Mat Roop Posted March 8 Report Share Posted March 8 I have a violin with a split peg box that would normally be ok to reglue with proper fit and clamping... problem is it has been previously glued, promptly fell apart, but now, the glue type is unknown ( not hide glue)... 1-Is there a way to identify the type of glue used from a piece of the old dried glue? 2-If it was a carpenters type of glue or Titebond, what is the best way to remove the dried residue. I am concerned with using vinegar as that can deteriorate the wood, and acetone will damage the varnish 3- If I use high temperature, at what point will the dried glue soften? 4- Any suggestions?... other than the "dustbin" solution. Many thanks... Mat Roop Quote Link to comment Share on other sites More sharing options...
HoGo Posted March 8 Report Share Posted March 8 If it'snot epoxy or some kind of PU try getting De-glue-goo. Vinegar works as well. You don't leave it on for long enough to damage wood. Quote Link to comment Share on other sites More sharing options...
jacobsaunders Posted March 8 Report Share Posted March 8 Vinegar can stain the wood, leaving an insurmountable re-touching problem and reducing your options to the “dustbin solution” Quote Link to comment Share on other sites More sharing options...
HoGo Posted March 8 Report Share Posted March 8 Are you sure, Jacob? I haven't seen any visible staining caused by pure kitchen vinegar (8-10%) used sparingly on light colored woods like maple or spruce? Guitar restorers use it all the tme to clean failed joints or bridges before regluing. The de-glue-goo is actually some sort of vinegar in thickening agent so it just stays where it is applied and wont run or spill. Quote Link to comment Share on other sites More sharing options...
jacobsaunders Posted March 8 Report Share Posted March 8 16 minutes ago, HoGo said: Are you sure, Jacob? I haven't seen any visible staining caused by pure kitchen vinegar (8-10%) used sparingly on light colored woods like maple or spruce? Guitar restorers use it all the tme to clean failed joints or bridges before regluing. The de-glue-goo is actually some sort of vinegar in thickening agent so it just stays where it is applied and wont run or spill. I experimented with vinegar, and still have a black bench Quote Link to comment Share on other sites More sharing options...
Spongebob Posted March 8 Report Share Posted March 8 Maybe a photo of this peg box would help, then you can assess what technique to use, suggest something. Quote Link to comment Share on other sites More sharing options...
HoGo Posted March 8 Report Share Posted March 8 24 minutes ago, jacobsaunders said: I experimented with vinegar, and still have a black bench Vinegar turns iron to black stain so your bench was likely contaminated with iron (or some other stuff) from sharpening? I have used various weak household acids (vinegar, formic?, oxalic) and peroxides for bleaching or other experiments and they generally didn't stain clean wood at all. Quote Link to comment Share on other sites More sharing options...
Brad Dorsey Posted March 8 Report Share Posted March 8 10 hours ago, Mat Roop said: ...Is there a way to identify the type of glue used from a piece of the old dried glue?... Maybe. Try soaking it in water. If it's white glue (like Elmer's) it will turn soften and opaque white in a few minutes, and if it's yellow glue (like Titebond) it will soften and turn opaque yellow. You will recognize it if it's hide glue, because you know what that looks like. If it is unaffected by water I don't know how to identify it, but you could test to see if it softens in acetone. 10 hours ago, Mat Roop said: ...If it was a carpenters type of glue or Titebond, what is the best way to remove the dried residue... Keep it moist with water and scrape it off as is softens. Quote Link to comment Share on other sites More sharing options...
Mat Roop Posted March 8 Author Report Share Posted March 8 thanks everyone... I appreciate the comments. I am also wondering about the acetone option... maybe use it very judiciously on the heated surface and then touch up any damage? I'll certainly test the little bit of dried glue with both vinegar and acetone & see what happens. Cheers!.. Mat Quote Link to comment Share on other sites More sharing options...
Mat Roop Posted March 8 Author Report Share Posted March 8 just fyi... here is the response to my inquiry to Henkel (LePages) We do not have a way to determine the type of glue that has been previously used. Our Carpenter's Glue can be removed mechanically once cured. Rubbing with hot soapy water or steaming will aid removal. Paint strippers will also remove dried glue. Cheers!... Mat Quote Link to comment Share on other sites More sharing options...
Michael Richwine Posted March 8 Report Share Posted March 8 Heat softens most plastic glues. They give up around 200F, which doesn't harm wood. A household iron can apply controlled heat, and I also have a large chunk of aluminum that I sometimes heat in an oven. Steam works if you can control the application. As a restorer, I often removed black stains from wood with Oxalic acid solution. Don't know whether you can get it in EU nanny state any more. Quote Link to comment Share on other sites More sharing options...
Mat Roop Posted March 8 Author Report Share Posted March 8 Thanks Michael... I have one of these... might just work... https://canada.bissell.com/bissell-steamshot-handheld-steam-cleaner-2994B.html I'll also maybe try a hot air gun for stripping paint. Cheers! Mat Quote Link to comment Share on other sites More sharing options...
Evan Smith Posted March 8 Report Share Posted March 8 36 minutes ago, Mat Roop said: I'll also maybe try a hot air gun for stripping paint. Cheers! Mat Careful there, I hope you're kidding? With that much heat the wood can suddenly darken before you know what happened. It would take quite a setup to make that safe at all, along with sacrificial pieces to warn you as you approach the threshold of disaster. Just don't. Is it completely broken off with the glue surfaces exposed, or is it still a crack? Quote Link to comment Share on other sites More sharing options...
