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Hello. I have a Martin J-40 and the heel cap has fallen off and gone missing. I have a replacement blank coming and need to fashion a new one. I am looking for some guidance on the process. When the guitar was being built, Martin glued the heel cap on the heel and sanded it down for a custom fit. I can't do that now. I have in mind to trace a template and then cut the material to size. Not sure what is best to cut the material and then how to get a super smooth finish. I would then spray the outside with lacquer and then glue it down. Those are my thoughts, but wanted to hear from others. Thanks! Doug

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Guitars...One's too many...Twenty is not enough.

I think you are on the right track with the way you are thinking about it. I would place the blank piece on it and firts make sure it mates to the sides perfectly then hold it in place and trace it on the heel itself. Cut that out as close as possible and then go back and forth test fitting and scraping/sanding till it's a darn near perfect as possible fit. Glue it in place with some medium CA and then VERY carefully make any adjustments.

I would first fit the blank to the bound body, trace around the heel, cut it reasonably close and glue it to the heel. Then using a file and holding it at a slight bevel angle, carefully file the heel cap to fit until there is only a "wire edge" remaining which can removed by scraping with a razor blade. Lightly sand and polish Then mask and finish the heel cap.
There are a number of ways it can be done so just pick one you are confident with doing.

Masking tape on the heel is your friend...

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Peter Havriluk

Yep, get it close, glue it on, thin masking tape right on the boundary with the wood.

Sand to the tape, easy to see when you are hitting it. Finish off with a razor blade scraper at a slight angle. Airbrush on some finish.

Based on my vast experience of maybe two

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Sometimes that's enough experience...

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Peter Havriluk

Hey Everyone,

I wanted to ask a few more questions. I shaped and cut the heel to near size and, wow, it wasn't easy. I had to deal with the arch of the binding and then the heel end against the binding is at an angle. So, I tiny hairline gap exists.......best I can do.

1) The heel blank is from Martin. I ordered it mentioning the guitar (J-40). As you can see, there is a significant color difference. Is there a way to match this? I don't recall the previous heel or binding being this white ever.....even when new. Maybe the lacquer has yellowed since 2003.

2) I am ready to glue the heel in place. Do you recommend CA or Epoxy?

3) What do you suggest I do to protect the sides while I file right up to them? I was thinking a layer or two of painters masking tape.

Thanks all!......not as easy as I had hoped!

Doug

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Guitars...One's too many...Twenty is not enough.

The tape around the heel as others have suggested will provide some protection to the finish while gluing and filing/sanding. Epoxy has some gap filling qualities and if you color it white it may fill that small gap you mentioned. CA will work also and may be quicker.
Adding a small amount of amber pigment to the finish may allow you to blend it in with the existing binding. (watercolor or coffee for waterbase, oil paint (small amount) or dye stain for solvent based. As with anything finish related - test on scrap!).

If the upper bout is curved you can trace that curve onto a piece of paper and transfer it to a convex wood sanding form. Put some adhesive sandpaper on it and sand the curve and angle onto the edge of the heel cap that fits against the body.

I do it that way on my new builds too. It’s a little harder but you can also put a narrow strip of adhesive sandpaper on the body mating area and sand against that.

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It's not what you don't know that hurts you, it's what you do know that's wrong.