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| Fibers pull out of top easily http://luthiersforum.com/forum/viewtopic.php?f=10101&t=45219 |
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| Author: | Imbler [ Mon Feb 23, 2015 10:12 am ] |
| Post subject: | Fibers pull out of top easily |
I've just completed finish sanding my latest, and have a concern about the top. It is italian spruce and the fibers pull out extremely easily with masking tape. I had lightly masked off next to the fingerboard (not really pressing the tape in well), and suffered a number of fibers pulling out when I removed the tape. I was able to sand out the remains, but it was close. I experimented with some leftover soundboard cutoffs, and it is scary how easily tape will pull out fibers. I think when I mask for the bridge, I'll have to "de-sticky" the tape some by pressing it on my jeans before using it on the soundboard. I'm guessing this is due to runout? Both sides of the soundboard do it, but one side is noticeably worse. Do I need to worry about the bridge staying glued on, or does glue tend to help stabilize the fibers? BTW, when I taped the bindings on with packing tape, the top had shellac on it, and I had zero problems removing the tape, thanks, Mike |
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| Author: | johnparchem [ Mon Feb 23, 2015 10:32 am ] |
| Post subject: | Re: Fibers pull out of top easily |
I look at the problem of tape pulling fibers off a top as a pretty normal but avoidable issue. If I put tape down on a top I will warm it with a heat gun before I pull it up. Also when I can I leave a wash coat of shellac on the top, I have had tops that it was easy for tape to pull fibers, put the I have never had any issue gluing down the bridge on those tops. |
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| Author: | Michaeldc [ Mon Feb 23, 2015 10:38 am ] |
| Post subject: | Re: Fibers pull out of top easily |
Tape choice is also a factor. Frog makes a tape for delicate surfaces that works well for masking the bridge and fretboard extension area prior to finishing. |
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| Author: | Glen H [ Mon Feb 23, 2015 10:44 am ] |
| Post subject: | Re: Fibers pull out of top easily |
Always apply a coat of shellac or lacquer on the top prior to applying any tape. |
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| Author: | Michael.N. [ Mon Feb 23, 2015 11:00 am ] |
| Post subject: | Re: Fibers pull out of top easily |
Yes, Shellac the Top. It saves it from getting grubby as well. If you can read the soundboard runout there's a correct direction in which to pull the tape. |
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| Author: | kencierp [ Mon Feb 23, 2015 12:20 pm ] |
| Post subject: | Re: Fibers pull out of top easily |
Warm with hair dryer -- gently peel off - done -- has always worked for me. |
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| Author: | DennisK [ Mon Feb 23, 2015 3:04 pm ] |
| Post subject: | Re: Fibers pull out of top easily |
The glue should stabilize it. If you're worried, you could use a slightly larger bridge footprint than usual. Your idea of de-stickying the tape before applying is a good one. Also the various mentions of heating before peeling it off. You can also wick a drop of alcohol under the tape as you peel it to release the adhesive, but that wouldn't be a good idea if the finish is alcohol soluble shellac. Or you can just finish the whole top without masking the bridge, and then score around the bridge and chisel/scrape or route through the finish. |
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| Author: | John Arnold [ Mon Feb 23, 2015 4:17 pm ] |
| Post subject: | Re: Fibers pull out of top easily |
When you pull off the tape, pull it across the grain. If you are sure of the runout direction, you can pull it in the 'non grabbing' grain direction. But cross-grain works best for me. |
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| Author: | dnf777 [ Mon Feb 23, 2015 4:55 pm ] |
| Post subject: | Re: Fibers pull out of top easily |
In addition to a shellac washcoat (I keep a can of Zinnser spray for this) when pulling the tape, pull perpindicular to the grain, and keep a very LOW angle. I pull the tape back over itself, rather than up an away from the surface, and it seems to work well. |
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| Author: | phavriluk [ Tue Feb 24, 2015 6:18 pm ] |
| Post subject: | Re: Fibers pull out of top easily |
pulling tape back over itself - - slowly - - is very helpful, mentioned above. So is using low-tack tapes. 3M sells a 'blue' tape meant for delicate surfaces, and a bit of heat and patience should be good additions to the technique. Pulling straight up is a prescription for pulling away fibers. It's a good idea to remove tape as soon as it's not needed, and apply it just before it is needed, the least time stuck on the surface. |
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| Author: | Bob Shanklin [ Wed Feb 25, 2015 9:37 pm ] |
| Post subject: | Re: Fibers pull out of top easily |
+1 kencierp Bob |
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