Official Luthiers Forum!

After finishing my first 4 guitars with lacquer, I want to use Tru-oil on the next - not just the neck, the whole thing. There are lots of posts in the archive here on people's approaches and as usual there are a variety of approaches, different in both small and more significant ways.

For something like this, I think a first timer needs a recipe/procedure in reasonable detail that is known to work. So I am latching on to LMI's documentation on this ....
http://www.lmii.com/CartTwo/TruOil.htm

....but with a couple of proposed variations.
I'm not asking forum members to repeat what you have probably already outlined on the forum previously (i.e. don't want to waste your time), but instead would be interested to know if the LMI procedure worked well for anyone, and if you think the following changes are ok.

The changes relate to the pore filling stage....
Firstly they use their water based filler in conjunction with the Birchwood sealer/filler. I have just been through a traumatic experience with their pore filler and would rather not use it again. There is plenty of evidence to show that z-poxy can be used successfully. Should I simply substitute z-poxy in the procedure for the LMI filler but still use it in conjunction with the Birchwood sealer/filler, or will a couple of applications of z-poxy do the job adequately on its own. I guess I'm puzzled about what the Birchwood sealer/filler does that the LMI pore filler can't do on its own.
Secondly, I would spray a light coat of shellac over all surfaces before applying the Tru-Oil. There's lots of evidence on the forum to show that this is a good thing to do.

Finally, I use a decal on the headstock, but am doubtful that I can get the build thickness to cover it with Tru-oil, and will probably need to apply nitro here. It is a vinyl "best-decals" decal that needs over .007" to sink it. I haven't see any figures on Tru-Oil build thicknesses, other than they are thin. Can anyone give me a view on this?

That's it.
Thanks. Frank.

By the way, in researching this on the forum via 'Search', if I enter "Tru-oil", it finds nothing. Fortunately, there were quite few entries where it had been spelt "truoil" that it did find. But I know there are plenty spelt "Tru-oil" which I cannot track down. Does anyone know the reason, or the workaround. I tried various things with search wildcards etc but no luck.

The problem is the hyphen '-'. For example, search for "z-poxy", you get the same problem.
Frank

I just emailed MicHhael Dresdner who is a finishing expect on the www & asked him about what tru oil is; & if & when I get a reply I' ll let you know. I don't see any problem with what you are suggesting, re. the z-poxy, shellac, etc. Who know what the selaer does? My guess it's a thinner version of the top coat. So with the shellac I would try a sample avoiding the seal coat. There's no doubt oil finishes are simpler to build up whatever that means. They look & feel like silk; ababys bum..., 100% oil does tend to dry out but if it has even 10 or 20% solids (resin varnish) in it, then you should get some few thousandths to stick permanatly. I was thinking about trying what you are about to do myself. Let me know how it goes.
Mike McNerney

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Mike McNerney

I'm a fan of tru oil. I use zpoxy as a pore fill and have sometimes sprayed a layer shellac (mainly when applying dyes) before applying tru oil. After experimenting with different techniques, I more or less followed LMI's schedule on my last guitar and was very pleased with the resulting uniform satin finish. The key, I think, is to remove any excess finish. As you noted, build will be minimal, have you thought of burying your decal in the shellac or zpoxy coating?

Ok , Bear in mind I have not used z-poxy.
The birchwood casey Sealer-filler is pretty thin and low build, but what it is really good for is on a spruce top to seal the surface prior to applying the tru-oil to avoid excess absorbtion or uneven colouring.
If you have an open pore back and side wood then the slurry sanding method with the tru-oil works well for pore filling (use a few drops of mineral turpentine to keep from drying too quickly)
Burying a vinyl decal is hard enough with nitro, don't like your chances with tru-oil.

I've only used Tru-oil on necks and it does give a superb finish. I stopped using the Tru-oil sealer as it didn't seem to do much, but I did notice one thing about it. On woods that 'bleed' the sealer makes them bleed less than anything else I tried (shellac, etc.) and less than the Tru-oil itself. It could be useful in those cases.

Can you do that? I have only used zpoxy as a grain filler and a fine coat of shellac prior to applying lacquer, so have no experience with this sort of thing.
So what are you suggesting? Several applications of z-poxy until decal is covered, followed by a mist of shellac and then tru-oil? The headstock veneer will be a piece of figured myrtle - light/orange colour.
How long do you need to leave z-poxy to fully cure when building it up fairly thick in this way?

ok. The LMI procedure doesn't do this. You just put Tru-Oil straight onto the spruce, though in my case, I plan to spray a very light coat of shellac first. I think this achieves much the same outcome, but please tell me if I'm wrong.

Thanks Dave. So what did you use as your pore filler?
Also, a question showing my very limited experience.... - can you give me some examples of wood that typically bleeds.

