MIMF

by **Chuck Tweedy** » Thu Jan 24, 2019 1:40 am

Hey People - I've not been around a long time, but I'm back in the shop, and the MIMF is still here so...
I'm repairing my first-ever guitar (from 2001!). I set the bridge wrong my first time round - just a 1/4" too far forward - Oye!
The guitar is FP'ed - cedar top - parlor size (Antes).
So I remove the old bridge, make a much better new one, and I'm fixing the finish on the top to cover the bare strip in front of the bridge - and generally just pretty the old thing up.
I get the old FP stuff out, make some shellac from flakes, and find I even have some olive oil - but it is old and rancid. I try a bit and, it makes a horrible smudge instead of helping the FP "work". oye again.
So I grab what is handy, odorless mineral spirits, thinking it might at least help clean out the rancid olive oil from the pad...
Holy crap, it works so smooth and easy I can't believe it. I've not done any significant FP for years - only repairs - so I'm totally out of practice. And even so this was perfect, first time.

anyone else tried this? After discovering it by mistake I see that Ron Hock was touting it as something Brian Burns had recommended. That was back in 2010 from the posts I saw.
If anyone still does FP (man i'm feeling old!)
Try it! Just substitute odorless mineral spirits for the oil. I maybe used a bit more because it flows more quickly.

by **Bryan Bear** » Thu Jan 24, 2019 10:11 am

Chuck!

I still French polish so there is at least 1. On the last two, I even used you pal Vejay's Royal-Lac.

Never heard of using mineral spirits but I am interested. I usually just get a dab of olive oil on my finger and swipe it across the pad when I think I need it. How are you applying the mineral spirits? Isn't it too thin to wipe on enough with a finger?

by **Chuck Tweedy** » Thu Jan 24, 2019 12:30 pm

Mr Bear!
it is too thin to apply as you describe.
i use a squeeze bottle with a luer lock top so i can change the tip to whatever is best. i've always used these for FP - all liquids. The 4oz one here. with a pink or green tip.
i was just squirting shellac and spirits on there like a madman and it just kept working. i dunno - this stuff is magic.

now - i used the odorless stuff - which is actually pretty heavy bodied - it is kinda like really thinn oil

by **Barry Daniels** » Thu Jan 24, 2019 12:33 pm

I use a lot of it in my shop for all kinds of cleaning purposes.

Good to "see" you again, Chuck!

by **Bryan Bear** » Thu Jan 24, 2019 12:42 pm

I have to admit that I have never used/seen odorless mineral spirits. I was thinking along the lines of naptha. Isn't it just a further purified form of naptha? I guess it is heavier than I was picturing. It just seemed like it would be hard to control how much went in the pad (rather than on the pad).

If it is magic, then I want to try it. I have found that FP with Royal-Lac is similar to regular shellac but feels a bit stickier and I added oil more frequently. I'm wondering if this would help.

Does it flash off by itself or do you still spirit off?

by **Chuck Tweedy** » Thu Jan 24, 2019 2:10 pm

Barry, good to see you again to.
Bryan, naphtha is much more lighter/thin/volatile than this stuff.
I'm pretty sure that this stuff is sold here in CA because it evaporates much slower than old-school "paint thinner" - and naphtha as well. That way they can claim lower VOC.
it is a longer chain hydrocarbon, but it will all flash off, so it contains a pretty narrow distribution of chain lengths. sorry - nerdy stuff

Bryan, I did some "spiriting off", and that worked like i expected. Then i got impatient and i just wiped it down with a micro-fiber cloth, which will pickup anything "oily". both worked great.
give it a try - i would recommend getting the _odorless_ stuff tho - i think it may be the magic

by **Alan Carruth** » Thu Jan 24, 2019 2:34 pm

I got a gallon of Mohawk's 'Rubcut oil' for that many years ago, and still have most of it. It's a heavier fraction than kerosene, but similar. It work well enough, but you do need to be very thorough about spiriting off. All in all I prefer raw cold-pressed walnut oil from the health food store, for several reasons:
1) it smells nicer,
2) you don't need to worry so much about getting it all off the surface, as it incorporates into the film, and
3) I've got it. I bought a couple of pints thirty years so ago, and have only recently broken into the second one.

by **Chuck Tweedy** » Thu Jan 24, 2019 2:44 pm

Alan, what worm-hole did you throw that pint of oil through? even in a tin can I can't imagine that 30 year old walnut oil is still good!

by **Bryan Bear** » Thu Jan 24, 2019 2:47 pm

The old growth walnut oil from 30 years ago is worlds different than the stuff you get these days. . . <G>

by **Chuck Tweedy** » Thu Jan 24, 2019 3:54 pm

chocolaty brown, not that ugly gray?

by **Bryan Bear** » Thu Jan 24, 2019 4:40 pm

I'm glad you're back Chuck. . .

by **Barry Daniels** » Thu Jan 24, 2019 5:08 pm

What you thinking Chuck? C7 to C12 probably?

by **Clay Schaeffer** » Thu Jan 24, 2019 9:19 pm

"Alan, what worm-hole did you throw that pint of oil through"

Speaking of worm holes :lol:

....... Nice to see you back Chuck!

by **Chuck Tweedy** » Thu Jan 24, 2019 11:14 pm

watch out - Ellie may pop through the next worm hole. Hey Clay.

Barry, from the link i just read, the boiling point of C12 (dodecane - cool name eh?) .... is 216C at 1atm, I could not find the vapor pressure curve.
that seems high, but there is probably some in there - it would be at the tail of the curve so - yea.

by **Waddy Thomson** » Fri Jan 25, 2019 1:10 pm

For what it's worth, Walnut Oil does not go rancid. The hard part is keeping it from drying, over a 30 year period.

by **Mario Proulx** » Fri Jan 25, 2019 2:20 pm

I've had plenty of walnut oil go rancid, including the bottle I just checked right now.

If yours does go rancid, it isn't pure.

What's sold here(Ontario) as oderless paint thinner is naphtha. Can you see anything on your can that even hints at what the contents are? Interesting find...

by **Mario Proulx** » Fri Jan 25, 2019 2:26 pm

Found the MSDS... All they declare for contents is "Hydrotreated light distillate (petroleum)".

by **Alan Carruth** » Fri Jan 25, 2019 3:06 pm

The walnut oil I got was cold pressed stuff from the health food store. The original intent was to use it making varnish, but I bought two pints and only made one small batch of varnish, so the second bottle stayed sealed until recently. It has not thickened up, and still tastes OK, although probably not as good as fresh. A bottle of cold-pressed linseed oil that I got at the same time, and also only opened recently, is about the consistency of honey.

I'm told that even a small amount of canola (rapeseed) oil mixed in with walnut oil will prevent it from hardening. This is apparently not uncommon, as they use the same presses and may not clean them well between uses. A 'draw down' test is always a good ides. Put pieces of tape on the ends of a razor blade, so that it will leave a gap in the middle. Put a drop of oil on a plate of glass, and use the razor blade to draw it out into a film of uniform thickness. If it dries OK you're good to go.

Another student of my guitar making teacher tried making his own varnish. For whatever reason he used olive oil instead of linseed or walnut. The varnish never hardened; it just went rancid. It proved impossible to get it all off the guitar, which still stinks.

by **Chuck Tweedy** » Fri Jan 25, 2019 5:23 pm

Mario - i'll check the can tonight, but i'm confident it's not going to be any batter than the MSDS you found.

It's lighter than lamp oil, but heavier then old-school paint thinner

I'll let you guys fight it out over walnut oil - all i know is the stuff i had went real bad long ago.