System 3 Mirror Coat Epoxy on Fretless neck

[JacoNOT]

New day, new idea.

Regarding rinsing cloth-backed sanding sheets. Probably a bad idea to send those particles down a drain, since you say the issue is uncured epoxy resins. I'll bet they would stick to the pipes - and if you send enough of that stuff through, well, Murphy's Law applies to plumbing, too.

I'm thinking a 5-gallon bucket that gets dumped someplace where it'll do no harm each time it fills up.

Hey, is that epoxy cured yet?

How about now?

How about now?

How about NOW?

Can't wait to see what happens next. PUH-LEEZ consider taking photos per my earlier Requests post.

[joeyl]

Originally Posted by JacoNOT

How about now?

How about now?

How about NOW?

Can't wait to see what happens next. PUH-LEEZ consider taking photos per my earlier Requests post.

I will take pictures, I started peeling a side of the neck dam to see what's up, so far so good.

[Bruce Johnson]

I do a lot of shaping, sanding, and polishing epoxy in my work. Here are a couple of tips:

1.) To break off the meniscus at the edges, and any rough shaping, use a file. A large flat Smooth cut file works best. Take light stokes and brush out the teeth with a bristle brush every couple of strokes.

2.) Do your level sanding (that is, getting it flat and to the correct radius) dry, using a stearated paper. Stearated sandpaper has an extra coating to reduce clogging. I suggest 3M Fre-Cut gold in 220 grit, followed by 400 grit. You can even get the 3M Fre-Cut in 600 and 800 grits from Stew-Mac, but it isn't really necessary in this application.

3.) One of the key tricks to sanding epoxy is to sand it lightly, that is, using very light pressure. A couple of light strokes, then brush off the sandpaper with a bristle brush or dust brush. If you press hard, you'll just roll up little balls of epoxy dust, which stick to the paper and prevent it from cutting. Sand lightly!

4.) You can wet sand epoxy with finer grits, like 800, 1000, and 1500. Use water with some dishwashing detergent in it. Use a good quality paper like 3M's wet/dry. However, I wouldn't wet sand an epoxy fingerboard surface like this. There's too much risk of the water soaking into the wood at the edges, where the epoxy feathers out. If water gets under there (and how could you stop it?), it could cause the wood to swell and lift up the feathered edge. I wouldn't risk it.

5.) Instead of wet sanding, I'd bring the epoxy up to a gloss with Scotchbrite and buffing. After the 400 grit dry sanding, scrub it with gray Scotchbrite, and follow that with white Scotchbrite. That will bring it up to a semi-gloss. Finally, buff it with a cotton wheel and a good rubbing compound. I personally like Meguiar's #105. As with the sanding, don't lean too hard on it or run the wheel too fast. You don't want to melt lines in it. Epoxy works best with gentle pressure.

[joeyl]

Originally Posted by Bruce Johnson

I do a lot of shaping, sanding, and polishing epoxy in my work. Here are a couple of tips:

1.) To break off the meniscus at the edges, and any rough shaping, use a file. A large flat Smooth cut file works best. Take light stokes and brush out the teeth with a bristle brush every couple of strokes.

2.) Do your level sanding (that is, getting it flat and to the correct radius) dry, using a stearated paper. Stearated sandpaper has an extra coating to reduce clogging. I suggest 3M Fre-Cut gold in 220 grit, followed by 400 grit. You can even get the 3M Fre-Cut in 600 and 800 grits from Stew-Mac, but it isn't really necessary in this application.

3.) One of the key tricks to sanding epoxy is to sand it lightly, that is, using very light pressure. A couple of light strokes, then brush off the sandpaper with a bristle brush or dust brush. If you press hard, you'll just roll up little balls of epoxy dust, which stick to the paper and prevent it from cutting. Sand lightly!

4.) You can wet sand epoxy with finer grits, like 800, 1000, and 1500. Use water with some dishwashing detergent in it. Use a good quality paper like 3M's wet/dry. However, I wouldn't wet sand an epoxy fingerboard surface like this. There's too much risk of the water soaking into the wood at the edges, where the epoxy feathers out. If water gets under there (and how could you stop it?), it could cause the wood to swell and lift up the feathered edge. I wouldn't risk it.

5.) Instead of wet sanding, I'd bring the epoxy up to a gloss with Scotchbrite and buffing. After the 400 grit dry sanding, scrub it with gray Scotchbrite, and follow that with white Scotchbrite. That will bring it up to a semi-gloss. Finally, buff it with a cotton wheel and a good rubbing compound. I personally like Meguiar's #105. As with the sanding, don't lean too hard on it or run the wheel too fast. You don't want to melt lines in it. Epoxy works best with gentle pressure.

