Help with center seam


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Hi All,

I am making a new violin. When I hold the top against a strong light, I can see a very faint clear stripe at the center seam. The seam is not open, but I am worried about it. It may have happened when I took the top off (another story.)

I tried heating it up with a heat gun, rubbing in some hot glue, and using those curved clamps that arch across the bouts. I thought it was tight when I clamped it, but now it looks like it did before.

I am thinking of trying either:

1. The heat gun again (or an alcohol lamp) and waiting until I see the glue bubble slightly, then using the arch clamps.

2. Heat plus thin glue or *very* hot water, plus clamping.

3. Something from one of you people who know a heck of a lot more than I do.

4. Last resort: make a new top or stop worrying about it.

Thanks for you help

Doug

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It could be the two top blocks were not matched enough when gluing them? I know nothing about heating and all that but it sounds like a risky business. Perhaps you could cleat the seam from the inside.

Let's hear more experienced opinions though.

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Doug,

Glue a small block on each side if the center seam gap near the middle of the gap on the under side of the plate and squeeze them together with a clamp until the gap closes.

Then wam the glue joint with a alcohol lamp or light bulb until the glue softens. Snug the clamps a little more and clean off any glue that comes out of the joint with a damp sponge and leave until dry.

If the edges of the gap don't line up perfectly flush, the sides of the blocks that that face each other can be tapered either towards each other or away from each other to eliminate a "curl" up or down, and the blocks can be gently tapped to raise one side od the plate or the other. Small brass hammer works great.

-----Barry

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When using pillars (the blocks Barry is referring to), the alignment of the crack to the arching can be easily controlled by using a wedge between the pair... no need to trim the pillar itself.

Try a search for wedges and pillars on this site... The technique has been covered before.

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