Finish question for Red OaK

Don't

Mark Mandell - Gone Round in New Jersey

Shellac with 3lb cut for an inch or 2 on each side of the crack, then apply some paste wax, then fill your crack. Any extraneous epoxy outside of the crack with be easy to remove.

If you want a durable smooth finish, use bar top epoxy after giving ity a coat of dewaxed shellac.

mark beat me to it

David Weaver

dewaxed shellac - a little sprayed on or wiped on.

Re: Finish question for Red OaK

Bill Tindall, E.Tn.

It seems the others didn't understand your question. The material needed is called grain or pore filler, available in water based or oil based formulations. It takes some experience to use it to yield a smooth surface.

Re: Finish question for Red OaK

Bill Tindall, E.Tn.

If the oak dries after filling the shrinkage will squeeze the filler out of the pores yielding an interesting surface appearance.

Re: Finish question for Red OaK

Mark Hennebury

Adventures in wood finishing by George Frank I seem to recall had a good bit of info on the subject, way back in the dark ages when I experimented with it.

Re: Finish question for Red OaK

William Duffield

I used to get good results with the oil based Por-O-Pac. It is basically ground silica (quartz) in a BLO binder and either with or without a powdered pigment. For black pores, you can use vegetable black, but for oak, I usually like a dark brown, e.g., burnt umber and VDB. I would add some mineral spirits (odorless) to thin it and carry it into the pores better, and apply it vigorously across the grain with the worst "beater" brush in the shop. When it starts to glaze over, rub it off, again vigorously across the grain, with the coarsest burlap or jute I could find. If you don't get it all off before it defeats the burlap, just reapply and rub off some more. If you work with the grain, you will just pull it out of the pores, and have to do it again.

Re: Finish question for Red OaK

TomD

Apparently a lot of guitar guys use drywall compound it goes transparent when the finish is applied. I have never had the courage to try that.

https://www.youtube.com/watch?v=Zhk6rZ2UI1Y

I Understood Quite Well

Mark Mandell - Gone Round in New Jersey

That my method may differ from yours does not make one better than the other. Personally, I don't care much for the grain fillers I've tried over the years. As always YMMV.

Re: I Understood Quite Well

Bill Tindall, E.Tn.

as I read your reply you seem to be advising what to do before the epoxy. This is Barry, he has already created the problem and now needs to know how to deal with it, not prevent it.

Re: I Understood Quite Well

William Duffield

He has lots more of those oak slabs. I suspect he would also like to know what to do next time, to avoid the problems he had this time.

You are all correct....

Barry Irby

I did create this problem by not anticipating the difference between red and white oak and the way it reacts to the black epoxy.

My brain is running wild like the squirrel you are about to run over in the road.

I actually considered the Shellac Mark suggested, but only after the problem presented itself.

I thought about using sheetrock compound. Oddly, I made some shelves for my son's bookcase. Movers lost them. Maybe some of Ikea's best. Tried to fill the pores with blackened sheetrock compound and painted them dark coffee brown. Smeared it on, let it dry and sanded it off. Pretty good job, but it's still obvious it's red oak under the paint. This was about a week ago.

And yes, I have lot's more of these slabs and need to figure out a good finishing schedule. I had the slab flattened on a CNC with a five inch head on it. The head went back and forth length wise stepping over 2 1/2". It looked like somebody had mowed the grass. Fibers leaning left on one pass and right on the next one. Very smooth to the touch but very visible.

The smart move would be to find someone with a four foot wide sander and send then through on that. At least everything would be leaning the same way.

On this one, I will sand and then then sand, and sand some more.

And it may have been smart to practice on some scrap. Come to think of it, I am. This was one of the worst slabs in the bunch.

Re: Finish question for Red OaK

David Weaver

I may have misread it - I assumed he was asking how to keep the pore filler from soaking in.

Interestingly, Tom's video from Obrien guitars - the guy talks about sealing the guitar with a thin coat of shellac before applying pore filler.

Two ways I've filled grain...

John in NM

A can of Pore-O-Pac I got at Woodcraft years ago. Worked pretty good but as Bill says there is a learning curve. Basically what I did was work the stuff around the top using one of those Bondo spatulas you get at the auto parts store. Worked ok but I think it needed two applications with some drying in between - doing one I had the filler tend to pluck out as I passed over it with the spatula. I think I did that then sanded and that worked well. Second application might have reduced the need to sand, I don't know.

