Official Luthiers Forum!

After hundreds of hours, I'm now at the stage of putting on the finish of my first guitar.....( Gulp)

I know this subject has been done to death ,but please bear with me . My fear of screwing the thing up at this stage has me a wee bit concerned. (to say the least). I have read all the OLF archives on the subject!

I am going to finish with hardened shellac and have been practicing filling the pores on scrap mahogany.

I tryed filling with a slurry of fine wood dust and shellac as I like the idea , and read where Robbie O'Brian has used it successfully for years.I can get the pores filled , but when it comes time to level , there are patches of colour diference, where it seems I've taken off all the shellac. I've tryed not to , but it still happens.Ive also thought that if I don't take it right back ,I'll be leaving shellac with suspended wood particles in the finish.

Attempt NO. 2 I practiced the epoxy method and found that this too, can give you the patch effect. (colour difference). I put it on with a piece of plastic (like a credit card thing).I try to lightly get it back to level ,then find a patch (curses)

Attempt No. 3 Egg white...... changes the mahogany to a different sort of red colour and doesn't(for me) fill the pores.

I'm hesitant on sanding back to wood once filled as I have some thin sides an also some three way mitres on my florentine bindings (with side purfling) that I dare not touch again.

I see your guitars with that perfect finish and wonder what the hell am I doing wrong?

I have even considered going open grain !!

I look forward to your most welcome replies!!!!!!

Regards KiwiCraig

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CRAIG LAWRENCE of AUSTRALIA
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I have had good luck with Stew Mac clear water based filler in the past where I dont want to affect the color of the wood.

Did the epoxy thing with LMII epoxy and have never had good success with that but I think it is my lack of ability to read or follow directions. Lots of people have good success with it. For me, it just seems like the view is not worth the climb.

My favorite for Mahogany is actually good old fashoined paste filler that I bought from LMII and comes in colors for rosewood and mahohany. It does color the wood but I happen to like the color and the end result.

Thanks Rich,
             I should have mentioned that I have a maple side purfling that would probably take in colour if I were to use coloured paste.

   Kiwi

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CRAIG LAWRENCE of AUSTRALIA
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Craig -
What ever method you use,(Epoxy or shellac) after you've filled and sanded back to level you should give it one last wet coat, to even up the coverage.

I use z-poxy and after the pours are filled and sanded back to level, I mix up a 50/50 batch of Z-poxy and denatured alcohol. Then using a cotton tee shirt scrap, I give the body one wet coat, this evens up the areas where I burned through.
I presume you can do the same with either shellac or expoy.

Obviously - test on scrap first - but I think this may help.

LanceK

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Lance@LuthiersForum.com

I'm a newbie here. Great forum, all!!

I've had good results with paste fillers and like them very much.

Here's my schedule:
stain if desired
light sanding if water-based stain
wash coat of shellac
very light sanding
paste filler, well-rubbed
wash coat shellac
light sanding
brushing lacquer

The wash coat before filling keeps the filler from coloring the wood, also
seems to give me nice contrasty pores. I gleaned this from the
Overholtzer book, one of his better ideas. The best part is that, if you do
sand through the filler a bit, it doesn't show so much, since the filler is
only in the pores. My next finish will have KTM-9 instead of lacquer. So
far, tests good.

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now known around here as Pat Foster
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http://www.patfosterguitars.com

Lance, (et al!)

Where do you get z-poxy and will work under nitro? Like Craig, I most concerend about the "filling" stage more than any other. Where I live when I go into the paint store and ask for pore fillers I just get a long and deep blank stare!

Thanks

Shane

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Canada

I use the exact same process as Lance but with system 3. The epoxy also seems to pull the look of the grain out, I've even startted to wipe down figured maple with a thinned downed mixture just to enhance the look of it.

