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Hello all,
I just purchased and watched the Robert O'brien finishing DVD and like it. I was wondering if you can alter the saw duct / shellac method he uses. I mean buy some system 2 silica, sprinkle it on the guitar via handy salt shaker like he has and then come in with the cotton ball loaded with a 1 lb cut of dewaxed shellac and fill. Another thought is to put some in the shellac and make a weak past and brush it on. Either way I would let dry for a day and sand level with 220. Any thoughts to this method?

Thanks for any info.

I wouldn't use a cotton ball if I were you. Sometimes the polishing process can get a bit sticky and you'll be picking pieces of cotton out of your finish for a long time.

Matthew,

In the DVd I show several ways and materials to use for pore filling. The shellac and sawdust one is one of my favorites because it is quick and easy and goes well under a high solids product. There certainly is more then one way to get the job done. I have even seen folks use ground coffee to fill the pores. Whatever method you decide to use, test on some scrap first.

Good luck.

Wow a post from the author himself! Thanks for the advice. The reason for the question is I thought that this way I do not have to preseal the lighter colored woods first because the silica is clear. To answer the above post of why not zpoxy or others.....just following the advice and experience of the DVD....he said it is his favorite method and it quick.

To add another question to this mix. Mr. O'biren, I see you used KTM9 as a the waterborn of use on the DVD. I was thinking of using the Target USL product because it claims full burn in. For a novice like me I like this very much because I do not have to worry about witness lines. Do you have a preference? Is the KTM a tougher prduct or just looks better in your eyes?

Great DVD and thanks for the follow ups!

Matthew,
You can search the archives here at the OLF and see posts about the Target product. It would also work just as well if not better than the KTM9. I olny demonstrated KTM9 in my DVD. Waterbourne products are "usually" water white products and need some color to warm them up. I therefore would use Zpoxy under it because of the amber color. You could also tint the mixture.
Sealing the lighter colored purfling lines takes no time at all. Just use a 50/50 mixture of lacquer or sanding sealer and apply it with a Q-tip. Then you can pore fill and then sand everything back. The purfling lines will clean up nicely.

I'm not familiar with the silica product you mentioned. The fumed silica/cabosil I use is very light and is dispersed into the air by the slightest breeze. If I am mixing very much of it into epoxy (for boats, not guitars) I wear a dust mask- it can be nasty stuff.
There is no way I would ever try to use it without mixing it into a liquid to get it under control. So your second idea (mixing with shellac) might be a better starting point for experiments.
BTW, not all the silica thickeners are actually transparent when mixed, so I would definitely do some tests before spreading on your instrument.
Cheers
John

Just like to second John's comments on breathing silica -- don't! My experience with it is also in boatbuilding and it is a great filler, but I don't think I'd dispense it in dry form with a salt shaker. I do use pumice and rottenstone in salt shakers.

_________________
Jim Howell
Charlotte, NC