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| finishing question help http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=21583 |
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| Author: | rebel34 [ Sun Mar 22, 2009 8:23 am ] |
| Post subject: | finishing question help |
I am getting the guitar resdy to spray with the em-6000, i just sealed the guitar with the zinnser sanding sealer, now is it safe to use the z-poxy (tinted black for walnut back and sides),? should i sand the sealer to level any runs first or should i apply the z-poxy first then sand it all lightly to level? Any tips on the correct way to apply the z-poxy? |
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| Author: | Mark A Thorpe [ Sun Mar 22, 2009 9:27 am ] |
| Post subject: | Re: finishing question help |
Look in the Video and Pictures Tutorials section about epoxy pore filling, read through it because he recomends not sealing the guitar first |
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| Author: | Rod True [ Sun Mar 22, 2009 10:00 am ] |
| Post subject: | Re: finishing question help |
Epoxy doesn't like to stick to shellac very well. I'd sand it all off and start with the epoxy. Look in the tutorial section for Hesh's tutorial on using epoxy to pore fill (Just as Mark mentioned). |
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| Author: | rebel34 [ Sun Mar 22, 2009 10:05 am ] |
| Post subject: | Re: finishing question help |
Instead of sanding it all off could i use the colored drywall filler instead? |
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| Author: | Rod True [ Sun Mar 22, 2009 10:45 am ] |
| Post subject: | Re: finishing question help |
Sure, that would work. It's not the best pore filler though, but it will work. I'd use something else like thick CA, or honestly, it would take very little to sand back the shellac and use a different method like egg whites and sawdust or shellac and sawdust. This is where picking a method (the full procedure) knowing what and how you're going to do it is a very important step in the whole process. |
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| Author: | rebel34 [ Sun Mar 22, 2009 11:23 am ] |
| Post subject: | Re: finishing question help |
rod, could you give me an ocerview of how to do the filling with ca, thanks |
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| Author: | Rod True [ Sun Mar 22, 2009 11:42 am ] |
| Post subject: | Re: finishing question help |
First off, work in a well ventilated area. The fumes can get pretty bad. Wear a respirator too. Get thick CA (medium is fine, but thick is better). Work in small areas. Pore about a 1/2 teaspoon of CA onto the surface. Use a single edge razor blade to spread it perpendicular to the grain. Make sure the corners of the razor blade are rounded over first though, other wise you can scratch the wood with the sharp corner. Work until the CA just starts to set (you have about 20-30 seconds depending on which viscosity you use). Move onto the next section when the one you're working on is "set". Once the surface is done, sand back to wood and repeat as needed till all the pores are filled. |
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| Author: | woody b [ Sun Mar 22, 2009 11:48 am ] |
| Post subject: | Re: finishing question help |
Like others have said, Epoxy doesn't stick to shellac. I seal with shellac (zinsser seal coat) and fill with gel CA. It's the easiest method I know of. I use 2 coats of shellac, then lightly sand it with 320 grit. (I know some people use a coarser grit) It doesn't take much CA to fill, you're only filling the pores. A 4 ounce bottle will do 10-12 guitars for me. (I use CA gel, not sure what thickness others use) I start with a small spot of CA and spread it with a razor blade scraper. Keep the blade at an angle so you don't knick the wood. I do the back, and then one side at a time. The fumes are terrible, and probably not healthy. I wear my paint respirator while I'm doing it. I don't use accelerator because I have a tendency to use too much, causing bubbles. After drying 30 minutes or so sand it again with 320 grit. If you didn't apply too much it's pretty easy to sand. Remember you're only filling the pores, not "painting" the guitar with it. I normally do 2 coats. After filling I spray 1 more coat of shellac, and then finish. |
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| Author: | Flori F. [ Sun Mar 22, 2009 11:50 am ] |
| Post subject: | Re: finishing question help |
Rod True wrote: Epoxy doesn't like to stick to shellac very well. This is a myth. |
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| Author: | Rod True [ Sun Mar 22, 2009 1:09 pm ] |
| Post subject: | Re: finishing question help |
Flori F. wrote: Rod True wrote: Epoxy doesn't like to stick to shellac very well. This is a myth. Try telling that to the epoxy! For me, this doesn't matter one way or another, I don't use epoxy to fill pores. There are many who do who swear that epoxy doesn't stick well to shellac so you can take it up with them. Now, shellac sticks well I'm told to epoxy, just not the other way around. |
