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Efficient way to remove mirror silver & leave clear glass?

topic posted Mon, January 16, 2006 - 7:51 PM by  Coral
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A customer of mine wants to remove silver from a mirror in order to paint-in details from the back. Is there an efficient way to do this? I faintly remember hearing something about a "silver etch", but didn't find anything with a net search. Sandblasting won't work - he needs a non-fuzzy surface so the painted-on details will be clear. Any ideas? Thanks.
posted by:
Coral
Colorado Springs
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  • JD
    JD
    offline 0

    Razor blade?

    Mon, January 16, 2006 - 11:42 PM
    Won't a single sided razor blade work just fine?
    • fire polishing

      Mon, January 16, 2006 - 11:54 PM
      maybe try fire polishing in a kiln after sandblasting, or other etching.
      i've never tried it with a mirror,
      but, it just may work!!!
      • Re: fire polishing

        Tue, January 17, 2006 - 1:38 AM
        why cant they just replace the mirror with sheet glass and paint on that?
        • Re: fire polishing

          Thu, January 19, 2006 - 4:11 PM
          He's working on the process of subtraction from a mirror, and wants to be able to paint details onto the clear glass portions. I'm just the go-between on this. His work looks pretty cool, so I'm trying to help him get it done.
    • Re: Razor blade?

      Sat, January 21, 2006 - 8:59 PM
      Razor blades work, but since my customer has asked for a more efficient form of removal, I thought I'd try to see what's available. Thanks.
  • Mirrors are made by sealing a layer of the silver mirror material (which i think is mercury based but don't quote me on that one) followed by a copper layer followed by a sealing material, usually an enamel based paint but sometimes a vinyl on cheap mirrors.
    Most decent stained glass shops carry two-part mirror stripping kits (mines out in my studio; don't have the name in front of me but will find it in the next day or so and will report back).
    The two part chemical system consists of a paint remover that liquidizes the paint surface (which you must then remove; not always easy and very caustic process) but leaves the copper/mirror layer intact; and then a second stripper that will dissolve the two metal layers, leaving you with perfectly clear glass, no frosting like from acid or sandblasting. You can control the stripping pattern by using any masking material that is impervious to chemicals, anything from white glue to electrical tape to proper sandblast resists. That way you can selectively remove a window area in the middle of the mirror, or pinstripes, text, a pattern, whatever.
    What's REALY cool is that by using jewellers silver oxydizer, you can strip the copper layer away, but leave the pure silver layer. So with multiple masks you can end up with areas of clear glass, shiny copper, and reflective silver mirror. Very trippy, but also VERY fragile. You can in turn reseal it , to protect it from tarnishing which it will begin to do almost immediately, with a microcrystaline wax available from art supplies stores or you can use Turtle Wax; same thing. The catch is that even sealed it's very fragile to any abrasion, so the multiple metal efect is really only useful if you plan on using it in a double sealed unit or within a framed box etc.
    If you are just going to remove the mirror selectively and then repaint (for text, logo, whatever, just clean the glass really well and use signpainters or auto enamel as you colour fill. it will self seal the exposed edges and you won't need to worry about the exposed silver tarnishing.

    Good luck
    Eric
    • Hey, Eric, thanks for all the info. Would love to know the mfr. on the kit you have. I AM a stained glass supply, so am trying to be sure I'm providing what people want. Talked to my supplier, but they did the "um...er....well...." dance, so knowing the name on your kit will give me a place to start. FYI, I found an article out on the net that talked about using lye for simple removal and undiluted nitric acid for stickier removals. May be the same as in your kit, but, I'm thinking the kit would be easier to buy, sell, and store (less hazardous waste lying around). I've now had a second person ask me about this process, so may be a trend re-starting.....
      • Hi Coral;
        The kit I have has the oh-so-imaginative name "STRIP SILVER" and is manufactured by

        Armour Products, Wyckoff NJ 07481 (no other info on the label)

        According to the label, they also manufacture "Rub'n'Etch" and "Peel'n'Etch" which I ass/u/me are stick on resists for acid cream etching.

