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Glass Discussion & Research. NO IDENTIFICATION REQUESTS here please. => British & Irish Glass => Topic started by: Paul S. on January 06, 2013, 04:36:10 PM

Title: acid removal of heavy scratching on u. glass.
Post by: Paul S. on January 06, 2013, 04:36:10 PM
sorry to drag this one up again.             Bought this Webb's Gay Glass Sunshine vase early yesterday morning, in the rain (always fatal) - and dried it when I got home only to discover that the bottom two inches or so of the inside are very heavily dulled and scratched as can be seen in the pic.                        This is way beyond my abilities to bring back from the dead, partly because of the composition, and partly because the scratching is severe, so wondered - in view of Neil's comments (below) re the professional use of acid - if this damage might be cured by a few dips in hydrofluric or whatever they use.           There's no backstamp or cutting for the acid to damage, so could be a goer perhaps?  -  or might it be that acid won't remove sufficient glass to cure the problem.   
About 6.25" - 160mm tall.                 I may decide to pass it on if the concensus is that acid won't help, but it's a great piece and I did want to keep if poss.                     All thoughts welcome, and thanks for looking  :)

Neils's comments were part of a Cafe disussion from the 28th November last year.

"Hi, the restorer I mentioned only works for the trade.  I'm happy to take it in for you if you either a) want to mail it to me - send me your email address and I'll provide shipping details; or b) let me know where in the UK you are, and next time I'm in the area I'll pick it up from you to save you the shipping costs.  In either case I only visit the restorer about once per month, or every other month, so turn around time won't be quick I am afraid.

The professional restorers use Hydrochloric Acid to take off residue but this is incredibly toxic so be very careful if you use it.  If the acetic acid (vinegar) took off 80% of the staining then you might just want to leave it in there a lot longer to take off the remaining 20%.  If it will come off then prolonged exposure to the vinegar should work.

Hope this helps"
Title: Re: acid removal of heavy scratching on u. glass.
Post by: Frank on January 06, 2013, 06:08:53 PM
Acis is not the solution, grinding and polishing is.
Title: Re: acid removal of heavy scratching on u. glass.
Post by: Paul S. on January 07, 2013, 08:35:03 AM
thanks, and no doubt that would be a solution  -  it was just that I didn't consider it a safe propostion to grind and polish this type of glass. :-\
Title: Re: acid removal of heavy scratching on u. glass.
Post by: aa on January 07, 2013, 07:39:03 PM
I recently discovered "micro-mesh". This is used by picture restorers, among others, and basically starts off where "wet and dry" leaves off. It is really quite amazing. Also quite expensive, relative to other abrasive media but definitely worth it. Whereas "wet and dry" grades go up to 1200 mesh (2400 and 4000  are difficult to find) micromesh starts at 1500 mesh and goes up to 12000.

If you go through the grades, and are prepared to take the time, you can polish scratches and water damage out.

This is actually something you can try at home, but it needs a lot of elbow grease!
Title: Re: acid removal of heavy scratching on u. glass.
Post by: Paul S. on January 07, 2013, 07:52:30 PM
hello and thanks for the mention of 'micro-mesh', which I recall having seen advertised before - seem to remember that the finer grades are designed for polishing perspex or similar.         However, my concern was for the fact that I'd probably not attempt a piece such as this in view of the uranium content, although the professionals might have a process that avoided any health risk. 
Title: Re: acid removal of heavy scratching on u. glass.
Post by: johnphilip on January 08, 2013, 09:31:03 AM
A well known restorer once told me if the scratches were very deep you may just end up with polished scratches . hmmmmm  :-\
Title: Re: acid removal of heavy scratching on u. glass.
Post by: Frank on January 11, 2013, 12:30:45 PM
Polished scratches are ok. You can then call it cut glass  8)
Title: Re: acid removal of heavy scratching on u. glass.
Post by: Nemmie on January 11, 2013, 12:45:07 PM
Thanks for the micro mesh tip. Just used it on a vase that has been bugging me for years.