Dale

Shane- You can get z-Poxy at hobby shops. Here is where I bought mine: Z-Poxy

KiwiCraig - I avoid blotches by working a small area and squeeging off the excess epoxy quickly. If you leave it thick in spots as you are spreading the epoxy, the spots will saturate the wood and leave uneven areas. I've also noticed that I got more blotches when I used the thinner Z-Poxy finishing resin. I prefer the Z-Poxy 30 minute epoxy.

When I sand back I make sure that I use the same grit as when I sanded the wood. Recently I've switched from epoxy to UFO CA after a thinned spray coat of catalyzed urethane. That keeps the CA from wetting the wood too much. At least that's what I use on EIR since it bleeds and shrinks into the pores a lot.

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

[QUOTE=KiwiCraig]
Thanks Rich,
               I should have mentioned that I have a maple side purfling that would probably take in colour if I were to use coloured paste.

   Kiwi

[/QUOTE]

I had the same challenge on one guitar and what I did was brushed on a couple coats of shellac on all bindings. Also taped them off. Once it wasw done I simply scraped the bindings with a razor blade and everything worked out.

Now I am not the pro that many of the others are here but it did work well for me. Now that I think of it, I was doing a rosewood with maple bindings.

In the end was still a lot less work compared to the epoxy (at least from my perspective).

Everyone else seems to have such good success with epoxy I will probably revisit on the next build and this time follow the instructions to the T.

Why not try wiping the epoxy on with a rag - do a couple of thin coats. Wipe-on, wipe-off, Kiwi san. You should be able to get better control over how much you're putting down, and you won't have to muck around getting it back to level.

I've never had much luck applying epoxy with a sqeegee, even after using it for several hundred hours building a couple of 17' sea kayaks, I still don't think sqeegees give you enough control over the final film thickness. Use a low-blush formulation when doing epoxy over epoxy (actually, low-blush for any application) or you'll have adhesion problems between coats and with your final finish.

How're you liking the hard shellac?

I use an 8 inch window squeegee it works great.

Thanks for all your replies !

Paul, lance and others use Z-poxy and I can't get it here.I,ve been trying 5 min. araldite. I've tried thining it with alch. but it ends up a little sticky anddoesn't fill as good as the straight mix. I haven't tryed the rag method, but wouldn't it be too thick and sticky?. I also thought that a rag would not fill level as it is soft and able to enter the pores.Have you tried this yourself yet paul? I appreciate your experience with epoxy. What brand should us locals use?
Also ,what do you mean by low blush?
I have the Shines clear hard shellac (just to satisfy myself), and it appears a low cut and slow build. I will get the U-Beaut one in the mail today!

I would try the LMI and Stewmac fillers ,but living in Australia, it takes a fair amount of time to get here and can't wait that long (Too anxious).

The idea of using the same grit of sandpaper to level as used to final sand is good, as I have noticed that every grit change ,delivers a different colour to the wood. If I burn through at least I'm burning the right tone colour.

I will continue to experiment, which is really dragging out now!!! All your help and any other ideas , is really appreciated!!

Kind regards to all, KiwiCraig

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CRAIG LAWRENCE of AUSTRALIA
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Kiwicraig,