        I've "misplaced" bottle #1, the paint remover (but have found any commercial paint remover to work) and bottle #2 contains Chromium Trioxide, which is no doubt a regular ingrediant in Kool-Aid or Twinkies.
        Hope this helps!
        E
        • Aahhh, good old Armour Products. (They're the Armour Etch people.) That's the same kit that my supplier will be getting for me. Perfect. Also wanted to let you know, in case it comes up, that there's another product out there called "Nickel Pickle", which apparently does the same thing. Thanks.
          • I am in the same situation and had been following your thread. I emailed Armour this morning only to learn that they discontinued the Strip Silver a couple years ago. I haven't located a supplier for the Nickel Pickle yet.
            • Hey, if you find something, would you mind posting it? Thanks.
              • Dang, and after all that... guess it's been a while since I last restocked. Paint stripper is pretty straight forward, it's the copper/silver stripping chemical that's the missing Secret Ingredient...any ideas as to what Chromium Trioxide is and how to find that?
                • I'm a little late in stepping into this topic, but seeing as no one has as yet spoken up about metal etching techniques from other fields I thought that I'd add this to the discussion.

                  You're right that any good paint stripper should be able to take off the protective paint.
                  But the silvering metal can be either Silver or Aluminum.

                  I'd start by trying a solution of dilute Nitric Acid for disolving any Copper and Silver, you should be able use a very dilute solution for safety (under 5%), it will just take longer.

                  If the Silver does not disolve with Nitric, then its probably Aluminum. in that case rinse it off very well and then try dilute Sodium Hydroxide (Lye, a strong alkali). This also happens to be one of the main ingredients in Crystal Drano ( en.wikipedia.org/wiki/Dr%C4%81no ) so it's easy to get and use if you don't have access to a a good chemical supplier. But if you use Drano be sure to test your resist first to be sure that it won't get disolved (I've had that happen when trying to etch aluminum before)


                  BTW here's the info on Chromium Trioxide aka Chromic Acid.
                  www.jtbaker.com/msds/engli...l/c4400.htm
                  en.wikipedia.org/wiki/Chromic_acid

                  Chromic is some really nasty stuff.
                  I'd stick with the Nitric it's far safer in my opinion, and is the generally prefered method for etching copper and silver.
                  And Nitric is used extensively and very safely in the zinc plate printing technique (Intaglio).

                  here's the info for Nitric
                  www.jtbaker.com/msds/engli...l/N3660.htm
                  en.wikipedia.org/wiki/Nitric_acid

                  and here's info for Sodium Hydroxide
                  www.jtbaker.com/msds/engli...l/s4034.htm
                  en.wikipedia.org/wiki/Sodium_hydroxide
                  • This is the maximum depth. Additional responses will not be threaded.
                    I just ordered some "Nickel Pickle" which it was said earlier works the same as the discontinued silver remover mentioed earlier. I hope to be able to use some 2mil PVC as a template then apply paint stripper followed by the Pickle to clear an area of my mirror.

                    Still waiting for the stuff to arrive so I can't offer any feedback yet on that process.

                    For my first test I used a dremmel with a polishing head (a sort of rubbery substance) which was ok but not great. Combined with a steel erasing shield it can be fairly accurate but it seems to mark the glass a bit and also the mirroring tends to flake off at times which results in a rough edge.

                    I'm hoping the chemical process will give much smoother results.
                    • Well... my tub of Nickel Pickle arrived today, it's a little plastic tub with a mainly white powder in in, odd red flecks. The instructions leave a little to be desired but clearly indicate it is nasty stuff.

                      I haven't had much success with paint stripper on the enamel on my mirror so I'd scraped some off such that only the silvering was left, this created a nice little indentation which was handy.

                      I put about half a teaspoon of nickel pickle in a plastic cup with about half an inch of warm water then agitated it a bit with a paint brush, it turns in to an orange liquid. I then started dabbing it in to my gaps wondering how long I should leave it.

                      What was odd was that as I dabbed my first gap I could see the paper towel under it so I figured I'd accidentally dabbed an area I'd already tried removing with the dremmel or wet sanding so I move on to the next spot.

                      Low and behold the same happened, this stuff works so well it could be silver dust you're wiping away, it si quite astounding, the silver literally disappears before your eyes, I'm very impressed.

                      I'm still undecided if it will work for me overall as the shapes I need to make are small, some for example circles that are less than 1/8" diameter, I don't know if I can scrape them off or not yet, we shall see. But as far as a chemical to remove silvering... nickel pickle rocks!

                      I got mine from www.lonniesinc.com/ it was about $4 but they have a minimum order value of $15 so I got some tweezers and other odds and ends.

                      For my particular task I have two more methods I am going to try, first I have a friend with a laser cutter who says he can burn off the paint and mirror and leave the glass almost unblemished, if that doesn't work out I have an option to have all the silver removed, apply a mask then have the mirror re-silvered leaving the target area clear.

