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Anybody use CA as their primary pore filler?

Mike

Hi:
I've been experimenting with CA as a pore filler, it works great! Very fast and smooth with just one coat. However, it doesn't make the grain "pop" like zpoxy, so I will stay with the epoxy based filler. The finished grain and colors are more important to me than the time saved....... Mikey

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The Biggest Little City, Nevada
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In the "unstressed" areas, zpoxy works great. But where the wood is bent (rosewood), I just seem to be having a difficult time getting the pores to "stay" filled.

Mike

Yes, I use CA as pore filler.

Get the thickest CA you can, use a razor blade with rounded corners as the spreader. Works great on EIR.

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I use CA for pore filler. Usually medium viscosity but it depends on the size of the pores. I seal with shellac first. (zinsser seal coat). Getting the right viscosity for the size pores really makes it easy. If it's thicker than needed you have to pack it into the pores like Rod but if it's too thin it takes a bunch of coats. With a little experimenting you can find a viscosity that you can just wipe a couple coats with a paper towel.

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I didn't mean to say it, but I meant what I said.
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OK. But I do not understand why z-poxy would do anything to cause the grain to "pop". Ultimately, if done right, the only residue of either will be what is left in the pores. Anybody else got reference points here?

My biggest complaint with epoxy is the long cure time. And mostly, it is difficult to sand back. With CA, it cures in minutes. Ready to sand in less than an hour, and sands back easier.

Mike

Exactly

I always put on a couple of seal coats of shellac after the CA pore filler too. This pops the figure and grain just fine for me.

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Someone had posted (I think it was Al Caruth) that the refractive index of the surface coat plays an important role in making the grain 'pop'.

You are correct, Sir.

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Unless I'm understanding this wrong then the filler should have little to do with this. Especially is the filler is sanded until it's only left in the pores.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

wouldn't shallac be the surface coat in both of these cases then? sorry for the obvious question, im not experienced at finishing.

and surely the role it plays in making grain "pop" would depend on what you put on top of it.

on an additional note of making grain "pop" (sorry for the slight hijack), is this why in the Alex Willis book he stains the guitar with a 50/50 mix of linseed oil and turps? the picture seems to to show the grain has popped, so could this just not be used and then grain fill?

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"Anything that happens, happens. Anything that in happening causes something else to happen, causes something else to happen. Anything that in happening happens again, happens again. Though not necessarily in that order." Douglas Adams

My point exactly. Unless one leaves a thin layer of epoxy, I cannot see how it effects the look. It must also be related to the "open" pore area to non-pore area. The more pores, the more impact. But I don't think typical body woods fall into a range where there are so many pores that the remaining "in-pore" filler (after sanding back to wood) will have a noticable surface effect.

I do remember some folks saying that they do not sand back to wood with epoxy. Thus, that is their sealer coat. I am using shellac (before and after pore fill).

Is there a retarder available for CA?

Mike

Lots of the guys who use Zpoxy put a final thinned 50/50 mix with alcohol on, after sanding back, to pop the grain. The finish is applied over that.

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Waddy

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In my experience, the amount that the first coat that goes on penetrates into the wood has a big effect on how much the grain pops, or rather, how deep it appears. WEST systems epoxy will penetrate a little and does a great job at popping the grain. An oil finish is usually seen as the "best" because since it is penetrative you can sand to a higher grit before applying which makes the effect even more pronounced. I could be mistaken and someone please correct me if I am but I have found these things to be accurate.

Hypothetically it should be possible to sand as high as you feel comfortable, apply a base coat of some sort of oil finish, rough it up slightly, and then CA (or whatever) fill over it. With a penetrative base coat, however, damping becomes an issue.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

Take this with a grain of salt since I have little guitar experience.......but I don't think the finish that penetrates into the wood has any affect on the appearance......you can't see it. I've listened to in-the-wood vs on-the-wood finish dabates and just can't see how finish in-the-wood contributes to anything. I think Al had a good explanation that a refraction index that is close to that of wood gives makes the wood figure stand out nicely (my words, not his). I would guess oil finishes look nice because the refaction index is where you want it......not because it penetates into the wood.

As a side discussion, why would you want finish on a music instrument to penetrate into the wood? It makes the wood heavier (finish on the surface plus what's absorbed inside the surface), affects the density, etc. As long as there is an alternative finish that adheres to the wood well and provides protection seems it would be better. Isn't the point of sealing the guitar with shellac to not allow penetration of the finish into the wood?

