Seven String Plans/Safest Naphtha?

[Colin007]

Hi all, I've been lurking for a while and finally registered, I'm learning a lot here.

I ordered a Warmoth flat top seven string, black korina body with a Goncalo Alves/Pau neck. I am *not* going to fill in the grain, I want a natural looking finish so probably just a couple layers of Tru-Oil.

It looks like I'm going to use Naphtha to wipe stuff down and possibly thin out the Tru-Oil. I've been reading that Naphtha is some pretty dangerous stuff, I was wondering if any particular brands or types of Naphtha are safer (less carcinogenic ingredients)?

Also, Goncalo is listed as not needing a finish, but as it's being used as a neck wood would that require extra stability from a finish?

 

[bagman67]

Hi, Colin, and welcome aboard.


Tru Oil is nice stuff, extremely easy to apply, but it will be a little shiny unless you dull it down with steel wool (real or synthetic).  With unfilled grain, to my eye you're better off with a matte finish than with a glossy one.  So just think about taking that extra step.  Alternatively, you could use a matte-finish wipe-on poly and get the same result with similar effort.  The Tru-oil is less durable, but easier to repair - but because it's less durable, it will be more likely to need repair, also.


Use the naphtha outdoors with appropriate gloves and an activated carbon respirator and you're fine.  If you're using it outdoors, of course, you can probably forgo the respirator too, but if you want to be extra cautious, this is the way to go.  Naphtha boils off pretty rapidly.  If you can still smell it, it's not gone yet.


Of course, if you're in the vast frozen tundra of the American interior, it may not be feasible to work outdoors in winter, in which case, consider an air compressor to blow sanding dust off your piece; and use cotton or nitrile gloves to handle it so you don't get greasy fingerprints on the bare lumber.  Omit the dangerous chemicals to the extent conditions permit.


As for finishing the goncalo alves neck, I have three words for you:  Don't do it.  The beauty of these tropical hardwoods is that they do not need a finish - even when the application is a guitar neck.  Warmoth's construction is rock solid, and they honor the warranty on such necks even unfinished.  If, as a manufacturer, they see the risk of neck failure as low enough that they won't require a finish, you can guess they've done the arithmetic and it favors them.  Playing a raw neck is very pleasurable compared to a hard-finished maple neck, for many people.  I'd string it up and play it for a while and decide later if you want to add a finish - but if you start by finishing it, going in the other direction is much more difficult.


Also, you didn't ask, but STAINLESS STEEL FRETS.  Because they're slippery as can be, and make bends easier/smoother than conventional nickel-silver frets.

 

[Cagey]

The only way Naphtha is unsafe is if you pour a couple gallons over your head and immediately light a cigarette. If you're inclined to do that, make sure somebody's nearby but at a safe distance with a camcorder, because it'll be spectacular in a jackass sort of way. Also, don't use it to mix drinks; the alcohol is dangerous enough. Otherwise, it's pretty safe stuff.

Goncalo Alves does not need a finish, nor will it benefit from one. Leave it raw - you'll be glad you did. You may want to review this thread on treating raw necks. Makes a world of difference and is well worth the effort.

 

[Colin007]

Thanks for the replies!

First, I did go with the stainless steel frets, I was going to go with normal frets because I'm not hard on my frets when I play by then I figured what's the extra investment on a one of a kind instrument?

Second, so if I use the compressed air then wiping it down with Naphtha isn't necessary? Is there an alternative to it?

Finally, I agree that a matte finish would be best. I've read that there are some minwax wipe on poly products? Are these as easy to use as Tru-Oil?

 

[Cagey]

First, I did go with the stainless steel frets, I was going to go with normal frets because I'm not hard on my frets when I play by then I figured what's the extra investment on a one of a kind instrument?

Second, so if I use the compressed air then wiping it down with Naphtha isn't necessary? Is there an alternative to it?

You're going to love stainless steel frets. Best thing for guitars since strings.

