Magnus Nedregard Posted March 16, 2009 Report Posted March 16, 2009 Just got a question from a colleague where to obtain Deft in Europe, I really don't know. Does anyone know where to get it? American shops won't send it overseas as it seems... I admit it is a handy product sometimes, but apart from that, I have serious doubts about Deft, and I think it is over-used. Isn't it just a polyurethane varnish with some kind of matting agent in it? I've seen that polyurethane finished are advised against for exterior use, due to their deterioration exposed to UV light. Hardly a good indication of violin-friendly product. It is also quite easy to recognise a crack that has been filled with Deft (too easy!) It is often used regardless of the reflection of the varnish surrounding... It is pre-matted and seems to darken with time, so just how smart is it? Well, it is still a useful thing to have in the workshop sometimes, so has anyone found it on this side of the pond, or perhaps if you know about a similar product?
Andres Sender Posted March 16, 2009 Report Posted March 16, 2009 The stuff often used for filling is a brushing lacquer I believe.
Magnus Nedregard Posted March 16, 2009 Author Report Posted March 16, 2009 The stuff often used for filling is a brushing lacquer I believe. Yes it is, it is just this stuff: http://doitbest.com/Varnishes+and+shellacs...-sku-776360.dib I am not sure if it is polyurethane though, I would like to know. Isn't polyurethane just some sort of, er.. plastic?
Jeffrey Holmes Posted March 16, 2009 Report Posted March 16, 2009 Yes it is, it is just this stuff:http://doitbest.com/Varnishes+and+shellacs...-sku-776360.dib I am not sure if it is polyurethane though, I would like to know. Isn't polyurethane just some sort of, er.. plastic? It's a nitro-cellulose lacquer. http://www.deftfinishes.com/assets/tds/CWF%20TDS3.pdf I know a number of restorers that do use it, but I haven't used it on a fiddle for almost two decades.
Magnus Nedregard Posted March 16, 2009 Author Report Posted March 16, 2009 Thanks for that, then it is not quite what I thought, nitro-cellulose is what they use on guitars, isn't it?
Magnus Nedregard Posted March 16, 2009 Author Report Posted March 16, 2009 ... but I haven't used it on a fiddle for almost two decades. It is so awesome to consider that the last time Jeffrey used "Deft" I was 13!
Brad Dorsey Posted March 16, 2009 Report Posted March 16, 2009 "Isn't it just a polyurethane varnish with some kind of matting agent in it?" I'm looking at the label on the can. Non-volatile ingrediants are nirtocellulose, coconut oil alkyd and stearates. There are also volatile ingrediants, but presumably they all evaporate. The label also says "Non-yellowing crystal clear."
violinbridges Posted March 16, 2009 Report Posted March 16, 2009 We used to use it allot years ago, but heard rumours of it being Hygroscopic and going black with time, which seems strange for a boat varnish. I seem to remember it was very easy to use but killed brushes, best appied with a sharpened cocktail stick. Very handy to have now and again. Regards Gerard www.violinbridges.co.uk http://cdbaby.com/cd/taran1
Jeffrey Holmes Posted March 16, 2009 Report Posted March 16, 2009 It is so awesome to consider that the last time Jeffrey used "Deft" I was 13! Oh my goodness... That's scary.... especially considering I was already 33 then... :-)
Michael_Molnar Posted March 16, 2009 Report Posted March 16, 2009 Stop bragging, Jeffrey, I was 43. Mike
Jeffrey Holmes Posted March 16, 2009 Report Posted March 16, 2009 Stop bragging, Jeffrey, I was 43. Mike !!!!
Ben Davis Posted March 16, 2009 Report Posted March 16, 2009 Deft is a Nitro-Lacquer, not a polyurethane. The main difference to me is that poly seems to be quite insoluable after it has cured, whereas lacquer remains soulable. Nitro has been used quite extensively on guitars (now banned in CA for some years) as well as Poly. I use Deft semi-gloss (spray can) on some newer lower quality instruments that were originally finished with nitro with excellent results. Deft is cited in Hans Weisshaar's "Violin Restoration" as an acceptable crack filler, but I prefer to use traditional materials on real instruments. Sorry this doesn't help the original post, but I think there would be some European equivilant to try, or see if an American contact can ship some to you directly.
David Burgess Posted March 17, 2009 Report Posted March 17, 2009 I never found the product very useful. Seemed like it was slow to dry completely, and would shrink under retouching. It's interesting that it's mentioned in the Weisshaar book, because while we experimented with it a bit there, we never used it much. Any use was based on a fascination with all the recommendations. On that basis it would be tried, discarded as inferior, then eventually tried again when enough time had elapsed to forget why we quit using it.
Andres Sender Posted March 17, 2009 Report Posted March 17, 2009 classic. A similar process led me to end up with 3 tubes of a particular color of oil paint. I think it's lack of sleep, that must be it...