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I kind of thought this idea of wood having an index of refraction was going to come up again. And this is a bit OT, but wood does not have an index of refraction much above zero. I realize that someone is trying to explain something, and it has to do with bring the depth out of the grain, but it has nothing to do with wood's refractive index. It may have something to do with the reflective nature of the wood cells... I dunno

Mike

Mike, the index of refraction of wood is about 1.5

Interesting article: http://www.cs.cornell.edu/~srm/publicat ... 5-wood.pdf

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I am curious exactly what kind of CA are people using to fill the pores. Is it just regular superglue? If so, how much does it take to fill the pores, it seems like you would need somthing bigger than the little 1oz bottles. Someone also mentioned they wipe it on with a paper towel, how do you keep from glueing the paper towel to the wood, do you just keep it saturated? I am very interested in learning this because I hate working with the epoxies, I have tried both Z-poxy and system 3 and just hate dealing with either one.

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John Thiessen
http://www.iszacguitars.com

I buy 8 ounce bottles from Woodcraft. I can do several guitars with 8 ounces. I'm going to look into getting it from Rockler since Rockler is now an OLF sponsor. To rub it on with a paper towel you have to work quickly, and in small areas. I put a little on the guitar and spread it with a paper towel in an area the size of 1/6 of the back at a time. Just put a little on the guitar and take a quick swipe with the towel. 10 seconds or so, and you can move to the rest of the guitar. It own't take long to learn how much to use at a time. Don't touch it until it's dried or you'll be stuck to the guitar. I wear gloves and also my paint respirator while doing this. The trick for my method is picking the right viscosity for the size of the pores. I use medium with Mahogany and Walnut, usually thick or gel with most Rosewoods. Too thick and it won't get down into the pores. Too thin and it will take a bunch of coats. 2 coats is usually all it takes, with an hour or 2 between coats. I don't use accelerator, but that could probably cut down on the time.
Rod True said he uses the thickest he can get. He spreads it with a razor blade (with the edges rounded) and I assume pushes it into the pores. This would make choosing the right viscosity easy, but make it a little harder to apply.

Rod, how many coats usually, and do you use accelerator?

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Why bother with an accelerator? I would be much more interested in a retarder. But I can't find one. And I think that is because CA is not "solvent based". Mustang, CA is sold in a variety of viscosoties. For this application, medium at the very least is required. The thin stuff they sell at wal-mart, for example, will just wick into the wood, leaving nice, shiny pores behind. I guess you could keep applying it, but the thicker stuff works much better. I go to a local hobby shop. I bet Hobby Lobby has it too. I buy a big bottle and put some in 2 oz squeeze bottles (not too full). A little goes a LONG way with CA.

BTW, I am still struggling with the concept of wood having an index of refraction. I read part of the article, but not ready to render my thoughts on this yet. Thanks for the article, however. If Michael Payne sees this, I am done for.

Mike

Ya, the thickest I can get (from a local source that is) is a medium viscosity. The reason I like to use the razor blade is that there is no waste (ie: no paper towel in the trash) therefore the cost is less (over multiple guitars). I put a drop about the size of a nickel on the guitar and just spread it with the razor blade at about a 45* angle to the grain. Work an area about 4 square inches till the CA just starts to set. Than move on to another area with another drop of CA. When the razor blade gets 'gummed up' with cured CA, just use another blade to clean it off and your good to go again.

Woody, I usually do two coats, just to be sure. If the pores are really big or deep even two coats isn't enough. A little bit really does go a long way though. I can probably pore fill 3-4 guitars on one 2 oz bottle of med visc CA. You really don't need much at all.

No need for an accelerator, as most med visc CA's will set in about 15-30 secs.

Mike as far as a retarder goes, get some of the Medium thick or Thick CA from StarBond which should have a much longer open time. I don't think you'll have to worry about getting the CA into the pours as my guess is that the viscosity of the thick CA is still lower than epoxy would be. It will fill the pores and using the razor blade as a 'squeegee' would work well.

I wish Michail Payne would weigh in on this thread. He's been doing some experimenting with CA as a finish on necks. That would be interesting.

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"Generosity is always different in the eye of the person who didn't receive anything, but who wanted some." Waddy Thomson

Finishing epoxies can be very much thinner than thick CA. Thinner than medium CA in many cases.

Acetone dissolves CA, and reaction with a mild base or buffer can kick it (baking soda), so it's possible that the addition of acetone (if it's miscible with the CA) or a small amount of an acid could either slow the cure or cause it to not cure until accelerated. In the case of the acid, it would need to be measured very accurately so as to avoid making the CA un-curable.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Thanks for that, Bob. I just don't use finishing epoxies so I really don't know what their viscosity level is like.

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"There's really no wrong way, as long as the results are what's desired." Charles Fox

"We have to constantly remind ourselves what we're doing....No Luthier is putting a man on the moon!" Harry Fleishman

"Generosity is always different in the eye of the person who didn't receive anything, but who wanted some." Waddy Thomson

Thanks for the info on how its applied, I am going to try this soon.

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John Thiessen
http://www.iszacguitars.com

You can spread the CA with a piece of masking tape on your finger, too. I've used CA and West System epoxies and I like the look of the epoxies better.

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Ken Franklin
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