Compressed air is not an option or a replacement for Naphtha any more than it would be for washing your car. You have to touch the thing. If you have some concern about the stuff - and you shouldn't - you could use denatured (not rubbing) alcohol instead. Just be aware that alcohol will attack some finishes, like shellac or any of the various "oils". Compressed air will get rid of the gross coverage of things like sawdust, but it doesn't clean, degrease or leave a finish-ready surface. You should always have a can of Naphtha around, kinda like you should always have a roll of duct tape, a set of screwdrivers and indoor plumbing.

 

[bagman67]

Agreed as to the compressor's limited utility.  It'll get the dust off, but not the grease.


The wipe-on poly products are, in my experience, very easy to use.  I have not used the Minwax product, but this one I am familiar with:


http://generalfinishes.com/retail-products/oil-base-top-coats/gel-oilbased-topcoat#.UsNDVfRDtsk


Decent stuff.  Available at Rockler and Woodcraft, and possibly at other outlets in your area.  Here's the store-finder:


http://generalfinishes.com/where-buy

 

[Cagey]

Agreed as to the compressor's limited utility.  It'll get the dust off, but not the grease.

Doesn't really even get the dust off, just the big chunks. The fines stay on there unless you wipe it with something, as it's kinda like a film. Although, you can get closer to clean (not degreased) using a tack cloth. Myself, I blow the thing off, then wipe it down with Naphtha, then tack it just before shooting in case something settles out of the air because I shoot out in the garage rather than an environmentally-controlled paint booth. Even that's not entirely foolproof, because I shoot lacquer and bugs love acetone, even though at the concentrations used for painting it'll kill them. Sort of a "moth to the flame" thing.

Silly bugs.

 

[Colin007]

Again, thanks for the replies.

As a cancer survivor, I try to reduce exposure to bad stuff like benzene, but I understand that this could get out of hand if I'm not reasonable. Sounds like Naphtha is OK.

Are there any wipe on options that don't add an amber tint?

 

[bagman67]

Generally oil based finishes will yield a tint to some greater or lesser degree.  There are some lacquers that claim to be "water white."  Tru-oil yields a very faint tint,  not enough to significantly change the color of mahogany or korina.  It's much more evident (and still pretty mild) on maple.  Water based finishes tend more generally to be un-tinted.  Minwax's water-based wipe-on polycrylic may do the trick.


Here are some anecdotal data via blog comments:


http://www.finewoodworking.com/item/33113/can-you-wipe-on-a-water-based-finish

 

[Cagey]

Behlen's "Master Gel" is a water white poly finish, but any finish you put on wood is going to change its shade to some degree. For instance, this is Mahogany with a wipe of Naphtha on it...

30 seconds later, that darker area was the same color as the lighter area again as the solvent boiled off. That's pretty dramatic - not all woods will change that much. For instance, this is a Maple neck that's been finished with Behlen's Master Gel...

As you can see, even "clear" finishes will tint to some degree.

 

[Colin007]

So would you say that a gel application is easier to do than the Tru-Oil with coffee filters?

 

[Cagey]

It's pretty much the same job either way, although you wouldn't put as many coats of the gel on. The gel is also a much more robust finish than Tru-Oil, so that's the route I would take. Tru-Oil doesn't stand up to much of anything. Water, alcohol, sweat, etc. will eat into it, and it's also a softer material that will scratch/scuff/wear faster. On the plus side, it's easier to repair if you're so inclined. Polyurethane stands up to all those insults quite well, but if you do manage to break the finish somehow, it's very difficult to repair.

 

[stubhead]

I've done both, and I actually got it worked out where the workflow is about the same. I thin the poly way, way down, so it flows on like water. (It IS about half water). The thin coats -

A: don't dry with drips...
B: Dry really fast.

