I want to clean, prep and paint my '74 transaxle. I was thining of using a POR 15 product. Is there a problem with doing this? What type of metal is the trans case? My car is just a Sunday drive. I've read that some people think painting a trans could cause over heating which if this is true painting it with POR 15 would be a real problem considering it creates a completely non-porous surface. Any thoughts would be helpful. Thanks.

If any moisture gets under the por paint if it's like por15 it will corrode pretty bad. Do a search on recoating magnesium and aluminum trannys. I think the tranny is magnesium. I'm pretty sure if it was bead blasted a epoxy primer would stick though. Harbor freight has a small hand held spotblaster that might work well with soda to clean it after all the cooked dried grease is off.

I've done it on the race car

a lot of people will tell you not too
you can argue it either way
some will say it will insulate the heat and cause problems
others will say that black helps disappate heat (radiators are painted black on watercooled cars)

on my application, the magnesium was already corroded some and pitted. I did it to protect the metal (similar to painting a car to keep it from rusting). I know the sand rail guys paint 914 trannys religiously with no ill results. I can say that I have 2 race trannys (1 painted, 1 not) and the paint hasn't hurt anything. I abuse the crap out of my race tranny and use an F first gear which most say is not possible... so the paint doesn't seem to matter.

I cleaned it very well
then use epoxy refrigerator paint (rattle can)
it completely sticks with no peeling, no problems.

brant

I simply scrubbed it with cleaners that don't harm magnesium. You should not paint magnesium, from what I have heard.

It is hard work to clean it and not scratch it, but it is not easily painted.

And if you paint it, find something that can stick to Magnesium.

Magnesium cleans up nicely, but certain cleaners can etch it and harm the overall finish. Some people put naval jelly on it, but I think it looks better just clean and unpainted.

I have a steam cleaner, and that was good at getting the old oil off of it.

And Brakleen. Not Carb Cleaner.

John

Thanks for the input Brant. I think I will paint it. I too want to protect the metal.

I had a set of Dymag Magnesium wheels on my race bike for years. They were painted. Same with the Magtek Wheels I had on my NSR they were also painted from Honda.

GunKote.

< http://www.kgcoatings.com/ >

Had good results with GIBBS brand penetrating oil.

http://getgibbs.com/tips.php

Click to view attachment

I like high temp clear

Mine was painted black. Not sure with what. It was that way when I got the car but has held up very well with no problems.

some people say...
I heard that...
I read on teh internet...
...that if you paint a jackalope's ass green it jumps higher

I have painted early aircooled vw cases and had no problem. Why is magnesium supposed to be hard to paint? Motorcycle manufacturers paint magnesium wheels all the time. I found this online and it looked useful, from a website about restoring vintage aircraft:

Process:

Here is a safe process to follow for stripping, preparing and painting Magnesium control surfaces.

Supplies needed:

Paint remover (your choice), although there are some preferred types for magnesium that are less caustic for this type of metal. I don't have a list to provide at this time.

Magnesium metal prep, Poly-Fiber has a product called Magnadyne (about $4.50 per Qt.) Locations of distributors that sell Magnadyne


Action:

1.) Remove control surface

2.) Take Weight and Balance optional or required

3.) Strip and smooth surface clean & dry

4.) Apply conversion coat & dry

5.) Apply Non etching epoxy primer

6.) Apply top color coat, then check balance with-in spec.

7.) Install and check tension & rigging



For magnesium you want to strip to bare metal, clean with water and soap and scotch-brite pad (the gray fine grit if possible) and inspect the skin etc.



Prep the magnesium:

Beech/Raytheon provides a Mil-spec Mil-C-3171, AMS 2475 Conversion Coat process for magnesium called DOW 7 and DOW 19. If you search "google" with the term, "Conversion Coat" you will find the pdf file to download. This involved process is not required for existing control surfaces, but Beech or their subcontractors used it on the bare metal magnesium parts originally by utilizing dipping tanks.



For repainting all you need to do is use some of the brush on types. The company Polyfiber www.polyfiber.com/where has a product called Magnadyne (about $4.50 /Qt.) that you mix with water (follow directions by manufacturer). Poplawski uses a product from Eldorado Chemical, there are others too. This stays on about three minutes and then wash off with water. Dry the control surface very well. Use a hair dryer or heat lamp or forced air if heated. You have to get rid of the moisture !!!!! Don't touch the surfaces with your bare hands either, get some cotton gloves etc.



Get ready to apply the primer:

Wipe down the entire control surface with MEK (of course it's bad for you, so are Krispy Kreme fat pills). Use a non etching epoxy primer. Make sure you use a NON etching epoxy primer. Did I mention non etching epoxy primer!!! Good. Polyfiber has a brand and so do all the rest.



Get ready to paint the control surfaces:

You can use what ever paint you want over the NON etching epoxy primer including Acrylic Enamel (may be lighter weight for older ruddervators), Imron or other Poly Urethanes etc. Remember many of the painters at the aircraft paint shops started out by painting automobiles and the more paint the better. We all know that this is not the case for ruddervators or control surfaces. When you select the paint shop for your airplanes, are you talking to a salesman or to the person that is going to actually paint your airplane ??? Go and talk with the person that is actually going to paint the airplane. When you call Poplawski, guess what, he is the same person that actually paints the airplane. (OK, so he's booked up for a year or more).

Now see if you can get the control surfaces to balance according to the Beech specifications.

http://www.vintagebonanza.com/prep_magnesi...or_painting.htm

Alumna blast from Eastwood.

It's not.
Of course manufacturers get to start with new, virgin parts that haven't been exposed to oil for 30 years and have no existing corrosion to be concerned with.

'The Deal' with magnesium is that if you do somehow manage to encapsulate a bit of corrosion or there is film-penetrating damage, it can turn horrible and powdery without you knowing it (for a while...).

That's something to be said for the Gibbs approach.

And those were excellent links you provided - thanks for that !

It's worth a look to compare this topic with the other approach, which is Tectyl or something like it. This is a fairly comprehensive thread on that subject.

http://www.914world.com/bbs2/index.php?sho...9&hl=tectyl