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I want to finish my first acoustic guitar in my garage as I don't have any other place to do this. To make it a little more difficult I have a gas furnace and gas hot water heater in the garage. So I am trying to figure out what I can use to finish the steel string guitar without an explosion. I also do not have any spray equipment but I do have a 5 hp compressor. I thought about buying a spray gun and trying to spray outside but living here in the northwest where I I'm about to develop web feet this year from all the rain don't see how I can do this outside. So I am thinking of doing a French Polish because I can't come up with any other ideas. So any ideas of what to use to get a high gloss finish given where I live and where I have to do the finishing would be greatly appreciated. Thanks. Chuck

GF Enduro-Var, waterbased, can be brushed on but probably better sprayed, keep a window open for ventilation, use a mask too, and temperature above 70 degress I believe, a quick search of the forum will turn up threads/schedules.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I have used Tru-Oil on two guitars and a ukulele. Just wipe on thin coats with a soft cloth or paper towel. Helps to prep surface to remove scratches down to 400-600 grit sand paper.


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Just an option, wipe on poly.

I also live in the PNW (east side of the Cascades so its a bit drier) and build/finish in a garage. I use a small compressor and either nitro or water born lacquer (KTM-9). When I'm shooting nitro I step outside, with the KTM-9 I'm comfortable shooting inside. I built sort of a "booth" out of cardboard that contains most of the over spray but there is still some dust on cars in the garage.

My first couple of guitars were done with rattle cans (again, stepping outside to shoot, taking it back in after the finish flashed off). You'll get a bit of dust in the finish but it sands out easily. I try to be aware of both temperature and humidity when I finish.

This is KTM-9 - it certainly can be very shiny if thats what you want

If I was to do finishing in a damp environment, I would do it like this:

A spray gun would be much easier than brush on. I would look for one that is stainless steel since you most likely will be using a water based finish (much safer, no explosions, not near as dangerous or smelly as nitro and much easier to apply in higher RH conditions). Also a non-stainless unit will rust with WB. Also spray on as warm of days as possible. Also, I would use a space heater to warm the garage (that will also lower RH)

I have used a lot of KTM 9 and would recommend it, but I think the product line was sold to Camger Coatings so I don't know what's in the future. People here also swear by EM6000 and Enduro Var but I have no experience with them. (Either should be fine once you learn an application process)

To get the look of Freeman's guitar above you will need to use a pore filler. I would recommend a non-blushing epoxy like System Three's SB 112 or Clear Coat. A lot of people use Zpoxy but it does form an amine blush when the Relative Humidity is to high. It can be removed but I would just as soon avoid it. Also System Three is less ambering (is that a word?) than Zpoxy. Clear Coat is the clearest of the three and SB 112 is in the middle.

The other thing you will need is a way of buffing the finish product. A buffing wheel is ideal but you can also use things like a foam pad on a drill motor with the right buffing compounds.

Good luck!

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Joe Beaver
Maker of Sawdust

I finish in my garage. ​I have constructed a spray booth using dense foam insulation.  The wings are hinged so it can be collapsed and stored easily.  A simple 20"X20" box fan is placed behind the booth w/ a 20"X20" opening that accommodates a furnace filter to capture overspray.  The window behind the booth is open to the outside.  I don't need an explosion proof fan because I am using water based finish.

​My finish is Target Coatings EM 6000.  I have been very pleased with this finish and after a few guitars I have become accustom to it's characteristics.  It has excellent properties that are conducive to application and the end result is a pleasing nitro-like appearance.  I use a Fuji Q3 HVLP (High Volume Low Pressure) spray system.  The spray gun is retrofitted to accept a smaller finish reservoir which is more conducive to guitar finishing.

If you go to the bottom of this link you can see my set up. Maybe you can get some ideas...

http://www.swiftcreekguitars.com/on-the-bench

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Steve Sollod (pronounced sorta like "Solid")
www.swiftcreekguitars.com

Good advice from Joe. That was pore filled with Zpoxy and buffed on a wheel (that turns too fast so I'm very careful). While I have never tried it I do know that people brush KTM-9 - there was an article in American Lutherie a while back. Also, I see that LMII still sells KTM-9, maybe I should stock up

I've been wiping Minwax high gloss poly thinned 50/50 with mineral spirits.
The results are pretty good.
This top has not been buffed or polished yet.
I brushed two coats on and level sanded up to 1000 grit.
I do a coat every evening. I have around a dozen coats so far.
I did not like the feel of the back of the neck.
I found I could dry sand with 600 and rub some polish on for a very nice satin look.
Dan

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Another option is a brushing varnish. Many of these are very cooperative for indoor application. They dont generally generate nearly the huge amount of evaporating solvent as spray - so You brush them with less thinning than wiping or spraying - so you get a faster finish build. All you typically need to do is open a window or the garage door when you are brushing.

