Official Luthiers Forum!

Good to here from you Mike. It has been a while. interesting desission you made. I think I woud join you as well but I have a big big issue with MEK so I am stuck here with less toxic finishes.

I am pretty pleased with KTM9 and have done French polishing since I was 15 or so, but being ever inquisitive, really would like to try catalyzed polyester. However the issues mek and finaces make it prohivitive at this time

Sorry to be the one to tell you this Michael, but this is a post by Terken (AKA Terence Kennedy) not Mike Doolin, although it would be great if he were here.

Thanks for sharing this Terken.

_________________
My Facebook Guitar Page

"There's really no wrong way, as long as the results are what's desired." Charles Fox

"We have to constantly remind ourselves what we're doing....No Luthier is putting a man on the moon!" Harry Fleishman

"Generosity is always different in the eye of the person who didn't receive anything, but who wanted some." Waddy Thomson

oops

As y'all know, I also gave up on waterbornes, a year ahead of Mike. As he says, for the home hobbiest, they do fine, but if you're putting your guitars "out there", it's a risk.

I need to tell Mike he doesn't have to wait 5 days with the polyester. <g> 24 hours will do! Anyone have an address? Can't access his website for some reason...

Terry

I had a similar experience. One of the top luthiers in the are told me to ditch the water based stuff and switch to something like Nitro.

Like hesh I also have an unopend can of KTM since switiching. I don't know what to di with it.

Josh

_________________
Josh House

Canadian Luthier Supply
http://www.canadianluthiersupply.com
https://www.facebook.com/canadianluthiersupply?ref=hl
House Guitars - Custom Built Acoustic Instruments.
http://www.houseguitars.com

Wow I just bought a large can of KTM-9. It hasn't even arrived yet.   

Oh well I don't have much choice because I can't afford to get the proper equipment for the other stuff.

Maybe Grafted Coatings will come out with some sort of additive to make it cure to a harder consistency.

    I used MFadden's Nitrocellulose on more than 350 acoustic guitsr before switching to the UV cured polyester that i now use. I'd experimented with waterborne finishes and few catalyzed finishes before deciding to take the dive to the UV finish. The waterborne finishes can;t give you the results that are possible with the polyesters that reach a full cur very quickly and stop shrinking at that point.

   I've seen guitars from the best builders in the world that have used the waterborne finishes (KTM 9 included) and always wondered wy they would settle for those results when safety precautions could be taken to be able to get the finish right. The initial expense is high, but the gear lasts a long time and the finish results are what the cusomers want.

    I have the booth and outside air supply mask and hav really enjoyed the process so far. I still use the hand held UV cure light, but am considering a move to an automated botth like Kevin Ryan and Jim Olson have.

   The waterborne products are perfect for a budding luthier or hobbyist, but as they move into the marketplace, they'll have to commit to a more professional or industrial alternative.

Regards,
Kevin Gallagher/Omega Guitars

Sorry to hijack the trhead, but..

Kevin, how long between coats, using the hand-held UV light? Do you shoot a coat, wave the light to kick the process, then shoot another coat rigth away, wave the light, etc?

Or do yuo stuill have to walk away from the booth for a set amount of time between coats, even after waving the light over the work?

thanks in advance...

Looks like I can pick up some KTM-9 here, at the KTM-9 "fire sale"...

If someone's really interested in bailing out, please PM me. I could use an quart.

Thanks,

Dennis

_________________
Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia

I was wondering if someone could post a link to, or a couple of product names as recommendations, regarding catalyzed polyester and UV cured polyester.

Thanks

Larry

_________________
Thank You and Best To All

I was able to make KTM-9 work just fine, but it's just to soft in the long run and like other lacquers and like Doolin says shrinks over time. I'm switching to catalyzed finishes as well, I will send most of my work off but I'm going to setup so I can do special projects on site. Most likely my little building that will house the dust collecter and air-compressor will have a chamber made for spraying (with explosion proof fans and the whole 9 yards).

Mario and Kevin can you provide details on your procedure and materials, I read Taylors research on what they did and have seen some light boxes for curing and am starting to work out how I'm going to do this...

Thanks

-Paul-

_________________
-Paul-

Patriot Guitars

No lights needed with the system I use. Same product that Kevin uses, most likely(McFadden's R-1775). I have to add coblat(T-526) and MEKP to kick mine. Kevin(and Taylor and all) will use soemthing different to cause it it kick with the UV light).
Either system requires a sealer(R-1704), as this stuff doesn't not like sticking to wood all that much... But the sealer is tenacious with wood, and the topcoats stick like crazy to the sealer.... McFadden's supplies the sealer as well, which is also two part(hardener CV-2117?). It is also nasty, nastier than the polyester, in my opinion.

This is not for home use. It is also expensive, and available in 5 gallon minimums. With a one year shelf life, you better be making enough guitars to justify the cost.

There's also a heck of a learning curve.

If you thought buffing KTM or nitro was tough, you ain't seen nothing yet. If your neighbors complained of the smell of nitro, forget this stuff. It can be smelled 500 feet away...

There's good reason to go with any method; you just need to weigh the positives against the negatives.

I'd like to see what the advantages of the UV system are, myself. Speed isn't an issue with the MEKP system(24 hour spray to buff if I want to), but perhaps it's the booth time that really wins with the UV?

