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Discussion Starter · #1 ·
I did some searching and did not really find any satisfying information on materials and process to fill holes (e.g. when relocating thumbrest, shifting a post, etc) on clarinets. I'm curious what folks do. On plastic clarinets, I have read that most folks just use ABS plumbing cements...makes some sense; I'm pretty sure these are NOT solvent cements like the PVC type. Would this work on hard rubber and/or wood clarinets?

The approaches that I have seen are:

PERMANENT FILLERS (i.e. these cannot be removed cleanly)
- Epoxy, low-viscosity, with or without a black filler (like the carbon black often used in fiberglass layups or the pigment that West Systems provides)
- Epoxy, putty-based, comes in black, but hard to get into small holes convincingly
- Hard wax, generally used with a hot knife and pressed in.
- Cyanoacrylate (super-glue, CA) with or without black filler or grenadilla wood dust. This is often used for crack fill, but I would not imagine that it is a good solution for filling, e.g. thumbrest screw holes

TEMPORARY FILLERS
- Soft wax (e.g. candle wax)
- Shoe paste/polish...I have found that black shoe polish is useful for restoring a uniform black sheen, and might fill shallow dings, but would guess it's unsuitable for deep holes

I would be interested if folks want to share what their material and process of choice is. I have used the black epoxy putty (APOXIE Sculpt brand) in the past with Meltonian brand black shoe polish, and it's satisfactory, but not spectacular.
 

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I'd give Sugru a try, Jeff. It works for me.
 

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Low viscosity superglue on its own is really only suitable for very narrow cracks, and it is ideal for them. But it is a very poor filler because it shrinks so much during curing.
With Grenadilla powder (and some skill/experience in use) it fills well, and finishes to cosmetically almost undetectable. The powder is the filler; the glue holds it together.

I find superglue gel frustrating as a filler because it gives the illusion of being cured when it is still soft beneath the surface. I far prefer to use blackened, slow setting (for a hard result that finishes better) epoxy.

Note that a soft, waxy filler is a serious contaminant if a strong filler is needed later.

Any filler that relies on evaporation to harden is rather a tedious approach, and will probably shrink considerably during the evaporation process.
(I am not familiar with ABS-specific glue. Epoxy works well on ABS.)
 

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Low viscosity superglue on its own is really only suitable for very narrow cracks, and it is ideal for them. But it is a very poor filler because it shrinks so much during curing.
With Grenadilla powder (and some skill/experience in use) it fills well, and finishes to cosmetically almost undetectable. The powder is the filler; the glue holds it together.
This is the standard in guitar repair. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

If you don't have grenadilla powder, visit your local guitar shop, get a scrap of ebony, and make your own.
 

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Discussion Starter · #5 ·
I did some experimentation with an old busted barrel that i had. Drilled a bunch of holes and played with superglue, epoxy, sawdust and carbon black. I found the carbon black mixed with a low-viscosity epoxy to make a very satisfying 'plug' that was easy to manipulate with good working time. I built it up a little above the surface and shaved it with a sharp carving chisel after about 45 minutes, which allowed me to level it with 600 grit wet-dry after full hardening overnite. The ratio of carbon black to epoxy was important...add as much as you can keeping it 'flowable'. Once it stops flowing, it is impossible to get into the hole, but too little and it appears translucent. For the record, the carbon black I used was "Jacquard Pearl Ex Powdered Pigments carbon black". I bought it from Amazon.
 

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If the viscosity of the epoxy is too high, then it can be coaxed into the hole with a heated wire (or small crochet hook). That lowers the viscosity.
 

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Epoxy with ground up ebony works well.

Not every hole is the same, you need to analyse the shape, grain orientation if it has some, colour, density, even plastic clarinets have fake grain, all these need to be considered when hiding a hole.

Steve
 
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