# Spraying Spar Varnish



## slick1 (Apr 12, 2010)

Has anyone had any experience spraying marine spar varnish with a Critter spray gun?
I have twenty newly-made adirondack chairs, stained & ready. I sprayed the stain on ok with the Critter gun; but I have found nothing about spraying spar varish with it.
Do I need to thin the varnish, etc? Thanks!


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## gfadvm (Jan 13, 2011)

I spray undiluted Spar with my cheapo Home Depot spray gun and it works great. Dont know about a "critter" but try it on scrap or cardboard and let us know how it goes.


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## wisno (Feb 26, 2010)

Yes, basically your can spray he marine spar varnish.
Thin the varnish little bit to fulfill the viscosity requirement according to the spray gun.

Thanks

god luck


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## Arthouse (Feb 22, 2011)

spar varnish is not recomended to be sprayed because you have to thin it so much it looses it consitisancy . The solids don't stay together and usually you have a huge runny mess. It brushes better anyway.


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## gfadvm (Jan 13, 2011)

Arthouse - With all due respect, I couldnt disagree more. I spray a LOT of MinWax Spar with really good results using a HD cheapo sprayer and undiluted Spar. Check out my projects for examples. Not trying to start a fuss here.


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## stevenhsieh (Jan 8, 2010)

Maybe you should go buy the spray can version LOL


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## slick1 (Apr 12, 2010)

Well, I guess I will try spraying it on some scrap first and see how it goes. 
1st with no thinner & then with thinner if I have too. Brushing is not an option here; with 20 chairs to do & 3-4 coats each. I'd be old and grey by the time I'm done…LOL.
Thanks for all your input gang!!!


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## mechanicalengineer (Sep 27, 2010)

I would recommend you thin spar varnish with one part mineral spirits to every two parts varnish. Spray light coats to avoid runs.


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## JJinAK (Jul 12, 2011)

At the risk of going "off topic" a bit, what do you all think the minimum air compressor capacity would be for pushing spar through a spray gun? Thanks.


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## stevenhsieh (Jan 8, 2010)

You would have to keep tuning it until it spray efficient.


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## slick1 (Apr 12, 2010)

OK !! Looking good!
Just finished spraying first coat of Spar Varnish on the chairs.
Had to practice lots on scrap wood before doing chairs to get air pressure, mix ratio of mineral spirits & spar varnish & distance from wood.

First, a friend of mine who paints auto's for a living recommended & let me use his old Devilbiss JGA-A-502-30X spray gun. (30X being the cap and needle size), which handles reduced varnish just fine. This gun will atomize the spar varnish into just the right particles for the perfect finish. On my Porter Cable pancake compressor, I set the air pressure at the gun at 50 pounds. Also, make sure you use an airline filter for moisture.
I opened up the material control valve almost all the way and adjusted the fan width to a 4" width at about 10" - 12" away & 50% overlap each spray pass. Clean tip end with clean rag after 3-4 passes or else varnish will build-up on tip causing spray pattern to sputter.

Mix Ratio: First, mix an equal amount of Naphtha and mineral spirits (50-50) together. I added in the naphtha, which is a much faster evaporating solvent than mineral spirits. (50% Naphtha & 50% Mineral Spirits is roughly, what lighter fluid is). Careful, you are working with big-time flammables here!
Second, mix ONE part of the Naphtha/Mineral spirits mix to THREE parts spar varnish.

The key here, being to get a smooth, level, and even coat applied, with no runs…that is the trick, isn't it! If you reduce (or thin) the coating too much, you will not get enough of a dry film left on the surface to cover and fill.
Save your lungs and wear a cartridge-style, organic respirator. Wear old long sleeves shirt, hat, and a pair of pants you don't mind ruining. Better yet, buy a cheap Tyvek suit for a few bucks. Use disposable surgical gloves. I always have a box of these in my garage…blue nitrale works good. If you wear glasses like I do, wear a full-face respirator.

I was quite surprised at the results so far, no runs or sags, nice even coat & not much of an over spray cloud.


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## gfadvm (Jan 13, 2011)

Rod - I set my gun up about like you did: 50 psi but have never thinned my Min Wax spar at all. I put my projects on a shop made turntable. That way I can stand in 1 spot and spray with a big fan about 20' behind me while I rotate the project. This really keeps the spray off me and out of my shop.


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## slick1 (Apr 12, 2010)

I tried spraying just un-thinned spar varnish with this gun, but it just came out in spurts & gobs. Using Old Masters Spar Varnish (satin). 
I have converted an old 12'x 14' polycarbonate paneled greenhouse as a paint spraying booth. Added two large filtered box fans, one for air in, one for air out, works great!
The turntable idea is great idea, no more untangling air hose from around my feet; but I would need a very large one to do adirondack chairs.
Uhmmm….I have a large old 3' round wood wire spool out back…. Thinking….Thinking….need large lazy susan type Bearing Mechanism….uhmmmm..


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## gfadvm (Jan 13, 2011)

Slick My gun either has a bigger orafice or Min Wax Spar is thinner than yours. My turntable is much simpler than you imagine. No bearings or engineering needed. I dont know how to post pics in blogs [even after Bentlyj tried to smarten me up]. If you'll pm me with your e mail address I think I can send pics to you then you can put them on LJ if you want to.


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## gfadvm (Jan 13, 2011)

Slick As you can see, this aint rocket science: a short piece of pipe welded to a disc blade. A piece of plywood with a hole in the center just larger than the pipe. A stack of drilled scraps beneath ply dictates how high off the floor the base is. I have sprayed a 6' table by laying 2×4s across the ply to stand the table on. You can see the overhead door in the pic which I open when spraying. I think this could be done with ply and 1" dowel if disc blades, welding, etc arent possible in your case. PM me if you have questions. Bentlyj Thanks so much for posting this for me. I appreciate it. Someday, after I'm grown i'll be able to do this for myself. LOL


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