1st stage piston reg bore restoration

[superstar]

I found an effective way to restore the piston bore in a corroded regulator body. I took an automotive break cylinder flex-hone and used it to hone the bore of the regulator body just like you would hone out a rear break wheel cylinder on your car. It remove all the pitting and gave the bore a fine cross hatch finish. After a cleaning and new o-rings the reg works perfect. I was able to restore an old Aquarius wall hanger into a fine useable reg.

 

[Zung]

Interesting topic. I've nearly got the whole range of "decay", from like new to no more chrome left, and anywhere in between. So far, a little polishing with Brasso à la awap works fine, so I assume the soft o-ring(s) (70) of the crown deals with the small imperfections effectively.

Now the real question is: for those that have small patches of brass showing up, is it better to use your technique and possibly sacrificing some chrome, or the "softer method of Brasso?

 

[superstar]

I have piston 1st stages with various ammounts of chrome in the piston bore. I suspect it is from the original chrome process. Some have good chrome the complete depth of bore and others the chrome is very shallow and thin. If the chrome is flaking off that would be a problem in itself. If the bore is deeply pitted the o ring would not seal well or wear out quickly where as a flaking chrome bore could cut an o ring. My Aquarius had very thin chrome that did not go very farr into the bore. It also had a very deeply pitted ring of corosion where the piston o ring seats. I honed the bore untill the pitting was gone. The chrome was gone too. The one thing I should have done was to mike out the bore before and after to see how much material I removed. Based on my results from the Aquarius I feel confident that honing the bore is a good solution for restoring a pitted corroded bore.

 

[Zung]

Thanks.
Maybe I'm lucky in the sense that I don't have any pitting deep enough I can feel it by running my finger on it. So far a bit of Brasso works wonderful.