Both epoxy and shellac or even water based fillers will give you the results of filled pores. The drawbacks to me for epoxy and water based fillers, and I have used them all, is that with water base you need to tint the stuff to get a close match to the species of wood you want to fill. It dries very quickly as you apply it and if not thinned down a bit with water it makes a mess on your work surface. If you use water to spread it this helps but you are adding water to your work piece and sometimes you need to fill again cause the water thinned it too much and pulled it back out of the pores. Alot of sanding is required to get it off the workpiece and if you don't remove it all you get ugly opaque colored blotchy areas on your guitar. (Can I hear an amen?)
With epoxy you have some pretty nasty chemicals in your finishing enviornment. Secondly you have a mess trying to apply it. Thirdly, you have a long dry time, in most cases overnight before you can recoat it. And recoat you must, sometimes two or three times.You have to sand between coats as well. With that said, I always use epoxy under waterbourne finishes cause of the water white nature of these products.
The more I use other methods for pore filling the more certain I become of the simplicity and ease of the shellac and sawdust method and find myself returning to it more and more often.
   This method of shellac and saw dust is quick, easy and not messy like other methods. Also, it can be done in an hour as oppossed to a couple of days with epoxy. I learned this method from some old Brazilian furniture guys who didn't have the convenience of epoxy or water based fillers around but they did have plenty of shellac and sawdust. Let me see if I can help clarify this method.
Use about a one pound cut of shellac and end grain sawdust. If you use a heavier cut of shellac you just make a paste that is hard to apply and remove. When you sand it back you just remove the dust from the pores that you just filled. Use a cotton ball with a bit of your one pound cut of shellac on it and then sprinkle some sawdust on the surface. It doesn't take much. Rub the sawdust into the pores and it should wipe almost clean with the cotton ball. The shellac works as an adhesive to hold the sawdust into the open pores. If done right then you should have almost no sanding to do afterwards. There is no leveling to be done either, just a light sanding. I usually just scuff sand with 220 grit paper. The shellac imparts a bit of color to the workpiece as well and "warms" the wood's appearence. (It will not "pop" the grain with the deep amber color like epoxy however.) One session of filling is usually enough but you can do it again if necessary. I even use this method under my French Polish finishes with great results. Just remember to seal any lighter colored woods such as purflings or bindings before using this method. I use a solution of sanding sealer or lacquer thinned 50/50 with a thinner. Use a cotton swab for cleaning your ears to apply it in no time. (apply it to your guitar not your ears)
Another benefit of this method is that you always have scraps left over from the same species of wood used to build your guitar. Use this wood to make your pore filler dust and it is always a perfect match every time. You don't have to worry about tinting your filler if you are using a water or oil based filler for example.
Another benefit with this pore filling method is that adhesion and compatability problems with topcoat products are a thing of the past. Anything sticks to shellac.
If you are not worried about time frame and learn to work with the stuff then epoxy or water based fillers also work well.   
A bit longer than I intended... happy finishing!

[QUOTE=KiwiCraig]
I haven't tryed the rag method, but wouldn't it be too thick and sticky?. I also thought that a rag would not fill level as it is soft and able to enter the pores.Have you tried this yourself yet paul? I appreciate your experience with epoxy. What brand should us locals use?
Also ,what do you mean by low blush?[/QUOTE]

I haven't tried it on a guitar yet, but I have noticed how evenly it spreads when I've wiped up all the spills on my boats. It is very sticky stuff, so I'm not saying it wouldn't be messy . The rag being able to enter the pores is why you'd need two or more coats, it'd take a few thin coats to fill the pores.

There are a few places making epoxy over here, Bote-Cote is probably the most well known, though I haven't used it 'cause I could get International epiglass (also known as interlux epiglass) at the local boating supplies place - actually I think this brand was developed in NZ. It's available in small bottles too, some only come in 5L containers.

Blush, or Amine blush, is a waxy film that forms on the top of the epoxy as it cures. I think it's a byproduct of the hardner reacting with atmospheric moisture.
In any case, it has to be removed before you put on subsequent coats of either more epoxy or finish. Warm soapy water and scotch bright pads get it off boats, as does acetic acid (if I remember correctly)though these methods might be a bit severe on guitars. There are some low blush epoxies (such as the epiglass that I've been using) where you don't have the hassle of removing the blush. I suspect that the epoxies sold by Stewmac and LMI are the low blush varieties. I also suspect that when people have reported adhesion problems they've not been aware of amine blush. Epoxies ain't all equal.

Just sanded back last nights epoxy and got the best results so far,although there is still a little burn through (particularly the edges). Now....I wonder if my shellac will adhere to it ?. I read where some have no problems with that and others ( M. Doolin) say not to. Anyhow ,I'll try it . I have a good feeling about it and have found in the past that shellac will stick to just about anything.