Where I've used it on necks they were maple,which doesn't need a pore filler. The only body was a solid body in padauk. In that case I wanted a 'natural' look so I didn't pore-fill either. I finished off with very fine steel wool and burnished with a bristle brush. If I did pore-fill I'd use Z-Poxy.

The woods that bleed are typically rosewoods, EIR, cocobolo, etc., padauk. Try wiping an offcut with acetone or cellulose thinners on a paper towel.

Tru-Oil goes on very well over shellac. You can seal a water-slide decal with shellac by misting several light coats until covered. IMHO this would be less work than using Z-Poxy and with less chance of a sand through error. Test your technique on some scrap. Go to Wally-World and get a model airplane kit -- this will give you a lot of decals to test.

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Jim Howell
Charlotte, NC

I've never worked with decals so I might be leading you astray, but I see no absolutely difference between burying them in nitro or shellac. Zpoxy "can" be sanded after 12 hours but is easier to work with after 24 hours. Puddles left over on my mixing board seem to cure as well as the layer applied to my guitars, so I wouldn't worry about a layer the thickness of a decal. Try it both ways on a some scrap. It should only take a few thin coats of zpoxy to give you enough coverage to level. Shellac will be easier to apply and level. Both will tint your final finish, so try to keep the layer at a uniform thickness across the headstock.

I've never worked with decals so I might be leading you astray, but I see no absolutely difference between burying them in nitro or shellac. Zpoxy "can" be sanded after 12 hours but is easier to work with after 24 hours. Puddles left over on my mixing board seem to cure as well as the layer applied to my guitars, so I wouldn't worry about a layer the thickness of a decal. Try it both ways on a some scrap. It should only take a few thin coats of zpoxy to give you enough coverage to level. Shellac will be easier to apply and level. Both will tint your final finish, so try to keep the layer at a uniform thickness across the headstock.

On My last I used a thin coat of shellac on all surfaces prior to binging to seal against glue marks, but this was all sanded off prior to finishing.
I don't think there is any problem using shellac(dewaxed) under tru-oil but I really liked the BC sealer-filler and it is quick and easy to use. I wanted a sealer on the top to ensure that I did not have to scrape too deep for the bridge glue area.
The thickness of the vinyl decal (much more than thin waterslide) is going to be hard to bury

Tru Oil is not 100% pure oil, it has solids and is very much like a varnish.

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The member formerly known as erikbojerik....

i just got an email from Michael Dresdner who is a professional finisher consultant. He says tru oil is a mixture of linseed oil, 56% mineral spirits, & modified oil. The modified oil is code for another polymerized oil or an alkyd resin. If it is a resin then it will have something solid that will build up as a solid. The oil & thinner just make it a lot easier to apply without it getting sticky. Where does it leave us. Well if a year down the road, if the finish looks the same in an area that has little direct abrasion, then it is close to a varnish. If it looks dried out & more matte then it is closer to oil only. Personally I'm going to try the filling then maybe more like 3 or 4 coats of shellac. Then rub on lite coats of naptha thinned varnish applied with the same technique as the tru oil.
Mike McNerney

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Mike McNerney

...Michael Dresdner...that's a coincidence. Yesterday I ordered a wood finishing book from LMI written by him. I also ordered the Robbie O'Brien finishing DVD.

My current focus is still just trying to make a basic dreadnought very well, involving nothing too fancy. That being the case, finishing still remains my biggest challenge!! (and if you care, number two is voicing the top.)

Frank

It's a couple of months since I put up the original questions on this. The job is now done and the finish is curing. I will up some final photos once it is all done. Just a couple of points for now...
- I think the process given on the LMI site is fine. It seemed more complicated when I first read it than it actually is. I used Zpoxy instead of their water based filler.
- This is only my 5th guitar but I think I learned more about preparation on this guitar than I knew before, because it is so critical to get it spot on for an oil finish. I really feel like I have a handle on this now.
- As far as the vinyl decal went, I experimented with shellac, zpoxy and KTM-9, but ended up taking the easy way out and sinking it in nitro.
- As for the tru-oil finish, the shine and general look after 4 coats is pretty stunning and that's before final sanding & polishing.


Frank

Looks great I'm waiting on my Tru-Oil finish to cure also. It was real easy to work with. The only problems I had were with lint/fibers from the cloths I was using. I wiped on with a cotton cloth and wiped off the excess with cheesecloth. It worked ok but there were still always a few fibers left behind. I don't think it is a problem though because the coats go on so thin once you start sanding the fibers get knocked off. Did you have any problems with that Frank?

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Jeremy Douglas

Jeremy - I used lint free cotton for wiping on and another bit for wiping off - so no problems with that.
Frank