Learning to weld with a non-aircraft project

Veeduber wrote:

As for the original thread, I've found vee-blocks, step-drills and a couple of
throw-away angle-head grinders to be handier than any of the tools mentioned,
other than basic hacksaw & files. Being able to maintain the axis of your
notches is more important than a perfect fit.

Again, Tubemiter program to the rescue. I can't overstress how much my
work improved after I got ahold of this program. It prints a template
for the fitup. Well, part of the template is a couple of lines running
down the side. You first use these lines to get the template wrapped
correctly around the tube, using the bottom one to make sure you're not
wrapping a helix. The lines down the side now run parallel to the tubes
axis. Put a template on both ends, lay the tube on a table and roll a
smaller diameter piece or a yardstick up against it. You'll easily see
when the lines are colinear and be able to maintain the axis.

A point most novice builders fail to appreciate is that the actual amount of
time spent welding is insignificant in relation to the overall project. It
looms large simply because you don't know how to do it or lack confidence in
your skills. The key to success is the same as for any other manual art, be it
typing or car-quals -- you have to practice. The basic principles can be
mastered in about thirty minutes. You'll then need about twenty hours of
practice to produce welds deemed 'safe for flight' (which doesn't mean they'll
be pretty :-)

-R.S.Hoover

I spent 2 hours in the garage today. 1.75hrs in preparation and .25hrs
welding.

--
http://www.ernest.isa-geek.org/
"Ignorance is mankinds normal state,
alleviated by information and experience."
Veeduber

Ed Haywood wrote:
Don't know much about the science of it, but I know that the different types
of laser protective glasses that I've been issued in the military are not
dark at all. They are simple plastic safety glasses with a very light
colored, slightly reflective coating. I assume it employs some sort of
polarizing or refractory principle to disrupt the beam. We never carry
them.


LASER is special in that it is monochromatic, or one color. If you know
the type of laser, you can build a lens that will filter exactly one
wavelength. A dark lens takes the brute fore method of blocking everything.

--
http://www.ernest.isa-geek.org/
"Ignorance is mankinds normal state,
alleviated by information and experience."
Veeduber

Again, Tubemiter program to the rescue. I can't overstress how much my
work improved after I got ahold of this program. It prints a template
for the fitup.

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

This is yet another nice example of how computers can ease the task of
airplane-building. (The Old Fashioned Way is to coat the tubing with soot or
Dykem, fix the thing at the proper angle, then slide a flat-sided scriber
around the intersecting tube.)

While templates for tubing joints are an especially good example of using
computer-generated patterns, the same principle may be applied to any part
requiring the lay-out of holes, bending lines and so forth. For those
interested, the article for the carb heat box in the Fly5kfiles Group archive
uses this method to create both the box and the tubular ducting connectors.

-R.S.Hoover

Veeduber wrote:
Again, Tubemiter program to the rescue. I can't overstress how much my
work improved after I got ahold of this program. It prints a template
for the fitup.


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

This is yet another nice example of how computers can ease the task of
airplane-building. (The Old Fashioned Way is to coat the tubing with soot or
Dykem, fix the thing at the proper angle, then slide a flat-sided scriber
around the intersecting tube.)

While templates for tubing joints are an especially good example of using
computer-generated patterns, the same principle may be applied to any part
requiring the lay-out of holes, bending lines and so forth. For those
interested, the article for the carb heat box in the Fly5kfiles Group archive
uses this method to create both the box and the tubular ducting connectors.

-R.S.Hoover

Find a friend with a plotter (or the Kinko's type places charge about
$1/linear foot), and you can have full size rib layouts done. Get an
exact curve EVERY time.

This is especially important with a Delta aircraft. Each rib is
different, and small variations can really ruin your day.

BTW, I took your advice...sort've...on building my elevon ribs. The
part about beating the edges down to form a flange. Found a new friend
who has a shear and a brake. Cut and then bent the ribs, but being less
than an expert, the ribs once again did not taper properly. So I cut
some blanks out of an old oak shipping skid. I put matching ribs back
to back with a form inside each, ran a few bolts through the 'sandwich'
and beat the flanges down to the forms. I'm still welding the ribs into
place, but both sides should be exactly the same when I'm done.

