Epoxy as a grain filler

[barking_spider]

I like to use the little plastic Dixie cups for measuring, and Solo cups for mixing. Almost anything can be used for filler- sawdust for large areas, microballoons for the fine stuff. If you want a "bright" (clear) finish, be sure to specify "non-blushing" epoxy. The blushing stuff will leave white streaks.

Another trick is that if you want to do two or more coats, apply a very thin first coat that really soaks in. Just after it's kicked, and before it's hardened, apply the second coat. This gives you a mechanical and a chemical bond, and eliminates the need for sanding between coats. Which you should do otherwise.

Epoxy isn't that tough as a final coat, and reacts poorly to UV, so something else like lacquer, poly, or varnish should be used as a top coat.

NEVER MIX EPOXY IN A METAL CONTAINER! As the epoxy catalyzes, it releases heat. If the heat doesn't dissipate, the reaction goes faster, releasing more heat. Before you know it, you have a flaming bucket of a napalm-like substance!

 

[Freekmagnet]

Thanks for the feedback. I guess I'll do the whole thing. A follow up question: how much do I need to mix to do a whole body?

I usually mix 15ml. If I need more, I just mix another 15ml.

Another tip: If I do any masking, I use packing tape or Scotch tape. Epoxy will soak into masking tape and it’s a PITA to remove. Epoxy won’t stick to packing or masking tape.

 

[Gilmourisgod]

NEVER MIX EPOXY IN A METAL CONTAINER! As the epoxy catalyzes, it releases heat. If the heat doesn't dissipate, the reaction goes faster, releasing more heat. Before you know it, you have a flaming bucket of a napalm-like substance!

Heh. I kinda did that with some very expensive two-part boat bottom epoxy sealcoat. It didn't burst into flames, but gave me a hell of a burn when I tried to pick up the bucket. The fact that it was actually smoking might have clued me into the little chemical inferno I had going.

 

[Jon Clegg]

Heh heh.. mixed a little too much in a plastic cup once, no fire, but the cup collapsed in an interesting way.

 

[Thumpin6string]

I've been refinishing guitars for about 20 years. On a body that is getting painted a solid color, I wouldn't waste my time with epoxy. On all of the guitars I've refinished, the bad ones were primed with polyester primer (very high build) and the rest with catalyzed urethane primer. Both are easily applied with a spray gun and both sand pretty easy. Also, both are compatible with body fillers. For clear finishes on wood, I've used wipe on polyurethane jell. It fills the grain and leaves a smooth finish that you can leave as-is or spray over.

 

[Thumpin6string]

my apology for a derail/tangent, but: would this (zpoxy) be an informed choice for a fretless fingerboard 'treatment'/finish (vs. CA or other epoxy choices)? thanks.

A lot of guys use epoxy on fretless finger boards. My preference is to mask off the board and spray with an automotive catalyzed urethane. I've been using it on fretless basses with round wounds for years with zero wear to the finish. It also adds to the mwaa.

 

[dwizum]

I hate mwah. Everyone seems to talk about every fingerboard finish adding mwah. I'm about to finish my first fretless, I wanna know what finish reduces mwah.

 

[JRA]

A lot of guys use epoxy on fretless finger boards. My preference is to mask off the board and spray with an automotive catalyzed urethane. I've been using it on fretless basses with round wounds for years with zero wear to the finish. It also adds to the mwaa.

cool beans!

I hate mwah. Everyone seems to talk about every fingerboard finish adding mwah. I'm about to finish my first fretless, I wanna know what finish reduces mwah.

i didn't ask about mwah. i asked whether zpoxy would be considered another choice for coating fretless fingerboards.
maybe you aren't sure! thanks.


again, OP, i apologize for the tangent!

 

[Thumpin6string]

I hate mwah. Everyone seems to talk about every fingerboard finish adding mwah. I'm about to finish my first fretless, I wanna know what finish reduces mwah.

A coat of rubber should get rid of the mwaa. Otherwise adding frets works too.

 

[Gilmourisgod]

Seems like the softer the wood or finish, the less mwah, but it will also wear faster. Maybe just good old rosewood.

 

[Jisch]

I haven't tested the theory of higher gloss = higher mwah, but to me mwah is more a matter of playing style than it is construction. I have a bass that has excellent mwah (I like it when I want it), but I can certainly play that bass without any mwah by adjusting my string attack and finger roll.

