I like the idea of stripping (using 'eco' stripper)the wood, but I know that you can damage it also from stripping wood with a scraper.
I also want to add a sound port
. Then my $600.00 tacoma might be worth keeping...!!
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| Stripping poly from factory top? http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=19312 |
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| Author: | Frei [ Fri Oct 24, 2008 5:12 pm ] |
| Post subject: | Stripping poly from factory top? |
I would like to refinish my factory guitar tacoma with french polish, and soundhole. How do I strip off the poly top? Yes, I can sand it, but is there another way? |
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| Author: | Steve Saville [ Fri Oct 24, 2008 5:21 pm ] |
| Post subject: | Re: Stripping poly from factory top? |
Sanding is probably the best way. You could scrape. I would not try a chemical stripper. |
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| Author: | Jonas [ Fri Oct 24, 2008 5:37 pm ] |
| Post subject: | Re: Stripping poly from factory top? |
I stripped a Guild Classical front and back. It had Mahogany top, back and sides with a poly finish. I just used run of the mill generic paint stripper and a scraper and it came off perfectly. No marks or any complications. I used paint stripper cause i thought that sanding would remove too much mass from the soundboard but now I think it was just because it was easier. |
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| Author: | Jon L. Nixon [ Fri Oct 24, 2008 7:36 pm ] |
| Post subject: | Re: Stripping poly from factory top? |
I have read that a heat gun, properly used, can make the stuff come on in sheets. I have never tried this. Obviously you would have to procede very carefully..... |
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| Author: | Frei [ Sat Oct 25, 2008 12:05 am ] |
| Post subject: | Re: Stripping poly from factory top? |
I like the idea of stripping (using 'eco' stripper)the wood, but I know that you can damage it also from stripping wood with a scraper. I also want to add a sound port . Then my $600.00 tacoma might be worth keeping...!!
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| Author: | Mike OMelia [ Sat Oct 25, 2008 11:05 pm ] |
| Post subject: | Re: Stripping poly from factory top? |
I have a Taylor 810 that the previous owner abused. The top had bad surface issues near the fretboard and sound hole. So, against the advice of many, I resurfaced it with nitro. I sanded it down. It may take you a while (it did for me). But the result was worth it. That poly crap is really hard. Use 80 grit until you see real wood. Then graduate to finer grits. The binding makes a nice "stop" to the process. Heat guns could most definitely damage the binding material (as well as chemical strippers). Poly is cross linked, and for the most part, unaffected by solvents. Mike |
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| Author: | stan thomison [ Sun Oct 26, 2008 12:59 pm ] |
| Post subject: | Re: Stripping poly from factory top? |
One other thing on the heat gun, and I am not any expert here at all on this subject, but would think to have the finish come off in sheets or otherwise, thing would have to get really hot. That could cause compermise to the glue joins under the top, back or whatever stripping. I don't know how hot the heat gun gets or needs to to make the the poly to come off, but would be a concern. I guess the type of adhesive would be a factor if hhg, titebond or epoxy. Also if say doing it to strip nitro or cellouse material on binding and other things, the hot heat gun could make a new definition to the term flamed wood. |
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| Author: | Bob Garrish [ Sun Oct 26, 2008 1:59 pm ] |
| Post subject: | Re: Stripping poly from factory top? |
If they're using the McFadden UV polyester that Taylor uses, your best and possibly only bet is to manually remove the finish (ie: scrape or sand). The stuff bonds -really- well to the substrate, better than pretty much any other finish, and as mentioned above it's essentially impervious to most solvents. Why are you stripping the finish? If you're hoping for a non-psychoacoustic sound difference I think you'll be disappointed after all that work. There's maybe 3.5-4 grams of finish on the whole top right now, 6 if they laid it on really thick. |
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| Author: | Hesh [ Sun Oct 26, 2008 3:29 pm ] |
| Post subject: | Re: Stripping poly from factory top? |
PM Joe White - Joe has more experience with Poly than any of us. |
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| Author: | Mike OMelia [ Sun Oct 26, 2008 10:39 pm ] |
| Post subject: | Re: Stripping poly from factory top? |
In my case, there were a lot of cracks in the poly and crap was getting into those cracks and it just looked awful. I read about heat gun use to remove the poly, but I did not have the guts to do it. Prolly a good thing. It took me about 3 days, hour or so per day, to get the poly of the top using a small palm sander. If you are going the heat rout, perhaps get some of those scissor jacks to hold the cracing in place? Mike |
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| Author: | David Collins [ Sun Oct 26, 2008 10:48 pm ] |
| Post subject: | Re: Stripping poly from factory top? |
A heat gun is certainly easier than sanding and more effective than chemical strippers on these finishes, but a spruce top is probably not the place to learn. You do have to heat the finish to a near melting/bubbling point for it to come off cleanly, and it is really a dance of keeping the heat gun moving at the right temperature and speed right in front of the spatula at the right distance and pressure. When you get it, it works beautifully and comes off extremely cleanly. If you move a little too fast, push a little too hard, too steep, or too cold, it can be very easy to gouge in to the wood. Go too slow or too hot, and the finish can start to smoke and burn, come off less cleanly, and in extreme cases even scorch the wood. Once you learn the feel of it, it's really a piece of cake, but a spruce top may be a bit high risk to learn on. |
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| Author: | RaymundH [ Mon Oct 27, 2008 10:29 am ] |
| Post subject: | Re: Stripping poly from factory top? |
I stripped a 69 Yamaha top that had a crazy hard finish on it with an ROS and 60 grit. I tried a small spot first with industrial strength chemical remover and it just sat on the top of the finish like water...Tough stuff they were using in Japan in the 60's. They even sprayed the entire inside of the top. If you do sand, be careful that the top is not a laminate one as it will sand through in an instant. Ray |
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| Author: | Kevin Gallagher [ Mon Oct 27, 2008 11:07 am ] |
| Post subject: | Re: Stripping poly from factory top? |
You can forget about a heat gun taking the UV cured poly finish off of a Taylor...or any other guitar that it is on. With the temperature of the curing lights in the booth that Taylor uses being several hundred degrees, a heat gun will not affect the final finish without substrate damage. Heaven forbid it was cured with the 1100 degree hand held lights that some of us still use. You'll have to burn the guitar to separate it from the finish. Sanding is probably your best et for removal.....and starting at 150 pr 220 grit the thin the finish and then cleaning it up with the 220 grit. Regards, Kevin Gallagher/Omega Guitars |
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| Author: | David Collins [ Mon Oct 27, 2008 11:40 am ] |
| Post subject: | Re: Stripping poly from factory top? |
Of course it's not the heat that cures the UV finishes, but rather being catalyzed by UV exposure. And while the temperature of the bulb may be 1100 degrees, the finish and wood are not brought to high temperatures or made more heat resistant. A heat gun works fine for stripping those finishes (they soften around 85-90℃ in my experience, which can definitely damage binding if you're not careful), and can come off quite clean. Still, a spruce top is probably not the best place to learn. |
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| Author: | Kevin Gallagher [ Mon Oct 27, 2008 2:41 pm ] |
| Post subject: | Re: Stripping poly from factory top? |
David, The UV cured finish will prove to be much more heat resistant than most when trying to use a heat gun to remove them. I have some test panels here that I used during my R&D efforts as I made the switch to the finish years ago. I can light a wooden kitchen match, lay it on the UV cured finish and let it burn all the way down and then wipe the area to see no damage from the heat or flame, but slow down too much when using the handheld curing fixture and you can turn the substrate black while not harming the finish over it at all. it's not the heat that does the cure, of coarse, hence the designation "UV cured", but the finish is more durable under heat exposure than most. It will take more heat to remove a UV cured finish with a heat gun than the top and glue joints between it and the bracing will take. The wood and finish do get pretty hot during the cure cycle, and that's in every shop using this finish whether they're using a booth or the handheld units. It would impossible to expose anything to the high surface temp of the bulb and in the close proximity needed to get a full cure without it getting pretty warm. The key is to keep the light moving at a rate that keeps the temp from reaching a dangerous level. It takes some time to develop the proper technique to get full exposure on every area of the surface of an object shaped like a guitar. Twenty seconds of exposure to the right bandwidth or UV output equals a full cure with any other finishes and that would be 45 days or so with nitrocellulose lacquer. It's cool technology and has found a nice place in the guitar building industry. Sanding will be the best bet since the use of a chem stripper will make sanding necessary in the long run anyway. That's what I would still advise as the best coarse of action to remove it from a factory finished top. Believe me, I've sprayed hundreds of guitars with the UV cured poly and did loads of tests with it to be sure of what can happen in any possible scenario during and after the finish process. Regards, Kevin Gallagher/Omega Guitars |
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| Author: | Mike OMelia [ Mon Oct 27, 2008 9:32 pm ] |
| Post subject: | Re: Stripping poly from factory top? |
Kevin, What kind of investment do have in UV finishing equipment? Is this process a bit out of reach for the typical small shop builder? Mike |
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| Author: | Bob Garrish [ Mon Oct 27, 2008 11:30 pm ] |
| Post subject: | Re: Stripping poly from factory top? |
Depends on what you consider a small shop builder to be. If you're talking an amateur, then probably. For a pro, I wouldn't say so. You're looking at a couple thousand for the gear when all's said and done, on the low end. The stuff'll kick in sunlight if you leave it out long enough... Mike Collins (the Selmer book/video Mike Collins) got a lamp and UV setup recently, he can put exact numbers to it. |
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| Author: | Kevin Gallagher [ Mon Oct 27, 2008 11:52 pm ] |
| Post subject: | Re: Stripping poly from factory top? |
Thanks for jumping in Bob. That's about right that the gear will run you a couple thousand dollars. You must wear the protective clothing, gloves and mask, though when using this stuff. The bandwidth and output of the lights involved put out many times what the sun does on a bright sunny summer day. Although it's true the the UV cured finish will kick in sunlight, it will take a good month or so to do so....and then you may never get a full cure. After that first month, you'll have to flip around for the other side to bask in the bright sunlight to be cured and then flip itup for the butt end to get it and...well... it really just would never happen the way you need it to, not to mention you'd have a beautiful insect collection in the finish to show off to your friends. If you watch the vendors sites, you can find a used light system for around $1500.00 if you catch it before it gets snapped up. If you're building a half dozen or so guitar a year, this is not the finish for you, but the same material is available from McFadden in a two part catalyzed system that cures chemically and is ready to go the very next day. It's hard and durable so it can be built up and finished in extremely low thicknesses. I've spent time talking to every other builder who's using the UV stuff...from the small shops to the largest and have even consulted one of the bog guys as they were testing it as a consideration for a change from their current finish. We share things that we've all discovered to work well...or to not work so well in an effort to broaden our R&D base as the finish has been able to dig in and become a lasting element in the guitar industry when it comes to finish alternatives. It can be quirky and stubborn at times....and that's in every shop...no matter how much time and money has been invested in the gear to make it work. Regards, Kevin Gallagher/Omega Guitars |
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| Author: | Mike OMelia [ Tue Oct 28, 2008 10:12 am ] |
| Post subject: | Re: Stripping poly from factory top? |
With the two part system, what percentage volitiles are present? Taylor went to this stuff because it dramatically reduced volitile emissions. Also cause it was hard, durable, and fast (with UV). So, do the 2 part (non UV) finishes emit more than the UV finishes? Mike |
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