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Using a spraygun for varnishing.


DiemViolins

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Nowadays I see a lot of perfect varnished violins and violas mainly originating from China. I know there are a lot of imperfect Chinese instruments but focusing on the better qualities they have a very nice varnish. For example see:

post-5985-0-57330300-1325072205_thumb.jpg post-5985-0-15298900-1325072247_thumb.jpg

I suppose that they are spray-gunned using an ethanolic varnish (spirit varnish). I was wondering how the f-holes are filled to protect the inner side of the upper blade. How is that done and with what?

Is there on MN anybody who has experience with varnishing by a spray-gun?

Frits

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I've done a LOT of spraying, but not on instruments.

We also import Chinese instruments by the container full, but I can't say any of them look sprayed. There are certain areas that are very difficult to get spray into, such as the recesses of the scroll, and it's pretty easy to tell if an instrument has been sprayed.

We brush the instruments we make in the shop, but we tape the f-holes from the inside before we glue the tops on, and push & peel the tape off and pull it out through the sound holes after the varnish has dried.

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We brush the instruments we make in the shop, but we tape the f-holes from the inside before we glue the tops on, and push & peel the tape off and pull it out through the sound holes after the varnish has dried.

I'd never thought of doing that but it sounds like a great idea. What type of tape do you use? Do you have any problems with tape residue sticking to the plate?

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The varnish guys use something like duct tape - a fabric tape at least, that's not as easy to tear as masking tape when you are getting it out. Never had any problem with tape residue, but the f-holes take a bit of cleanup from varnish accumulation. We darken them anyway, so that's not a big deal. Better than having varnish runs inside, IMHO.

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I've done a LOT of spraying, but not on instruments.

We also import Chinese instruments by the container full, but I can't say any of them look sprayed. There are certain areas that are very difficult to get spray into, such as the recesses of the scroll, and it's pretty easy to tell if an instrument has been sprayed.

Do you think that those instruments are varnished with an oil varnish applied by a brush?

We brush the instruments we make in the shop, but we tape the f-holes from the inside before we glue the tops on, and push & peel the tape off and pull it out through the sound holes after the varnish has dried.

If the varnish is applied by brushing is it needed to tape the f-holes?

I've varnished a lot of instruments with a brush but never taped the f-holes. IMHO this is a must when a spray-gun is used.

What is the main difference between spray-gun and air brush if there is any?

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I'm not so sure that I can see many advantages to spraying, unless it's in a more production type set up. If you can learn to Spirit varnish well with a brush, then there are some advantages over the use of a spray gun. Small scale it's probably just as quick and you have absolutely nothing to clean. The equipment is about as simple as it gets, with relatively little outlay. There is no need for extraction equipment or booths. No real need to worry about overspray or health and safety concerns. It's becomes that small matter of learning to Spirit Varnish well. . . . and also find a Spirit Varnish that you like the look of. It won't be Cremonese but I doubt that Mr. Strad had a DeVilbiss in hand either.

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The way the guitar guys do it, is to blow up a balloon through the soundhole, so that the expanding balloon stops the hole quite firmly. After all the spraying is complete, they pop the balloon. A guitar's soundhole is usually more round than those on violins.

Something similar may work for violins, but the balloon would have to be oversize so that it could stretch around and accommodate all the odd shapes, and still seal the f-holes.

I think Mr. Richwine's way is best.

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Do you think that those instruments are varnished with an oil varnish applied by a brush?

If the varnish is applied by brushing is it needed to tape the f-holes?

I've varnished a lot of instruments with a brush but never taped the f-holes. IMHO this is a must when a spray-gun is used.

What is the main difference between spray-gun and air brush if there is any?

Some of them are finished with an urushi varnish. Great for rental instruments, very tough and durable. In the others, I see an occasional brush mark that didn't get rubbed out. Certainly the antiqued finishes are done by hand.

I never paid a lot of attention to what the specific varnish is. On a rental or student violin, as long as it's flexible, not too thick, looks good and wears well, it really doesn't matter much what it is, IME. (Blasphemy to some, I know ;) )

Anything priced over $1500 retail, we varnish in our shop.

It's not needed to tape the f-holes, but you can work faster, and you don't get varnish runs inside the instrument. We varnish 10 to 15 instruments at a time, so it's a semi-production operation.

Air brush

intended for illustration and other fine work. A little small for instruments.

Touchup spray gun Meant for small jobs, finer control and less volume than a production spray gun. Most suitable for small instruments such as mandolins, IME. Could do violins, but I don't see the advantage.

Production spray gun

is meant for production finishing. The gun illustrated can spray up to 15 liters an hour from a pressurized pot or pump, and still lay down a fine finish. Can also be set up for very low flow rates and fine work, if needed. If I could only have one spray gun for custom finishing, this would be it.

There are other technologies for production finishing that are quite a bit faster. Some airless rigs will spray 20 liters per minute with high viscosity materials, and there are curtain coaters, flow coaters, electrostatic rigs, powder coatings, dip tanks, etc. for different applications.

When I get a chance, I'll ask our guy who spends a lot of time in China working with our suppliers, what kind of varnishing operations he sees going on these days. (I was never that curious)

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Some of them are finished with an urushi varnish. Great for rental instruments, very tough and durable. (.....)

You mentioned Urushi varmish. This type of varnish is unknown to me. After searching on the web I read that this is a Japanese lacquer in use for thousands of years.

Is this varnish too flexible or tough to be a useful varnish in violin making? Is it easier to apply with respect to let's say a spirit varnish?

Frits

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You mentioned Urushi varmish. This type of varnish is unknown to me. After searching on the web I read that this is a Japanese lacquer in use for thousands of years.

Is this varnish too flexible or tough to be a useful varnish in violin making? Is it easier to apply with respect to let's say a spirit varnish?

I doubt that you can get it in the west. For many people, it acts like poison ivy, producing itching and blisters. It's pretty common in East Asia, though.

Here's an article on its use: Urushi

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I believe John Masters has posted previously about spraying varnish... might contact him by pm?

Best regards,

E

I spray clear emulsion coats, but not color. (There is a reason for this which would be obvious to anyone who experimented with similar emulsions.)

I just take a rectangular piece of newspaper which will lay in the bottom of the violin. A couple of arcs to make a cut like this () in the middle with a width of a half inch or a little less and length 4-5". Masking (blue) tape this to the back. You can cut 2" squares of paper and lay them up against the lower blocks and tape to the first piece of paper.

Use the broad face of an sp setter to work it loose from bottom to top.

It works fine. Tape on the insides of the f-holes makes for a fillet which you would have to cut off.

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Unfortunately, urushiol isn't the varnish, just a tiny component of the sap. A nanogram of urushiol is enough to cause a reaction, and the usual exposure is on the order of 100 nanograms, so a few ounces could give everyone in the world a rash. Hard to see what the survival benefit is, though, since most animals are immune. Goats eat it, and birds eat the seeds. (I read up a little...)

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