Poly, lacquer, and oils

[kdownes]

Hi everyone,

I'm a newbie gearing up for two Warmoth builds -- an alder J-bass, and a black korina VIP -- and could use some finishing suggestions.  The J-bass will have a birdseye neck finished by Warmoth, but I'll be doing the finish for the neck of the VIP myself (the neck is also black korina).  I love wood color and figure of the VIP, and want the body and neck to have the same look, ultimately with a satin finish.  For the J-bass, I'm going for a tangerine-colored stain, then a clear satin finish there as well.  I've done one mahogany body with Minwax wipe-on poly and had pretty good luck.

I'm particularly curious about using wipe-on poly or aerosol lacquer over WATCO Danish oil and/or pure tung oil.  My experience with tung oil so far hasn't been great, but given the figure of the VIP (pic below) it seemed like a good choice.  I haven't used Danish oil before, but thought it might be a good option for the J-bass (and maybe the VIP, too).

I figured using an oil finish would bring out the figure, but wanted to add a hard topcoat for protection and for validating the warranty on the neck for the VIP.  Are their issues applying poly or lacquer over (thoroughly dried) oil?  Would it be better to forget about the oil and just go with straight-up poly/lacquer (or vice versa)?  For lacquer, I'd probably have to wait until the spring to spray it outside since I'm working in a small basement that also houses a gas furnace.

Thanks a lot!

Kieran

 

[jackthehack]

May I suggest some Tru-oil on that? See thread:

http://www.unofficialwarmoth.com/index.php?topic=2669.0

 

[big bob]

I would go with either oil or finish, but not finish over oil...

 

[Keyser Soze]

You can apply poly over oil, so long as it is an oil based poly.  General Finishes makes some nice brush on products (Arm-R-Seal being one of them.)  You can also make pretty much any brush on oil based poly into a 'wipe on' finish by diluting it 50% with mineral spirits.

The downsides to oil based poly finishes are witness lines if you wet sand it to level, and they yellow over time (which in this case is not really an issue, but if you had a stained/dyed body your deep red may one day end up looking very orange.)

Jack's suggestion of Tru-oil is a good one.

 

[kdownes]

Thanks so much for the feedback, guys.  Tru-oil is sounding/looking good, especially given Jack's LS5.  Jack, you mention down in the thread that in the future you'd use a filler rather than just Tru-oil -- is there a particular filler you'd suggest using with Tru-oil?  I wouldn't mind leaving the pores open, although it looks from other posts like the finish will be lots more robust with them filled.  Would folks suggest a black filler or just clear?  That tele thinline Jack did a couple of years ago looks pretty excellent with the black...

I imagine Tru-oil can be applied with a rag like Danish or tung -- does it need to be thinned for the first coats like tung?  Could I use citrus solvent as a thinner with Tru-oil?  And do I need a sanding sealer after I fill?

Sorry for all the questions -- I have a piece of black korina coming my way for testing so I'll figure out the best way before putting anything on the body or neck, but any advice is much appreciated.  Thanks again!

 

[Keyser Soze]

No apologies necessary.  Those are all important questions.

Tru-oil is indeed a wipe on finish.  Basically you wipe on a layer (thin layers are better), wipe off any excess, allow it to dry, scuff, then repeat.  If you build up a decent thickness and allow it plenty of time to harden it can be level sanded and polished to a wicked high gloss.

First applications can be thinned.  This might help with penetration, but is not really necessary, just have everything at room temperature.  If you do thin I suggest mineral spirits (it's the solvent already present in the product anyway.)  Citrus solvent might work just fine, but I have no direct experience with it.

If you already have some citrus solvent but no mineral spirits then just run a test on some scrap wood, or even better some glass.  Yes glass - mix up the diluted solution and wipe on a fairly heavy layer of diluted and then plain onto two halves of a glass pane (or hand mirror.)  Then when the plain layer has properly dried you can compare it to the diluted layer for proper hardness, if it isn't as hard and/or clear as the plain then you know your solvent is messing up the performance of the finish (this is also the way you check your shellac to see if it has gone bad over time.)

Grain filling is a mainly a matter of how you want the final appearance to look.  If you are looking for a 'natural' soft satin type of look then grain filling is not necessary.  If you are going for a smooth gloss surface then good grain filling is absolutely essential.

IMO nothing looks worse than a glossy finish with grain dimples showing through.  Over time most of the surface will get some wear while all those little depressions remain bright and shiny.  Ugh.

If you do grain fill I'd say your choices are either clear or black.  Either one can look good (but quite different from each other.)  I Doubt you'd be pleased with a grain filler lighter in color than the natural wood.  If you use an oil compatible filler then there is no need to seal prior to finishing.  Check the specifics of whatever product you use.

 

[kdownes]

Awesome -- thanks Keyser!  I'll be making a trip to Woodcraft this weekend for some testing supplies.  Ultimately I'm going for a satin natural finish, but we'll see how the grain filling looks on the test pieces.  From the pictures, the wood looks so lovely that I don't want to do too much to change it!  I'll post some pix once I actually have the body and neck in my hands.