Bruce, thanks for the tips, they are very good and make total sense to me. I have noticed that epoxy does ball up and clog the sandpaper quicker the harder the pressure. So light pressure with epoxy: got it! I do use fre-cut and it is very good.

How about using naphtha instead of water as wet-sanding agent?

[JacoNOT]

Originally Posted by Bruce Johnson

I do a lot of shaping, sanding, and polishing epoxy in my work. Here are a couple of tips:

1.) To break off the meniscus at the edges, and any rough shaping, use a file. A large flat Smooth cut file works best. Take light stokes and brush out the teeth with a bristle brush every couple of strokes.

5.) Finally, buff it with a cotton wheel and a good rubbing compound. I personally like Meguiar's #105. As with the sanding, don't lean too hard on it or run the wheel too fast. You don't want to melt lines in it. Epoxy works best with gentle pressure.

Bruce, thanks for saving me from myself. Left to my own devices (wet sanding, specifically) my neck might have swelled up like a blowfish.

Item 1 above: Do you a) hold the file horizontal/across the neck and push the file from the side of the neck OVER the fretboard face, or the opposite, b) hold the file horizontal to the neck and push from the face over the edge of the neck, or c) file IN LINE with the length of the neck as much as possible? I want to know how to avoid blowing any 'chunks' off (IF that's a possibility with epoxy like this).

Item 5 above: Do you mean a buffing wheel as mounted on a bench grinder - so the circumference edge of the cotton wheel is applying compound to the epoxied surface?

[Bruce Johnson]

JoeyL;

Supposedly, you can use Naptha for wet-sanding. I've tried it a few times and never really seen any advantage over water. For this case, the epoxy coated fingerboard, I'd worry that the Naptha could seep under the edge of the epoxy and loosen the bond. I'd stay away from liquids if possible.

JacoNOT;

When filing, you want to stroke from the center outwards, always cutting off of the edge. If you stroke from outboard in towards the center, you risk peeling up a chunk at the edge. Work in gentle strokes, with the file at about 45 degrees to the centerline of the neck. Just use the file for the rough work of taking down that outer lip. Then use the 220 and 400 dry paper on radius blocks and flat hard blocks to get the surface correctly radiused and true.

Note: Getting the radius perfect isn't that important. What's really important is getting the string paths true. The "string path" is the strip of wood, about 1/4" wide, that's directly underneath each string. That needs to be straight and flat with no dips or lumps. The rest of the wood in between those paths is just there for decoration! Radius blocks are a help when shaping out a fingerboard, but don't get too obsessed with them. I do the final truing of the string paths with a straight maple block, about 1 3/4" x 2" x 11" long.

For the buffing, yes, use a cotton buffing wheel 6" dia x 1/2" or 3/4" wide, buffing on the circumference of it. However, a bench grinder is usually too fast, unless it's one of the old-school types with a v-belt drive. I prefer to clamp the neck down to the bench and use the buffing wheel with a 1/4" shank arbor, in the chuck of a variable speed electric drill. I find that gives me much better control of the speed, direction, and pressure of the buffing. With a 6" wheel, you want to go about 1000 rpm. As with the files, buff from the center outwards, off of the edge, to avoid the risk of peeling the feathered edge. Apply a few dabs of the rubbing compound right on the neck and spread it around a bit before hitting it with the wheel.

A general note about buffing, whether on epoxy, paint, or metal: The purpose of buffing is to remove the scratches left by the prior sanding. If I didn't mention it before, you should always do the fine sanding (including with the Scotchbrite) in a straight line. Don't sand in circles or off at random angles. You want an even pattern of straight-line scratches. On the fingerboard, you want the scratches straight down the neck, parallel to the fingerboard. When buffing, the direction of the buffing needs to be perpendicular or at some angle to those scratches, in order for the buffing action to remove them. If you try to buff parallel to the scratches, you'll make them deeper and wider. So, buff across the fingerboard, at some angle, going off the edge.

Hopefully I don't have to remind everyone to wear safety glasses. And an old shirt!

[JacoNOT]

Bruce, you're "A Whole Tutorial in a Can". I'm sure JoeyL will speak for himself, but I shudder to think how many mistakes I would have made if not for your generous instructions.

In fact, if for some reason I DON'T do my own neck myself, and assuming you ARE interested in doing this work for hire - I'll be talking to YOU about doing mine.

Obviously you know what you're doing.

Thank you

[ian_s]

I vote for this thread to get stickied. I'm doing an epoxy fingerboard and I would have more fun with the epoxy if I read threads like this first.