--
http://www.ernest.isa-geek.org/
"Ignorance is mankinds normal state,
alleviated by information and experience."
Veeduber

On Sat, 27 Mar 2004 03:23:08 GMT, Ernest Christley
wrote:

Veeduber wrote:

As for the original thread, I've found vee-blocks, step-drills and a couple of
throw-away angle-head grinders to be handier than any of the tools mentioned,
other than basic hacksaw & files. Being able to maintain the axis of your
notches is more important than a perfect fit.

Again, Tubemiter program to the rescue. I can't overstress how much my
work improved after I got ahold of this program. It prints a template
for the fitup. Well, part of the template is a couple of lines running
down the side. You first use these lines to get the template wrapped
correctly around the tube, using the bottom one to make sure you're not
wrapping a helix. The lines down the side now run parallel to the tubes
axis. Put a template on both ends, lay the tube on a table and roll a
smaller diameter piece or a yardstick up against it. You'll easily see
when the lines are colinear and be able to maintain the axis.

A point most novice builders fail to appreciate is that the actual amount of
time spent welding is insignificant in relation to the overall project. It
looms large simply because you don't know how to do it or lack confidence in
your skills. The key to success is the same as for any other manual art, be it
typing or car-quals -- you have to practice. The basic principles can be
mastered in about thirty minutes. You'll then need about twenty hours of
practice to produce welds deemed 'safe for flight' (which doesn't mean they'll
be pretty :-)

-R.S.Hoover

I spent 2 hours in the garage today. 1.75hrs in preparation and .25hrs
welding.

I just fishmouthed one end so that it fit properly and then guaged how
the other end should line up by holding a tube in the already
fishmouthed end and marking the opposite end by eye.

Then I went to the grinder and cut the other fishmouth. I always left
it a bit long so that I could adjust the opening one way or the other
if necessary.

Even if the tube ends up having an eighth inch play or slightly more,
it doesn't matter. You will be putting enough filler material on the
weld that the fuselage won't care, and no one will be able to tell
that it wasn't precisely flush. Won't matter in terms of strength and
safety either.

Corky Scott

Even if the tube ends up having an eighth inch play or slightly more,
Corky writes:

it doesn't matter. You will be putting enough filler material on the
weld that the fuselage won't care, and no one will be able to tell
that it wasn't precisely flush. Won't matter in terms of strength and
safety either.


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

I try to keep the gap to the diameter of the filler rod or less. In fact, I've
found a tiny piece of filler rod or snippet of MIG wire to be a handy means of
wedging a tube in place.

The typical fillet produced by gas welding is 3x to 5x the thickness of the
wall, depending on the included angle of the joint. Anything more serves no
purpose since that is all it takes to equal the strength of the tube. Some
amount of filler is required but standard practice is to keep the gaps fairly
small so as to conserve weight.

Overall, I've personally never found it to be a major concern. Some of my
welds are prettier than others but all are sufficiently strong. The only
definitive study I've seen comparing TIG, MIG & gas for welded tubular
structures was a thing for helicopter tail booms. All met spec for strength
but they went with MIG. It was fractionally heavier but it was faster,
produced the boom at least cost. Someone like NASA, with a virtually unlimited
budget but critical weight constraints, would probably have gone with TIG.
Home-builder or someone doing repairs, O/A will usually win the Practical
Factors test.

Folks who get all excited over things like welding procedures or 1020 vs 4130
are usually telling us more about themselves than about airplanes :-)

-R.S.Hoover

Corky Scott wrote:

Even if the tube ends up having an eighth inch play or slightly more,
it doesn't matter. You will be putting enough filler material on the
weld that the fuselage won't care, and no one will be able to tell
that it wasn't precisely flush. Won't matter in terms of strength and
safety either.

Corky Scott


My experience has been that the tighter I get the fitup, the less warp I
get in the finish piece.

Another tip. When welding intersecting tubes, especially when at an
angle, weld in 1/4 round steps. Weld each side (ie, the tips of the
fishmouth) and let it cool. Then go back and fill in the crease.
Welding the sides first pull the tubes straight together, then the extra
material help to hold them in place when the crease weld tries to pull
them out of whack.

--
http://www.ernest.isa-geek.org/
"Ignorance is mankinds normal state,
alleviated by information and experience."
Veeduber