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Used it on first 2 guitars and and was more interested in just finishing builds so I didn't pay a whole lot of attention to the process, however I just recently used it again on 2 more and decided to develope a standard finish schedule. Pore filled with z poxy, sprayed on 1 coat of shellac, shot 6 coats of lacquer , level sanded , 6 more coats then started final sanding with 1000 grit , wet sanded, and got sand thrus on both guitars. shot 4 more coats and letting harden another week.
A couple of thoughts/ questions should I build more with sanding sealer before lacquer ? Start with 1200 or 1500 for final sanding? I do think I was shooting light coats at first.
Any thoughts , recommendations ?

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MK5acoustics.com

12 coats seems like way too little if you're inexperienced with finishing. I usually spray about 20 coats which gets me a film of .006 to .009 - ish depending on where I measure. I figure I'm probably around .004 when I'm done sanding and stuff.

I typically use a plastic container top to plug the sound hole and like to crack a piece of finish off of there when I'm about 15 coats in to measure thickness. I'd recommend doing the same. I'd target a rough finish thickness of .008" and you can work your way down from there as you get better at leveling etc. Personally, I've only done 4 so I'm still targeting .008.

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

Agreed. I usually go 18-20 coats. They should look wet the instant they go on, although lose that in a few seconds.

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Dave
Milton, ON

I am working on one right now trying to get it done for ASIA. I spray wetter than Dave for sure, mine will stay wet looking for 5-10 minutes but still levels out nicely. I think for that build 12 or so is okay, for a thinner coat obviously more. I am rushing this one so everythging is pushed a little but I like Gerald Sheppards schedule. He did a nice post on it, it is in the archives. He waits a few days between sessions and with the waterbase I like to do that. I don't have a ton of experience with it, only a few guitars really, but it has worked well, especially when I take my time. Getting the pore fill done perfect before the first sessions is really important (I think). Also, I found that laying down a coat of waterlox, or any other oil type wettener (some of the epoxies are good for this too) under the shellac makes it look better, or richer. You may know this of course, but I thought I would mention it.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

Thanks for the info...as I sprayed more coats and got familuar with the laquer my coats got thicker...in fact it seems that a good coat just gets barely milky and looks wet...
Unlike other finishes I have sprayed in the past , I have yet to get a run with this stuff..

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MK5acoustics.com

I'm certainly not an expert, but the times I tried going heavier (headstocks on a couple of recent ones) I ran into a bit of deterioration (sinking into pores) a while after buffing. Needed resanding/buffing in those areas. Probably heavy enough to need longer cure. (I use Geralds schedule of 3/day every 3 days as well although find 2 weeks cure is ok for EM6000 vs 4 wks for USL)
Interesting your comment about the oil Burton....I used polymerized tung oil under shellac sealcoat on this one viewtopic.php?f=10101&t=31912 & felt it also made a big difference.

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Dave
Milton, ON

I have sprayed 14 over the last while.
Totally agree on the shellac (I pad it on), 6 coats, 3 days, light level sand, 6 coats, 3 days, medium level sand, 3 days 6 coats, 2 weeks, final sand and buff.
Burton - thanks for the tip on Waterlox - I have had the best grain pop with epoxy, but don't like working with it - use Timbermate now.

Burton, what are you using for pore fill? Loved your idea about Waterlox... gonna go get some. No adhesion problems?

Another sound hole plugger idea: Balloons. Use them all of the time. Even been known to use a latex glove (filled with air).

Mike

PS: I have been thinking about trying this: Let EM6000 thicken in the open air, then when it is almost jelly, use it for pore fill. This would be on top of a shellac coat to avoid wetting the bare wood.

I have been using all sorts of things for pore fill, WEST 207, CA, you name it. I don't like any of them but they all work with enough attention. I do the waterlox coat first then pore fill over that. I always sand through in a spot but don't worry too much. After the first sanding coat just reapply the waterlox. It should always be the first thing touching the wood. On almost every kind of wood it is dry enough after 24 hours. Some woods take longer but I have never had it not cure, unlike tru-oil which can be very annoying on some of our favorite woods. When applying it I put it on as thin as humanly possible, i.e. rub some on one half of the back, wait 20 seconds and then rub as much off as I can. I always end up with the CA brush hitting the last few pores before the shellac goes on. Actually, usually I find a few more even after the shellac. I don't trust the EMtech as a pore filler, it shrinks too much.