[powerbass]

[quote=joeyl;12633160]There is also another product called System 3 Clear Coat, that is supposed to be water thin as compared to the honey consistency of Mirror Coat. I have not heard anybody use it on a fretless board except Wilser Ramirez.

I used Clear Coat on a few fretless FB's as well as on a few other wood items. I used it several years ago and what I didn't like was the room temperature had to be 70º or above or it wouldn't cure. Since my basement was cold I made a tent and used an oil filled heater to speed up the curing process. I think there is a catalyst product that will speed cure times. The other issue I had was I did a couple of coats - there were sanding lines where I sanded through various layers. I think doing one larger pour like you are doing would work better. I actually finished a whole neck in Clear Coat thinking it would help the tone of the bass. I ended up stripping it all off and using tung oil instead. As for buffing I used wet/dry sand paper to 600 grit then 0000 steel wool or Scotch Brite. I used Murphy's Oil Soap cut with water for the buffing lubricant. I think I used my FB radius board for the buffing as well. I used a piece of thick felt as a pad between the sand paper and the radius block. Felt pads are what pro finishers use for buffing since they are soft and conform to a surface without leaving pressure spots like a block of solid wood does

[joeyl]

[quote=powerbass;12643283]

Originally Posted by joeyl

There is also another product called System 3 Clear Coat, that is supposed to be water thin as compared to the honey consistency of Mirror Coat. I have not heard anybody use it on a fretless board except Wilser Ramirez.

I used Clear Coat on a few fretless FB's as well as on a few other wood items. I used it several years ago and what I didn't like was the room temperature had to be 70º or above or it wouldn't cure. Since my basement was cold I made a tent and used an oil filled heater to speed up the curing process. I think there is a catalyst product that will speed cure times. The other issue I had was I did a couple of coats - there were sanding lines where I sanded through various layers. I think doing one larger pour like you are doing would work better. I actually finished a whole neck in Clear Coat thinking it would help the tone of the bass. I ended up stripping it all off and using tung oil instead. As for buffing I used wet/dry sand paper to 600 grit then 0000 steel wool or Scotch Brite. I used Murphy's Oil Soap cut with water for the buffing lubricant. I think I used my FB radius board for the buffing as well. I used a piece of thick felt as a pad between the sand paper and the radius block. Felt pads are what pro finishers use for buffing since they are soft and conform to a surface without leaving pressure spots like a block of solid wood does

Thanks for the input. I was wondering about that Clear Coat. I hear you about the witness lines, I had a neck that was finished in layers by the previous owner and every time I would sand a little bit more to get the imperfections out, I would hit the next layer. I could see what pattern he used to spread the epoxy on top of the previous layer! It was a good job though minus those witness lines.

[joeyl]

Originally Posted by JacoNOT

Bruce, you're "A Whole Tutorial in a Can". I'm sure JoeyL will speak for himself, but I shudder to think how many mistakes I would have made if not for your generous instructions.

In fact, if for some reason I DON'T do my own neck myself, and assuming you ARE interested in doing this work for hire - I'll be talking to YOU about doing mine.

Obviously you know what you're doing.

Thank you

He is: I just went to his website, good stuff on there!

[joeyl]

So I started pulling the tape. I had a bad feeling about the nut slot, I knew I did not stick the tape all the way in the slot, and the epoxy crept up the sides and flowed behind the tape, so the wall closest to the tuners got some epoxy and so did the flat area behind the nut.



The good thing is that it is still early in the cure, so the epoxy was not rock hard. I dropped some acetone in the slot and waited for the epoxy to soften, then I was able to scrape it off with a small screwdriver. I did not want to risk a chisel in there.

During cleaning





You can also see some micro bubbles, I can only see those in the pictures, not in real-life so I am ok with them.

JacoNot wanted a shot of the thickness and the meniscus




Still glossy for now until it cures and gets the sanding treatment




Clean nut slot except for the whitish residue from the scraping

[joeyl]

pretty even thickness





Another clean nut slot just for the hell of it (that cleanup was so avoidable )

[joeyl]

couple more

[Bruce Johnson]

About the nut slot: The trick is to find a little piece of aluminum, 1/8" thick x maybe 1" wide and 1 3/4" long (the width of the neck). It should fit nicely down into the slot, to the bottom. Give it a light wipe of wax and slip it in there, as you are masking up all of the edges and dams. Then wait until the epoxy is fully cured. A light tap on the edge of the aluminum will pop it loose, leaving a clean slot. Waxed aluminum is great for masking off parts and areas from epoxy.

