Aluminum materials related questions

I've started on my plane!!!!

I have a couple of questions that should be easy for you guys to
answer...

The first one is almost stupid but I'm anal about these things: What
grit of sand paper is ideal for sanding/deburring the cuts I've made in
6061-T6? The saw/blade I used really did a good job to the point that
it almost doesn't need sanding but like I said - I'm anal about this
stuff.

The second question is more technical: I'd planned to use 6061-T6 plate
in .125" thickness for my gussets. I've found a source for plate in the
same sizes but in 5052 w/no "-" number listed.
I looked up the numbers and 5052 appears to have very similar strength
to 6061. Can someone advise me if using 5052 is advisable and if I need
to look for a specific "-" number?
The 5052 is only slightly cheaper but much easier to find...I'm
interested in doing the job right.

BTW: Here is where I'm at on the build...

http://68.35.241.46/plane/index.htm

5052 is very soft compared to 6061. 5052 is often used for fuel tanks.

Stick to 6061, or whatever the designer specifies.

John

In article , John T
wrote:

5052 is very soft compared to 6061. 5052 is often used for fuel tanks.

Stick to 6061, or whatever the designer specifies.

John

Not only that -- but it is potentially fatal to use something in a
structural location if you don't know its temper.

nondem wrote:
I've started on my plane!!!!

I have a couple of questions that should be easy for you guys to
answer...

The first one is almost stupid but I'm anal about these things: What
grit of sand paper is ideal for sanding/deburring the cuts I've made in
6061-T6? The saw/blade I used really did a good job to the point that
it almost doesn't need sanding but like I said - I'm anal about this
stuff.

The second question is more technical: I'd planned to use 6061-T6 plate
in .125" thickness for my gussets. I've found a source for plate in the
same sizes but in 5052 w/no "-" number listed.
I looked up the numbers and 5052 appears to have very similar strength
to 6061. Can someone advise me if using 5052 is advisable and if I need
to look for a specific "-" number?
The 5052 is only slightly cheaper but much easier to find...I'm
interested in doing the job right.


The *-* number is commmonly referred to as 'the temper', it tells
you how the material has been heat-treated. That is really important
as the strength depends on it. If you buy the material in the
annealed state, which is the softest state, you'll need to get it
hardened. That in turn, is non-trivial.

6061 has good corrosion resistance, I dunno about 5052. Electrolytic
Corrosion is always a consideration when mixing alloys.

Respectfully, you should be at least as anal about material choice
as about finishing the cut edges. Speaking of that, I suggest
you get a 'multipack' of sandpapers and work your way down
through the grits until the edge is shiny without visible scratches.
Then you can guage how much of what grits you'll need to buy.

BTW: Here is where I'm at on the build...

http://68.35.241.46/plane/index.htm

Looks good. Thanks for putting up your pages.

--

FF

nondem wrote:
I've started on my plane!!!!

I have a couple of questions that should be easy for you guys to
answer...

The first one is almost stupid but I'm anal about these things: What
grit of sand paper is ideal for sanding/deburring the cuts I've made in
6061-T6? The saw/blade I used really did a good job to the point that
it almost doesn't need sanding but like I said - I'm anal about this
stuff.

The second question is more technical: I'd planned to use 6061-T6 plate
in .125" thickness for my gussets. I've found a source for plate in the
same sizes but in 5052 w/no "-" number listed.
I looked up the numbers and 5052 appears to have very similar strength
to 6061. Can someone advise me if using 5052 is advisable and if I need
to look for a specific "-" number?
The 5052 is only slightly cheaper but much easier to find...I'm
interested in doing the job right.

http://www.aircraftspruce.com/catalo...s/aluminfo.php

is a very good explanation.

5052 isn't considered heat treatable, that is mostly why there is a "-".
This also makes it a good choice of alloy for welding (it is popular
for fuel tanks). The heat from welding usually results in a heat
treatable alloy (such as 6061, for example) not being tempered anymore
(starts out as -T6 but becomes O after welding, for example).

I would use a file to clean up the edges and burrs. I wouldn't use
sandpaper because bits of the abrasive material may become embedded in
the workpiece and create a corrosion problem later on. For similar
reasons, I've been told not to use a pencil for marking aluminum
(measurements, notes), although a Sharpie pen is acceptable. Then
again, the designer may have taken these issues into account.

The other responses address the question of substituting one for the other.

Nice webpages

Really, you couldn't find any? Try these,
http://www.metalsdepot.com/products/alum2.phtml?page=sheet&LimAcc=$LimAcc&aident=

http://www.onlinemetals.com/merchant...owunits=inches

Jim Carriere wrote:
nondem wrote:
... What
grit of sand paper is ideal for sanding/deburring the cuts I've made in
6061-T6? The saw/blade I used really did a good job to the point that
it almost doesn't need sanding but like I said - I'm anal about this
stuff.

...

I would use a file to clean up the edges and burrs. I wouldn't use
sandpaper because bits of the abrasive material may become embedded in
the workpiece and create a corrosion problem later on. For similar
reasons, I've been told not to use a pencil for marking aluminum
(measurements, notes), although a Sharpie pen is acceptable.

WIth pencils, the issue is the graphite. There is a similar problem
if steel wool is used on aluminum.

A lot of sandpapers use Aluminum Oxide (Alundum) grit. That is
the same oxide that forms naturally on aluminum so that should not
be a problem. But most of the wet/dry papers use silicon carbide,
(carborundum) which may be a problem.

--

FF

wrote:



WIth pencils, the issue is the graphite. There is a similar problem
if steel wool is used on aluminum.

A lot of sandpapers use Aluminum Oxide (Alundum) grit. That is
the same oxide that forms naturally on aluminum so that should not
be a problem. But most of the wet/dry papers use silicon carbide,
(carborundum) which may be a problem.


You don't sandpaper the edges - you file them...

The trick to good looking parts is finishing the edges.

Are they smooth, flat, free of nicks and scratches?

Sandpaper alone won't do that...

Richard

To deburr use a deburring tool which will take the sharp edge off the
inside of the tubing and the edges of sheet, finish with scotchbrite
pads. Use the 6061-T6.

Bob

To deburr use a deburring tool which will take the sharp edge off the
inside of the tubing and the edges of sheet, finish with scotchbrite
pads. Use the 6061-T6.

Bob

There is also a rotary version of the scotchbrite pad(s) that is really
slick.

Peter