Double Bass Finish question for our esteemed luthiers

Generally, Nitrocellulose is very thin, and shouldn't affect the tone all that much. Though, I wouldn't use it on a Double Bass. I just finished re-finnishing one of my basses with a dark brown spirit varnish. I wanted spirit, because it doesn't take long to dry(about 2 hours vs 1-2 days for oil), and it leaves a very even and brilliant finish. Oil can take up to a year to fully harden. However, oil is much easier to work with, and generally provides a longer lasting finish and better protection.

I found it funny when you said that after refinishing the neck you wanted to refinsh the bass. I once made a replica of a Greenland eskimo kayak paddle and then realized I needed to make a kayak to match.
Definately do it! I have done this more than once and noticed significant tonal diff. As far as advising you what to use-well, tomes have been written on this subject, so consider this a thumbnail sketch. I use oil on my new basses-there is some evidence of tonal superiority and I just like the look. But I have used spirit in numerous revarnishes as well. Each varnish type has its difficulties in application and both need skill with the brush. One other option is a rubbed-on finish such as danish oil. This can be very simple in its application and can yield a very nice result.
Colorants can be added to any "clear " varnish or one can purchase the varnish with the color already added. See if you can get a catalog from Howard Core co. and International Violin co. Both catalogs have tons of info and sell all the relevant ingredients. You may need to put on a luthier's hat when you request the catalogs.

The aforementioned catalogs have lots of good varnishes and pigments. Some other tips I could offer....
Spirit (shellac) is an excellent finish. But, more coats are usually needed. I have seen entire new instruments varnished with Tru-Oil; made by Birchwood Casey. It is a linseed oil, with driers, and is sold at woodworking stores as gun stock finish. It can be tinted easily, and unlike most oil varnishes, the application is EASY. You can use a rag! (Learning to brush most oil varnish is not an overnight lesson. However, spirit does brush well.) Tru-Oil is a product I would recommend with your skills.

Whatever you decide, make sure to seal the spruce with clear varnish, or other sealer, before applying any pigmented varnish. Unsealed spruce, and maple, has a stained, furniture look that isn't pretty.

Finally, make some test strips of similar spruce (good pine would work) and maple. It doesn't have to be instrument tonewood, just something that you can experiment on. Stripping and re-stripping an instrument is a big ol' time waster.

Good luck; hope some of this helps you!

Only because AES is not speaking here, I'll add that Arnold spends big bucks on brushes. You won't find them at Home Depot.
Patience is a virtue. Arnold coached me on a joint project. The varnishing took me about a month. Then again, he has Barbara, and I don't.

A great finish for ease of application is Waterlox. It's a thin oil varnish you can rag on, but it has a tough resin content which will protect the instrument. And it dries nicely overnight. You'll end up with a matte finish that will easily rub out with steel wool and wax, or you can just leave it be if you've kept the dust away. You can tint it with artist's oil colors--try to find ones that are lightfast. For a nice reddish-brown, Burnt Umber and Alizarin Crimson should do it. Add black to intensify and darken. I would expect a nice finish in 6-8 coats. You'll need to lightly scuff between coats with 0000 steel wool or a gray scrubby pad.

Don, are you coveting my spouse?

No, just reporting your own admission that she can do wondrous things with a boar bristle brush.

Originally posted by arnoldschnitzer
A great finish for ease of application is Waterlox. It's a thin oil varnish you can rag on, but it has a tough resin content which will protect the instrument.

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If you were finishing an instrument that was in the white, would you need to thin Waterlox with a solvent for the first coat(s), as a sealer, or could you just start wiping it on straight from the can?

I'm thinking about doing such finishing, either with Waterlox Original Satin, or with Watco's Danish Oil.

I've heard not-so-great reports on the satin Waterlox. Anyway, a satin finish should only be used for the final 1-2 coats, because the flattening agent prevents "depth" in the look of the varnish. As far as sealing, I would thin 40% or so with Turp or Naptha for the first 2 coats. You may want to lightly tone the wood first with a water-based stain. When you apply the finish, make sure the thinning solvent is fresh and wear a respirator!

Naptha is Zippo ligher fluid, isn't it?

Originally posted by arnoldschnitzer
I've heard not-so-great reports on the satin Waterlox.

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Thanks, Arnold! Great reply!

Yeah, I saw something in one of the descriptions of the Satin that seemed to indicate a need to apply the satin over the gloss, instead of just by itself, but it wasn't really very clear about it, just a mention in passing.

I still haven't decided for sure between Waterlox or Danish Oil.

Originally posted by Ray Parker
Naptha is Zippo ligher fluid, isn't it?

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Also Energine Cleaning Fluid, "white gas" and Coleman fuel.

For folks interested in this sort of thing, I've found Bob Flexner's "Understanding Wood Finishing" to be quite helpful. Like a lot of woodworkers -- luthiers are a part of that gang -- I got into it because I love wood and making stuff out of it, not due to any predilection for gassing myself in the basement. I love the results of finishing, but I'd rather make plane shavings anyday.

Flexner helped a lot in figuring out how to get the best results with the least possible nastiness, and I like his no-BS approach to describing how all these noxious substances do their jobs. I've been using oil varnishes pretty much ever since, although I like the speed of alcohol-based shellac (not for basses or coffee tables, though!)

cheers,
Damon

After reading this and other posts, and doing quite a bit of additional reading, I decided to refinish my 1977 Mathias Thoma which was extremely scratched up and had graffiti scratched into it. Since I own a wood shop and the bass was very cheap and beat up I figure I had nothing to lose. I did use a random-orbit sander (very carefully) with 150-grit discs on the large areas and hand-sanded and used a set of cabinet scrapers on the details. Then hand-sanded it all to 220, then 400 grit smoothness. It took about 8 or 10 hours of sanding to completely strip the bass. The old spirit varnish was very powdery and came off easily, barely loading the sandpaper. I put a lot of time into cleaning up the joints and details with the scrapers.

