Powder Coat on 4130

On Mar 22, 8:29 pm, "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

The thing about powder coating aircraft structure, is that the places
that do it are not controlled as well as FAA designated shops. Some
might do it right, and some, well.... Also, there is a big difference
in steel vs aluminum, as the temperature involved (~400 F) does not
harm 4130, but might heat treated aluminum, especially if the shop
doesn't pay close attention and gets the temperature much higher
during the process. Most 4130 tube aircraft structures use normalized
4130, so there is no heat treat to worry about. Aluminum is almost
always heat treated, so there is an issue. It is a fact that 10 years
or so ago, a scuba diver had his aluminum tank powder coated when it
started looking bad, and when he was having it filled, it exploded
killing one guy and causing another to have his leg amputated. If the
structure doesn't use heat treated steel, you are probably OK. Powder
coating heat treated aluminum is a definite no no.

Bud

On Apr 1, 4:16 pm, John T wrote:


Responding to an "old" thread here, but powdercoat cures at about 400
deg. F.
----------------------------------------------------------------------------------------------

Whoa. 'Powder-coating' is a generic term that applies to everything
from ceramic frits to vinyl. The temperature/atmosphere needed to
cause the powder to melt and flow together can be anything from 150
degrees to over a thousand degrees.

Key point here is that all 'powder coating' is not the same. Some
shops use but a single type of coating, say a urethane. Others may
offer a variety of coatings, from low-temp vinyls to chemically inert
epoxies.

You CAN do it at home -- it is easier than applying ceramic thermal
barrier coatings. But you have to know what you're doing. Most of
the information (and mis-information) commonly available has to do
with vehicular applications done mostly for the sake of appearance,
most of which have no place anywhere on an airplane. But it's the
cat's pajamas for things like a battery box, cabin fixtures and the
like.

-R.S.Hoover

On Apr 8, 3:26 pm, " wrote:
On Apr 1, 4:16 pm, John T wrote:



Responding to an "old" thread here, but powdercoat cures at about 400
deg. F.
---------------------------------------------------------------------------*-------------------

Whoa. 'Powder-coating' is a generic term that applies to everything
from ceramic frits to vinyl. The temperature/atmosphere needed to
cause the powder to melt and flow together can be anything from 150
degrees to over a thousand degrees.

Key point here is that all 'powder coating' is not the same. Some
shops use but a single type of coating, say a urethane. Others may
offer a variety of coatings, from low-temp vinyls to chemically inert
epoxies.

You CAN do it at home -- it is easier than applying ceramic thermal
barrier coatings. But you have to know what you're doing. Most of
the information (and mis-information) commonly available has to do
with vehicular applications done mostly for the sake of appearance,
most of which have no place anywhere on an airplane. But it's the
cat's pajamas for things like a battery box, cabin fixtures and the
like.

-R.S.Hoover

Excellent points. If someone tries to use a 1000 deg temp process to
powder coat a heat treated steel part, then the heat treatment will
almost certainly be lost, as even some of the highest strength, high
temperature alloys start to lose temper at as low as 800 F. Also, the
chemical reaction caused by exposure to high tempearture and the
presence of the materials that are being used to "powder coat" the
steel could cause God knows what to the surface of the steel. Hydrogen
or nitrogen embrittlement comes to mind. For lightweight structure
that your life depends on, you need to KNOW.
Many builders have their 4130 steel parts annealed after welding
by heating the structure to a cherry red temp and slowly reducing the
heat, in order to relieve any stress concentrations created during
welding. People that have powder coated normalized 4130 probably are
OK, even at 1000 F, but you never know for sure until a chemical study
of the effect has been done.

Bud

Your definition of powdercoat is too broad. Its generally accepted that
powdercoat in the powdercoat community refers to a plastic like powder
that transforms into a solidly linked coat at temps between ~300-400F
(the coatings generally start flowing out at about 300F, but need to
cure at about 400). Urethanes and ceremic coatings are not considered
powdercoating.
Doing powdercoating at home is quite doable, but you need to but a
powdercoating gun and colors. You also need an electric oven you won't
be using for food. You can get these and read forums on powdercoating at
eastwoodco.com.
Powdercoating isn't just for looks. Like paint, it protects surfaces,
but as has been mentioned, its heavier than paint. Its stronger than
paint though.

wrote:
-----------------

Whoa. 'Powder-coating' is a generic term that applies to everything
from ceramic frits to vinyl. The temperature/atmosphere needed to
cause the powder to melt and flow together can be anything from 150
degrees to over a thousand degrees.

Key point here is that all 'powder coating' is not the same. Some
shops use but a single type of coating, say a urethane. Others may
offer a variety of coatings, from low-temp vinyls to chemically inert
epoxies.

You CAN do it at home -- it is easier than applying ceramic thermal
barrier coatings. But you have to know what you're doing. Most of
the information (and mis-information) commonly available has to do
with vehicular applications done mostly for the sake of appearance,
most of which have no place anywhere on an airplane. But it's the
cat's pajamas for things like a battery box, cabin fixtures and the
like.

-R.S.Hoover

John T wrote:
Your definition of powdercoat is too broad. Its generally accepted that
powdercoat in the powdercoat community refers to a plastic like powder
that transforms into a solidly linked coat at temps between ~300-400F
(the coatings generally start flowing out at about 300F, but need to
cure at about 400). Urethanes and ceremic coatings are not considered
powdercoating.
Doing powdercoating at home is quite doable, but you need to but a
powdercoating gun and colors. You also need an electric oven you won't
be using for food. You can get these and read forums on powdercoating at
eastwoodco.com.
Powdercoating isn't just for looks. Like paint, it protects surfaces,
but as has been mentioned, its heavier than paint. Its stronger than
paint though.



Generally accepted by whom? The Powder Coating Institute, a national
trade organization for the Powder Coating industry doesn't seem exclude
urethane based or ceramic components. Since Eastwood bills itself as
providing "unique automotive tools and supplies, as well as expert
advice and solutions, for the classic car and hot rod enthusiast" I
would expect the enthusiasts that hang out there and utilize Eastwood's
"DIY" home shop equipment would be more limited in their capabilities.
It is of interest that Eastwood quotes PCI as well. PCI technical briefs
cover powders that flow and or cure at 250F to over 1000F, as well as
those that are UV cured. I think maybe your definition is too narrow.
The fact that multiple definitions may exist just highlights the need to
verify the process and the shop in question before making any
decisions.

Charles