Next time I did one it was a gunstock, and it was going to be a pain to apply the goop and push it around with a spatula. So I bought some of that pumic for rubbing out a finish and used some gelled up Waterlox as the rubbing oil. That worked well but it did take a long time. If you're patient that one is very easy.

The second method might look better on oak, more subtle in color perhaps. But then if you are trying to match to black epoxy you should use a dark filler, naturally.

I've seen other...

David Weaver

..things on really high end guitars that I'd never have guessed, but it's interesting that the low end of the market (Trending to beginners) is filled with enormously expensive specialty things (like multi-hundred dollar repair kits of tinted CA and marketing efforts to get people to use CA to fill pores, etc).

And, the higher end of the market seems to be builders using inexpensive fast drying pore fillers (like in the video you linked) and the difference in the look of the finish is going to be down to the skill and eye of the person doing the work.

Not sure what commercial makers use to fill mahogany, but I'll bet it doesn't cost much, take long to dry or require much fiddling.

The videos demonstrating pore filling and finishing entire guitars with CA just make my eyes burn.

Re: Finish question for Red OaK

Larry Clinton At Frankfort, (Central) Indiana

Been several years but I had a small table (I believe it was white oak) in a custom van that had several stains, scratches etc. I sanded it and found it had a lot of open pores! Robert Dresdner had recommended a water based filler from an outfit based in California.

The filler was basically transparent and after drying took stain well. As I remember I applied 2 or 3 coats until all pores were filled. I then stained the oak to match the other trim in the van and sprayed a couple of coats of Minwax poly, rubbing it out between and after the last coat.

After waxing it looked good as long as I owned the van.

I

Re: Obsession

William Duffield

I built a solid body mahogany guitar for a guy who had an obsession with a very bright sound. He took it to a guy who filled the pores with spray lacquer, many, many coats, and very fine sanded between coats. The lacquer was the first, last and only finish. (I didn't include the wood bleach and dye in the finish process.)

Re: And the mos timportant thing...

TomD

Another way to fill guitar pores that was the ticket on very high end custom hand finish jobs, started with using 5 minute epoxy and a razor blade or a credit card. You mix several batches in a row, and just squeegee it on. You don't want anything left above the level of the grain, this is not an epoxy float finish. It works well on acoustics, as they have flat surfaces, or minimal compound curves at least. I would not try it one a swoopy electric body with large roundovers.

Funny story. There were some folks who were famous for their ability at French polishing guitars, and they did seminars, wrote articles, etc... After years of reading about them it turns out they used the above technique prior to French polishing. Not really much to it when you start with a surface like glass...

-------------------

The very important thing is to test whatever you do on a sample. In some cases you can finish your actual wood over some test area, then just run it through the planer to your final dimension. With guitars there are always waste areas in the waist of the guitar that can be used for test swatches. They have other uses, but it beats blowing a whole guitar.

shellac or lacquer...

David Weaver

.. french polish is sort of that, but with the bias that you can keep doing it, wait for pore shrink over a month or two and then do it again (real french polish).

A very labor intensive way to do things other than french polish (which is pleasant and relatively quick if you don't work too thin).

I could see some guitar fanatics trying something like that to keep the finish as thin as possible and at the same time, all of it as hard as possible (gibson uses a vinyl sealer and then a plasticized lacquer, but they're not exactly high end work. Not sure what collings does - collings is pretty much the top end of production guitars and their finish is still lacquer, but thinner and much neater. The danger of putting a preferred thin finish on a guitar is that over the years, the lacquer will still shrink to grain or wood movement will result in a little bit of telegraphing, but I don't like thick entombment just to be able to pay a lower skilled buffer and avoid shrink over time. )

Nitro is sort of a no-no here as the shop is attached to the house. Any time I've sprayed in the winter at the door edge and then hung a guitar outside, the lacquer has cracked, and bugs are a problem in the summer.

Re: Finish question for Red OaK

Hank Knight

Larry, do you remember the name of the water based filler from the California outfit? Every water based filler I've used dried fast and you had to hurry to get it applied and worked in. How easy is this one to work?

Re: Finish question for Red OaK

Larry Clinton At Frankfort, (Central) Indiana

Sorry, memory fails - this was over 15 years ago! As I remember the filler didn't dry real fast - but this was a small 16~18" table so didn't take long to fill. Maybe Mr Dresdner will reply. To me he is by far the best finisher expert around!