Case cleaning problem!
 

Great books Wayne! They have arrived! Keep up the good work!
I've just bought a basket case 911 engine, and a previous owner has painted the case ('65) and heads (2.2,..) red.
I know I can bead blast the heads but don't really want to blast the case.
Vapor blasting?
Paint stripper?
Cold tank?
Any ideas on how to remove it?
I'm a bit wary about dipping the case into a tank of chemicals! What's safe?
What about blocking up all the passages and then blasting?
Besides mental health problems what could be the reason for painting them. Heat retention doesn't seem sensible to me in a 911 engine...

Use paint stripper, airplane quality. You can buy this at home depo or good harware store. Water will nuetralize stripper after you have removed paint. Make sure you use proper safety protection.

don't even think about glass beading it. if someone has a cold tank that large, that should work, otherwise aircraft remover. you may never get it out of all the cracks and crevises though.

If you work carefully and bolt the case together and seal *every* crevice and hole to the outside, you can blast the outside with no problems...

-Wayne

Cheers guys. That puts my mind at ease... at least I know I have some options.
Let the fun begin....

Sorry Wayne, can't agree with you on this one.

DO NOT EVER, EVER under ANY circumstance bead blast ANY part of the case. Those %^%(^ beads get every where and if ANY get into your engine, its HISTORY. There are even good reasons not to bead blast the heads, because the beads, tend to embed into tbe metal and then somehow end up in the oil system. Almost any chemical stripper is preferable, as the result is only a plugged oil spicket. With beads, not only can the spicket be plugged, but the rest of the beads can grind grooves in the crank, the cylinder walls, and wreak havok in general.

If you seal up the engine for the purpose of getting the paint off the case, then it should be okay. Many people argue against bead blasting the heads as well - but most machine shops don't have a problem with it.

In reality, I probably wouldn't go right to blasting - I would use some paint stripper chemicals first...

-Wayne

So Wayne says you can blast, then snowman says you can't. Hmmm, they never disagree do they?

The guy who does my heads uses an ultrasonic bath to clean them. I thought that was pretty cool.
(Yeah, I know, I know, I need to get out more.)
-Chris

Other than putting a nice even finish on the exterior crankcase surface, I don't see any advantage in bead blasting the case if other, more invasive methods do an effective job in cleaning the oil passages. You must close up every single opening, otherwise there's a good chance the glass beads will find their way into the oiling system. As pointed out by Snowman, that's bad news. Are many shops (or owners) accomplished enough to do this correctly? One can also remove paint with carb cleaner, paint remover or even brake fluid.

Sherwood
http://members.rennlist.org/911pcars

Blast yes, but use some other media than glass beads.
The pro who did my heads used a walnut shell media. Safe and tasty, too.

Cheers guys, this is getting good.
I know of Walnut shell being used on motorcycle cases here so I may look into it. Food for thought?

FWIW, when the Statue of Liberty was restored, it was blast with crushed walnut shells.

Did they have to plug Liberty's orifices too? :)

Sherwood

Are you sure? I heard they used a giant lufa. :D
-Chris

bead blasting
 

What, are you out of your mind? If you have been in the business long enough, you KNOW that the only way to clean a case is to hot tank it and then clean it with solvent and blow dry. If you want to go beyond that, you have the case ultrasonically cleaned. But, know way in hell should you use an abrasive to clean a case, you can never chase all the particles out of the case.

I think I've gone off the idea of beads, but Otto, with hot tanking don't you risk dissolving the alloy? Surely only cold tank? Or with your experience how long in hot tank and what temp?
Haven't found anyone here with an ultrasonic tank large enough, only jeweller types.

Tim, when they cleaned the statue of liberty the media used was granular baking soda (sodium bicarbonate) supplied by Church & Dwight, the Arm & Hammer people.

I founded a soda-blasting business in Detroit, we were a contractor for the big three. The advantage of soda is it's completely non-agressive-- you can depaint with high pressure and not erode the substrate. Works on glass, etc. without scratching, but will take off industrial epoxy coatings.

If you could find someone in your area with a soda blaster, you could depaint the case without disassembling it, and then spray diluted vinegar over it- Remember that trick as a kid? Turns the bicarb into c02.

Why do people pick on the early cars?

p.s. nice to see OTTO on the board

John, Both soda and walnut media were used to clean different area of the statue. Other media were tried, but proved to damaging.

I had the honor of being involved with the restoration of statue, during the time I was on the island pallets of crushed walnut shells were staged right next to the blasting equipment.

Kelvin,

If you really need to get the paint off the case and heads (you see so little of them anyway), why not try a die grinder and some abrasive points or rolls, scotchbright discs etc.

I agree, scotch-brite, wire wheel, dir grinder/Dremel tool.