Of course - it doesnt hurt that these brushing and wiping finishes aren't nearly as equipment intensive as spraying.

Except for the sandpaper.

Do you use a certain type of brush or a certain type of cloth? Also can I put it down after a short period or would I need to do the top and sides then wait till they dry , if so how long, before I can turn the guitar over and rest it on the top while I do the back.
Finally I have been thinking of using Aqua Coat as a filler so can I put poly over it or do I need a coat of shellac over the pore filler?
Sorry for what are such basic question . I am just beginning my journey into all of this. Thank for your understanding. Chuck

Chuck, I'm using foam brushes. I get bubbles, but I sand it down afterwards.
I use paper towels to wipe the poly on. I found cloth left lint on it.
Seems like a coat takes around four hours to dry.
It's not a fast process, but I'm doing what I can to avoid spraying a finish.
Dan

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Chuck, I'm using foam brushes. I get bubbles, but I sand it down afterwards.
I use paper towels to wipe the poly on. I found cloth left lint on it.
Seems like a coat takes around four hours to dry.
It's not a fast process, but I'm doing what I can to avoid spraying a finish.
I have not used Aqua coat, so no advice on it.
Dan

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Chuck, I'll add a couple of more comments. The cardinal rule is to practice on scrap. Most of us can tell you what we use and like (and don't like) and maybe some tricks that we have learned, but for a newbie finishing is a really hard part of building and you will learn from your experience and mistakes. As I've said, I use either nitro or KTM-9, sprayed outside with a small compressor and gun, altho I have also done two guitars with nitro rattle cans (a very good option). I've tried TruOil on an electric guitar, didn't like it, stripped to bare wood and redid it with nitro. I just did two more electrics with TruOil where I wanted more of an organic furniture finish and am satisfied with it - that is an option. I've never done a French polish but if I ever build another classical that is the finish I will use just because it is "correct" for that style of guitar.

All of the other options are viable but you need to do the research and experiment until you are satisfied, then commit to the guitar that you have worked so hard on.

If you ever come to the east side of the state - to climb or ski or go to the lake or whatever, I am in Wenatchee and would love to show you what I do and how I do it. I would also suggest coming to the GAL convention in June in Tacoma - a chance to meet a bunch of really wonderful folks who just happen to build musical instruments.

There's nothing wrong with a French Polish. That's all I done recently; inside the house on my pool table.

That's a lot of work, french polishing a pool table.

Well, no wonder that is all he's done recently. He's probably been polishing that table for months now...

I'm not an expert, but I've tried most of the above. All can work very well. But french polish is my favorite. I do it in the living room while watching a movie. I don't get cancer. My house doesn't explode. My lungs are in good shape. Total investment including a bottle of Everclear -- about $30.

If you do spray, don't forget good lung protection.

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Mike Lindstrom

I've found it a holy nuisance to set up and break down a spray gun for five minutes of spraying. And care and feeding of a piston compressor is its own art form. And oil-less compressors are deafening. And need moisture traps anyway. My suggestion is to listen to the folks who advocate wipe-on finishes or make friends with rattle cans for lacquer.

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Peter Havriluk

Rattle cans are a poor replacement for a proper spray setup. Yeah, it takes some effort to keep a true spray system in working order but nothing beats the finish you can do with the real deal.

And just a splash in yer lemonade makes a fine drink too.

Mike and Peter both have good advice. I recently watched a you tube video of an experienced finish "expert " apply a wiping polyurethane finish to a table using a folded paper towel with excellent results. Wiping poly is, I think, simply a thinned polyurethane.
I've been spraying nitro lacquer for 3.5 years. There is a learning curve involved but that will be true of any finish material and technique. How about French polish?


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"It is easier to fool a man, than it is to convince him that he has been fooled"
Mark Twain

I wish I had started with french polish.

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Pat

I've taken the time to learn to spray finishes including lacquer, EM6000 and Royal Lac. I am now French polishing for the first time. I am finding that it is not as hard to do as people make it sound (I did take a couple of classes though) and it is very relaxing. I also wish I had tried this about 10 years ago.

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Steve Smith
"Music is what feelings sound like"