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questions on finishing mahogany body
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10123&t=25224		 Page 1 of 1
Author:  jaredgroom [ Tue Dec 29, 2009 11:52 am ]
Post subject:  questions on finishing mahogany body
i will be starting my first guitar build in the next couple of weeks and need some tips on finishing the body. it is mahogany and i want to do a dark red stain on it. that is the easy part. i want to keep it as close to raw-looking as i can and was told to use tung oil or a similar product, but i don't want to have to continuously re-apply. i need something that will seal the wood permanently while avoiding a glossy sheen. I have also been reading about applying a wood filler before i start the process. I am looking for something that gives a depth to the look of the grain. maybe a gloss is the way to go. i don't know. just a newbie. any tips are greatly appreciated!
Author:  MRS [ Tue Dec 29, 2009 1:03 pm ]
Post subject:  Re: questions on finishing mahogany body
You can seal the wood prior to the wiped on tung oil type finish with zinsser's seal coat a dewaxed clear shellac. It's great out of the can. After sealing the wood sand it with 220 grit and apply the wipe on finish. I also recomend to seal the wood prior to applying stain. This helps produce a even non blotchy stain finish. Then reseal over the stain to prevent the top coat from leaching the stain from the wood. This stuff is available at most home centers...Mike
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Author:  Michael Dale Payne [ Tue Dec 29, 2009 1:35 pm ]
Post subject:  Re: questions on finishing mahogany body
Mahogany is a fairly open pore wood. The finishing process will require you to decide if you want an open pore finished surface or to fill the pores to have a level smooth surface. if you want a smooth surface then there are several ways to fill the pores, water based fillers, oil based fillers wood dust and shellac, pumice and shellac, epoxy finishing resin and CA are just a few of the options. you need to decide on your filler first if you planed to fill the pores as this will be the first major step in finishing the body. i will say stay away from water based fillers as they tend to shrink a lot. For a first timer shellac and wood dust is a good option for filler as is epoxy.

After you have completed the fill process next will be sealing. Some finishes do well as their own sealers such as shellac, tru-oil, tung oil and Danish oil varnishes. Some top coat finishes require a sealer over some types of pore fill such as epoxy. Shellac is a good all-round sealer as well as a good top coat options. Shellac can be brushed padded, French polished or sprayed and is simple to repair at any stage of the process. Shellac can be top dressed to a satin or gloss finish.

For a first timer I would say shellac is the most fool proof option then followed by tru-oil.
Author:  jaredgroom [ Tue Dec 29, 2009 5:03 pm ]
Post subject:  Re: questions on finishing mahogany body
thanks for the tips they will help me out tremendously
Author:  avengers63 [ Wed Dec 30, 2009 12:43 am ]
Post subject:  Re: questions on finishing mahogany body
With all due respect to MRS, I think he's leading you down the wrong path. A sealer does just that - seals the wood. Nothing further can penetrate the wood while it's there. Anything applied over the top of that will sit on top and either dry (if it's a barrier finish) or get gummy & nasty (if it's an oil). You must understand that a real oil finish is meant to penetrate into the wood, not sit on top. Therefore, applying an oil over the top of a sealer won't do you any good.

That being said, most finishes sold as an oil is really an oil/varnish blend, or some kind of wipe-on finish.

Before you do anything even resembling the finishing stage, you should get ahold of Bob Flexner's book "Understanding Wood Finishing". It'll dispel all the finishing voodoo and potential bad & confusing advise you can run into on-line.
Author:  MRS [ Wed Dec 30, 2009 3:17 pm ]
Post subject:  Re: questions on finishing mahogany body
Sealing with a shellac wash coat before staining is a tried and true process that has been used for years by many with great results prior to staining. It also works well before applying wiped on finish like poly or varnish. Do a google search and you'll find millions of post on just this subject. Some makers even sell specialty products called pre stain sealers, controllers and conditioners...Mike
Author:  Ziegenfuss [ Thu Dec 31, 2009 7:53 am ]
Post subject:  Re: questions on finishing mahogany body
avoiding a glossy sheen is probably the easiest thing to do when finishing a guitar.

satin finishes, tung oil, etc...are exceptionally easy. You will not have problems. However, as Michael pointed out, filling pores is still a good idea.

