Gap filling.....

[Robin Harrison]

There is shrinkage between the outside veneer and the mahogany ( i think) action board.

    Everything is very solid but the veneer needs to be supported underneath.

       Just run some epoxy in the gap ? Can epoxy be diluted a little so it runs in rather than having to smear it in. Or inject it in from the bottom of the gap ?

Thanks

Robin

[Don Taylor]

What sort of epoxy do you have in mind?  Liquid epoxy can be thinned with acetone but I doubt you would want to do that as the stuff is very runny in the first place.  If it is epoxy paste then you could try thinning it with acetone, but experiment first.  

 

If you want a black epoxy then West Systems have a graphite filler that you can add to liguid epoxy:

https://www.westsystem.com/423-graphite-powder-2/

You would buy this at a marine store.  Wear a mask when handling this stuff, you do not want to breath it in.

 

There is black epoxy paste called Milliput Black that is touted for repairing antiques.  I have never tried it.

Edited February 13, 2019 by Don Taylor
Corrected my use of viscous to runny!

[Sprunghub]

I have used the Milliput on projects.  It is very easy to use - bi-coloured 'sausage' cut off a small length, incorporate outer and inner elements by working like Plasticene - for those who remember Plasticene - which most of us of the pre-Play-dough generation will.  

 

Works in well, cleans up well and goes off hard. 

 

For ultra strong fixes, including bridging, 'thick' Super-glue and Baking Powder is very good, but probably 'too' strong for a fix like that.  

[Wolf Molkentin]

Yes, Milliput worked a treat for me as well - however it's far from being fluid, so maybe you'll find a better solution here.

 

Best wishes - ?

[SteveS]

Fill with slivers of veneer gluing into place with hide glue (makes for a reversible joint).

Use a sharp knife to level the slivers of veneer.

I prefer not to use filler for this kind of repair.

[Don Taylor]

If you do use an epoxy paste like Milliput then you can get a nice finish to it by smoothing it over with a wet finger before it sets up.  Mix the paste wearing those thin gloves (nitrile or similar) both to protect your skin and to keep your fingers clean so that when you work it into the gap you don't make a mess with the residue stuck on your fingers.

 

Having said this about epoxy, I like Steve's proposal to use hide glue and slivers of veneer.

Edited February 13, 2019 by Don Taylor

[Robin Harrison]

Tx all for the suggestions.

Robin

[d.elliott]

Under these circumstances I have gone away from using any form of filler, epoxy or otherwise. on thin cracks I use fine card doused in PVA glue, shaped pack after curing, More usually I shape wood and again use PVA. Why PVA? you have lost wood volume through drying out and subsequent shrinkage over many decades. What we are doing is replanting that volume to make the instrument stronger and stable. we want, we need a good hard fix. I smooth off with a very sharp blade, I dont like using abrasives for fear of affecting air tightness