ibreakemineedtobuildem Posted January 23, 2004 Report Share Posted January 23, 2004 Do you always use grain filler or is that only for an opaque finish. Would I use clear? Quote Link to comment Share on other sites More sharing options...
Alchool Posted January 23, 2004 Report Share Posted January 23, 2004 Do you always use grain filler or is that only for an opaque finish. Would I use clear? From my little experience, if you don't use grainfiller on mahogany it will absorb everything. But then again I only made solid color finishes. Quote Link to comment Share on other sites More sharing options...
ibreakemineedtobuildem Posted January 24, 2004 Author Report Share Posted January 24, 2004 If I wanted the grain to stand out wouldn't I use Black filler? Quote Link to comment Share on other sites More sharing options...
Reaper Posted January 24, 2004 Report Share Posted January 24, 2004 Do you always use grain filler or is that only for an opaque finish. Would I use clear? When I went to finish my axe (mahogany), the people at the paint shop advised me against grain filling mahogany. FWIW... Quote Link to comment Share on other sites More sharing options...
Southpa Posted January 24, 2004 Report Share Posted January 24, 2004 eeeeeeeeeeee, tough calls and don't want to step on any toes, so I can only speak from my own experience. Mahogany is a porous wood. That said then the rest should just follow common sense. My last guitar was all mahogany and I didn't use grain filler. I did lay dark red mahogany stain, literally soaked the wood with it. The stain shrunk when drying. I was hoping the stain would do some filling as well as enhance the grain. When sanded back down the grain was darker but there were still lots of low spots. It took a lot of layers of polyurethane to fill those low spots before I could wet sand without touching wood. If I used grain filler I'm sure I would have needed less poly. Its nice to start with an even surface when applying your paint or clearcoat. Quote Link to comment Share on other sites More sharing options...
guitar_ed Posted January 24, 2004 Report Share Posted January 24, 2004 Howdy, The challenge with mahogany, and similar woods, is that the finish will subside over time into the pores of the wood if you do not use grain filler. As for color? LMII sells grain filler tinted to a mahogany color. You can find clear in lots of places. Again, my $.03 is to use some kind of grain filler. Guitar Ed Advice worth what you paid for it. Nothing. Quote Link to comment Share on other sites More sharing options...
westhemann Posted January 24, 2004 Report Share Posted January 24, 2004 i could swear that polyeurethane has no need for filler or sanding sealer...and that it does not sink into the pores over time i have heard that nitro does this on my mahogany guitar i used shellac as a sealer coat(to fill the pores and create a base) and i am using nitro for the rest. the book on finishing that i bought at drak's suggestion(insistence? )says that this works well i guess i will know after a few years,eh? Quote Link to comment Share on other sites More sharing options...
westhemann Posted January 28, 2004 Report Share Posted January 28, 2004 from the book "filling the pores with the finish is less problematic and,with small pored woods ,quicker.also it produces a surface with more clarity.....it is possible to (fill the pores) with any finish except wax,oil,or oil/varnish blends,(as they) don't cure hard." also this one "some finishers like to fill the pores with sanding sealer...because it is so much easier to sand.this is not a good idea,because it weakens the overall finish significantly" this all comes from the book "understanding wood finishing" by bob flexner Quote Link to comment Share on other sites More sharing options...
Morben Guitars Posted January 28, 2004 Report Share Posted January 28, 2004 I think a lot of times we guitar builders forget that we're just borrowing our finishing skills from hundreds of years worth of fine woodworkers. Woodworkers of this caliber are few and far between, but I suggest asking around music/piano stores about who they would have refinish a $200,000 Steinway Piano...that's the guy you want to talk to...buy him a coffee and pick his brain. You want someone that turns their nose down at products like Minwax.. Old school finishing..not the new age "short cut" depot finishes. That said - yes, you really need to fill the grain of mahagony. Is there a reason not to? If you're trying to complete a great finish, you know it's not a 2 week process...so what's another day? In the past woodworkers filled the grain by rubbing pumice into the surface with a shelac medium. It's much easier today. A finish is only as good as the surface you're applying it to. If you want a great, thin, flat finish...then the underlying surface has to be flat. Loading it up with sanding sealer and sanding it flat doesn't count...it will be far too brittle in the future. One can of grain filler should last for 4-6 guitars. It's very easy to apply, and not difficult to sand back. 2-3 coats and you'll have a glass finish. Shoot a coat of sealer, sand flat, then hit it with the clear coat and you've got one hell of a finish. Quote Link to comment Share on other sites More sharing options...
