Official Luthiers Forum!

It's the Reslack line, methinks. Part number "750-001"

Isolante sealer # "401-033", hardener #"99-066"

Also requires Cobalt and MEKP.  NEVER, EVER mix these two, or even store them near one another!

anyone serious about trying this stuff needs to call and talk to a technical guy for up-to-date numbers, and the mix recipes, etc....

Also be prepared for a steep learning curve, because if something goes wrong, it goes wrong in a big way. I had Rick's guidance and exact part numbers, etc..., and still, from one mistake(not letting the sealer cure long enough...), lost a year's work.... But in the end, it(and the Maestro, here),  saved my career. Nitro threatens to kill me, and waterbornes are not near to being ready. Varnish is interesting, but not the look I, nor my target market, want(s).

Thank you greatly. Good to have you back!

_________________
Eagles may soar, but weasels don't get sucked into jet engines.

Dang. Great stuff, and thanks for sharing all this Rick and Grumpy...

_________________
"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=grumpy] 'pick tracks": skid marks left by the pick scraping the top[/QUOTE]

In my house, "skid marks" are what we find in my daughter's undies when she hasn't wiped so well.

Maybe I just have to take a close look at one of Rick's or your guitars that's been played a while to see what a "pick track" aka "skid mark" is, as compared to a pick scratch on a nitro or FP finish. Unfortunately, I have not yet had the pleasure of meeting either of you guys's guitars in person.

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Rick, would you mind explaining the process for your bursts a little bit
more? Do you burst or stain, then waterlox, sealer, poly, and more poly?

_________________
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

Grumpy, would you mind explaining the procedure if you're brushing on?
Do you brush everything on? Will the technical guy give me the recipes
for brushing?

It sounds like you just go sealer over the bare wood, then the poly. Is this
correct?

Does one layer burn into the next?

What kind of problems did you have?

Bursts and stains 101

Sata MiniJet gun equipped with 3M PPS interchangeable disposable cup system

US Cellulose MEK soluble dyes...about $45.00 a gallon. I keep the following colors on the shelf:

Yellow
Warm Brown
Van Dyke Brown
Red
Black
Blue

I have cups ready to go with each color in a rack in my spray booth. Changing colors takes all of 30 seconds.

I'm shooting on bare wood or water based pore filled wood (Behlen's) for mahogany or walnut.

For bursts, I'll first do warm brown around the edge and feather it in as much as I think I need. Then I'll go in with yellow, producing a kind of tobacco burst. Then I go back over the very edge with Van Dyke brown to get it really dark. That's my kind of Loar era tribute finish. I'll then go in with red if I'm going for a "three color" burst...even though it's really four colors.

At this point it looks kind of like sh.., and there is a leap of faith required to move on.   The next step is a coat of Waterlox foam brushed on and wiped off with blue paper shop towels.   

WARNING: YOU MAY NOT BELIEVE IN SPONTANEOUS COMBUSTION, BUT I DO. I'VE SEEN OILY TOWELS BURN...

A second coat of Waterlox completes this stage.

Then I mist on a light coat of McFadden's rosewood sealer. If you spray too wet, the solvents will burn through the Waterlox (which does help seal the color) and you'll get these little eyes of dye coming up into the clear sealer.   Not good.   Ugly...   In an hour or so, I'll spray a wetter coat of sealer, and then much later do a full final coat.   If I'm looking to achieve a more opaque "modern burst" look, I'll go back with straight color between the last two coats of sealer. The dye will bite into the sealer and then be locked in by the last sealer coat.

Next day scuff with maroon ScotchBrite and shoot first three coats of polyester. Next day flat sand taking care not to burn through the color, and shoot three top coats.   You can rub out in 24 hours, but it's actually easier in 48.   

Rub out...400 grit only if needed to knock down sags, 600, 800, 1000, 1200 (can be done wet), Menzerna 38, Menzerna 16, done.

On instruments and parts that get satin, I do that after the three build coats of poly.

My procedure is different when I'm not shooting color; that's when I go for the epoxy fill.

