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Pore filling mahogany
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10123&t=53306		 Page 1 of 1
Author:  Conor_Searl [ Thu Jun 25, 2020 6:42 pm ]
Post subject:  Pore filling mahogany
My dad bought a 335 kit from Stew Mac and has asked me to finish and assemble it for him.

I've never really tried for a classic gibson style finish. And so have some questions about pore filling the "mahogany". I really like the natural brown I see on a lot of lighter les pauls. I've got some dark brown pore filler, I understand that's how the grain lines jump out. Where my question comes in is how do you know when you've sanded the pore fill back enough. The jar says to sand with 320 once the fill is dry, but that's it. Do you need to sand right back to the wood, so its the original wood color and the pores remain filled, or should one expect the wood to be slightly stained by the brown pore filler. I did one coat of pore fill and sanded back with 320, and when I wet the wood with naptha it looks nice and uniform (how I would like it to look under finish). But the wood is definitely not the same color it originally was. It seems there is still some pore filler on the surface.
Author:  Chris Pile [ Thu Jun 25, 2020 10:55 pm ]
Post subject:  Re: Pore filling mahogany
First of all - what color will you be finishing it?
Author:  Glen H [ Fri Jun 26, 2020 8:05 am ]
Post subject:  Re: Pore filling mahogany
What kind of pore filler? Traditional Oil based type? If so, it will color raw wood, basically staining it. You can minimize this by spraying a coat of finish or sealer prior to pore filling. I use oil based but don’t let it dry, just set up and wipe off excess. But maybe your using something else.
Author:  Freeman [ Fri Jun 26, 2020 10:28 am ]
Post subject:  Re: Pore filling mahogany
Depending on the product you are using and the effects that you want the techniques can be slightly different. When I have used paste pore fillers (the old StewMac stuff) they were intended to stain the wood as well as fill pores - I would apply two or three coats sanding back to wood each time until all the little dark pores were filled. I now use Zpoxy almost exclusively and the process is somewhat different.

The cardinal rule for any finishing process is to practice on scrap until you get exactly the effects you want before committing to your guitar. Some of these steps are not reversible.
Author:  Conor_Searl [ Fri Jun 26, 2020 11:31 am ]
Post subject:  Re: Pore filling mahogany
Thanks guys.

I've got some of stew mac's water based pore filler. It's dark brown.

I would normally practice on scrap of course, but have nothing lying around like what is on this kit guitar. And it's not the kind of mahogany you'd find at the local lumber supply. Perhaps a poor excuse. If everything goes south, I'm prepared to live with a black guitar. :lol:

I'm not so concerned about color. Some sort of pleasant natural brown with the grain lines popping is good enough for me.

I'm just wondering if there's a definitive way to tell you've sanded it back enough. Everything I've read and watched is a little light on the details of what to expect. I no longer see any smears of paste filler on top of the wood, when I wet it with naphtha the grain doesn't seem to be obscured, and everything looks pretty even. The wood is darker than how it started, but that's a good thing. This is some sort of cheap mahogany substitue and its kind of pink.

I'd just keep sanding until I was sure, but the body is all laminated, and the sandwiched layers are definitely not the same kind of wood as what's on the surface. So I want to go easy.
Author:  Digelectric [ Wed Jul 29, 2020 2:02 am ]
Post subject:  Re: Pore filling mahogany
Conor_Searl wrote:
I'd just keep sanding until I was sure, but the body is all laminated, and the sandwiched layers are definitely not the same kind of wood as what's on the surface. So I want to go easy.


I don’t think that water based filler will really stain the wood but it depends on the wood and the filler and how dark the filler is and how they color it. So I would not trust my guess. :)

I would really do my best to sand it back a little and then do some tests on part of the guitar by scratching places where you know there is filler and see if you can’t differentiate between the feel of the wood and the filler to determine where the grain and filler is. I’ve never used that filler but when I’ve used other fillers it’s had a different hardness and porosity and was easy to tell apart. You don’t want to remove any wood as much as you can avoid it. The filler is, as you know, just to fill surface voids.

I think you’re pretty much of the same mind already and just want confirmation. It’s only your eyes on the wood and filler to know for sure so you’re going to have to find a way to study it and convince yourself you can tell them apart.
Author:  Tim Mullin [ Wed Jul 29, 2020 5:32 am ]
Post subject:  Re: Pore filling mahogany
You want to leave filler in the pores, not on surface. Wiping down the sanded surface with naphtha will help highlight areas where you still.have a coating of “mud”.


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Author:  Skarsaune [ Wed Jul 29, 2020 6:34 am ]
Post subject:  Re: Pore filling mahogany
I'm building that same kit for my brother in law, using the same filler for the back.

We're doing a dark burst though, so I wasn't worried about the appearance of the mahogany.
I just sanded it till there was filler in the pores and wood visible around them. Got a nice smooth finish out of it.
Author:  Mike_P [ Wed Jul 29, 2020 5:12 pm ]
Post subject:  Re: Pore filling mahogany
Tim Mullin wrote:
You want to leave filler in the pores, not on surface. Wiping down the sanded surface with naphtha will help highlight areas where you still.have a coating of “mud”.


Sent from my iPad using Tapatalk


^^^this^^^

pore filler doesn't really bond to wood so leaving any on the surface is like a layer of dirt...e.g. the finish will bond to the pore filler, but the pore filler isn't bonded to the wood, so the finish is very poor (tends to flake off, easily scraped off, etc...)

this concept really makes me wonder just who the hell came up with the concept of glazing gel stain over a finish then finishing over it...I saw this being done once, opened my mouth about the "stupidity" of it...got blown off by everybody...the finish flaked off pretty soon afterwards...you just can't cure arrogant stupidity...
Author:  Conor_Searl [ Wed Jul 29, 2020 6:32 pm ]
Post subject:  Re: Pore filling mahogany
Thanks guys, I forgot I posted this here. I did end up using naptha, and found that it highlighted where the filler still was. I also found it might have colored the wood a little, but not much, it was still quite pink after the filler, so I dyed the wood with a little dark brown/orange to give a more golden hue, kind of like the honduran mahogany in my minds eye. :D I'm happy with the combination...
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