Evan Smith Posted March 8 Report Share Posted March 8 If the surface is exposed, I've taken needles and made miniature tools out of them to clean everything out of the wood fibers before gluing, microscopes are your friend. Quote Link to comment Share on other sites More sharing options...
Michael Richwine Posted March 8 Report Share Posted March 8 I'd rather use a hair dryer than a heat gun for softening glue! Heat range is more apropos. Alumin(i)um foil and strategic air gaps can be useful heat shields. Agreed hottish needles and such can be somewhat helpful, but general heat at around 200 - 220f, well controlled, has the least potential for collateral damage. Quote Link to comment Share on other sites More sharing options...
Evan Smith Posted March 8 Report Share Posted March 8 I borrowed a hair drier from "The Girls" and found that it got quite hot, enough to burn yourself, or blister varnish if I held it a bit too long, so in my concern for their safety I told them I'd get them a new one so they wouldn't ruin their hair. Of course it's still in the shop being watched over very carefully, best one I ever had. I vocally detest Black and Decker stuff, so my wife has to ask occasionally, hows that Black and Decker blow drier holding up for you. It's heated up many a center joint and bass bar,,,, why do you ask darling, do you need a new one? Quote Link to comment Share on other sites More sharing options...
FiddleDoug Posted March 8 Report Share Posted March 8 I think that the hot air or steam options are perhaps too broad an area for localized glue joints. Perhaps an adjustable heat soldering pen might give you the heat in a small area. Quote Link to comment Share on other sites More sharing options...
Brad Dorsey Posted March 8 Report Share Posted March 8 7 hours ago, Mat Roop said: …I am also wondering about the acetone option... I have very occasionally encountered instruments that were (badly) repaired with glue that water had no effect on but that were softened/dissolved by acetone. I have found acetone hard to use in this situation because it evaporates so quickly that it has to be constantly re-applied. And you also have to worry about its effect on varnish. I am thankful that I rarely have to try to do anything with it. Quote Link to comment Share on other sites More sharing options...
Michael Richwine Posted March 9 Report Share Posted March 9 5 hours ago, FiddleDoug said: I think that the hot air or steam options are perhaps too broad an area for localized glue joints. Perhaps an adjustable heat soldering pen might give you the heat in a small area. Main thing is, not to over heat, hence low heat source, heat shields, etc. Most varnishes can stand 200F, but test first. Soldering pens can char if they aren't regulated. Charring occurs around around 450 500 deg F, which is minimum required for soldering. All of this takes a modicum of skill and awareness; none is child proof. I've used steam on odball glue, applied thru a 1/16" tube with no ill effects, the same way I would on a guitar or mandolin. Lots of dams, drainage, etc. I've also used an iron, aluminum block, etc. Whatever it takes. I just recently bought a regulator for my burn-in knife which should turn out handy for this kind of application. I'll have to make some custom bits, no doubt. Quote Link to comment Share on other sites More sharing options...
Mat Roop Posted March 9 Author Report Share Posted March 9 Thanks everyone... greatly appreciated... activates my brain! Hot air gun is something I use regularly( on student grade equipment) but I control the heat very carefully with a probe type of thermometer precisely at the at the point of heating... I have found 250 deg F is the absolute max and generally does no damage... I control the heat by moving the gun further or closer to the point of application and using a sweeping motion if necessary Cheers! ...Mat Quote Link to comment Share on other sites More sharing options...
Mark Norfleet Posted March 9 Report Share Posted March 9 15 hours ago, Brad Dorsey said: I have very occasionally encountered instruments that were (badly) repaired with glue that water had no effect on but that were softened/dissolved by acetone. I have found acetone hard to use in this situation because it evaporates so quickly that it has to be constantly re-applied. And you also have to worry about its effect on varnish. I am thankful that I rarely have to try to do anything with it. One can make an acetone gel to control both its evaporation and propensity to get to where you don't want it. Vapors could still be problematic though. The dwell time required will be extended as well. Quote Link to comment Share on other sites More sharing options...
Mat Roop Posted March 9 Author Report Share Posted March 9 Thanks Mark... So how does one make an acetone gel? I know that the DeGlue Goo is a water based starch gel.. would acetone work the same way in water based starch? So now just thinking... Instead of using de glue goo for usual hide glue, I cut paper towel into shapes or strips to suit, then with an eye dropper, I drop water onto the p towel just enough so that it soaks but does not run or drip. .. so my guess ... would that work with straight acetone? Quote Link to comment Share on other sites More sharing options...
Mat Roop Posted March 13 Author Report Share Posted March 13 In case anyone is interested... I tested vinegar and acetone on bits of the old glue, and acetone for sure was more effective. The next issue was that acetone is very fluid, is a paint stripper and how to keep it off the nearby varnish. I cut a doubled paper towel exactly ( well, almost) to the shape of the surface with the old glue. Keeping that surface horizontal, and with a small pipette I carefully dropped acetone on the paper towel one drop at a time, to the point that it would not run. Now, acetone is highly evaporative liquid so, about every minute or more I dropped another drop of acetone onto the paper towel. After 15 minutes, the old glue became rubbery soft and then I cleaned the wood grain with a brass brush, then a needle point along each grain line, finally washed it with an ammonia solution and let dry... looked very clean. Glueing up tonight ... stringing up tomorrow...we'll see. Btw... not a bit of the varnish was affected by the acetone Quote Link to comment Share on other sites More sharing options...
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