Official Luthiers Forum!

Anyone here using Urethane finishes? I hear urethane holds up better than lacquer.
I would like to find out what brands are recommended!

Thanks

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

I used a 2 part polyurethane finish on my last guitar, except the top which I french polished. It was easy, fast, and looks great, but it's lethal. It made me sick, and I sprayed in a nice booth and wore a respirator. I wouldn't want to use it much more without a fresh air system, but I would like to use it again. I believe the brand is called Ilva. It comes from Italy and is expensive as hell.

Mike

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

Sorry, it just occured to me that a "urethane" finish might be different from a "polyurethane" finish. Hope I didn't give you useless info!

Mike

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

Thanks Mike, I think there is a difference! But thanks for trying!

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

-SniderMike38807.8604166667

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

I have been using McFaddens 2 part Urethane Lacquer for about two years now with excellent result. It's 4 times more expensive ($100/gal) than nitro but I can take it to the buffer in 2 days vs 30 days with nitro. Repairs are more difficult than nitro. I have used CA in inconspicuous areas but if the repair is required in the middle of a panel you have to shoot the entire surface again.

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

I believe I read that Robbie O'Brian uses catylized polyurethane finish. Perhaps he will chime in here.
I would be interested in hearing about it too.

Back when I used to spray my own finish I used McFaddens urethane for a
while near the end. I liked it (as much as I liked doing finish) really well.
Easy to use, and mix, builds really fast and dries hard and fast and clear.

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John Mayes
http://www.mayesluthier.com

Yes, I do use catalyzed urethane finishes on some of my guitars. It holds up and wears better than lacquer in my opinion. It also doesn't get those awful spider web cracks or chip like lacquer. It is a reactive finish as opposed to lacquer which is an evaporative finish. Therefore, it builds in layers instead of making one layer. The drawback is that you can sand through a layer during the sanding or buffing stage and get witness lines. This is not bad unless it is done on the final coat. The remedy is to sand back and recoat. IT also doesn't repair as easily as lacquer. You must recoat an entire area (back, side etc) instead of just that spot that needs it. Over the years I have become used to using the urethane and have had excellent results with it. You don't need any special equipment other than what you already use to spray lacquer. I use a European 2 part urethane brand that comes from a company called ILVA but basically it is just a 2 part conversion varnish. They have a Stateside rep. A qt of the urthane, 1 qt of the hardener and 1 qt of the thinner will run you about 35 bucks but then you pay about the same to get it to you bencause of the hazardous shipping costs. A gallon of each will run you about 60 bucks plus shipping. YOu mix it at a 1 to 1 ratio and then spray normally. This stuff is highly flammable and full of nasty chemicals, therefore you need to take the same precautions you would with lacquer.    

It seems like people are using "urethane" and "polyurethane" interchangeably. Are they confused like I was, or am I just even more confused now???

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

I'm like Tim. I use the McFadden catalyzed urethane. It works great. I fill with either epoxy or UFO CA, level with 220, spray on three coats 15 minutes apart, level with 220 the next day, spray on three more coats, level with 600 then 1500 and buff with Menzerna. The longer you wait to buff the harder it is to do. Make sure you get the butyl acetate thinner but you can clean up with regular lacquer thinner. The stuff is expensive but it goes a long way. Keep the hardener in smaller bottles. I like the way it off gasses quickly. Good luck.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

I am so confused....

For you guys that use McFadden's catalyzed urethane, are we talking about McFadden's L-4108? The one they call Polyurethane? It mixes 4 to 1 with hardener? And they say it is a "workhorse in the fretted musical instrument industry"?

Thank you in advance for the clarity you've added to the subject and perhaps to my guitars!

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Joe Beaver
Maker of Sawdust

[QUOTE=Joe Beaver] I am so confused....

For you guys that use McFadden's catalyzed urethane, are we talking about McFadden's L-4108? The one they call Polyurethane? It mixes 4 to 1 with hardener? And they say it is a "workhorse in the fretted musical instrument industry"?
[/QUOTE]

I've been wondering the same thing, but it seems like everyone wants to keep it a mystery    It seems to me that my original thinking was correct, and that the polyurethane finish I used is simply referred to as "urethane" by some. Someone please correct me if I'm wrong    

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

Just to make it more confusing...there are mono-urethanes and polyurethanes both I believe.   

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"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

[QUOTE=Don Williams] Just to make it more confusing...there are mono-urethanes and polyurethanes both I believe.    [/QUOTE]

Aaaaarrrrgh!!!

