Help: Film on crystal stemware and vases

Hi Folks, We have been repairing crystal for a number of years successfully, but... we are getting more and more requests on the removal of some cloudy film in the interior of (mostly lead crystal) glasses and vases, etc. We have tried the "CLR" product, and it seems always to remove about 80% of the film, but then leave a visible film layer still on the items. We are only worried about the interiors of stemware and vases with this problem, since we can bring the exterior to a polish with our usual bevelling and polishing techniques. We usually cannot get to the interior of these items with a tool for cold polishing. Any advise would be appreciated. Thanks.

Reply to
John O. Riordan - Riordan Artistry
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Ask you clients if they are washing their crystal in a dish washer. Dish washer detergent has caustic in it. It has to be more aggressive than normal dish soap you would put your hands in. Lead glass (and soft glass) is not resistant to caustic like Pyrex is. That's why Pyrex is used in laboratories.

In time the caustic will start to etch the finish. Being you put glasses in a dish washer facing down, the interior of the glass gets the brunt of the spray.

If this is the case, CLR will not work because there is not a deposit left on the glass. The surface of the glass is etched as if you had used an etching cream on it.

How to polish it out still remains to be a mystery to be solved. I would think something like the "buff ball" might work.

Randy Hansen SC Glass Tech Scam Diego, Comi-fornia

Reply to
Randy H.

I may be wrong here, but I'll risk it.... I seem to remember a long while ago in STAINED GLASS (SGAA) Mag there was an article, and it goes way back... The jist of it was that straight HF is a polishing agent for glass because it dissolves that surface. (also The Patte de verre guys of old would dip their stuff to remove extraneous impurities when things came out of a mold, and cause the glass to shine again) It is the addition of ... may be wrong here... Sodium Biflourite( or ate or some such stuff), that caused the glass to etch with a cloudy surface. Straight HF, while still very nasty, was not an "etch" as we think of it today.

Bet it was tricky stuff to work with tho... "Barkeepers Friend" is an etching agent, read the label, contains HF .

Reply to
Javahut

barkeepers friend is 100% oxalic acid. h2c204. there is no fluorine in it at all.

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Reply to
Charles Spitzer

The lead crystal manufacturers use acid polishing after they have done the cutting of the ware. It's a mixture of HF and HNO3, and the time of immersion is carefully controlled. It's not a DIY job.

Reply to
Terry Harper

Is HF the one that will eat away your bones? Or is that HC?

Reply to
C Ryman

You mean HCl (Hydrochloric acid). Yes, HF (Hydrofluoric acid) is the very dangerous one, strictly speaking H2F2.

Reply to
Terry Harper

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