Hints and Tips - Powder Coating and Distortion

From: Mike Rambour
Sent: 17 June 1999
To: British-Cars-Pre-War
Subject: Ok people. don't laugh

and lets not have too much fun with this really stupid question. My really wonderful wife purchased a Eastwood powder coating kit for me as a fathers day present. Since my garage is getting small, she got it with the Infrared curing lamp. For those of you that don't know, the IR lamp cures about 12 inches at a time and then you move the lamp the next 12 inches. Its kind of a pain but it works and I don't have to have a oven taking up space in the garage and of course I can do big parts that way.

Now for my probably VERY stupid question. I was thinking of powder coating my 1934 Singer front axle, its a (drop forged?) solid front axle. My concern and its probably a stupid one is that by heating the axle 12 inches at a time to 400 degrees F (204C) I will be cause the axle to warp since the entire axle will never be evenly heated.

Part of me says, you don't even get a color change at 400 and don't worry its no problem. The other part says, its a pretty accurate part that I CANT replace easily and lets not do anything stupid with it. A friend of mine brought up the concern when I was preparing to coat it and he says because I will only heat a little at a time I will cause problems. I said its not enough heat and it will be ok, but now he has me worried. I did the rear axle and it looks good, but the rear is not as critical.

mike (who cant wait to get to the easy stuff, like body/paint)
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If you want to learn more about the ULTIMATE BRITISH sports car,
then take a look at http://www.singercars.com/
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From: Mike Rambour
Sent: 17 June 1999
To: British-Cars-Pre-War
Subject: Ok people. don't laugh

By the way, its already (WOW) suggested by 4 people that I call Eastwood and ask them. I did call them, they were very non-committal about it. The guy on the phone said it should not be a problem but he also said that he didn't know.

mike

**********************************************************************
If you want to learn more about the ULTIMATE BRITISH sports car,
then take a look at http://www.singercars.com/
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


From: Dennis E Nelson
Sent: 17 June 1999
To: Mike Rambour
Subject: Re: Ok people. don't laugh

Of course Eastwood wouldn't comment. There is a liability question there! I wouldn't know, but I do share your concern. If sandblasting can cause warpage on metal, and that is not even hot in that sense of the word, then I would think that the 400 degree temps could cause twisting in the axle. Good luck, and let us know how it turns out.

Dennis Nelson
39 MG TA


From: Hoskins, Bill
Sent: 18 June 1999
To: Dennis E Nelson
Subject: RE: Ok people. don't laugh

Dennis:

Warpage caused by sand-blasting (or bead-blasting) is a result of one of two things: either excessive air pressure (in the case of sand-blasting) or stress-relieving (in the cases of bead-blasting [on thin sections] and shot-peening [on thick sections]). 400 degrees fahrenheit should not be a problem on something like an axle (or any other part of relatively thick section). BTW, it might not be a bad idea to have the axle Magnafluxed while its out and apart, but be sure to do it BEFORE its blasted (blasting hides some surface cracks).

Personally, I've found that there is a material available that is just about as bullet-proof as powder coating, and for a lot less money...its a model-airplane material called "Formula U" and is made by Pactra paints. (Don't know if this stuff is available in the UK guys, sorry.) Its a filled Polyurethane, and is "hot fuel proof" (model airplane fuel is a mix of Methanol, NitroMethane, and Castor Oil!) - the only thing I've found that will attack it is DOT 5 brake fluid, and even THAT takes awhile! I got onto the stuff several years ago when I was working on formula cars - they get so badly sand-blasted on the track that we were painting the springs and such every race...a real pain. Anyway, this stuff goes for about $5.00 a 16-oz spray can, and they have a fair selection of colors.

Hope this helps...

Regards,

Bill


From: Mike Rambour
Sent: 28 June 1999
To: British-Cars-Pre-War
Subject: Re: Ok people. don't laugh

a little update on my question a week ago about heat and front axle and warpage. I took the plunge this weekend and made some measurements and a plywood jig out of scrap. I then powder coated it with the Eastwood kit and cured it with their infra-red lamp. I checked the axle later and granted the measurements and the jig I made were very rough but I would say the axle did not move at all. Best of all, I like it, it looks good and is in the shop right now getting new kingpins, I should have it back tomorrow.

The Eastwood powder coating kit is nice, I am not sure about the lamp though. I did some parts with the lamp that would have fit in a oven and they took quite a long time and you have to watch the temp constantly. In a oven you can "Almost" put them in and forget them until the timer goes off, the lamp is nearly constant work to make sure you don't burn the powder. But then again, finding a oven large enough for a front (or rear) axle would be prohibitively expensive even if I had the space for one.

I did a "hammer" test of my lower shock bracket too, since I had a scrap one that I practiced my coating on. WOW that stuff is pretty tough, it took quite a few blows to chip, although even the first blow scratched it up pretty well, it didn't actually "chip" or get into metal until quite a few more. I think I am going to like this stuff. By the way, NO this will not be a show car. I intend on driving the daylights out of this thing but there is no reason it can't look good after many thousands of miles.

mike (with a great looking 34 Singer front axle)


From: Dr G W Owen
Sent: 29 June 1999
To: Mike Rambour
cc: British-Cars-Pre-War
Subject: Re: Ok people. don't laugh

It sounds like a lot of trouble to me. When I built my Riley Special, I built the whole thing without a drop of paint. I then took it apart and took all the bits off to the local powder coater including the chassis with various brackets and cross members welded in to it.

Less than a week later the rust pile was ready for collection in fine powder coat. I think the whole bill for the chassis, wheels, axles steering arms brake drums and back plates, spring hangers etc etc etc even including lots of small bits was less than 200 quid. I then had a beautiful clean meccanno kit!

3 months later I did the same with the body tub and had that done. Again 3 day turn around and 150 quid.

Those wanting concours finish can then paint it if you feel the need. It makes an excellent primer for ali panels

I used:

Pharon Services
Beech Rd
Box Hill
Corsham
Wiltshire
SN13 8HF
Tel: 01225 743507

The owner is a VSCC member and they do quite a lot of old car stuff

Geraint Owen


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