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My third guitar has been wet sanded to P3000 and "ready to buff".
After some repairs after falling off the bench, and a six week hang time (the unrepaired portion has cured since JUNE) the entire guitar has been wet sanded dead flat.

The lacquer has shrunk back in several places and, after wet sanding, several very small gaps, in the binding have emerged. These are three very small linear gaps that you can see, and feel with fingernail.
Can these be filled with GluBoost and then buffed? Or should the CA be lacquered over before buffing?
I've learned a ton with this one but I'm ready to move on

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Measure Twice,

Karl Borum

Hi Karl you can fill with GluBoost and it's an easy fix.

We were late to the dance with GluBoost but we just tried it recently and it's certainly superior to the quality CA products that we have used in the past for filling gaps and imperfections. We find it builds MUCH faster and the non-foaming accelerator is a joy to use. For us a commercial operations it's cut some days off our ability to deliver for our clients and that's always a good thing.

Wanted to suggest something else to you. Gaps should get filled with the pore filling operation when building or at least they often can be. I struggled with pore filling and almost walked away from Lutherie over it. The crap that I tried that was said to be what the f*ctories used drove me up the wall. Burlap this and that and no matter what I did when I went to sand the pore filling came out of the pores....

For gaps like you describe we would fill with Gluboost and then scrape back with a single edged razor blade with the corners safed with scotch tape and finally wet sand. All of this can be done the next day with GluBoost. Because it's a binding one of the safed corners of the blade will be hanging out in space providing you with the opportunity to scrap the finish off the flats of the bindings which is not what we want to do here so be careful.

I have actually scraped down a dime sized GluBoost repair on a black finish after about 30 minutes and it still looks level after a year. But I do try to wait till the next day if the job allows the extra time.

God I hate pore filling!

I'm about to build guitar #75 which is a kind of milestone I suppose and can humbly but honestly say I have NEVER finished a guitar to find it came out perfect without needing some sort of fill because some stupid pore got away with it.

I guess I still have to learn that 95% of finishing is prep work.

GluBoost is fantastic stuff and has saved me countless times. With nitro I tend more to doing nitro drop fills though since it melts in so well. But it does take more time.

Thanks for the replies.
I just recently became one with GluBoost. Glad it will not need lacquer overcoat.
My struggle with this guitar (besides falling on concrete) has been tiny gaps between the BWB on the bottom of the binding, and the channel on the side. The gaps didn't become visible until finish was applied.

It was bad, really bad. I laminated .040 BWB to the bottom of my binding with Titebond II then bent it in bender. That interface between purfling and binding is where the gaps have kept showing up. I've probably had to fill tiny gaps of 75% of the perimeter before finish, after finish (several times as I let it hang for a while after a lacquer drop fill). This is my last Nitro finish, I dont want it to be my worst.

I read a tip, maybe on the OLF, to ease the back-lower corner of the binding and it will lay in the channel better. We will see on my current #4.

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Measure Twice,

Karl Borum

Exactly the same here. Waterbased grain filler, dyed black, turning white in the pores, after lacquer, was a huge challenge I soon won't forget.
How do you fill grain now Hesh? It's the gaps that pop up later that are killing me. I can't see for shinola - that is probably a big part of it. Here and now I hereby add magnification and acute angled lighting to my binding inspection process.

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Measure Twice,

Karl Borum

I had to get better at finding those tiny gaps in binding because the finish I use will build up around them like Hoover dam.

You mentioned relieving the inside corner of the binding, that will help with seating it for sure. Also be meticulous about cleaning the channel up. I use those reloadable sanding sticks, magnify the area, and take my time.

For detecting the gaps naphtha and low angle light can help to spot them.

I’ve started putting porefill around 1/2” perimeter of the top and sanding completely back to try to fill in any gaps as well. This is an area where the UV cured porefill is a luxury, but could be done with any porefill.

Congrats on #3!


Sent from my iPhone using Tapatalk Pro

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Once I have finish sanded to 320 I use air to blow off the guitar and I pay special attention to the binding and rosette edges. Any gaps get the CA treatment before I seal and pore fill. Those little gaps can get packed with sanding dust and hide during pore fill but they always seem to show up at some point.

And yes to a slight bevel on the inside bottom edge of the binding. I just use some 120 on a small eraser block (about 1” sq). Be careful, I broke a curly binding the other day doing that.


Steve

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Steve Smith
"Music is what feelings sound like"

I have used every pore finish out there and I keep coming back to the old-school, oil-based, paste wood pore filler. It takes tints well and if you get it plenty dark it will not do the white pore thing. The first time I used it (back about 1975) I did the burlap wipe but that was a hassle and did not work that well. Since then I have used an old terry cloth rag to wipe it down. There are a couple of tricks to using it. Just wipe the surface across the grain and one time only. Any residue can be lightly sanded off after drying for 48 hours. Also, the stuff works MUCH BETTER if you apply a couple of coats of sealer before filling. Occasionly, I will apply a second coat of filler if the pores and large and don't quite fill completely.

Hey Karl I read an article back in 2005 from Mike Doolin about using System III to fill pores. He messed with the viscosity and it worked great for him. I did as he advised and it worked great the very first time for me too. In time after befriending two professional guitar finishers they showed me how any decent epoxy will work and no messing with the viscosity is needed.

Todd Stock did a great tutorial on epoxy pore filling and he uses a squeegee to remove the excess. I used a credit type card and that worked fine for me. Of the 45 guitars that I finished with nitro and pore filled myself with epoxy none of them had open pores, not a one after two coats of Z-Poxy finishing resin what I used back then. Again though any quality epoxy will work in my experience.

The thing to understand is the first coat is to wet the pore especially the bottom. Once there is epoxy in the pore the second coat will stick like.... well... glue And so it did for me.

You can leave a wash coat on the wood surface too to pop figure and increase visual contrast. Or you can sand back to bare wood and the stuff stays put unlike that other crap I tied in the beginning.

Check the tutorials here for Todd's toot on this and I have one here too in that section.

Ive been using glue boost for pore filler lately it works excellent.

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I know at one time, Cindy Burton was using 5-Minute epoxy for pore filling. They also polished their finish with an auto(car)finisher instead of the usual power buffs and stuff. It works great and doesn't take up much room in the shop.

Brent