Paul, I have just applied some epoxy with your rag method (one layer of thin cotton over my index finger). It is a bit of a sticky arrangement and doesn't seem to fill like the squeegy method, but maybe you know something I don't?

How do guys find thinning it down with alch.? So far I have found it to not set properly. Maybe it will in time?

Shane,You want to see the look I got when I asked for pore filler in my local hardware store (very very small town) They have absolutley none in stock,,,never heard of it,,and looked like they wanted to beat me with a big stick

The 5 min. epoxy I'm using isn't all that bad, as it drys so quick it doesn't get a chance to penatrate to deeply into the wood and doesn't dry too brittle.

I love this forum, and love all you guys (not intended as a gay remark ) ........NOT THAT THERE'S ANYTHING WRONG WITH THAT !

Regards KiwiCraig

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CRAIG LAWRENCE of AUSTRALIA
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Oh! just got your brilliant reply Robbie and yours too Paul, while typing myself, Great stuff!! thank you !

It's back to the workshop again !!! Crikey!! ,,I'm running out of scrap Mahogany!!

KiwiCraig

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CRAIG LAWRENCE of AUSTRALIA
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This thread was just what I needed. I got blotches also when I used the credit card application. Thanks Ctaig for bringing this up.

I suspect that filling is a bit of an issue with a lot of builders Doug. I remember looking at one of Lance's guitars way earlier on , thinking, boy , I hope I can get a finish like that. Kind of knew in the back of my mind it would be a bit of a big deal when it came to my turn..
The good news for me is that I've been getting a fairly good result with epoxy.
Lance, I find my thinned epoxy is not setting properly. Maybe it will in time, or maybe it's my epoxy.How does your 50/50 solution behave?

I'd like to say I've had good results with the dust method.......but , I haven't.As a matter of fact, I got a better fill with the slurry mix ,rather than wiping on shellac over the dust. Too much shellac.....rubbing too hard...not hard enough.....how much dust? I don't know Robbie ? It maybe one of those "have to be there " things.It's not filling for me . Any suggestions Robbie?
If you mean cotton balls ,as in cotton wool balls, Don't threads of it land in the shellac?

Thanks to Ken also for bringing up the ,same grit for finishing and leveling method. Smart thinking !

Paul, I received the U-beaut hard shellac and gave it a quick trial tonight . Yes it builds faster, but I'll reserve my judgement until I've used it for a while .

Hopefully this thread will help others like Doug , Shane and myself. Where would we be without this wonderful forum and the fanbloodytastic family within !

Cheers to you all ! Craig

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CRAIG LAWRENCE of AUSTRALIA
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[QUOTE=KiwiCraig]
I'd like to say I've had good results with the dust method.......but , I haven't.As a matter of fact, I got a better fill with the slurry mix ,rather than wiping on shellac over the dust. Too much shellac.....rubbing too hard...not hard enough.....how much dust? I don't know Robbie ? It maybe one of those "have to be there " things.It's not filling for me . Any suggestions Robbie?
If you mean cotton balls ,as in cotton wool balls, Don't threads of it land in the shellac?

[/QUOTE]
If you are getting threads from the cotton in your fill then you are using too heavy a cut of shellac. I put my dust in a salt shaker and apply it that way then just a bit of shellac on the cotton ball and rub it into the grain. Go across the grain and don't concentrate too much on one area. If not, you just pull out the dust you just put in the pores. It is just enough pressure to do the job also. You shouldn't be killing yourself to apply it.

This is an interesting read on pore filling and its problems. Although I’m not a builder yet, I keep reading and planning until I can get enough space to work.

I found some good information on David Hurds web site on filling. He uses heat with his epoxy to help the flow and the fill. Here is a link to his web site.
ukuleles.com

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aka konacat

If you think my playing is bad you should hear me sing!
Practice breeds confidence and confidence breeds competence. Unfortunately, I'm stuck in practice.