Thanks for the compliments on my posts. I've been a pro Luthier for about 20 years, and I've been an engineer, machinist, and fabricator for much longer than that. This is a semi-retirement business for me. You may not have heard of me, because I deliberately keep a low profile. I specialize in the old Ampeg Scroll Basses, which I do complete restorations on, plus I build a line of new-generation versions of the Scroll Basses. But most of my other work is for other pro Luthiers and instrument companies. I do engineering, prototypes, tooling, and specialty parts that they aren't equipped to do themselves.

I'm sorry, but I don't do general instrument repair/custom work, other than a few nasty cases that are sent to me by other pro Luthiers. I'm just too busy with everything else. And you probably couldn't afford me!

[JacoNOT]

Bruce, with credentials like that I'm all the more appreciative of the advice you're making available here. It's like the difference between talking to my friends about a legal issue...and having a top-rank attorney discuss the details and offer advice, gratis. Yikes.

And JoeyL, you're no slouch, either. The combination of your detailed, captioned photo sequence and Bruce's guiding advice is just FANTASTIC!

Thanks to you both.

[JacoNOT]

Joey ==

THANKS for the new pictures. And that tip about clearing uncured epoxy with Acetone and a small blade will probably come in handy (oh no!) so thanks.

Post #32, photos 4 and 5 in the sequence:
Those photos show the meniscus and pour thickness at the heal of the neck.

Q1. Is it just a photo/optic quirk, or has the epoxy somehow followed the radius across the fretboard face? To me, it looks as if it did not 'level' but instead maintained a uniform thickness across the surface - and in effect, created a radius to match the rosewood radius...

Q2. The pour thickness appears to be about 3/16". Is that right?

Q3. Do you know how thick the finished epoxy surface will be. Perhaps I should ask, do you know for sure how thick it should be?

QUESTION FOR BRUCE:
Are there suggested minimum and maximum thicknesses for this epoxy layer? I would like to make mine "good and thick" so I can sand and rebuff if/when needed. I can shim my nut (I have metal shim stock on hand for machinist work) and I have lots of saddle height adjustment to play with - so is there any problem with making my epoxy "extra thick" (I don't know what 'extra thick' means in this case, so can you offer guidance on that?)

[joeyl]

Originally Posted by Bruce Johnson

About the nut slot: The trick is to find a little piece of aluminum, 1/8" thick x maybe 1" wide and 1 3/4" long (the width of the neck). It should fit nicely down into the slot, to the bottom. Give it a light wipe of wax and slip it in there, as you are masking up all of the edges and dams. Then wait until the epoxy is fully cured. A light tap on the edge of the aluminum will pop it loose, leaving a clean slot. Waxed aluminum is great for masking off parts and areas from epoxy.

thanks for the tip on the waxed aluminum JacoNot, you have been warned about the epoxy creeping into the nut slot!

[joeyl]

Originally Posted by JacoNOT

Joey ==

THANKS for the new pictures. And that tip about clearing uncured epoxy with Acetone and a small blade will probably come in handy (oh no!) so thanks.

no problems, happy to do so.

Originally Posted by JacoNOT

Post #32, photos 4 and 5 in the sequence:
Those photos show the meniscus and pour thickness at the heal of the neck.



Q1. Is it just a photo/optic quirk, or has the epoxy somehow followed the radius across the fretboard face? To me, it looks as if it did not 'level' but instead maintained a uniform thickness across the surface - and in effect, created a radius to match the rosewood radius...

That is strange, and now that you point it out. I think it is an optical illusion though. I'm at work right now and will check it when I get home.

Originally Posted by JacoNOT

Q2. The pour thickness appears to be about 3/16". Is that right?

That sounds about right, I will measure tonight.

Originally Posted by JacoNOT

Q3. Do you know how thick the finished epoxy surface will be. Perhaps I should ask, do you know for sure how thick it should be?

I think I can lose up to half of the thickness and be happy about it. It will be a play by ear thing though, I don't want it thin to the point where I am scared of a sand-through.

Originally Posted by JacoNOT

QUESTION FOR BRUCE:
Are there suggested minimum and maximum thicknesses for this epoxy layer? I would like to make mine "good and thick" so I can sand and rebuff if/when needed. I can shim my nut (I have metal shim stock on hand for machinist work) and I have lots of saddle height adjustment to play with - so is there any problem with making my epoxy "extra thick" (I don't know what 'extra thick' means in this case, so can you offer guidance on that?)

[JacoNOT]

The reason I ask about thickness is that I was warned (accuracy?) that epoxy wears the same way wood does - only at a slower pace.

Not sure how much "action" my en-route fretless will see (if I can master correct fretless intonation, probably LOTS) but I want the option of restoring the epoxy surface several times if needed. In fact, my first fretless may well turn out to be my first of several, so at resale time it'd be nice to be able to give it a perfect, shiny new fretboard surface.