I put on like five or six coats a half-hour a piece apart, then let it dry completely, overnight or at least a few hours. Hit it back with synthetic steel wool, 600-ish. You want to get the whole surface evenly matte, with NO breakthroughs. This is probably the hardest part - allot two hours for it (you won't need all of it), and DON"T SCREW UP. Get psycho, get your magnifying glass and Sherlock out... Oh and you can't touch it.  :glasses10: Then three more water-thin coats, then hang it up somewhere for a few weeks. If you can smell it, it's still outgassing. The thin coats speed that up, full-thickness poly takes a month to dry DRY. I do Tru-Oil more-or-less the same way? Only True-Oil thins with naptha.

Main thing, you don't want to touch it with your greasy skin or set it down somewhere, so you need to figure out what it's hanging from, how you can get to all the sides. I modified a $5 Salvation Army tripod to take a neck-plate contraption, but that was largely because I have to drag it into the kitchen, goop it and real quick hide it in the closet, drag->goop->drag->goop etc. cause I have two aerosol hairbomb cats. Who LOVE to supervise me when I act suspicious.

Every snooty tone-skank jiveass foolishness you hear awful about THICK POLY is about THICK poly, not about poly. So don't make it THICK...  :icon_scratch: The guitar finishing granfalloon is deeply & moronically polluted by information about how GIANT FACTORIES FINISH 250 GUITARS AT ONCE. Don't DO that...

I DO like Tru-Oil better these days, just for the feel. But the poly is very and unannoyingly non-smelly for an all indoor winter-type job. Water-based poly will pull water-based dyes right up into themselves, so you have to isolate those two from each other with a few coats of wax-free shellac. Doesn't sound like you're dyeing?

 

[Colin007]

What do you thin the poly with? Water?

I know I can't touch the raw wood, but at what point can I touch it? While I'm steel wooling it after the first bunch of coats?

No, I am not dyeing the wood, I want to see the unadulterated, natural look of the wood, grain and all, with the basic protection that the wood needs to last. No color.

 

[Cagey]

Poly comes either oil- or water-based. The oil-based stuff can be thinned with Naphtha, the water-based stuff with water. Unless you're going to spray it, I wouldn't recommend you thin it. Stuff wants to run easily enough as it is. That's probably why Behlen's goes in the other direction and makes it into a gel.

Once it's dry, you can touch it as much as you want, just be aware that you need to clean up afterward. Best shot is to wipe down with Naphtha before you start another coat. Then you don't have to wonder or worry.

 

[mark1178]

I sometimes need a translator for Stub's posts.

 

[Cagey]

He usually makes sense to me, but I'm somewhat brain-damaged so I don't know if it counts.

 

[Colin007]

Ok, so I'm going with a wipe on poly, I did the first coat today.

Questions  - Do I hit it with the synthetic steel wool in between coats? Do I hit it with Naphtha in between coats?

 

[Cagey]

In my experience, you don't do anything between coats. If it looks like you need to, you may want to re-evaluate what you're using to apply it, or your method of application. Makes a LOT of difference. Also, the condition the substrate is in will affect it. Apply it wrong, or on a surface that's less than pristine, and it'll come out streaky.. You'll want to level it, but poly doesn't respond well to that.

Fortunately, it's a somewhat self-levelling finish because it doesn't dry/cure as fast as some finishes do (I'm looking at you, lacquer!), so if you use a well-wetted applicator, you can cover up prior sins to some degree.

But, don't confuse a slower cure with permission to work. Once it's on, it's on. You can't re-brush or re-wipe the stuff unless you want evidence that you've done that left over. Do it right the first time, or go cry in your beer.

As far as the naphtha thing, that's for cleaning. If you touch it or sand it or dream about it while you're at work, then wipe it down with naphtha.

You really worry about the naphtha thing too much. Just pretend it's finishing water, sorta like what comes out of your faucets is hand/body/drinking/cooking water. You use it to clean things that may be contaminated. But, don't drink the naphtha. It'll cause you to grow thumbs out of your head and think voting for Democrats is a good idea <grin>

 

[Colin007]

I've more or less resigned myself to the fact that I'm going to be using Naphtha during the course of this build, and I'm OK with that. I just want to make sure that I'm not doing anything wrong. So if I touch the guitar tomorrow with my bare hands before doing the second coat then I need to wipe it down first?