What is best for filling small gaps between rosewood binding and a spruce top? Dan Erlewine's book on finishing says "acrylic wood dough". I can't find brand name for this. What is it? These are very small gaps on a new guitar that want to fill before scraping, sanding and finishing. I've read that super glue can discolor spruce. The top has several coats of shellac.
Thank you both for your help. Since I'll be finishing it with nitro lacquer and since the gaps are very small, what about filling it with nitro lacquer, or wiil that sink when the final finish is applied?
I've had very good luck doing the following.
Let's say we have a slight gap where the binding meets the side wood. Smear some Titebond original in the gap and then with 120 sandpaper sand in the direction that the gap runs and ONLY in the direction that the gap runs. This tends to take wood dust from the two respective types of wood and stick it in the Titebond and since we are keeping the direction the very same as the gap runs the two dissimilar woods tend to not mix and instead embed themselves in the glue closest to where the sanding dust was created. This preserves the sharp contrast instead of blending two wood and only take 30 seconds to do. Deeper gaps may require doing it twice.
Mind you this is for very slight gaps only and I've never experienced any issues doing it this way including after finishing, I can never find the gap again.
Never had any luck at all with fillers so I prefer real wood for a large gap and real wood dust for fine gaps and of course this need not be said but I'll say it anyway, building gapless is the best choice of all.
Before filling the gap, see if you can close the gap by heating that section of binding to soften the glue (assuming that you used something like Titebond or HHG to glue the bindings on) and then pull it in with tape. If that doesn't get it done, then I find that wood dust is the best filler. I usually use dust from the binding wood - but the trick Hesh just described sounds like it could be a good way to go. "Build gapless" - is a nice aspiration but I haven't achieved it in the six instruments I have made so far.
Hi ya Mark!
A couple of things that really helped me get gapless with binding are as follows:
1) Early on my bindings were tall and thick, likely near 1/4" tall and .090" thick. In time I started to like the look of both shorter and thinner bindings so I went closer to .060" thick and shorter and discovered that they were way easier to snug up in the channels.
2) Relieving the inner edge of the bindings (a couple of scrapes) that has to mate will with the channel inner edge AND doing a quick clean-up of the channel's inner corner helped things seat better.
3) I use a Williams binding jig and the thing works great at keeping my channels square and uniform.
4) Prebending the bindings in a Fox bender and trial fitting dry making sure that with minimal clampage the bindings seat well.
When I started doing all of the above things got gapless.
Hope this helps.