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| Author: | rebel34 [ Sun Mar 22, 2009 1:29 pm ] |
| Post subject: | Re: finishing question help |
to make sure i get this correct, as i can be somewhat dense, CA is superglue correct? |
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| Author: | woody b [ Sun Mar 22, 2009 1:36 pm ] |
| Post subject: | Re: finishing question help |
rebel34 wrote: to make sure i get this correct, as i can be somewhat dense, CA is superglue correct? Yep, Cyanoacrylate Adhesive, but there's a good chance I mis spelled it. This is what I use. I have a good source for it locally. http://www.woodcraft.com/product.aspx?ProductID=149440&FamilyID=21102 I don't actually know that epoxy won't stick to shellac. I've heard it for years so I've never tried. |
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| Author: | Howard Klepper [ Sun Mar 22, 2009 2:00 pm ] |
| Post subject: | Re: finishing question help |
I always use epoxy filler on top of a shellac wash coat, and have never had an adhesion problem. I use dewaxed blond shellac made from flakes. I sand back to wood after filling. What kind of adhesion problem are people having? Is the epoxy falling out of the pores (hard for me to imagine)? Or are you not sanding back and having the epoxy layer peel away from the shellac base? |
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| Author: | Todd Rose [ Mon Mar 23, 2009 3:58 am ] |
| Post subject: | Re: finishing question help |
If I were going to use CA to fill pores, I would wear a full face respirator, like this: http://www.jamestowndistributors.com/us ... espirators. A regular half-mask respirator isn't going to help your eyes, and that's where the CA really gets you! |
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| Author: | SteveSmith [ Mon Mar 23, 2009 7:52 am ] |
| Post subject: | Re: finishing question help |
Another possible option would be to use the EmTech 8800 Sealer and Grain Filler. The folks at EmTech said it was fine to use over shellac and, in fact, recommended I use shellac first to provide a color tone to the final finish. I say possible option because it is still sitting on my shelf as I won't be ready to finish for another month or so. I'd be interested to hear if anyone has tried this product and think it would work on Rebel's Walnut since that is what I'm using as well. |
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| Author: | Tai Fu [ Tue Mar 24, 2009 3:40 am ] |
| Post subject: | Re: finishing question help |
I tried epoxy for grain fill and quite frankly, they don't sand very well and the possibility of an allergic reaction makes me not want to use them. Cured epoxy sands like rubber and improperly mixed epoxy will kill sandpaper and be a pain to get off (it will be gummy all over). Some grain filled wood with large pore with epoxy, they swore by it but I found that colored spackling paste works very well and they sand easily. For mahogany dark brown paste looks very good and for rosewoods the grain is small enough that a few coats of shellac should fill the grain. I like to apply a washcoat over bare wood first because I do not want the grain filler anywhere except in the grain. |
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| Author: | Flori F. [ Tue Mar 24, 2009 11:36 am ] |
| Post subject: | Re: finishing question help |
Tai Fu wrote: I tried epoxy for grain fill and quite frankly, they don't sand very well and the possibility of an allergic reaction makes me not want to use them. Cured epoxy sands like rubber and improperly mixed epoxy will kill sandpaper and be a pain to get off (it will be gummy all over). Some grain filled wood with large pore with epoxy, they swore by it but I found that colored spackling paste works very well and they sand easily. For mahogany dark brown paste looks very good and for rosewoods the grain is small enough that a few coats of shellac should fill the grain. I like to apply a washcoat over bare wood first because I do not want the grain filler anywhere except in the grain. Really? Shellac for pore filling rosewood without pumice? I think that's a road to disaster. First, it would take me forever to pore fill rosewood with shellac. Second, the shellac will continue to shrink for years. Pumice and shellac will work, but it still takes far longer than epoxy. 5-minute epoxy, which I use, is easy/forgiving to mix. If applied properly, there's barely any sanding involved and it sands easily (NOT like rubber). I use a dulled razor blade so that I don't leave much (if any) epoxy on the wood surface. A light sanding with 320 grit sandpaper leaves a bare wood surface with the pores filled. Of course, to each their own. If you've found something that works for you, more power to you. |
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