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I'm finishing up build #2 and have noticed a spot where the white plastic side binding abuts the white plastic end trim strip has a thin line of mahogony dust in it that is visible now. It scraped flat and invisible but the line appeared after I had done more sanding. How do you keep your joints invisible? Should I have dropped a bead of superglue over it or sealed it with shellac before doing any sanding?

What works for you?

Of course the best way to avoid this is to make a tight joint with no room for a dust line to appear. I have never used plastic so I don't know if there is an easy fix. Someone might be along to help you out.

The best I can offer is to blow the dust out and try to put some material in to close it. Maybe plastic glue, maybe superglue or finish might do it. Or even epoxy if that is your pore filler. Before I tried this I would experiment with some scrape pieces to see how they worked.

Another way, and probably the best if the gap is large, is to remove the end graft and fit another one that is tighter.

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Joe Beaver
Maker of Sawdust

I'm no expert, only done one binding job with plastic. But seems I recall that there is a chemical, either naptha or acetone (can't remember which right off) that dissolves the plastic used in the bindings. When I did mine, I read a suggestion to use some scrapings, add a few drops at a time of the chemical, and stir it into a slurry/paste, similar to what you would do with glue and sawdust. That can be used to fill the gap, and will supposedly also melt all together, making a seamless joint.

can't remember where I heard that, but it might be worth a try.

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Phil

http://www.oleninstruments.com

"Those who tilt at windmills are only considered insane by those who can't see the dragon."

Acetone would be the solvent to use to melt plastics together. A super glue fill would work but may still be slightly visible after finish. When I go over a guitar that comes in for finishing I generally use burn in fills for all these small gaps. It's quick, easy,and looks good under finish. If not caught during the prep they will generally get filled with the pore filler paste and look really bad. Again, if caught before sealing the pore fill a burn in will work great and be virtually impossible to find.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

Thanks for the replies everyone.

Brian, can your describe what you mean by "a burn in"? I'm not quite sure what you mean.

Finally, a question I can weigh in on! I always make my own glue for plastic binding by simply dissolving cut off pieces in acetone. It makes for a "seamless" joint, if you will, because the "glue" is essentially more binding. It's a messy job, but once scraped leaves a nice transition between wood and binding. I always save the final scraping process (done with a razor blade, btw) until right before it's time to spray to avoid any sawdust making it's way into the mix.

I usually glue the butt end joint of plastic binding together off the guitar, using solvent glue (Duco). Problem solved. Does anyone else do it this way? This leaves only one joint to worry about: the one on the back next to the heel. If you creep up to it by filing it down a little at a time, it's possible to get a tight compression fit. At that point solvent glue should give you a near invisible joint - if things are kept clean. Superglue sounds like a really bad idea to me, at least if invisible joints are desired.

It is done with a hot knife and burn in sticks. They are available from many sources. Some of these are Behlen's, some Mowhawk ( I think). They come in many colors including clear and amber. They can be mixed together on a pallet to achieve custom colors. They are a very fast and durable way to repair defects found during the finish process. It takes a bit of learning to get it down on how to apply them but they are very versatile. I even use them to fill in the fret slots on the edge of an unbound board when doing re-frets.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/