Bronze portlight

[mherbert]

I just removed the opening portion of my bronze portlight because the tempered glass had a single crack. It turns out that after all glazing compound was removed that there is a bronze retainer ring that sits in a groove much like a piston ring except on the outside of the circumference. This is a 64 year old part and corrosion has frozen the ring. What chemical can be used to remove the corrosion and free up the ring?

[Victor]

Muriatic acid and then PB Blaster?

[Bob Cleek]

Depending on the design, you may be able to free the ring with heat. Heat expands metal, generally enough to crack the concretion from corrosion. The trick is to heat one part more than the other, which is easier said than done. A heat gun with a flare tip, or a braizing torch, or even a soldering iron will usually do the trick. You may need to run through a few heating and cooling cycles before it breaks free... or you get to try one of the other ideas that will likely turn up here!

[Buddy Sharpton]

Don't laugh untio you try. Phosphoric acid will break down copper oxidation. Try the southern field expedient of pouring Coca Cola into the works ( 5% phosphoric acid). Couldn't hurt.

[kc8pql]

I'm with Buddy. Try some Coke first.

[Canoeyawl]

I am making the assumption that you are trying to replace the cracked glass... The corrosion may be creating significant pressure against the glass making it difficult or impossible to remove the lock ring. Perhaps you could shatter the glass and pick out the pieces under the lock ring. This will relive any pressure under the ring and it should remove easily after the glass is gone. Wear your safety glasses!!!

[mherbert]

I should have relayed the fact that I already broke out the glass and removed all glazing compound. Alas the ring is immovable. Tried the coca cola for a twenty four hour soak. No luck. I'm off to find some phosphoric acid and muriatic acid. I'm reluctant to use a torch for heat because if the bronze were to crack I'd be up a creek. Thanks for all suggestions. Perservance will win out in the end.

[mherbert]

Success. Got some PB Blaster. Sprayed and lightly manipulated the ring with vice grips. After a couple of hours it released. Thanks to all for the suggestions.

[Paul Maselli]

PB Blaster !!!!!

The first time "As seen on TV" has actually panned out. This is the geatest penetrating oil I've ever used. Kroil is another great brand. PB Buster has one up on it. Kroil products can only be bought mail order direct. PB Blaster helped free up the 68 year old iron keel bolts on the "Elliot White". Just tonight I used it and my oxy-acetylene torch to free up a stuffing box gland nut. It burns a little but the heat drives it into the threads. 3 minutes later the stuffing box that sat for 40 years is loose and removed.

Pass it on!