For the waterlox get the red can, the original. The green goes on much thicker but is harder to wipe off cleanly and therefore harder to lay out in an ultra thin coat. Definitely get some bloxygen if you get the waterlox and use it liberally. The waterlox is expensive and comes in a relatively big can for what I use it for so I am very careful to severely limit its open air time.

I am sure many other things work just as well as the waterlox but it is what I have experience with. I first heard about it in the famous Poly vs. Nitro thread and have been using it since then.

I also want to mention that I believe KTM-SV is a superior finish to the Emtech in terms of waterbase topcoats. I am using the Emtech currently because I am in a hurry and have experience with it but there is a lot of posts and some very experienced waterbase finishers opinions about the differences and I do trust them. Randy Muth's KTM-SV guitars at Woodstock looked better than I could ever expect an Emtech guitar to look in my opinion.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

I did this to dropfil (although not to "jelly" stage)...some big pores & binding gaps. Worked pretty well. No shrinkback to date.

Burton, I like the look of SV as well but was a little spooked by some of the comments. Sounded a lot more iffy than EM6000.

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Dave
Milton, ON

Dave, I agree that it sounds more finicky. It makes me think I would almost just rather go to real varnish! The ease of use on the Emtech is, for me, the best thing it has going for it. I sanded, DA'd, and re-top coated a guitar that had been sitting for months with a nice layer of coats and the Emtech still burnt in invisibly.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

Yeah...I just finished spraying a bunch of test panels with it. The water cleanup...lack of fumes....the way it lays down....100% burn-in....all terrific aspects.

I'm laying it down pretty thin and still getting that slight white/blue haze that we are all used to. Target's instructions say to wait until that clears before respraying but does anyone think that laying down three or four coats and then waiting overnight to clear is a bad plan regardless of whether or not each individual coat is clear prior to recoating?

I can't visually see anything untoward when I've done this on panels. It looks clear and complely shrunk back in the morning. I'm always amazed at how thick it appears while spraying and how thin it shrinks back after drying. It's no wonder 15 coats are required.

What say you?

Also....do we feel compelled to use Target sealer or waterlox under EM 6000 or are we happy spraying this over scuffed shellac?

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Stuart, I do 3 or 4 coats, 1 hr apart, and don't really see much haze/blue when ready for the next coat.. I also think the 3 day wait between "sessions" is a good idea so you don't get ahead of the curing. Is this what you mean??

Also, I've only ever done it over scuffed shellac

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Dave
Milton, ON

Yeah....and it might be the orifice on my gun but I have to lay it on fairly thick to get coverage....so I get a fair amount of haze...and it's still there a bit after an hour.

Might point might be that I LIKE piling it on ....so I'm bound to have to respray when there is still a haze present.

I'm wondering, as long as it is clear in the morning, do I have to worry about anything?

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

I also do 3 or 4 coats per day, anywhere around 1 to 8 hours apart depending on how my day's going. I'll often do one in the morning and then 3 more after work.

I've never waited 3 days between sessions but I do have what looks like some shrink back on some seams but interestingly, not all of them. I can't speculate as to what the mechanism would be but, I've heard some say that titebond glue lines become visible years later under emtech where as HHG or other glues don't. Don't know what to think about that.

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

Is Gerald Sheppard still using waterbased?

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It's not what you don't know that hurts you, it's what you do know that's wrong.

I also spray 3 to 4 coats per day on consecutive days with about 1 hr or so between coats. I spray several coats of shellac till the color is right then put down around 12 to 16 coats of EM6000 before leveling, then another 8 to 12 before final sanding and buffing. I try to get a good wet coat when I spray but back off if it starts getting very milky looking.

Looking forward to trying Waterlox on the next few, thanks for the tip.

