Sealing Binding Mitres

[Pete Brown]

I'm working on my first F5, and have recently taken the plunge and applied the stain; I applied it by hand, with the assistance of a cheap air-brush to even out the "burst". Although I thought my binding mitres were tight, some of the stain found its way into the joints. A little scraping went a long way towards solving the problem, but wasn't 100% effective. Not surprisingly, I'm interested in avoiding this situation altogether when mandolin #2 takes shape.

Can the mitres somehow be sealed prior to staining? For instance, could acetone be used before the stain is applied, to "weld" the joints so that they're effectively seamless?

All suggestions gratefully considered!

[HogTime]

A Luthier's Tip from one of Roger Simonoff's recent monthly newsletters says to make a "slurry" of binding shavings and acetone to fill the gaps.

I'm just about ready to put on my binding and I'm sure I'll need a bit of the filler. :)

[amowry]

I brush on a little Tru-Oil (I learned that from Ward Elliot-- thanks Ward!) and in a lot of spots I fit a tiny triangle of tape for extra protection. No sense ruining a nice miter with dye.

[Pete Brown]

A Luthier's Tip from one of Roger Simonoff's recent monthly newsletters says to make a "slurry" of binding shavings and acetone to fill the gaps.

I'm just about ready to put on my binding and I'm sure I'll need a bit of the filler. :)
Ralph, do you use the filler at the same time you're gluing the bindings, or afterwards? I'm assuming the former as the gaps weren't really visible after gluing and would be difficult to fill. I used Weld-on #16 by the way.

[Michael Lewis]

Celluloid and ABS based bindings will work with the 'slurry', paste, goop, or whatever you wish to call it. Other plastics and wood are less likely to respond well to the acetone. Don't try to use celluloid butter on ABS or visa versa.

I make my "butter" a bit thick so it doesn't drip or run, place a small dab in the joint as it is being glued in place, and clean up the squeeze out when it is all dry. Make the miter fit well in the first place and you won't need much butter at all.

Something to keep in mind is that more thinner, acetone in this case, will make it more prone to bubbles forming in the joint. That is why I use it a bit thicker than many folks. If you have a dirty miter just saw the seam or carve it out and fill it with some of the butter. The smaller the hole is the less filler it will require and the less bubble porosity and shrinking you will encounter. Always wash your hands before dealing with this stuff, as dirt will be attracted to your miter like a magnet.

[Rolfe]

It can be a real bummer to have stain wick into an almost invisible crack in a joint. One possibility: stain the wood where the joint will be before adding the binding and then mask that area when staining. Another: use cyano on the joint area after binding and before scraping the binding down.

[sunburst]

I make my "mud" probably even thicker than Michael, more like a putty than a slurry or butter. I usually trowel a bit into the miters and squeeze it throughout the joint as I install the binding pieces. As Michael says, you can cut, dill, scrape away stained binding, bubbles or damage and pack the void with the ivoroid mud. You can even rebuild miters in multi-layered bindings where the lines don't quite line up with bits of plastic, mud and ingenuity.

Before staining, a brush of lacquer on the miters and other susceptible places will help seal out dyes. The dried lacquer can be scraped away after staining.

[Pete Brown]

Thanks everyone - some great tips to file away for next time.

There are so many other aspects of mando #1 which are less than perfect, so a little stain in the joints isn't the disaster it would have been had everything else been immaculate!

I've built enough guitars now to be producing pretty good results, but I'm still in awe of those of you who consistently produce first-class mandolins - particularly F models.

Thanks again.

[HogTime]

I'm glad this thread came up before I started my binding. :)