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I`ve got a couple of very tiny spots in the bindings where the pores didn`t quite fill.I was pretty sure I had them all,but not.Is threre a way to fix this with finish already on it.They didn`t show up until after several coats of finish.I tried drop filling ,but they just don`t want to fill.There very tiny and may not be worth fixing if I have to sand the entire finish off .I`m using em 6000,which I`m really happy with so far.What if I were to put a little shellac on the cracks ,and then a little ca ,sand flat,a little shellac and then shoot more finish.I`m sure some of you have run into this problem before.
James

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James W Bolan
Nashville Tennessee

Just keep drop filling - it takes a lot of drop filling with this stuff to get enough in there. When I find one of those I usually have to drop fill 5 to 10 times to get it flush.

Something else I just thought of but never tried is possibly using the target clear pore filler to drop fill. That stuff seems to not shrink as much when drying.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Thanks Andy.I`ve drop filled several times.It`s getting better.Is it okay to drop fill after all the coats are shot if it still needs it ,and then let it cure and go to leveling and buff out.I`ve also read on Targets forum ,that some people go head and sand level the next day after the final coat,with 800 .Does this make since?
It seems there`s always a learning curve with a new product. James

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James W Bolan
Nashville Tennessee

One quick point: my experience is with USL, not EM6000 although I will be using it for my next build. I understand that USL and EM6000 are pretty similar though.

What I've always done is to drop fill as I go, usually once a day at the end of the day when the finish has already cured enough to touch. I typically don't do any level sanding during the spraying process.

After all of the top coats are on, I'll continue to drop fill for a couple of days until I think the voids are filled. I then wait for about 4 weeks for the whole thing to cure before I start working on leveling the drop fills along with the rest of the top coats.

Typically this has worked well but the problem is that I have ended up with a spot or two where I didn't fill quite enough. I have not tried drop filling after the 4 week cure time as I don't have the patience to wait another 4 weeks to re-level and buff.

I don't think it would be too good an idea to level sand before the cure time as there will still be shrinking going on over the cure time but, I've never tried it either. I imagine that it's easier to level sand before the cure time but probably riskier too. I don't have that much finishing experience and while perhaps waiting until the finish is cured might save an hour of sanding, a screw up in soft finish could mean several days to weeks of more work.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Andy Thanks again for the input.So if your drop filling after all the coats are on,it seems there would be a bump or two to deal with.I suppose these are easy to level after cure.What about a little ca and then maybe shoot another coat or two? maybe I`ll ask this on another post.
James

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James W Bolan
Nashville Tennessee

Yep, there's always bumps to deal with. The funny thing is that when drop filling the stuff tends to build up around the pore to make a doughnut type effect. That's why sometimes it's hard to tell if you've filled enough.

Never tried the CA and probably wouldn't either. I'd bet that it would be visible against the lacquer and even if it's not, it's probably harder than EM6000 and would level differently.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

The EM6000 is pretty forgiving. I've drop-filled a number of small spots; takes several applications as already stated. I too use the razor-blade/tape scraper to even up the drop fills but I don't do any additional sanding. I also use several versions of the razor-blade/tape scrapers to take care of any nubs, runs, or other bumps prior to each days spraying. I spray 4 coats about 1/2 hour apart each day. I don't thin it and I only spray to wet it, I don't try to put on heavy coats. All told, IIRC, I put on 16 coats. I let it cure for 5 days and then level sand with small blocks, starting with P600. If I have an area that is hard to level I use P400. Once I get to P1000 I wet sand using mineral spirits. Most of my wet sanding is done with a 2"x2" rubber block on the bigger surfaces and a piece of eraser about 3/4"x1" on smaller areas. I work up to P2000 then polish by hand with Novus plastic polish.

I had everything filled before I sprayed the last 4 finish coats but you can fill after finishing. How do I know? Because I sanded through the finish on the headstock while leveling, a big spot about 3/8" x 2". And you guessed correctly, it was near the edge . Anyway, I just brushed on about 6 or 8 more coats (don't remember exactly) then re-leveled and polished. Worked just fine and can't see any witness lines and I would if they are there because it's on the player's side of the headstock.

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Steve Smith
"Music is what feelings sound like"

Thanks Steve,real good info.Especially the part about sanding and buffing out.Did you have to sand off all the tiny shiny spots with the courses grit and then move to the next.I can never figure out how much to sand with each grit.Also where do you get your rubber sanding blocks.
James

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James W Bolan
Nashville Tennessee

Not sure what you mean by tiny shiny spots although I'm guessing you're referring to the small areas that are still shiny after you've sanded with a relatively large sanding block. I wear my magnifiers to see what I'm doing and then go over those with one of my small sanding blocks. My favorite is made made from a drafting eraser and is about 1"x7/8"x3/8". Before I level sand I knock down any little bumps on the finish using a razor blade scraper with masking tape wrapped around each end so I can get the bumps as close to level with the rest of the surface as I can. The closer the surface is to level before you start sanding the less likely you are to sand through an area.

I also sanded with P400 after about 8 coats were on the guitar just to even everything out. That way when I was done with all my spraying, the finish was already pretty level so I could use the P600. I had a few small sags that I used the 400 on. One thing I've found is that when trying to level small sags or runs I have better luck using the small sanding block. The largest block I use is about 2"x3"x1/2" cut from a rubber sanding block I got at an automotive paint supply place; I use it for larger areas like the top, back, and sides.

I too have trouble deciding when to change grits and have not perfected that yet. Some time ago someone posted that you could change the direction you sanded with each grit so it would be easier to tell when it was time to move on but I haven't tried that yet. I would think you'd want to end up going with the grain at the end but maybe it doesn't matter. I wear magnifiers while I work and I also use bright lights to inspect the work as I go.

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Steve Smith
"Music is what feelings sound like"