Thanks a bunch Rick. It's really great to have guys like you and Mario
around (and the other pros here), willing to share your knowledge and
experience. Can't say that enough. Thanks again.

I've been spraying bursts and color with Transtitnt-dyed shellac. It has
worked pretty well with polyurethane and waterbased finishes, although
maybe some adhesion issues with the polyurethane. Is shellac
compatable with polyester, adhesion-wise and otherwise?

_________________
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

By the way, I do believe in spontaneous combustion. In oily rags, and
drummers too.

_________________
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 just playing devil's advocate, here, but it seems like no discussion of "poly vs nitro" is complete without somebody raising this issue. Some contend that nitro ages in such a way that complements the aging of the wood, and is significantly responsible for the improvement in a guitar's sound over time. It is said that poly and other modern synthetic finishes will not do this, or, at least, that they haven't been around long enough to prove themselves in this respect.

So, poly users, how do you answer these charges?

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

My guitars open up just the way I'd expect them to if they were finished in nitro.   Also I think that a lot of that bit about nitro being good for tone is vintage guitar collector bullsh.. There's no real proof of the claims as there's no control group of instruments finished in poly of the same age. The closest thing to a control group would be Martins and Gibsons finished with shellac and varnish...those from the early to mid 1920s, and they are in better shape than the earliest nitro guitars.

There is ample proof that nitro finishes won't make it to 100 years old without severe degradation.   A lot of nitro-cellulose (celluloid) binding is rotting off of vintage guitars, especially D'Angelicos and Gretches.   The stuff is simply not stable.   Pre-lacquer Martins look much better than the late '20s and '30s guitars.   I think that ultimately lacquer is a losing battle.

The myth comes from the early and mid 1930s Martins that set the standards for what we now think of as being great guitars.   But was it the nitro or the fact that suddenly we had OMs and D-28s with Adirondack tops, Brazilian rosewood, forward shifted "X" bracing, light scalloped bracing, etc.? Ditto Gibson with the AJ, Nick Lucas models, etc.   Great guitars because they were great guitars, not because of nitro lacquer.

If you go back another decade, though, you have what are arguably the most valuable and fine sounding Gibsons...the Loar designed F-5s and it's brothers and sisters and "baby body" L-5s.   What was the finish?   It wasn't nitro lacquer...and that varnish holds up better than nitro as well.   

So the argument is usually based on faulty logic.

What Rick said.

My instruments have never sounded better, and they still open up the same way as always. I've used nitro, shellac, various water-disasters, and polyester. The sound never really changed.... I kept each one as thin as possible, and I stand behind -that- as the key.

But even thinness(is that a word?) is overated. I took a beater of mine that had a thin FP finish on its top. By thin, I mean, a spit coat-only. We played it for many months, then one day, I masked it all up and shot a ton of nitro on it. There had to be .015" on every surface. Didn't sand and buff, but instead, took all the tape off, and tuned her back up.... The tone was a bit tighter, brighter perhaps. Most folks (if not everyone)would have said it sounded better after the lacquering! I eventually sanded it down and buffed it out, but there is still lotsa finish on there. I gave it to a friend's son when he was 8, for Christmas. This year, he was on stage at a big Bluegrass festival with us as our guitarist. He's now 14... And the guitar still is a killer, albeit with severe lacquer checking <g> Now i know how to replicate that old Gibson checking pattern; go extra heavy on the lacquer, then expose it to multiple sub-zero temps....


For sunbursts, I use either the StewMac liquid tints, or the LMI metal acid dyes. I mix them in alcohol, and add just enough shellac to make a binder. I shoot all the colors as usual, let it dry a day or two, then shoot the sealer and topcoats as usual. Shellac is okay, if you top it with the sealer. Don't try using shellac as the sealer, though. That fails(me tried).

The tech guys will laugh at you if you ask them about brushing this stuff. Just mix it like you would for spraying, but don't thin it. I use a foam brush, then toss the brush. One heavy coat will do a headstock, BTW! Just one swipe.....

