Sand blasting brake calipers - protecting the bores?

[obrut]

The calipers on my project 73 targa (aka yellow fright pig) were painted very yellow by the PO. One of many many questionable decisions he made...

Paint stripper is not troubling the baked on paint too much so contemplating sand blasting.

Question - what is the best way to protect the bores during the blasting?

[chris_seven]

We used to advise a local caliper refurbishing company about their test facilities and they have now been taken over by a large US based remanufacturer.

Their procedure thermally processes calipers in a controlled pyrolysis oven and then blasts in a tumble blast type machine.

They make no effort to protect the bores as the piston never makes any contact and runs in the seal.

Contrary to popular opinion bores are rarely re-worked and never honed as this would be far too costly.

[obrut]

Thanks Chris, very helpful.

[TZombek]

Ryan,
When I rebuilt my cast iron calipers I masked the bores before sand blasting. I then washed the clean caliper halves with brake cleaner before painting. I did hone the bores.
Ted

[chris_seven]

Honing the bore will have an effect on how the piston retracts due the energy stored in the seal.

The PMB Performance website says you should never hone the bore of a caliper and explains why and I have to agree with these comments.

I realise Eric will probably comment but just in case he is busy here is a link.

http://www.pmbperformance.com/brakehowto.html