Purflex purfling

[Diane Kauffmds]

I've installed Purflex purfling on the Irish OM build. I thought it would make a good topic for procedures.

Purflex is a flexible purfling, with a thin decorative relief. You can buy flexible abalone or mother of pearl, as well as flexible designs which have a maple relief. All are on top of a rubbery substrate, which is glued into place. They have matching back strips, bridge pins, and end pins, for every design. Purfling comes in varying widths.

Although really beautiful, it's not the simplest of purflings to install. The purflings with the raised designs have to be installed, then filled with black epoxy. After the epoxy cures, you sand it down to the design. The big problem here is that it's very VERY easy to sand right through the design, as you work your top.

This is how I handle purflex:

I rout my channels as usual, except in the instance of purflex, I rout the purfling channel a bit deeper. You want the purflex to lay deeper than the top (or back in the case of a back strip). I've not measured, but I lay purflex more than 1/64" deeper than the top, closer to 1/32". Always do test cuts to ensure you're deeper.

The idea is to sand the top down to the purflex. Although I do this with all purfling/binding, I make the channels even deeper. You'll see why.

You can use ca glue or Duco Cement to glue purflex. I prefer Duco. After cutting the channels and gluing the purflex and bindings' as well as any side purflings, I tape the sides and top, leaving the side tape a bit proud. The tape acts as a dam for the epoxy.

My choice of epoxy is 2 part.epoxy made by System Three. I use the epoxy that is used for pore filling. I color it with black epoxy colorant made by Alumilite. It's a true black with no red or blue overtones.

[Diane Kauffmds]

I use a plastic pipette to put the black epoxy into the purflex. The tape dam pretty much holds the epoxy in place. Let it sit overnight. Epoxy cures by an exothermic reaction (it heats up). I put the box in the furnace room, which is warm, to quicken hardening.

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[Diane Kauffmds]

Today I've removed all tape. The epoxy has hardened. There is a little lip. I use a miniature Veritas edge plane, which I've modified, to get that edge off. I do not go down to the design. I'm simply cleaning the edge, evening it out.

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I switch to my palm sander with 120g paper. I sand the top down until it just starts to reveal the design.

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Using 120g sandpaper and a wooden block, I sand the the top down to the purfling.

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Here it is.

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It still looks a little blotchy, but I have more sanding to do to ready the top for finish.

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[TEETERFAN]

Diane, that’s looking wonderful! Thanks for taking the time to post all the great information. Great results. That’s going to be one stunning instrument.

[Diane Kauffmds]

Diane, that’s looking wonderful! Thanks for taking the time to post all the great information. Great results. That’s going to be one stunning instrument.

Thank you Kevin

[tippie53]

I did the celtic knot a few years ago
one thing to add as I found that mixing the epoxy in a bottle made it easier and less messy
I added the resin , then the black color then the hardener then applied out the bottle the first time I had epoxy all over
pretty yes but I don't think I need to use it anymore
I like pearl

[MaineGeezer]

I found that the black epoxy dust from sanding got embedded in the top and made it look dirty. I found scraping to be a better alternative, where I could do it.

Heed Diane's warning -- it's really easy to cut through the Purflex design.

[Diane Kauffmds]

I put 3 heavy washes of shellac on the top and sides. I had no problem with the black dust. But yes, scraping is great. That's why I modified the edge plane.

[Rds 1st run]

Diane, Looks awesome and thanks for the info.
I do not have my kit yet, but should have in 3 to 4 weeks. I have started making jigs and accumulating what I believe necessary to get going. I have purchased some purflex for this build and searched a lot of looks. I have not seen the purflex used without a black white black strip. Seeing what you did without the added purfing is great. Very nice clean look. Would definitely lend its self to a first build for me.
I know it is all up to what someone wants to do, I just wasn't sure the purflex by its self would be a clean line and you have shown it can be.
You also stated that use use epoxy to fill the purfing which I understand, small areas with voids at the rims. You also mentioned you use epoxy as a pour filler. I do not quite understand the idea of using epoxy as a pour filler on an acoustic guitar. I have seen and read this in numerous places, I just don't understand it. I have only used Aqua coat on the electric guitars i have done, 2 solids 2 hollow bodies trying not to deaden anything tone wood wise.
Does the epoxy as a pour filler effect the tone wood?
In my previous live, I made Musky fishing lures almost 20 years worth. Epoxy was used to seal against water and air.
Do we not want the top to breath?
Am I wrong in this thought ? This is really a question, I can play a guitar I know nothing about making an acoustic.
Thanks

[Diane Kauffmds]

The epoxy I use for pore filling is West Systems. I will double check, but I think they're 105A and 206A. I don't use it on many builds.

My goto is Aquacoat. I've used ca glue (yes, you can use ca glue), but my advise is to avoid it unless you're outside; the fumes are horrific. I use Epoxy when I have a type of wood that needs stabilization. Some woods are known to check and easily crack, usually woods with crazy grain. I've also used epoxy on woods with little holes. Some cherry has these. Epoxy does not affect sound. In fact, one of the best sounding guitars that I've made has epoxy pore fill. It's got the craziest cherry I've ever seen.

There are many different ways to pore fill. Go with what works for you. You're fine with Aquacoat.