I, too, will probably be using KTM-9 on guitars that are finished in cold weather for the forseeable future. If this discussion is leading to any panic product dumping, I'll take a quart or two. PM me.

Jim

_________________
Jim Kirby
kirby@udel.edu

Mario
   With your spraying routine, how do you handle multiple coats and the occasional burn through. Does the second or third coat adhere to the already catalyzed lower coats, do you have to sand between coats to get adhesion, are there problems with witness lines?


John

Yes, you need to apply multiple coats. 3-4 is plenty. 3 more often than not is enough...

45 minutes apart. I use a timer and bell, as this time frame is critical. Too early, and you risk sags, as it hasn't cured enough, and too late, you'll have witness lines. All coats have to go on within that time frame of each other. The booth has to be very clean, as it takes a couple of hours for it to become non-tacky, so dust is a problem if you don't have a good booth, or at least a clean room to hang it in. Again, this is not for the home user...

Burn through? Sand the whole plate back, mask off the rest, and shoot again, from the start; sealer, topcoats, etc... Ain't nothing burning into this stuff... But, it cures so fast, that it actually takes less time than a touchup in lacquer would, and this never comes back to bite you. Just sucks to have to re-do a whole top, back, or both sides, just because you went through in a small area. I may be wrong here, and there may be a way to fix sand-throughs, but i haven't found any.Mario38746.8788541667

Like others I no loinger use waterbourne nor do I use Nitro for sake of time. I have switched to 2 part catlyzed McFaddens Urethane lacquer. Here are my notes for using McFaddens Urethane catalyzed lacquer:

McFadden's Urethane Finish:
800-877-7430     Neal or Peter

Not recommended to use sanding sealer as pore filler as it could cold check!

Spray one coat of vinyl sealer or shellac on bare wood
Pore fill wood with Z-poxy or standard oil base pore filler.
Wait 3 days for filler to dry
Scuff sand with 280
Spray a second vinyl wash coat
Scuff sand with 280
Finish (see below)

Mix:
Flush gun with Butyl Acetate
Mix:
4 parts L-4108 McFaddens Urethane
1 part       CV2117 McFaddens Hardener

Apply 3 medium wet coats per day
Wait 1.5 hours between coats to off gas
6 hour pot life or mix fresh batch each time you spray

Wait 24-48 hours
Level sand with 280-320 grit sandpaper
Stearate sand paper will not cause problems
Wash down with Naptha
Apply 2 more coats of Urethane finish and stop
Clean gun with lacquer thinner

Wait 5-7 days before buffing
Wet sand to 2000 grit
Buff with 3 compounds (medium, fine & extra fine)

Drop fills are not successful as it will not burn into the finish. Must re-shoot entire panel.

Clean up with Lacquer thinner

Thin with Butyl Acetate at 10% if needed

Be prepared as this product is almost 4 times the cost of nitro. Nearly $100 / gallon [w/hardener] in 5 gallon minimums. But, when you can take it to the buffer in 3 days, it's worth it, to me.

_________________
tim...
http://www.mcknightguitars.com

Please excuse my intrusion guys but after reading all this, what seems to be hell to go through, would you advise a hobbyist like me to start with french polishing, might be a bit harder on the arms but i can't afford a spray booth for now nor the long list of materials that is required ? Would it be a safer way to go for me ? TIA and sorry for interrupting.

Regards

Serge

Serge, stay with the KTM or the Target products. They are fine for your use. When you're ready to go up to the stuff we are using, you will know, and by then, there may just be a better way, still. The wood finish business is constantly evolving.

In think we're just doing show-and-tell here <bg> Ain't a whole many of you who will be able to use these things, but it is nice to know what they are, and that at some point, you can perhaps move to them. Do not, repeat, do not feel the need to use these products just because we use them. Nitro can be done at home if you use your head and take some precuations, and the waterbornes are still viable, as long as your exposure to the marketplace is limited.


Tim, what did you use as a medium for the colors for your sunbursts? The 'bursts you had at IBMA were really, really nicely done.

Hi, I've been lurking for quite some time and have finally decided to post.

Terry, when you took your guitars to the shop, did they know that it was waterborne just be looking at it or did they ask you? I'm just wondering if they knew it just by looking, or if it is just an industry bias against waterborne. If it's an industry bias, will there ever be an acceptable waterborne as technology advances?

Also has anyone tried the EM8000 precatalyzed conversion varnish sold by Target. Rolf Gerhardt of Phoenix Mandolins uses it and I have done one guitar with it, and I like it. So far no sign of shrinkage, only a few months old though. No blue cast, can be buffed in five days, and seems hard to me. I have tried Target USL, and SuperClear 9000. I didn't like either too much. Both had a blue cast and the USL is way too soft. I didn't like the way the SuperClear sprayed and it shows signs of shrinkage, although it is very hard. I have never used the KTM.

_________________
Randy Muth
RS Muth Guitars Website
RS Muth Guitars Blog
Facebook Fan Page

Thanks for the tip Mario, i'll probably go this way but i will need a bit more information on how to apply it, i guess i better start researching on the web or i might buy Robbie O'brien's DVD which seems to be appreciated by most here, would be wiser for the novice that i am to start there.

Hi Randy, welcome to the OLF,you're at the right place for sharing sir!

Serge