As the potentially offended OP: any derail is a good derail as long as we're talking basses, building and playing.

 

[dwizum]

As the potentially offended OP: any derail is a good derail as long as we're talking basses, building and playing.

As one of the potential derailers: Well good!

 

[Means2nEnd]

I use epoxy for a ton of things in my shop. I now use UV cured Solarez "I can't believe it's not lacquer" for grain filler and sealer it has micro beads of glass in it and never shrinks. I cure it in less than 3 minutes with a UV light and I'm sanding after applying in minutes.... I'm not blown away by the top coat but the sealer/filler is insanely awesome unless you need to dye through it like you can with Aqua Coat. FWIW

 

[jtrom]

Bring the zombie thread to life!

I'm currently doing a build and have found this thread to be quite helpful. I have a few questions though:

1). Do you use the epoxy as a grain fill prior to staining?
2). Would this replace the need for a stain primer?
3). Does using epoxy as a grain fill effect what you can finish the bass with?
4). Once you have a couple coats on, I suppose it doesn't matter if you sand down to wood because everything will be filled and level?

I have some American Chestnut that I'm using and it's very very porous...

You can see the build here if you like.

 

[Beej]

Bring the zombie thread to life!

I'm currently doing a build and have found this thread to be quite helpful. I have a few questions though:

1). Do you use the epoxy as a grain fill prior to staining?
2). Would this replace the need for a stain primer?
3). Does using epoxy as a grain fill effect what you can finish the bass with?
4). Once you have a couple coats on, I suppose it doesn't matter if you sand down to wood because everything will be filled and level?

I have some American Chestnut that I'm using and it's very very porous...

You can see the build here if you like.

Personally, I would not apply epoxy before staining or dyeing a body - epoxy basically dries into plastic and will not absorb any of the stain. Even sanded all the way back, it's not really good.

If I'm using dyes or stain on an instrument, I usually do not grain fill with epoxy. There's too much risk IME for sanding through to the wood and removing the dye or stain.

That said, you can spray colour coats (like trans) over top of the epoxy grain fill coat, but a rubbed dye/stain won't usually work.

 

[jtrom]

Personally, I would not apply epoxy before staining or dyeing a body - epoxy basically dries into plastic and will not absorb any of the stain. Even sanded all the way back, it's not really good.

If I'm using dyes or stain on an instrument, I usually do not grain fill with epoxy. There's too much risk IME for sanding through to the wood and removing the dye or stain.

That said, you can spray colour coats (like trans) over top of the epoxy grain fill coat, but a rubbed dye/stain won't usually work.

Thanks for the tips!

Just curious, if you're going for a stain finish what would you use as a grain filler? And would you use said filler pre or post stain?

 

[Beej]

Thanks for the tips!

Just curious, if you're going for a stain finish what would you use as a grain filler? And would you use said filler pre or post stain?

There are quite a few options

On walnut, I use a pore filler, like a regular wood grain fill. There is some shrink back, but overall, I sorta like the look. I've also used acrylic paint to fill the grain on things like ash and oak, then sanded back and filled over with epoxy, but no stain. I guess it depends on what kind of look you're going for. You're using chestnut? What colour do you want it to be in the end?

 

[dwizum]

Chestnut can look really good with a dark tinted filler (like, walnut colored) to highlight the grain, then a lighter yellowish or orangish stain.

If you want a dead-smooth surface with no grain showing through, you can always just tint the epoxy and/or whatever you topcoat with. Tinting in the topcoat removes the risk of accidentally sanding the color off if you try to stain the wood before grain filling with epoxy.

 

[jtrom]

There are quite a few options

On walnut, I use a pore filler, like a regular wood grain fill. There is some shrink back, but overall, I sorta like the look. I've also used acrylic paint to fill the grain on things like ash and oak, then sanded back and filled over with epoxy, but no stain. I guess it depends on what kind of look you're going for. You're using chestnut? What colour do you want it to be in the end?

I am wanting to finish my build with a dark walnut stain on the back, natural/light "faux binding" and likely a gold / yellow top (possibly semi-transparent). I think this will be a paint or spray? Not exactly sure on the method for the colour.

I just know that I would like the surface to be smooth and even. I don't want the finished product to have any grain dips or doodles.

Sorry for hijacking the thread... it's no longer about epoxy filler