The coats burn into each other, as long as you re-coat in time; if you wait too long(40-45 minutes, max), you'll have witness lines. I keep a timer and bell outside the booth to remind me.....

Thanks, Rick. Your perspective on and experience with polyester finish is extremely valuable to all of us, to say the least. And your arguments about the shortcomings of and myths surrounding nitro are also well worth heeding, methinks (I got that "methinks" thing from Mar... er, Mr. Grumpy ).

[QUOTE=Rick Turner] My guitars open up just the way I'd expect them to if they were finished in nitro. [/QUOTE]

That pretty much says it, right there.

[QUOTE=Rick Turner] The closest thing to a control group would be Martins and Gibsons finished with shellac and varnish...those from the early to mid 1920s, and they are in better shape than the earliest nitro guitars.

There is ample proof that nitro finishes won't make it to 100 years old without severe degradation.   [/QUOTE]

That's a very important point. I find it particularly interesting, also, that shellac is frequently said to be the least durable of guitar finishes, while nitro is said to be, by comparison, quite durable. I don't think anyone would argue the fact that nitro is tougher than shellac in the short term, but, given a handful of decades, shellac clearly seems to come out the winner over nitro in durability - in the truest sense of the term.

Polyester appears to be the king of durability, while having several additional advantages over other finish options as well.

Personally, I'm becoming increasingly convinced that there are two best guitar finishes for me to pursue: shellac/FP and polyester, the circumstances of each guitar (or each part of a guitar) dictating the choice between the two.

A varnish like Behlen's Rockhard offers a third option with some advantages as well. (I got to inspect and play some of Bruce Sexauer's guitars in Montreal; the finish looked great, and one of his guitars was among the very best sounding of all I played there, to my ears.)

I admit that I don't know squat about some of the catalyzed urethanes people are using, and what advantages they may present in comparison to polyester or other varnishes. I'll shut up now.

Well, one more thing: somebody needs to come up with a better name for polyester. The word polyester has negative connotations in our culture, while "french polish", and even "nitro", are steeped in mystique.

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Thanks, Grumpy, for your response as well (I was writing my last post while you wrote yours). I appreciate you guys telling it like it is, and educating us all.

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

[QUOTE=Todd Rose] Thanks, Grumpy, for your response as well (I was writing my last post while you wrote yours). I appreciate you guys telling it like it is, and educating us all.[/QUOTE]

Absolutely!!

Mr. Grumpy, an earlier comment was made related to where you might have been talking about "transitioning from nitro to poly for a one-man shop" on the MIMF. I searched for that, but couldn't find it. Can you suggest search words to find that? Thank you again!

Bill

_________________
Eagles may soar, but weasels don't get sucked into jet engines.

Thanks for the heads up on the brushing. I'm about to finish with
Rockhard brushed on. I actually brushed a few coats on and decided to
step back a bit to take care of some things I wasn't happy with in the
build. I'm getting ready for my second go. I'm not thrilled with the
yellowing though, and this poly sounds amazingly promising.

So you seal, then shoot the poly 20 minutes later at 40-45 minute
intervals being the absolute longest. Do you do the waterlox under your
seal? And do you only do one seal?

Optional water based pore fill. Shoot stains and bursts.   Waterlox one or two coats. Wait 24 hours. McFadden rosewood sealer, two coats about 2 hours apart. Wait over night. Scuff with Scotchbrite.   Blast three coats of polyester no more than 45 minutes apart.   Sand flat the next day, don't worry about little sinks, try not to burn through to wood. 3 more coats of poly. Wait 24 or more hours and rub out.   

That's just one version of the schedule, the one for stains and bursts.   For none colored finishes I'm doing the West pore fill version which results in one less day of poly spraying.   That's one more reason to upcharge for colors...it really is more work.

BTW, the LMI metal acid dyes are the US Cellulose dyes. I just prefer to buy the stuff in gallons for a really good price.

What do you guys do if you do happen to burn through to wood when
rubbing out? Obviously subsequent coats will not burn in. Do you sand
everything way back and shoot several more, or just one more coat and
be careful in the burned through area?