westhemann Posted January 28, 2004 Report Share Posted January 28, 2004 i also believe (correct me if i am wrong jeremy)that lgm has said with polyeurethane he doesn't use sanding sealer or grain filler in the book it says that polyeurethane should not be used over sanding sealer...and that it is an extremely hard finish...hard enough to not sink into the pores over time like nitro Quote Link to comment Share on other sites More sharing options...
Southpa Posted January 28, 2004 Report Share Posted January 28, 2004 in the book it says that polyeurethane should not be used over sanding sealer...and that it is an extremely hard finish...hard enough to not sink into the pores over time like nitro I recently asked about attaining sanding sealer at a local supplier and he sneered and said, "nobody uses that anymore". I'm not sure where he was coming from as I have little experience with its applications. And he didn't venture to tell me what has taken its place. Anyway, as far as laying poly onto a porous surface goes, its going to sink into the grain anyway when freshly applied. I WILL be using grain filler on the next mahogany guitar for the simple fact that less clearcoat will be required to get a perfectly flat, smooth finish in the end. I found that the initial poly spraying stages were doing nothing but filling up the grain. Roughly six coats were required just to get a level surface. Sand a little bit and you are still touching wood where the high spots are, so further coats (about another 6) are necessary before wetsanding and polishing. Quote Link to comment Share on other sites More sharing options...
westhemann Posted January 29, 2004 Report Share Posted January 29, 2004 what type of poly are you talking about?because the chemically cured stuff(multiple parts)cures much faster and goes on thicker,from what i understand yeah i am filling up the pores on mahogany right now with nitro..it is taking a while,but i think it will be worth it for the clarity. Quote Link to comment Share on other sites More sharing options...
Morben Guitars Posted January 29, 2004 Report Share Posted January 29, 2004 I recently asked about attaining sanding sealer at a local supplier and he sneered and said, "nobody uses that anymore". I'm not sure where he was coming from as I have little experience with its applications. And he didn't venture to tell me what has taken its place. I'm not surpirsed..you'll get the same answer when asking about grain filler ("Ya'll mean wood filler, yup, we gots that!") People still use it, but it's pretty much reserved for the fine woodworkers and refinishers. The typical weekend warrior who wants to refinish a yard sale dresser on a Sunday afternoon is using minwax stain and polyurathane. Find a shop that understands fine woodworking and chemical finishing. Rockler is a chain store that comes to mind. Homestead finishing is a good online resource. We're not finishing furniture, we're finishing a musical instrument. I may be a bit old-fashioned, but I always vote against the shortcut/easy way and opt for the time-tested methods. It's preferance, but I don't think anything can beat a hand sprayed/polished Nitro finish over a properly sealed/filled surface. Home Depot carries Parks products, including a pretty decent nitro and sanding sealer. Quote Link to comment Share on other sites More sharing options...
Southpa Posted January 29, 2004 Report Share Posted January 29, 2004 Most of the poly I have been using was Minwax fast drying high gloss in aerosol and paintable form. It usually sets in about 1/2 hour and remains tacky for the next 2 or 3 hrs. Its loose enough to settle into pores, regardless how its applied. Quote Link to comment Share on other sites More sharing options...
Setch Posted January 29, 2004 Report Share Posted January 29, 2004 If you don't grain fill mahogany you will get visible pores. They may not be there when you level and buff, but over time your finish will continue to shrink and harden as the solvents in it evaporate, and it will sink into the pores. You can fill pores with laquer, but this is an expensive way to do it, and you still stand every chance of the finish shrinking later. I would recommend CA or epoxy for a good glass clear fill. Quote Link to comment Share on other sites More sharing options...
westhemann Posted January 29, 2004 Report Share Posted January 29, 2004 the book suggests shellac for the bottom coat...i guess it shrinks less over time Quote Link to comment Share on other sites More sharing options...
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