Powder Coat on 4130

On Fri, 23 Mar 2007 12:40:12 -0400, "J.Kahn"
wrote:

Ernest Christley wrote:
clare at snyder.on.ca wrote:
On Thu, 22 Mar 2007 23:29:15 -0400, "Phil" wrote:

Hello
Was watching American Chopper this evening , I see things on that
show that make me cringe but I do enjoy the antics of that family,
they always refer to Pipe if they are building a frame out of Tubing
etc. , this evening they were working on a dragster bike for NAPA and
when it came time to paint the machine they said that powder coat
couldn't be used because of the heat involved would ruin the 4130
tubing , seems like a lot of engine mounts and other A/C parts will
have to be junked , would like to hear some thoughts on this concept
, as an A/C welder it is of interest to me.
Thanks
Phil Lohiser
EAA 12873
Powder coating won't hurt 4130, but is NOT RECOMMENDED for aircraft
use because it can hide developing cracks.At least that's what I've
been told.


Bwhahaha!!

Powder coating is done at what, 275 degree F? I gotten my airframe
hotter than that by cussing at it when members wouldn't meet up
properly. 4130 will see it as a pleasantly warm temperature, suitable
for shorts and maybe a light sweater.

Some people don't recommend powder coating because it may hide
developing cracks. Others swear by it because it give better protection
to keep cracks from ever forming. Truth is, if the only thing you have
to identify developing cracks is a visual inspection, you're not going
to have much luck. Use white powder coat, and linseed oil inside the
tube. A hairline crack will seep the oil and make and ugly black mark.

But if the hairline crack doesn't break the paint film the oil will
still be contained. Besides the oil, weld a boss on a longeron tube end
and install a tire valve and pressurize to 100 or so psi pressure during
the annual. The pressure should be enough to make the paint film fail
and cause leakdown. Find the leak by listening or water/soap.

Llama helicopters charge the truss permanently with dry nitrogen and
have a pressure gauge that is in view behind the cabin and can be
checked on a DI.

John

I find it very hard to believe that forces strong enough to crack 4130
wouldn't be strong enough to crack powder coating.
I suspect the real reason for not powdercoating the chopper frame has
a lot to do with filming schedules.

"Drew Dalgleish" wrote in message
[...]
I find it very hard to believe that forces strong enough to crack
4130
wouldn't be strong enough to crack powder coating.
I suspect the real reason for not powdercoating the chopper frame
has
a lot to do with filming schedules.

Whatever the reason for the FAA hostility for powder coating, I have
receive pma'd parts that were powdercoated, or "powercoated" as a
member of my EAA chapter calls it.

" jls" wrote

Whatever the reason for the FAA hostility for powder coating, I have
receive pma'd parts that were powdercoated, or "powercoated" as a
member of my EAA chapter calls it.

Cute g

Although I have never had, or seen, an aircraft "powercoated" part crack, I
have seen other powder coated steel parts crack, and the powdercoated crack
remained hidden.

I would not choose powdercoating for a finish for anything I built.

Besides that, I can spray paints, myself, and can not so easily powdercoat
anything.
--
Jim in NC

Morgans wrote:

" jls" wrote

Whatever the reason for the FAA hostility for powder coating, I have
receive pma'd parts that were powdercoated, or "powercoated" as a
member of my EAA chapter calls it.


Cute g

Although I have never had, or seen, an aircraft "powercoated" part crack, I
have seen other powder coated steel parts crack, and the powdercoated crack
remained hidden.

I would not choose powdercoating for a finish for anything I built.

Besides that, I can spray paints, myself, and can not so easily powdercoat
anything.


Besides that, the stuff is heavy!

"cavelamb himself" wrote

Besides that, the stuff is heavy!

Yeah, what he said! g

I can't believe I didn't think of that, too.

The stuff sure is pretty, though.

Another thing is, it is so tough, that it is not likely to show damage when
something smashes into it. If something hits my metal hard enough to chip
or mark paint, I would want to know about it. That stuff wouldn't show a
mark.
--
Jim in NC

"Morgans" wrote in message
...

" jls" wrote

Whatever the reason for the FAA hostility for powder coating, I
have
receive pma'd parts that were powdercoated, or "powercoated" as a
member of my EAA chapter calls it.