_________________
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, Rick. I'm making pdf's of notes on all this.

How are you guys sanding? It seems like the finish is quite thin. Earlier
Rick mentioned starting at 400. What do you sand with? I have
trouble with sanding through finish. Are you sanding by hand?

We do most of our sanding with Dynabrade orbital sanders. You just have to learn how to see what you're doing. The big issue is burning through on edges, so take a dry erase marker and draw lines around the guitar about 1/2" in from the edge. That's the last thing you sand.

We're mostly using the 3M gold sandpaper except for the very high grits.   I'll get all the part numbers together on one document.   I also love the 3M sanding sponge pads.

I stopped participating at MIMF when Deb's ridiculous policy against posting "commercial" URLs became too absurd for me.   She pulled my post suggesting that folks check out Frank Ford's www.frets.com site.   Yeah, like Frank is the Bill Gates or Larry Ellison of lutherie ripping us all off with his highly commercialized site... I won't support anyone making the Internet more of a pain in the a.. that it already is, so I bowed out. That you have to go Google suppliers who have been mentioned is just lame when a simple link would be so easy to use. I've never seen any abuse of URLs on lutherie sites other than the occasional cell phone offer...

The thought of brushing poly is intriguing....but am I correct to assume this is still a highly toxic product, and the fumes while brushing and off-gassing when curing mean this cannot be used in a residential enviroment?

_________________
David White, Toronto

"All my favourite singers can't sing."

I just have to say this:

This is one of the best OLF threads I can remember. Thank you guys for sharing so much of this. Rick, Kevin & Mario, this has been a great thread.

Oh, and Mario... glad to see you back.

_________________
Brock Poling
Columbus, Ohio
http://www.polingguitars.com

I've seen MEKP mentioned several times. What is that. In the auto finishing, we used to use MEK or Methyl Ethyl Keytone mainly as a solvent to clean certain parts and finishes to promote adhesion on them. Mostly plastic bumper covers. So what is MEKP in relation to polyester. Also, is there anyone using Polyurethane that wants to speak up and explain some of their experience with it. I used it once on a guitar repair, simple re-clear on the sides of an acoustic guitar. I did it about 5 years ago and had a look at it last month and it still looked fabulous.

Joe, I've used 2 part polyurethane on several guitars. It's pretty easy to
use and looks good, but it really seems to shrink quite a bit. It's also not
as tough as polyester, from what I'm told. And I've had adhesion
problems, which I'm sure could be solved if I was willing to put in more
time with it, but I guess I figure if I'm going to use really toxic chemicals,
perhaps I should just go all the way and use polyester. I've been trying
waterbornes more recently.

_________________
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 not sure why folks seem so freaked out about the chemistry of polyester, yet take nitro lacquer in stride. Around here, the fumes from the nitro seem much worse than the fast flash off of the MEK we thin the polyester with. 24 hours after spraying polyester, there is nothing coming off the surface, yet nitro out-gasses for years, and a room full of curing nitro-sprayed guitars will knock you over for days.   Of the finishers I know who have become sensitized to different materials, nitro is the worst. Then there's the nitric acid byproduct that etches away nickel plating on old instruments that have been kept in cases and probably attacks the wood as well.

MEK...methyl ethyl keytone...is a thin solvent. MEKP...methyl ethyl keytone peroxide...is a more viscous liquid that is a strong oxidizer.

None of this stuff is good for you...not even the overspray and fumes from water based finishes.   And even if you're French polishing, Everclear or lab grade alcohol...that is non-denatured spirits...are the only solvents that aren't poison.   Any finishing should be done in a well ventilated room, and if you're spraying, you absolutely need an explosion-proof fan and some sort of spray booth.   Otherwise send the finish work out to an expert who is set up properly. The cost may seem high at first, but getting set up to spray properly is really expensive.

A side note here...when I worked for Gibson, they figured that one third of the labor to build a guitar was in the finish process. I think our time in is below 25%, but that's still a lot of time.