RobertGT3

Hi All, I recently had my 4 speed gearbox rebuilt, unfortunately the workshop meaning well painted it a shiny silver colour, which doesn't look original, and worse, painted the side covers gloss black.


I was going to explore getting the paint stripped with dry-ice blasting, it looks very effective. Anyone used this method? Video looks appealing


Also what finish should the side cover be? Is this steel? Is it painted?


The car is mostly original and I want to ensure it stays as factory correct as possible.


Thanks


Robert

bweSteve

Clearly that video is showing a tranny being blasted BEFORE being pulled apart and rebuilt.

In your case, yours is already rebuilt, correct?

In your case I would be really careful with blasting. I have both a media blast cabinet, and a portable soda blaster that I use for my older projects. With such high pressures, both can very easily penetrate and destroy any gasket joints, o-rings, or any wiring connections, etc.

If it were me, I would only trust to do this myself. I would not trust anyone else to blast it, AND I would take GREAT care to tape off any spots I did not want any dry-ice (or any other media) to corrupt.

Sorry I can't help answer Ques on original correct colors.

Good luck!!
=Steve

MUSSBERGER

I almost bought one of those cryo blasters in a online real time auction. It sold for penny's on the dollar
They do amazing stuff with them

http://forums.pelicanparts.com/911-9...holy-cryo.html

bweSteve

Cryo is cool,... and yes it looks like that system allows you to blast without disassembling the motor / suspension.

I would never blast (w/ soda) parts that are still installed on the car (unless I could COMPLETELY segment it from everything else around it, .. and even then probably not). All the soda & media blasting I do is for metal parts that are OFF the cars (usually during the time I'm replacing bushings, gaskets, O-rings, rubber, etc), AND for those which do not have a original patina that needs to be preserved. Honestly I have never used either of those blasters for any of my Porsche stuff. Mostly for the old American Muscle where we've taken everything apart, and I can re-paint or powder coat back to original sheen.

But yea, my 964T control / idler arms & other parts under there could use a good Cryo.

Mark Houghton

Wonderful method, but really the only benefit vs. soda blasting is that it leaves no residue to clean up. That's convenient, but for what "they" charge for the service a person could purchase the necessary stuff to do soda blasting at the same result....with a little after cleanup.

I would agree with everyone's comments re: don't fark up the seals or gaskets. I'm seriously considering doing one of these two approaches for the tranny which came from my burnt girl (it's fine all in all, but has a baked on petina of burned oil, plastic, rubber, leather, carpet, paint, and fiberglass smoke). Need to make it more presentable for sale. I'll probably purchase a soda blasting setup to add to my arsenal.

RobertGT3

Hi All, thanks for the advice, I thought I'd show everyone the finish my gearbox has after using Aluminium safe paint stripper.


The only issue I'm left with is a few of the bolts, steel parts have picked up some surface rust

MUSSBERGER

Told you that would work!

So much for all of us trying to over complicate things. That looks really nice.

bweSteve

It does look good.

At this point, I might suggest a protective coating,... to preserve that look,... because if you don't, it will not take long for oxidation to set in,.....

http://boeshield.com/automotive-motorcycle/

I might apply a light coat of Boeshield T-9

=Steve