Official Luthiers Forum!

Just ordered some Platina Dewaxed Shellac (very light colored) for the purpose of sealing the rosette channel and the adjacent wood prior to gluing in the rosette with black CA. My purpose for this is strictly to keep the black CA glue from penetrating the top wood and keep coloration caused by the shade of the shellac to a minimum ( I will be finishing the top with Tru-Oil instead of my usual waterbase lacquer and I will not be pore filling).

Here is the catch for me. The wood is Monkey Pod which has humongous pores. I am trying to figure out the best application method (brush on lightly or heavily/or any other method?) and thickness of the shellac (1lb cut?) because I wish to definitely get the shellac in the bottom of these deep pores (so any black CA does not remain in them), but at the same time I do not want an obvious color difference between the shellac left in the pores after sanding and the rest of the top which will all be covered with Tru-Oil and the shellac sanded off.

Whew! Sorry about run-on sentences.

How would you approach this?
Thanks,
Bill

_________________
Formerly know as Mandodiddle.

I recently ran into an issue you will want to avoid. The shellac will seal the wood and that will stop the ca from wicking into the wood. But the CA will happily fill the pore shellac or no shellac. With shellac you will have a sealed pore but not a full one so that there is nothing to stop the black CA from filling the pore. I was lucky I had enough wood to sand after the rosette installation. So yes the shellac stopped any wicking of the CA but it still left CA on the surface of the wood and in the pores that needed to be sanded off. So I guess my solution is that I thickness the plates after I have installed the rosette leaving wood to allow me to sand or scrape the surface clean.

_________________
http://www.Harvestmoonguitars.com

Try brushing a thin coat of clear epoxy instead of shellac.... Make sure you get that into the pores......

Yesterday I had to rout out a butt wedge when the black epoxy sucked up the pores about 1/8" in Hormigo rosewood... And that was after I precoated it with a light wipe of superglue.

The worst was on a pretty Lutz spruce soundboard.... I didn't precoat the spruce and that black epoxy sucked up 2 full inches into the long grain. It was a complete catastrophe and I ended up scrapping the whole top....

I routed out that rosette and reinstalled it into another soundboard - this time pre-coating it with some epoxy to pore fill the spruce. The black epoxy didn't soak up at all after that.

Thanks John and John.

Unfortunately I do not have enough top thickness to sand away any black filled pores, so that option is out.(mental note - start with thicker top)

I will play with the epoxy idea on a scrap piece of wood and see if I can get it to work for me.

Again, thanks guys.

Bill

_________________
Formerly know as Mandodiddle.

One idea might be to brush\wipe the thin coat of epoxy on the entire top with the idea that you will sand it back (just the epoxy not the wood) that way you will end up with an even look. Otherwise I would be afraid of the area that had epoxy in the pores would have a different look than the open pore wood.

_________________
http://www.Harvestmoonguitars.com

Wow, you folks are brave using black CA.
Why not seal everything with shellac, use some ebony dust to fill any small voids and the hit it with clear CA?
Seems less risky to me.

_________________
Jim Watts
http://jameswattsguitars.com

Yeah, if the pores are going to be open in the end, then you're going to have to keep the black from getting into them in the first place. But ebony dust will go in as well, and then the CA will find it. Maybe could blow it out with compressed air before applying the CA, while using a piece of reasonably stiff paper in the other hand to make a wall to protect the dust that you do want to keep.

To be frank with you.... There's no way I would use black super glue given my recent experiences....

Super glue wicks into wood about 50x better than Epoxy - which wicks into wood pretty darned well. And I have no desire to see an ugly black blotchy stain soaked all the way through my wood.

I like the idea of staying traditional here.... Because people have already had this problem and worked out the solution....... Try something like ebony dust mixed into some regular white glue. That way - if the glue wicks up - it's clear.

If you want a thin, crisp black line - use some ebony veneer purfling lines and then glue it with wood glue or clear superglue.

I had to re-glue a rosette into some LS redwood after routing a purfling channel too deep and essentially cutting a 5" soundhole. I used the plunge feature of my router base to set my depth to the depth of my shell, which turned out to be thicker than the top. . I used black CA from Stew Mac because the purfling was black and didn't have any issues with it bleeding or looking bad in any way.

That said, if you want to be very targeted with the shellac, just get a small watercolor brush and brush it into the channel you're gluing the rosette into.

Thanks for the help guys.

I am using Purflex, so that's the reason for the black CA. Otherwise, I would stay away from it as well.

_________________
Formerly know as Mandodiddle.