Brad Dorsey Posted March 17, 2009 Report Posted March 17, 2009 I never found the product very useful. Seemed like it was slow to dry completely, and would shrink under retouching.It's interesting that it's mentioned in the Weisshaar book, because while we experimented with it a bit there, we never used it much. Then what do you like for filling cracks?
Jeffrey Holmes Posted March 17, 2009 Report Posted March 17, 2009 Then what do you like for filling cracks? Not sure what David's using presently, but I use a very clear spirit varnish I make for the purpose )that reminds me... I need to make a new batch tomorrow...). I believe I've mentioned the resins used to make it in a past thread on crack repair or two. I know several other restorers who use similar fill varnishes.
GMM22 Posted March 17, 2009 Report Posted March 17, 2009 Can you elaborate at all on the technique of filling a crack? As competent as I like to think I am at the mechanical aspect of repairs, rendering cracks invisible (like you do when you take pictures and then break the violin for maximum simulation ) is a technique that eludes me. More precisely, it seems that when one is filling the crack, filler spills over from the crack onto the violin proper, and the brush stroke ends up wider than the crack. Do you let this spill over dry, and then level? Or, do you apply varnish with laser like precision, thus avoiding any spill over?
hrobert Posted March 17, 2009 Report Posted March 17, 2009 If you figure out how to do the "laser like precision" thing let us all know how you do it. Also, weird side note; If you apply Deft in a cold environment (35-40 degrees) the more volatile parts evaporate first and the less volatile later leaving a surface that's permanently somewhat soft. I guess we could approximate Stradivari's soft varnish that way.
GMM22 Posted March 17, 2009 Report Posted March 17, 2009 I’ve already figured out that I cannot do it, but for all I know some are imbued with superhuman crack filling precision, and if any man possesses this talent, it's elementary that it is our very own Holmes. But of course if he does eat kryptonite or some other magical substance to accomplish this marvel, I fear there may be no hope for the rest of us, unless he makes all privy to his source.
Jeffrey Holmes Posted March 17, 2009 Report Posted March 17, 2009 More precisely, it seems that when one is filling the crack, filler spills over from the crack onto the violin proper, and the brush stroke ends up wider than the crack. Do you let this spill over dry, and then level? Or, do you apply varnish with laser like precision, thus avoiding any spill over? I use a pretty tiny brush (or sometimes a bamboo point) if I'm dropping fill varnish into a crack area, but a laser I'm not... there's always a small bit of overlap. For me, the trick to keeping this to a minimum is to apply the varnish when it's just the right consistency... it's thick but still (barely) flows.
GMM22 Posted March 17, 2009 Report Posted March 17, 2009 But how does one deal with the overlay? Do you work the consistency such that the overlay is quite unobtrusive, or do you level somehow afterwards? It would be nice if a substance could be squeegied such that just the crack filler remains? Have you any thoughts on this kind of idea?
Magnus Nedregard Posted March 17, 2009 Author Report Posted March 17, 2009 GM, the best result is usually obtained if you fill the varnish crack just a little bit too generous and then work it flat, (or similar to the things around) afterwards, with things like scrapers and micromesh. You can apply a tiny bit of retouch varnish on each side of the area to fill, to protect the original varnish. My impression is that people like Deft because it is quite easy to scrape. But it darkens and has this rather porous appearance sometimes, some instruments i receive have Deft all over, and that is quite unsightly. I use a fill varnish composed of about 50% copal and 50% sandarak dissolved in spirit and left to thicken a bit. But it isn't that much thicker than my normal retou varnish, actually. I sometimes combine this with an extremely nice matting agent that Magister Varnish now sells. Highly recommended! Deft is handy if you want to fill bumps in edges, c-bouts and stuff, it is quite though when dry, and dries quickly too.
Jeffrey Holmes Posted March 17, 2009 Report Posted March 17, 2009 GM, the best result is usually obtained if you fill the varnish crack just a little bit too generous and then work it flat, (or similar to the things around) afterwards... Yes. What Magnus said. Fill shrinks slightly as it dries (the amount depends on the material and the depth of application), so laying it on so that it comes up even (within a reasonable amount of time) is difficult/impossible. Best to lay it on "proud", then gently cut the bead back once it's completely dry. This leaves a good surface for retouching.
Brad Dorsey Posted March 17, 2009 Report Posted March 17, 2009 gently cut the bead back once it's completely dry. On the matter of drying time, I have found that even after several weeks of drying my sandarac/copal crack filler cannot be cleanly scraped level with the surrounding varnish. The filler is not hard; it is still a bit soft and gummy. Rather than cutting cleanly, the scraper tends to act as it might if I were trying to scrape a soft pencil eraser, cutting nothing and then too much and sometimes pulling the filler out of the crack. Is this normal? If not, how should the filler behave so I can recognize when I've got it right? Should I be waiting longer for the filler to dry? Applying it in several thinner layers?
GMM22 Posted March 17, 2009 Report Posted March 17, 2009 Gentlemen, the particulars are appreciated. One last question Jeffrey, do you feather the bamboo tip in any way, or do you bring it to a point?
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