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| Lacquer help http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=21370 |
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| Author: | Joe Sabin [ Sat Mar 07, 2009 8:50 pm ] |
| Post subject: | Lacquer help |
Hi, I promise I won't ask again, but before I "El Ka Bong" this instrument and toss it into the trash, I thought I'd ask one more question. I used cans of lacquer spray (why, I don't know perhaps I'm an idiot, but still...) to finish this bouzouki. Anyway, it looks terrific, sands down, polishes up beautifully...then it gets a foggy look to it like a week later in spots and the finish has an orange peel surface like a rash across parts of the top. Only the top, the back and sides look fine. (spruce top, maple and mahogany body and neck) I know you all would like to see pictures, but I cannot get a picture of the issue. It's really subtle and only visable when you look at it at the right angle. The orange peel, on the other hand is exactly orange peel. Why? It dried for nearly four weeks prior to final wet sand and polish. Any ideas? BTW it sounds great, just looks like it has leprosy. |
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| Author: | DannyV [ Sun Mar 08, 2009 12:26 am ] |
| Post subject: | Re: Lacquer help |
Joe , Lacquer is about the most forgiving finish you can use. A week is a really long time for a reaction to appear. Sometimes you can get foggy patches with high humidity but they appear fairly quick. It's hard to say for sure but I would say the two most likely causes would be old lacquer or some contamination on the wood. I think I would be inclined to sand the top back to bare wood and try some fresh lacquer. Maybe someone else might have some other ideas? Good Luck, Danny |
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| Author: | Rod True [ Sun Mar 08, 2009 1:56 pm ] |
| Post subject: | Re: Lacquer help |
The orange peal is more likely to be fish eyes which is caused by some contamination of the surface. What did you do to the top prior to finishing? What type of sand paper did you use to sand? What did you rest it on while you were working on the back? I suspect that you have some contamination of the wood. If so, you'll have to sand back to the wood and give it a really good cleaning with naptha or mineral spirits. Make sure it's well dry, give it a fresh sand with 220, put a coat or two of shellac as a sealer, let that dry and than try the lacquer again. |
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| Author: | Joe Sabin [ Sun Mar 08, 2009 3:40 pm ] |
| Post subject: | Re: Lacquer help |
I took a loop to the surface of the lacquer, it is crazing of the surface. ??? Every area that has an odd look, actually is caused by a very fine crazing pattern on the surface. It's not fisheye, it's like the surface cracked because it was very wet and dried too much...kinda like mud when it dries from no rain. I'm pretty convinced it wasn't fully cured now because I removed the strings and moveable bridge and the bridge left a relatively significant indentation in the finish. Thanks for your input, I don't think I rushed the final sanding, but perhaps I did as my shop is a bit on the cool side in winter. Not cold, just 62-63 degrees F. I'll let it sit for another few weeks and give it another shot at final sand. If that doesn't work, I'll have to take more drastic steps. I used waterproof paper down to 1500. The top rested on a clean cotton towel while I sanded the front and back. Different towel and I made sure it was clean I dry before starting. I'm open to other suggestions or outright statements that I need to sand down and refinish. I hope not. I want to put this one to bed and move on. |
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| Author: | Mike_P [ Sun Mar 08, 2009 3:43 pm ] |
| Post subject: | Re: Lacquer help |
was the rattle can lacquer pre-catalyzed? did you use an air dry sealer? this will cause what you are seeing....as will the opposite (pre-cat sealer and air dry top coat).... |
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| Author: | Flori F. [ Sun Mar 08, 2009 4:10 pm ] |
| Post subject: | Re: Lacquer help |
What brand of lacquer? Stew-mac spray can? Or something else? |
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| Author: | Rvsgtr [ Sun Mar 08, 2009 8:26 pm ] |
| Post subject: | Re: Lacquer help |
A friend of mine was doing a peghead repair on an old Gibson electric and the same thing happened. He was using the Stewmac cans. I think it may have been a Behlen's product. |
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| Author: | Joe Sabin [ Sat Apr 04, 2009 8:05 pm ] |
| Post subject: | Re: Lacquer help |
I have let this sit for a month now and here's the result. Apparently I fouled the lacquer with linseed oil. I let the lacquer set for 3 weeks, so I was sure it was cured. Apparently not. So the linseed oil from the bridge, the fretboard and my fingers spoiled the finish. I discovered this because the worst of it was around the bridge. So I sanded it down and reapplied finish. All is OK now. What a mess. I'll never use lacquer again. I've been doing wood finishes for about 40 years and this lacquer finish is the most annoying ever. Man it's finicky stuff! |
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| Author: | Aaron O [ Sat Apr 04, 2009 8:57 pm ] |
| Post subject: | Re: Lacquer help |
If you think lacquer is finicky, you should try a cat finish. I've used both McFaddens Nitro and ML Campbell's line - much prefer McFaddens. I guess there's a reason why they say its made for instruments. McFaddens Polyurethane is more difficult to spray, but way easier than House of Kolor. I like both, except Nitro takes a WHOLE lot longer to cure. If you treat Nitro like any other finish, you'll be fine. Don't give up just yet (okay, give up the spray cans). Keep it clean, and with 40 years of finishing, you already know what's compatible, and what's not (pretty much Shellac as a sealer, or lacquer sealer). Personally, Nitro is its own best sealer, just spray a tack coat and go (for me, anyway). I'm not getting how the oil spoiled the finish, after it was cured. Then again, I don't use linseed, so I haven't experienced compatibility issues. |
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| Author: | bluescreek [ Sat Apr 04, 2009 9:06 pm ] |
| Post subject: | Re: Lacquer help |
lacquer is more than a finish , it is a process. The advantages of lacquer far outweigh the problems. The back door of lacquer makes it a great finish for guitars. As you just discovered , you can mess it up real easy if you don't pay attention to the details. Don't give up after only one . Once you master this process you will be more than happy john hall |
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| Author: | Joe Sabin [ Sun Apr 05, 2009 1:44 pm ] |
| Post subject: | Re: Lacquer help |
I think I just don't have the patience required to wait over a month to touch the finish. I'm good with two weeks give or take, but over a month! My shop is a bit cool, it's like 62, good humidity and solid temp, but for lacquer I think it's too cool. I'll stick with finishes I'm more familiar with and can cure well in my shop's conditions. I've got easily twice as long in the finish/strip/refinish as I do in the build. That's crazy...I'm a really good finisher too, this has just been one challenge after another. Anyway, my next instrument is an 8 string Uke, so it won't get lacquer either way. So I might change my mind after a success. idunno |
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