.

I must digress to tell you of the handles. bunnings no longer stock
4oz ball pein hammers, in fact almost nobody seems to, because they
never wear out the one you have is with you in yeoman service for
life. the stores seem to think that no one needs one at all so they've
dropped them entirely ...the dumb *******s.
anyway in the middle of the gardening section of bunnings I came
across a box with an entire set of 4oz replacement ball pein hammer
handles.
I know that they were dumped there in the small picks and mattocks
section because no one in bunnings recognised what they were :-)
so I have a bunch of these el cheapo premium quality australian made
handles. I must go back and buy the rest, they'll think they're a hot
item and buy in more :-)
anyway after I sprayed the head black using the rattle can I use on
the backs of my prop I fitted one of these premium quality handles to
my new hammer head. ...oh it's like a finger in a bum. (you remember
the innocent old WW2 definition before poofters became a part of the
landscape, you're as old as me so you orta )

I needed some nylon for the faces because I have no access to rawhide.
so I used the end of the bit I turn my tailwheel bushes from. it is
inch diameter graphite filled nylon. I machined one end flat and
leaving 15mm for the head turned a 10mm dia pin out the other end.
I turned up two of these and using the vice pressed them into each end
of the mild steel head.
the entire head is black with this beautifully fitted 4oz ball pein
handle.

what surprised me is that it turned out to have perfect balance.
it just feels absolutely right in the hand.
for something I brewed up in a few hours just to tap the vice straight
cause I couldnt waste 70 bucks on a bought one I'm bloody chuffed!

my model engineers club just roll their eyes when I talk aeroplanes
but I think that even they will appreciate its fine qualities so I'll
repeat this as a quick talk next meeting.

I hafta wonder though. you talk of such different things when you talk
airplane that I wonder whether they are even similar to my aeroplanes.
I dont have a back yard big enough to grow really tall trees so I buy
in 6" x 2" alaskan yellow cedar poolside decking planks. I cut these
down on my 40 year old cast iron saw bench. I glue the raw bits
together into aeroplane parts using epoxy resin, which is probably
just wuna them there new fangled things to a fella like you.
there is a coupla tricks to using it which I could tell you about if
you wanted.
the aerofoil I use is called a naca23102 which is kinda neat but it is
difficult in that you cant use the sida yer thong to draw it like you
can with the adidas9 aerofoil. but lay one out on a sheet of mdf,
thats secret tla speak for medium density fiberboard, and it is a
cinch to make a building frame.
you guys have invented the steam engine havent you?
well another use for steam is softening the thermo softening lignins
in the alaskan cedar so that you can prebend the wood for use on the
building frame. I do that a lot and I use a technique called
laminating to make lotsa curved bits. If you havent heard of
laminating I can tell you about it.

one thing you have all over me though is the conversion of these
little german engines. I cant get suitable ones at all.
so today I made the casting pattern for the sump of an ET Westbury
Sealion engine. its only small but it is the first step on the way to
building my own aircraft engines. I figure I'd practise on little ones
that were cheap to build before I venture into one for my aircraft.
I intend building a few different designs in 4 cylinder engines as a
leadup to my own aircraft engine.
dontcha think a scaled down continental O-200 engine would make the
darndest little ultralight engine. :-) I could even cheat and use some
of the bits from the little german ones to make construction faster.

just before I go and get anotha beer from the 'fridge. do you know
about that there genetic engineering stuff. well ova here in australia
we kin git little bottles of a stuff called success. you mix this
concentrate in water and spray it over the tomatoes. the little
genetically modified soil bugs in it give the bugs one hell of a dose
of stomach poisoning and they all die. actually you shouldnt use it.
you'd have nothing to cuss about and from all reports your neighbour
rather thinks you're a hunk because of it.

well that beer beckons. next time I must tell you about casting my own
wheel hubs.
your friend unda the verandah
stealth pilot