On the advice of a luthier friend I used egg yolk for a ground - adding (on my own judgement) some denatured alcohol and shellac. Well the yolks curdled and left quite a bit of residue as well as raising the grain. I'd ask more questions before I do that again! Sanded all the mess off to smooth again.

Then applied 5 coats (so far) of Tru Oil tinted with artists' oil colors. It dries beautifully in just an hour or two to a medium-high gloss. After the second coat my luck ran out and it was almost impossible to apply without streaking as the Tru-oil really does not flow out at all. Maybe it needs to be thinned, but the coats are so thin already! It's hard to build the color - after the 5 coats it's still an unattractive peachy tan. Using very short strokes and a fine-weave cloth to apply the varnish minimizes the streaking. I went and looked at a bunch of expensive basses the following week and they were a lot more streaked than mine, so maybe streaks in the varnish just really aren't considered a defect?

On the other hand some new basses with spirit varnish look like they have been dipped in it, with no shading or color variation at all. I would really like to know more about applying the varnish to get it darker.

I had to go play the bass, so I let it cure for a couple days then strung it up. I was quite pleasantly surprised at the improvement in the tone!!! It is much louder and clearer with the Tru-Oil finish.

I figure I will add some more coats to darken it. The figures in the grain look like they are swimming in a 3D clear amber pool. The varnish has a lot of depth (in the good spots).

I had some trouble with dust settling on the bass even with the quick dry time of Tru-Oil. I sanded to 400 between coats and it took off the specks (just the way I handled it with my limited experience). Also some dried, tiny flecks of varnish fell back into it from the edge of the container and I had to pick a lot of those out of the finish.

I would not recommend using Watco on a bass. I have used it a lot on my woodworking stuff and although it's better than many oil stains, it's still a stain not a varnish. It's gummy and it highlights the tiniest scratches. There is a long dry time and it requires very judicious sanding to smooth the grain without loading the sandpaper or taking off too much stain. I'm not crazy about the color choices either (I have used it only on birch though). Just my $.02.

Before and after pics of the bass attached!

blue flame said:

On the advice of a luthier friend I used egg yolk for a ground - adding (on my own judgement) some denatured alcohol and shellac. Well the yolks curdled and left quite a bit of residue as well as raising the grain. I'd ask more questions before I do that again! Sanded all the mess off to smooth again.

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Your luthier friend had it half right. The part of the egg that is used for a ground is albumen which comes from the whites of the egg. Regardless, it looks like you did a nice job.

Our own mchildree did his is Strunal with TruOil. (The same bass I bought few months ago from him for our church) I think he experienced the same issue with it not getting as dark as he wanted it to.

I was seriously considering refinishing my Engelhardt before I decided to sell and buy the 180. I even went as far as buying some shellac flake and experimenting on a few pieces of maple veneer I picked up at the hobby store.

I had the same problem with the shellac. Even using the very darkest buttonlac that I could acquire, I couldn't get a dark enough tone even with 10 coats of build up.

One option would be to use a bit of dark stain in the ground, which goes against tradition and seems generally taboo.

If you are intent on keeping the color in the finish, as tradition holds, I would guess that you would need to use much more tint than you think and experiment until you get it the way you want it.

In your case, you could get some dye or other suitable tint and simply add the very dark finish over the existing finish for a few coats. Then come back and top it with a few coats of untinted oil to give it more depth.

Blue Flame, yours turned out more "color-full" than mine did. I stopped after about 8 coats of the Tru-Oil because I wasn't seeing much difference and didn't want to apply any more finish than necessary.

....and I was also highly impatient to play the bass. I don't have the patience of a luthier by any stretch of the imagination.

mchildree said:

Blue Flame, yours turned out more "color-full" than mine did. I stopped after about 8 coats of the Tru-Oil because I wasn't seeing much difference and didn't want to apply any more finish than necessary.

....and I was also highly impatient to play the bass. I don't have the patience of a luthier by any stretch of the imagination.

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Well I've been advised to try some ink to tint the varnish rather than the oil colours. Still, when one coat goes on significantly darker than the previous one, it's so apt to streak! I'm going to add about 3 more coats "just because" and hope it becomes less "peach" colored. I was really impatient to play, too!

My next big issue: whether or not to have the top re-graduated, or sell it and buy something better. My conundrum is: more expensive instruments aren't necessarily better, this bass has hardly any resale value, and it's an ideal size for me! Anyone successfully regraduated and have any remarks? I've read the posts about re-graduating, and Jeff Bollbach mentioned Thoma by name as an acceptale candidate for re-graduating as opposed to a better bass.

Has it occurred to you that you have not added enough artists pigments to the varnish? Ink does not sound like a very good idea to me.

Regraduation might be a solution, but it's not going to be a cheap solution and still might not give you what you are looking for as far as sound is concerned. If you're not happy with the sound of your bass, you would be wise to atleast look at other instruments before investing more money in the one you have now.

blue flame said:

Well I've been advised to try some ink to tint the varnish rather than the oil colours. Still, when one coat goes on significantly darker than the previous one, it's so apt to streak! I'm going to add about 3 more coats "just because" and hope it becomes less "peach" colored. I was really impatient to play, too!

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If you want to tone down the Peach color you will need to put a coat or two of blue on. Essentially, if you want to tone down any color, add the one opposite it on the color wheel. In the interest of assigning credit where due, this was shown me by Jeff B., master varnisher. If you really want a great job, do like Jeff; put on 20 to 30 coats, then rub it out for about a week!