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

I have posted my notes before but here they are again:

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

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


Spray one coat of vinyl sealer on bare wood
Pore fill wood with Z-poxy or standard oil base pore filler
Wait 3 days for oil base filler to dry
Wait 2 days for oil base 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
4 parts      L-4108 McFaddens Urethane Lacquer
1 part      CV2117 McFaddens Hardener

Apply 3 medium wet coats
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 220-320 grit sandpaper
Stearate sand paper will not cause problems
Apply 2 more coats of Urethane finish on top, 3 on back and sides
Clean gun with lacquer thinner

Wait 5-7 days before buffing (2 weeks is ideal)
Wet sand 600, 1000 & 2000 grit
Buff with 3 compounds of Menzurna (medium, fine & extra fine)

Drop fills are not successful as it will not burn into the finish

Clean up with Lacquer thinner

Thin with Butyl Acetate at 10% if needed

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

Well, since there is no "urethane" finish on McFadden's site (only "polyurethane"), then I'm going to have to assume that it's just been shortened to "urethane" by those involved in the conspiracy to keep me confused

Mike

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

Tim, thanks for the detailed instructions!

Mike

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

It also doesn't get those awful spider web cracks or chip like lacquer

I love those when there is some age on the instrument, its really part of the "vibe" of those old Gibsons and such - but are you talking about premature cracking and chipping? I have no finishing experience, and wasnt exactly clear on that.

Cheers
Charlie

I hope this doesn't cloud the issue, but, I pursued it a little further with Mc Fadden's. I asked about the L-4108 product and how it would fit in with the small shop. Here is their answer:

Hi Joe-
Enclosed is some info about the L-4108 urethane topcoat. Our minimum order is 5 gals (plus 1 gal hardner CV-2117). This really doesn't quite fit a small luthier due to the sensitivity of the coating and the pot life. The hardner may kick off in 4-5 weeks, and become very thick and unusable. We will send a sample if requested.
Sincerely
Peter Beck
The lawrence-Mcfadden Co

I went a step further and asked what products they had except nitro that might be a fit. Here is the answer:

Why not try nitro? It has to be better than water..and much easier to repair. Or with urethane, share it with some other luthiers closeby. That way, it won't go bad!
peter

So it looks like as far as McFadden's goes it's either nitro or nothing.

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Joe Beaver
Maker of Sawdust

[QUOTE=SniderMike] Well, since there is no "urethane" finish on McFadden's site (only "polyurethane"), then I'm going to have to assume that it's just been shortened to "urethane" by those involved in the conspiracy to keep me confused

Mike[/QUOTE]

Mike:
"URETHANE LACQUER" is printed clearly on my 5 gallon cans. I can't explain the info [or lack thereof] on their website. Even McFadden's rep referred to it as "URETHANE" in his reply. Hope this helsp.

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

Tim, thanks again. I guess McFadden's is in on the conspiracy too    I think I'll just stick with the Ilva for now since I don't need 4 gallons of McFadden's.

Mike

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

I'm with you Mike. I've been looking for a way out of the KTM dilemma. Guess I'll stay with it for awhile longer. Actually it is not bad stuff.

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Joe Beaver
Maker of Sawdust

[QUOTE=Joe Beaver] I'm with you Mike. I've been looking for a way out of the KTM dilemma. Guess I'll stay with it for awhile longer. Actually it is not bad stuff. [/QUOTE]

Hey Joe. I was thinking about trying the KTM, because I've seen a couple that turned out looking pretty good with it, but it just gets so many negative comments    
The Ilva that I used on my last one really was great except for its toxicity. It's easy, fast, and cheaper than McFadden's and you can buy as little as a quart. It's the same stuff Robbie describes in his post. I would certainly recommend trying it if you have a booth or can hold your breath for a while.

Mike

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

[QUOTE=SniderMike] The Ilva that I used on my last one really was great except for its toxicity.
Mike[/QUOTE]

I might try Ilva. Where do you get it? On-line?

I use KTM-4 but I'm out now. I was thinking about giving KTM -9 a try. KTM-4 is actually pretty good if you spray it in a dry envirornment (35% or less RH). Otherwise it seems to stay on the soft side, especially on woods like mahogany. (seems to harden a lot better on rosewood for some reason. I use a cross linker and don't have a shawdow effect problem. They say KTM-9 is self linking so it doesn't need a linker. The other concern I have with KTM-4 is that after a year or two it seems to lose some of it's shine.

What I do like about it it's easy to use, safer, doesn't want to check like nitro and seems to have long term serviceability.

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Joe Beaver
Maker of Sawdust