Worked like a charm and only took half an hour of rubbing with various grades.

Title: Re: acid removal of heavy scratching on u. glass.
Post by: Frank on January 11, 2013, 12:57:35 PM
Micro-mesh themselves say
Quote
Glass has a much harder molecular structure than acrylic or polycarbonate and although some damage might be abe to be removed, you would be unable to polish it back out to optical clarity...
but this might be good enough for glassware as Nemmie attests.
I guess you could you use it in water for U glass, preventing airborne particles.
Title: Re: acid removal of heavy scratching on u. glass.
Post by: Nemmie on January 11, 2013, 01:22:23 PM
The vase had a ring well more like a double ring or several rings from water sitting in it.

Nothing else I have tried over the years had made any difference so I am very happy. I suppose fogging would be a different matter.

I wish I had taken a before pic because the transformation is really impressive.



Title: Re: acid removal of heavy scratching on u. glass.
Post by: Paul S. on January 11, 2013, 02:13:25 PM
I'm glad that something good came out of this discussion :)         Useful to know that micro-mesh has its uses in the war against glass discolouration or whatever.         Not really possibly to show an image of the magnitude of scratches on this Sunshine Amber piece - but can say that for a couple of inches at the bottom they really are horrendous  -   looks like someone has been cleaning it with sand!        The only way out would be to go down through the grits, starting with something like 600!
I'm more annoyed with myself more than anything, for not spotting the damage before buying, but I'm really keen on these deco style pieces and they have a massive glow, so am loathe to bin it  -  guess some silocone grease and a location at the back of the cabinet will help. ;)
Title: Re: acid removal of heavy scratching on u. glass.
Post by: Anne on January 16, 2013, 07:43:42 PM
Paul, before you try anything else, it's worth mentioning that I had a badly water fogged old glass which defied all my attempts at removing the fogging, until I poured pineapple juice into it, and it magically lost all the fogging. It's a cheap option to try before anything else...
Title: Re: acid removal of heavy scratching on u. glass.
Post by: Paul S. on January 16, 2013, 09:44:04 PM
thanks Dame Anne  -  however, as I've explained earlier in this thread my problem is light years more extreme than 'fogging'  -  to the extent that a finger nail dragged across the affected area actually judders over the scratches. :'(         I really can't imagine how inept someone has been - when presumably cleaning the vase.       However, these pieces are so gorgeous that I'll close my eyes to the damage.
I have pineapple junks with my porridge on these cold mornings  -  do you think that has cleaned my insides ;)
Title: Re: acid removal of heavy scratching on u. glass.
Post by: Anne on January 16, 2013, 09:49:41 PM
I dread to think what it does to your innards Paul! But it shocked me with the results on my glass, I can tell you. Having tried every other suggestion made on the board short of a physical repolisher...  I do know that soaking meat in pineapple juice causes it to become incredibly soft and tender, so perhaps your innards are being affected... !!! ;D
Title: Re: acid removal of heavy scratching on u. glass.
Post by: Paul S. on January 16, 2013, 11:04:43 PM
.............I'm always soft and tender - with or without the pineapple ;)
Title: Re: acid removal of heavy scratching on u. glass.
Post by: Nemmie on January 17, 2013, 05:28:49 AM
Pineapple juice?

I have a few likely candidates for this method. I will report back with my personal findings.

Title: Re: acid removal of heavy scratching on u. glass.
Post by: Frank on January 31, 2013, 12:50:10 AM
It is the bromelin in pineapple juice that tenderises meat, but it is not found in canned pineapple/juice only fresh. So polishing effect may also differ from fresh to canned. Pineapple contains several acids as well as enzymes that it seems can affect things well stuck to glass.  Wonders of nature
Title: Re: acid removal of heavy scratching on u. glass.
Post by: Paul S. on January 31, 2013, 09:07:12 AM
quote................ "It is the bromelin in pineapple......"       -          so presumably that's why the whole group are called Bromeliads.         Just as a guess I'd have imagined that the citric acid might also have had some effect, but maybe not.