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Howard, I have used the Devcon and the West System epoxies and the Devcon is much faster setting. It's also thicker which can be good and bad. I've had good results with both.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

I'm old school. I've tried CA, epoxy, plaster of Paris, sheetrock mud, and every kind of commercial pore-fill I could get my hands on. What works for me is: pumice, shellac, a little oil. It's taken me years to make it work, but when you get it working, it really works. I wish I could communicate the process, but my sense is that too much of what's required is a feel in the hand--a feel that responds to changing conditions. Yes Indian rosewood is difficult. Brazilian can be much worse. If you have the patience, keep at it. Just pumice, shellac, and towards the end, a little oil.

I wish you would try to explain. How does this work? What does the pumice do? Is this about filling the pores with very fine wood dust?

Mike

Mike,
Go here: http://www.milburnguitars.com/fpbannerframes.html and you will find out how pumice works. I've been thinking of giving this a try myself but I can't find a local source for pumice and I don't have the patience to wait two to three weeks on the guitar I am building. Lee Valley used to carry it but no longer. I also know that this is how the DeJonge family pore fills their guitars and they offer a one day course on French polishing that I am considering taking.
Pat

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There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

The Milburn tutorial is very much worth studying. My process is a little different. I think every French polisher finds the techniques that work for him. The pumice is the pore-fill. It gets stuck together by a very small amount of shellac. Some wood dust usually gets mixed in because the pumice is very abrasive, but the pumice itself will fill pores, voids in the rosette, gaps in the binding seam, etc. The most common problems are:#1 you wash the pumice back out of the pores as fast as you put it in.(Each pass of the pad requires a short--30 second?--drying time, before you go back over it.) #2 Trapping dry pumice, or sanding dust in a pore resulting in very pale pores. (Each pass of the pad must thoroughly wet any pumice or sanding dust.) #3 Trapping air in the pores. This can be a nightmare. What looks initially like a perfect pore-fill later becomes an eruption of tiny bubbles. The only cure is sanding back to bare wood. (Trapping air is a result of too much shellac, and trying to fill the pores too rapidly. Filling pores with pumice works gradually. Again, your hand has to acquire the necessary feel. or touch.) Good luck.

Bob Milburn switched to epoxy several years ago.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Pumice was the original sand paper. It is hard to find except at some Finish specialties shops. It comes in basically 4 grades from F the coarsest to FFFF the finest. You will want to use FFFF. If you intend to use Pumice as a pore filler be aware it is the same amount of work as Robbie's shellac and dust method, maybe a bit tougher because if not properly cleared it can make a gunky mess.

In French polishing the pumice is used as both an abrasive to tear microfibers of the wood loose then deposit then along with cleared pumice and shellac as the binder into the pores. this takes a fair amount of rubbing to do. I have never tried trapping method but what I know of pumice it sounds like it would be troublesome plus you could very easily end up with tinny white spots all over the surface.

If it works to mash filler in, how about using a glue roller, like the ones used for contact cement?

Pat buddy I am happy to walk you through the process and I am sure that you will see that this is pretty simple.

If you are interested PM me and we can exchange phone numbers and a time that works for you and I to fill some stinkin pores....

Thanks

Thanks very much for the offer Hesh but I think I got it as of last night. As they say, "sixth time's a charm". Actually, I think I've had an "Ah Ha!" moment myself and I should acknowledge Todd Stock's youtube videos. What I noticed was how much attention Todd was paying to get rid of any epoxy ridge lines with the result being that he was doing a lot less sanding than me. Then I found that I could get the surface smoother if I kept going over it with my credit card, i.e. not really moving the epoxy around near the end but getting it smoother. So last night I did much less sanding before my last application and this morning when I checked, there no longer seems to be any open pores

Thanks all for your help. This is a great place.

Pat

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There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

Wiping off what's left on the squeegee every stroke or two looks like an important part of the process, too. In the later stages on the video.

I've never finished a raw guitar but I have worked with composites, and specifically epoxies for 15 years. So....take this for what it's worth.

There are two additives conventionally used to control such issues when epoxies must procduce a fine surface finish on molded parts: dilulents and surfactants.

1. Dilulents are used to reduce viscocity and alter rheology (the physical properties throughout the cross-link and cure cycle) and can usually be used with off the shelf epoxies in ratios up to about 10% without a large dropoff of mechanical properties and significantly reduce viscosity. Since these epoxies being discussed are not being used for structural applications it may be possible to use much higher ratios in order to seriously thin an epoxy but I wouldn't presume to suggest any course of action without testing it. Thinner epoxy may fill pores better but.....

2. Surfactants are used to reduce surface tension and are mixed at very small ratios. Typically, when using epoxies for molding, a combination of dilulent and surfactant is used to create bubble free surfaces in a specific process. The dilulent serves to reduce viscosity which allows small bubbles to more easily travel through a thin mass of epoxy. The surfactant helps the small bubble to pop once it reaches a surface.

I suspect using a surfactant would play a larger role in preventing the filling of pores in wood than attempting to thin the resin with dilulent.

When developing molding processes, I would typically experiment with both additives until the process functioned, then I'd submit the results to my formulator who would then file the recipe from which they would create the commercial product to sell back to me. This is a long way of saying that these compounds were originally supplied by them for my purposes and might be a little hard to come by. Nevertheless, one may find them on the internet with some effort. Google it and expect to experiment.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic