A more-or-less copy of a Martin OM

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MaineGeezer
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Joined: Wed Aug 13, 2014 12:14 pm

Tung oil....not a good choice for what I am trying to achiev

Post by MaineGeezer »

I learned something -- pure tung oil dries to a very "flat" finish with no gloss at all. In retrospect I probably shouldn't have used it. Oh well. To counteract the flat appearance caused by the tung oil I'm going to put on a very thin rub of Tru-Oil, which dries to quite a glossy finish, and see what happens.
Don't believe everything you know.
Anything is possible if you don't know what you are talking about.
When things are bad, try not to make them any worse, because it is quite likely they are bad enough already. - French Foreign Legion
Diane Kauffmds
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Joined: Sun Mar 09, 2014 8:13 pm

Re: Tung oil....not a good choice for what I am trying to ac

Post by Diane Kauffmds »

MaineGeezer wrote:I learned something -- pure tung oil dries to a very "flat" finish with no gloss at all. In retrospect I probably shouldn't have used it. Oh well. To counteract the flat appearance caused by the tung oil I'm going to put on a very thin rub of Tru-Oil, which dries to quite a glossy finish, and see what happens.
Maybe it's combination that's brought out the secondary figure in the wood. Whatever the reason, the guitar is stunning.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
MaineGeezer
Posts: 1711
Joined: Wed Aug 13, 2014 12:14 pm

Re: A more-or-less copy of a Martin OM

Post by MaineGeezer »

I've finally got a reasonably decent finish on the guitar. It's shellac, French polished. It's now at the stage where the grain visually shifts as you look at it from different angles.

I used a #8000 micro-mesh pad lubricated with naphtha for final smoothing.

Carter has recommended this stuff http://www.meguiars.com/en/professional ... over-16oz/ for the final polish.
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Don't believe everything you know.
Anything is possible if you don't know what you are talking about.
When things are bad, try not to make them any worse, because it is quite likely they are bad enough already. - French Foreign Legion
Diane Kauffmds
Posts: 3246
Joined: Sun Mar 09, 2014 8:13 pm

Re: A more-or-less copy of a Martin OM

Post by Diane Kauffmds »

I used Meguiars for the final polish on the OM; it did a great job. I don't know that any other finish brings out the 3D highlights in wood quite like shellac. Your guitar is really beautiful.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
ruby@magpage.com
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Joined: Thu May 24, 2012 8:03 am
Location: Chestertown Maryland

Re: A more-or-less copy of a Martin OM

Post by ruby@magpage.com »

Diane

Which Meguire's did you use - I have tried both #7 and #9 and can't decide which one is finer than the other.

Ed Minch
Ed M
Benjy
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Location: Irmo, SC

Re: A more-or-less copy of a Martin OM

Post by Benjy »

Ed, I'm not sure what Diane used but I am familiar with those products since I have been in the auto repair industry for 35 years...

Those 2 products are designed as a glaze, # 9 does say it has a cleaner so it does have some very very fine abrasive quality. They are used after you have buffed the paint finish to fill the scratches (swirl Marks) left from the buffing compound on a fresh paint surface. They work like wax but they do not seal the paint. If you put wax over fresh paint, the solvents can't get out and they will react and may cause paint issues.

One thing to look for on these polishes, if you are working on a paint finish that is less than 90 days old, you want a product that says "paintable" on it. That means that it does not have wax in it. Anything that says "with cleaner" has some sort of abrasive in it.

Both of those products will get rid of swirl marks if you keep rubbing it! I would use #9.


Beautiful guitar!!!!!

Benjy
MaineGeezer
Posts: 1711
Joined: Wed Aug 13, 2014 12:14 pm

Go back to zero and start over....

Post by MaineGeezer »

The back WAS progressing quite well. Then I applied a coat of shellac to get more "build" prior to a final finish sanding/leveling, and I decided to put the guitar outside so the sun could warm it up and really dry the shellac.

That turned out to be a really, really bad idea. The back erupted in hundreds of tiny pinhead-size blisters that went clear down through the finish. The only thing to do was to sand off the finish and start over. So I've sanded off the finish on the back and I'm starting over with an initial coat of shellac flowed on as a base coat. Tomorrow I'll sand that down and hope there is enough "build" to fill the traces of the blisters that remain.

Has anybody else had this problem? An internet search turned up some discussion of blistering shellac, so the problem is known.
Don't believe everything you know.
Anything is possible if you don't know what you are talking about.
When things are bad, try not to make them any worse, because it is quite likely they are bad enough already. - French Foreign Legion
phavriluk
Posts: 554
Joined: Mon Jul 09, 2012 9:49 pm

Re: A more-or-less copy of a Martin OM

Post by phavriluk »

My guess: The shellac skinned over in the heat of the sunlight and the shellac underneath the skin was still gassing off, and it punched its gas through the skin, making the blisters/pinholes.
peter havriluk
Diane Kauffmds
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Joined: Sun Mar 09, 2014 8:13 pm

Re: A more-or-less copy of a Martin OM

Post by Diane Kauffmds »

I went on the internet to find this photo. It shows what I had happen in 2 spots on my guitar.

If this is what happened to your guitar, the Sun may not have caused the problem, so don't beat yourself up. My guitar has never been in the Sun.

I used Meguiar's too, and now I'm wondering if the stuff has silicone that's not listed. This is the only thing I can think of that would cause this "non-adherence". After using the Meguiars, I found a small spot that needed to be corrected. I used alcohol to melt the shellac; bad idea. The area got larger. I can tell you unequivocally, do NOT use alcohol to remove the damaged finish. I think the Si just gets into the mix and will contaminate other areas that aren't damaged.

I used a cabinet scraper, scraping off the damaged finish, then I sanded a bit. I cleaned the spot with naptha on a cloth. The adherence issue had lessened, but was still a problem, which is why I concluded that there was contamination. Once I started treating everything associated with the areas as contaminated, I solved the problem.

I used small pieces of sandpaper, which I immediately threw out. I cleaned with naptha, using paper towels, which I threw out immediately. I washed my hands between each step. This is how I finally got the shellac to adhere again.

The good news (if there is any good news) is that I only had to do this to the damaged areas of the finish and not the entire guitar. I've not had any problems since and the repaired areas are undetectable.
Shellac-Fish-Eye.jpg
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Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
Diane Kauffmds
Posts: 3246
Joined: Sun Mar 09, 2014 8:13 pm

Re: A more-or-less copy of a Martin OM

Post by Diane Kauffmds »

I decided to update my research on Meguiars. I went to their forum and when asked if there is silicone in their products, you see an unqualified "maybe", along with an explanation of good vs bad Si. Needless to say, this is in relation to using the stuff on cars and not guitars.

I checked the unofficial martin forum and apparently, they no longer recommend the use of Meguiars because of silicone. I used a Meguiars Professional grade product and had this result. You used a professional grade product, and ended up with fish eyes. I'm forced to conclude that, even if they haven't added Si in the past, they're doing it now.

I read that Novus #2 plastic polish has no Si, then I read that it has a small percentage. I think I'm going with the Stewmac swirl remover for my next build, since they tell you that there is no Si residue.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
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