                      Hope this is useful!

                      Chris.
  • I too have been mulling over this possibility for months. I've been googling for quite a while, since I've never done ANYTHING like this! I was so glad to see someone else already asked how to do it. Thanks for all your input, everybody.
    • Jon
      Jon
      offline 0
      I am new to this but it sounds like the nickel pickel route is great for removing the silver. However I have a pattern that I need to etch that will require a photoresist be applied to the mirror and then the Nickel Pickel used to remove the silver. The problem is I don't seem to be able to find a source for a spray on photoresist. It seems that it must be spray on and disolvable for removal so as not to damage the remaining silver. Can anyone help me or offer an alternative method? Essentially I want to leave fine line mirrored text and graphics behind. I am located in Colorado Springs.
      Thanks
  • I am also in the process of removing silvering from my venetian mirrors. i have tried thpse suggestions, that you received , drano and brass polisher works alright , try use rust converter, it also works, but friend of mine, suggested to try sulphoric acid, and i did, surprise, was the fastest way to remove the silvering. try this . Leoncio
  • Almost anything you clean your toilet with, Snobowl, Lysol toilet cleaner, CLR, Limeaway, Zep. All work, if you have one that has bleach in it, it will turn it black first (bleach oxidizes silver) but it will still take it off.
    Just brush it around with a paint brush, leave a couple of minutes and scrape and rinse. Gone!
    HINT: I am an antique dealer, if you do this with an antique beveled mirror, have the glass shop cut a thin cheap mirror the same size and mount behind your cleaned beveled mirror. MUCH cheaper than having an new beveled mirror cut by at least $100, or paying to have the old one resilvered.
  • Rex
    Rex
    offline 0
    I've read all the preceding posts and and have not seen this method suggested. I've used this method on astronomical telescope mirror surfaces. The materials are readily available and will not damage glass. First remove the protective organic coating by your preferred stripping method--solvents (acetone, laquer thinner or similar, avoiding the fire hazards), paint remover, etc. Obtain printed circuit etching kit from your choice of supplier (even Radio Shack). Use the etching solution, which is ferric chloride, to remove the selected area after masking the piece with an appropriate organic resist. Don't be impatient, the copper, silver, or aluminum should dissolve with time if immersed in the fresh ferric chloride solution at room temperature or slightly higher. My boss, at the time I first tried this method, decided that the ferric chloride puddle I put on the mirror coating surface might damage the glass so he took the job away from me and rinsed the mirror to remove the ferric chloride and immersed the entire mirror in a sulphuric acid solution. Sulphuric acid will convert an aluminum coating to aluminum sulphate which will not be easy to remove or dissolve and will appear as a foggy gel. The result in that first test was a mirror which was completely undamaged in the spot stripped with the ferric chloride but which had to be sent back for many hours of optical polishing to remove the layer of aluminum sulphate that was produced. I'm sure you don't want to use it for this reason as well as the safety aspects. Refer to online Material Safety Data Sheets for ferric chloride to see any cautions in its use.

    Be careful with whatever you use, but you should be successful with the method I have described.

    Regards
    • Ron
      Ron
      offline 0
      Ive purchased a tub of the nickle pickle and after removing the top coating from the back of the mirror I mixed up the nickle pickle with water and placed it over the silvering but for some reason nothing is happening. I've tried leaving it on from a few minutes to all night but the silver is not coming off, any ideas?
    • I have 5 small mirrors from which I wanted to strip the mirroring. After reading all of the posts, I went to 2 hardware stores, 2 lumberyards, and a store called "Industrial Paint and Plastics" here in Victoria, BC, Canada. I asked the clerks at each store for hydrochloric acid or sulfuric acid. All of them reacted as though I must be an Alqaida terrorist preparing to throw acid at an ordinary Canadian! I am a 68-year-old, white female, born in the USA , and former philosophy professor!

      Guided by the previous posts, I settled on brake fluid to remove what seemed to be a plastic protective shield. Overnight soaking in this loosened the protective shield, which I then scraped off with a razor blade. (The rest was largely intact.) Then I bought a store-brand copy of Draino, added a little water and soaked each mirror for a couple of days in this solution. After rinsing, they were almost clean, clear glass. The remaining residue came off with a Magic Eraser and further rinsing.

      I don't know whether the cost of the brake fluid and Draino were more or less than the cost of having new pieces of glass cut. But I am an avid do-it-yourselfer, so any extra cost was worth it for me!

      Diane