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Steve Smith
"Music is what feelings sound like"

Burton,

Guess I am still confused. Are you saying Waterlox is a pore filler? What is bloxygen?

Yes, I have read many good things about KTM-SV, but its not a "non-toxic" solution, right?

Mike

Wow, that sounds like a heap of finish. Have you been able to measure the final film thickness?

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Cheers
Pete

IIRC, the SV is a very benign substance, according to it's MSDS...

Yeah, that seems right, but there seems to be (IIRC) one or two prep steps that are nasty (nasty chemicals).

I have spoken with Randy Muth several times and I know for a fact that there is at least one nasty stage in the process.

Mike

I agree. I do not use near that much. Too much risk for haze. I do 9, then level sand, repair, drop fill (jelly), sand, then 6 more coats.

Mike

I'm not sure I know what you mean. You prep the body according to your favorite method and spray. No prep of the SV itself required. Although I haven't used Em6000 itself, I have used the Stewmac stuff (Target as well, I think) and ktm-9, and SV lays down just as well if not better than those. The SV is an actual urethane, whereas the others are acrylics unless I'm mistaken. Anyway, what prep steps are you thinking of?

It's not really. The film dries really thin. That number of coats would probably be around .009 at it's thickest not counting the middle leveling step which would remove some of the thickness. As I wrote earlier, when I spray around 20 coats, I've measured between .006 and .009 in various spots.

What thickness are you targeting for for off the gun and buffed finish?

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

Hi, I've been asked to comment on this thread.

I've been using KTM-SV for quite awhile now. Don't assume waterbornes are not toxic. In fact the solvents in waterbornes are more bioavailable even if they are not as nasty. I use a good respirator and have excellent ventilation. I use it because it works very well and I don't have to be explosion proof. I have been able to do invisible repairs on it.

I spray 10 coats on the top and 12 on everything else. Six the first day and the rest the second day after leveling. I'm laying down 0.5 mils per coat, so 5 mils on the top and 6 mils on everything else before sanding and buffing. Rarely do I burn through anymore.

Assuming a dead flat pore fill, I find that a lot of burn through is a result of spraying error, not sanding error. It is typical to get into a routine with how you hold the guitar, the gun, and your spray pattern, and to routinely spray light in certain areas. If you are burning through in the same spots on multiple guitars, it is probably spraying error. Close visual inspection during spraying and then adjusting your technique will solve this.

The main issue with KTM-SV is that it does not cure over certain oily woods, i.e. EIR. It even has issues with ebony. The rock solid solution that I have found is to use a rosewood sealer over everything after pore filling. I use an Ilva product. It is solvent based and I guess "nasty". However, I don't spray it, I either brush or wipe it on. I use two coats before spraying the KTM-SV. Again I use a respirator and have good ventilation. To tell you the truth, given the option, I would rather breathe this while brushing than breathe aerosoled waterborne.

I have used a number of pore fillers and was recently using CA. Due to continuing concerns about adhesion, I am now back to using epoxy. My strong preference is for System Three SB-112. I know a lot of people have had problems because the ratios are exacting, but I have never had a problem. I just use small measuring cup and good eyesight. It still takes 3 coats, but a well tuned scraper makes leveling the pore filler much more pleasant.

Finally, here is a great trick that works with KTM-SV. Typically, I level by dry sanding my final coats with P1000 and then I wet sand with P1500 and P2000 before buffing. Of course it is easy to see what you are doing while dry sanding so that you remove all the low spots and don't over sand where you don't need to. However, it is much more difficult to get feedback when wet sanding to remove the finer scratches. Here's what I do. I take a black sharpie and scribble all over the guitar. You can even write a note to your customer and send him/her a picture. When I sand all the marks away, I'm done. Then I repeat the process again for the P2000. This way I know exactly where to sand, so that I don't over sand and I get feedback on when to change the paper. Don't do this if you have burn through! I imagine this might work for other cured finishes, i.e. varnishes. I definitely wouldn't do it for shellac or nitro. In any case, a test would definitely be required.

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Randy Muth
RS Muth Guitars Website
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