Blasting Brake Calipers

[h3rman]

The laquer on my capilers are starting to peel (too much abuse ) and the original Brembo red is now turning pink on the front calipers. I have found a very good how-to guide on refurbing them, but obviously it's recommended to remove all old paint. The guy that wrote the how-to said he blasted his.

Basically, I need to know, what medium would be good to use on brake calipers that will leave a nice smooth finish and just take the paint off, nothing else?

Also, I need a blast gun that can work off my compressor (9.5 CFM free air delivery). I know you usually need BIG CFM for blasting, but because I will only be doing 4 calipers, I should get away with it, shouldn't I?

So, can someone recommend me a blasting gun and medium to go with it?

Cheers!

 

[piman]

Hello H3Rman,

are you intending dismantling the calipers totally, as otherwise I would hesitate to blast clean them. I would be concerned about abrasive getting under the dust seals and into the piston\cylinder area.

If you are intent on going ahead then small suction blast pots are readily available and use a fine aluminium oxide abrasive.

Alec

 

[h3rman]

Yea, plans would be to get new seals & O-rings and to totally dismantle them.

 

[Chipper]

Max 3mm nozzle on a suction gun, I've got a similar comp and thats all it will manage. Will do calipers OK though.

Would soda blasting do it? Dissolves in water so easy to clean up after.

Might be as cheap to farm it out though, as buy a gun and media etc.

Or paint stripper. Although I had a set of brakes that stripper did nothing on, but ammonia oven cleaning gel took it right off...

 

[tigler]

I would advise removing as much of the paint , or it could possibly be powder coating with a paint stripper like Nitromors , this would obviate the need to use an aggressive blasting medium. Then for the final finish clean up , bead blasting. This would leave a finish that would provide a good key for the new paint.
Would I be correct in presuming that these calipers are off an Evo ?

 

[rtbcomp]

I wouldn't bead blast if you're going to paint them. You need a rough surface for paint to stick to.

Aluminium oxide or worn grit would be better.

Have a look here

http://www.mig-welding.co.uk/forum/album.php?albumid=882

 

[tigler]

Dry bead blasting does leave a micro rough surface , works well as a paint key in my experience. Vapour bead blasting doesn't though.

 

[h3rman]

Would I be correct in presuming that these calipers are off an Evo ?

Yes mate, off an Evo 5. So what should I go for then? Already established that a gun with a 3mm nozzle will do, but what medium do I need?

Should I go for bead blasting or aluminium oxide?

@ chipper, not sure if soda blasting would be able to do it.

Cheers!

 

[brightspark]

as rtb says grit or aluminium oxide the idea of beadblasting is to peen the surface smooth with no surface damage defeating the object of blasting which gives a good clean matt finish for the paint to key to . beads are small round glass balls no sharp edges

 

[BChild]

I've always had calipers blasted with all pistons and seals intact and sacrificial unions and bleed nipples fitted

Then I've stripped em down and cleaned properly before painting/coating - but then I don't get a choice in media used and it's normally fairly aggressive stuff

 

[ElvisDontSurf]

I recently had a full set done on my jallopy.

Rears are a mare to strip down - i did them all by hand but they were alloy so pretty easy- no rust! You have all the handbrake mech/workings to contend with. If you have boggo standard 37mm lucas type ones- swap then for recon ones or buy alloy ones from ralley designs etc.

Front ones ? Strip them down completely , use a piece of wood infront of piston and blow out the pistons with an airline (piece of wood stops it blowing out at 1000000000 mph).

Used two bolts (with PTFE , wound all the way in until they bottomed out) to replace banjo/bleed nipple.

Wrap the piston seal area in gaffa/electical tape and knock it back in with a soft faced mallet. Bang it right back in. The only face your worried about is the piston face.

I then got them blasted by a company me mate uses 50 miles away. then sent them for plating - passivated - 3 layers, zinc/gold/black. then sprayed them up (in Skoda VRS puke green)

 

[Wedg1e]

First calipers I blasted were Austin Princess 4-piston units... the 80 grit AlOx took the chrome off the pistons and I had to buy new ones.
Last pair were the Jax XJ6 inboard units from my TVR: I was fitting new stainless pistons so wasn't bothered about damaging the old ones but ironically this time the 80 grit didn't touch the chrome...