Stephen
Author:  avengers63 [ Thu Dec 31, 2009 9:57 am ]
Post subject:  Re: questions on finishing mahogany body
MRS wrote:
Sealing with a shellac wash coat before staining is a tried and true process that has been used for years by many with great results prior to staining. It also works well before applying wiped on finish like poly or varnish. Do a google search and you'll find millions of post on just this subject. Some makers even sell specialty products called pre stain sealers, controllers and conditioners...Mike


You 're 100% correct on all counts. I responded in opposition because 1) you didn't suggest it be a wash coat and 2) you were suggesting putting something over the shellac. He stated pretty clearly that he wants it very raw-looking. Putting anything resembling a barrier finish over the shellac will start to build up a finish, which in turn works against his stated desire.

Jared: What I think you might be missing in your thought process is that the stain (which I personally disagree with, but it's your guitar) will need some kind of protective finish over it. Any dents, scratches, etc run the risk of exposing the un-stained wood underneath. A thicker barrier finish will help protect you from this. Going with this, my suggestion would be to apply a few coats of regular shellac, rub it out with alcohol, then buff it with steel wool. Shellac is the most natural feeling of the barrier finishes, the alcohol will level it out, and the steel wool will keep it looking as raw as possible. If you go this route, just be careful about getting it too thick and losing the feel of the wood. What it sounds like you're wanting is a little in opposition to what you really need, so you'll be walking a really fine line between not enough and too much.
Author:  MRS [ Thu Dec 31, 2009 12:32 pm ]
Post subject:  Re: questions on finishing mahogany body
Pretty much everyone on here understands the use of Zinnsers seal coat as a wash coat. Sorry if you didn't. Second if he is searching for a raw look why even think of filling the pores like he is? Prior to filling the pores a seal coat is necessary to prevent color leaching everywhere from the filler not and then a seal coat goes on after the pore filling then again to prevent the color from leaching when a topcoat is applied. Or this case a wipe on finish.
Author:  avengers63 [ Fri Jan 01, 2010 1:11 pm ]
Post subject:  Re: questions on finishing mahogany body
MRS wrote:
Pretty much everyone on here understands the use of Zinnsers seal coat as a wash coat. Sorry if you didn't.


That sounded distinctively instigative and demeaning. This is just a difference in opinion - nothing more. Let's not start off on any more of a wrong foot than we have. [uncle]



Jared - You were looking for opinions and suggestions. You have them, they differ, and they'll all work but in different ways. From your posts, it doesn't seem that you have a significant amount of experience is finishing or how to take the road to where you want to go. I again highly advise you to get & read Flexner's book. It'll shed more light on your project than we can.
Author:  MRS [ Fri Jan 01, 2010 2:50 pm ]
Post subject:  Re: questions on finishing mahogany body
John I apologize if it sounded that way. I didn't mean it that way...Mike
By the way i looked at your blog. Nice guitar. I've seen that guitar before. Are you a member of the TDPRI forum too? Or did you post it here before?
Author:  avengers63 [ Fri Jan 01, 2010 6:12 pm ]
Post subject:  Re: questions on finishing mahogany body
MRS wrote:
John I apologize if it sounded that way. I didn't mean it that way...Mike
By the way i looked at your blog. Nice guitar. I've seen that guitar before. Are you a member of the TDPRI forum too? Or did you post it here before?


Thanks - we're cool. [:Y:] It's REALLY easy to take things the wrong way on the net, as well as say them hokey. I've certainly been guilty of both, so no harm done.

I don't remember if I posted it here or not. I was on Project Guitar for a long time - maybe you saw it there.
Author:  Mike Kroening [ Mon Jan 04, 2010 2:05 am ]
Post subject:  Re: questions on finishing mahogany body
Hi John,
Are you over here, getting yourself in trouble again? :)

Just Kidding, Good to see you, hope all is well with you and had a Merry Christmas.

BTW All, John really does mean well, he has the same problem as me, We stick our foot in mouth now and again. LOL!!

John , don't go to the guitar forum and ask about building a true flat top acoustic. Trust me you will never want to open another can of anything after that experience. Because that can of worms REALLY BITES, I know from experience. LMAO!!!

Mike
Author:  avengers63 [ Mon Jan 04, 2010 10:22 am ]
Post subject:  Re: questions on finishing mahogany body
Mike Kroening wrote:
Hi John,
Are you over here, getting yourself in trouble again? :)

Mike


So it seems.

As far as acoustics go, I got Benedetto's book on archtops for Christmas and found plans (with a live example) for a lightbulb/aluminum tubing side bender, so I'll be giving it a whirl sometime this year.
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