Cute g

Although I have never had, or seen, an aircraft "powercoated" part
crack, I
have seen other powder coated steel parts crack, and the
powdercoated crack
remained hidden.

I wouldn't use powdercoat on an engine mount, for sure and not on a
4130 fuselage. But it came on the lift strut of a PA-18 and a
rudder-- both PMA'd.

I would use it on the step (or stirrup) that helps you get into the
cockpit. There you need it because of all the wear you would have on
paint.

I have seen it used with great esthetic appeal on yokes.

I would not choose powdercoating for a finish for anything I built.

Besides that, I can spray paints, myself, and can not so easily
powdercoat
anything.

Eastwood has a kit you can buy which is cheap and easy to use. You
just need an oven to cure it in once you've got it sprayed on your
part. The powder is attracted to the part by a high voltage.

I would not use powdercoat on highly stressed parts but it certainly
has a use in places on some aircraft, especially where the wear on
paint keeps you having to recoat it.
--
Jim in NC


James in WNC

" jls" wrote in news:%9_Mh.30455$sC.5421
@bignews2.bellsouth.net:


"Drew Dalgleish" wrote in message
[...]
I find it very hard to believe that forces strong enough to crack
4130
wouldn't be strong enough to crack powder coating.
I suspect the real reason for not powdercoating the chopper frame
has
a lot to do with filming schedules.

Whatever the reason for the FAA hostility for powder coating, I have
receive pma'd parts that were powdercoated, or "powercoated" as a
member of my EAA chapter calls it.

I believe the reason is that the coating can lift if the surface
underneath gets a bit rusty, forming a pocket where moisture can form
between the coating and the steel. The coating won't deform and flake
off in the same way that paint will and the rust will continue until
it's eaten through something with little or no external evidence that
that is happening. There have been some real problems with tube
airplanes in wet regions and in fact the UK CAA is considering banning
it altogether.


ALC

Drew Dalgleish wrote:


I find it very hard to believe that forces strong enough to crack 4130
wouldn't be strong enough to crack powder coating.
I suspect the real reason for not powdercoating the chopper frame has
a lot to do with filming schedules.

Drew, I believe it is related to the fact that the film is somewhat
flexible and tough so that it can accommodate a small subsurface change.
It's a bit like polyurethane paint's ability to hide filiform
corrosion, which really hurt Cessna owners back in the 80s when their
late 70s 172s started showing filliform corrosion under the paint
because Cessna used washer primer instead of epoxy primer when they
first went to urethane paints.

John

On Sat, 24 Mar 2007 18:09:01 -0400, "J.Kahn"
wrote:

Drew Dalgleish wrote:


I find it very hard to believe that forces strong enough to crack 4130
wouldn't be strong enough to crack powder coating.
I suspect the real reason for not powdercoating the chopper frame has
a lot to do with filming schedules.

Drew, I believe it is related to the fact that the film is somewhat
flexible and tough so that it can accommodate a small subsurface change.
It's a bit like polyurethane paint's ability to hide filiform
corrosion, which really hurt Cessna owners back in the 80s when their
late 70s 172s started showing filliform corrosion under the paint
because Cessna used washer primer instead of epoxy primer when they
first went to urethane paints.

John

Thanks John I thought powder coat was more like ceramic and
inflexible.

On Mon, 26 Mar 2007 15:23:40 GMT, (Drew
Dalgleish) wrote:

On Sat, 24 Mar 2007 18:09:01 -0400, "J.Kahn"
wrote:

Drew Dalgleish wrote:


I find it very hard to believe that forces strong enough to crack 4130
wouldn't be strong enough to crack powder coating.
I suspect the real reason for not powdercoating the chopper frame has
a lot to do with filming schedules.

Drew, I believe it is related to the fact that the film is somewhat
flexible and tough so that it can accommodate a small subsurface change.
It's a bit like polyurethane paint's ability to hide filiform
corrosion, which really hurt Cessna owners back in the 80s when their
late 70s 172s started showing filliform corrosion under the paint
because Cessna used washer primer instead of epoxy primer when they
first went to urethane paints.

John

Thanks John I thought powder coat was more like ceramic and
inflexible.
Powder coat is basically a thermoplastic.

--
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