Spray Booth

[Steve Hinde]

Need some ideas on building a spray booth for laquer finishing. How can I heat it safely for cold weather use?
I have a small shop in my basement, but don't want the danger in the house from explosive fumes. The rest of my equipment is in my garage that isn't heated. I would build #a small booth in the garage, but I don't know a good way to heat it and exaust the fumes. I don't want to heat the entire garage. Any suggestions would be appreciated.

Steve

[sunburst]

You're right. You don't want to spray lacquer in the basement.
Checking with your department of building inspection might be risky. I know they say they're there to protect us from substandard housing, but sometimes the only thing they seem to be there for is to keep you from doing anything they don't want you to do. You might not want to tip them off, but they might have a book with pages and pages of regulations on what is acceptable as explosion-proof if you ask.

Flames or sparks are obviously poor choices, so no wood stoves or gas heaters. I suspect electric heat, the expensive resistance kind, might be among the safest for a small space like you're talking about. Maybe some kind of heat pump also.

If you have a good exhaust fan (explosion proof hopefully) you'll suck all the heat out in short order anyway, so heating the whole garage might be better anyway.

Not an easy problem, good luck.

[Michael Lewis]

Bright lights will be needed for good visibility while spraying, and also have the benefit of generating radiant heat. They heat surfaces and objects, not the air. Wire the switch just outside the door of the booth, in case any sparks occur. Don't make the booth for comfort, you shouldn't spend any more time in there than absolutely necessary.

[Bandersnatch Reverb]

Dunno how it is by you, but here in Florida, ANY spraybooth needs a permit, and relaimation system. Maybe you dont want those building inspector guys around....

[johnwilson]

Take a look at the small article spray booth at Spraytech.com. This was designed to work without outside ducting and does a good job - although the cost of the booth is currently $1865 plus shipping, It weighs in at over 300 lbs with a half horse industrial motor. ALL electrical items need to be kept 5' away from the opening of a booth. The lights the live inside one of these are Class 1, Div. 1 explosion proof fixtures - the Loar of lights with a price to match, about $1,465 although this does include assembly of the booth. I'll be happy to answer any questions you may have, Yes, I do work at Spray Tech, but that gets you a toll free number and lotsa free advice. 800 535-8196

[Steve Hinde]

Spray Booth
You are right Sunburst, any exaust fan will suck out any heat that the building has. That's my biggest dilemma with this issue.
I can get an open spray booth with the fans and lights, and even radiant heaters. But, the main problem is heating enough of the incoming air to keep the work warm. It is a bit tough justifying enclosing an area, insulating it, finding a safe heating device, and installing proper spraying/ventilating equipment. Especially if my goal is only a few instruments per year. But, I want to do this, and I have to do the finishing somehow.
I am interested to know what you guys have done about this situation. Maybe I can only do my finishing in the summer months? Any more info is appreciated.

Steve

[nar]

Hi Steve. I don't know where you live, but I live in Victoria B.C. and I spray all year round with out heat and have never had any trouble. I find humidity more of a problem than anything.
Neil

[sunburst]

When I went to work for an instrument manufacturer many years ago my first job there was finish work. As Kim Breedlove was showing me the procedures, he showed me the spray room and turned on the exhaust fan.
I asked "what do you do in the winter time?" He laughed and said "freeze your a-- off."

[Mando Medic]

Steve,
Yours is a good question. For years I have sprayed Nitro and three years ago I quit spraying. I have gone to French polishing, I work a lot with Lacover and Blendal which I can apply like french polishing. When I have to spray, I use rattle cans from Stewart MacDonald Guitar Supply and go in the back room or open the back door and rattle can to the outside and then vent the room very well. I keep a few ounces of lacquer mixed at 50/50 on the bench. I have a small air brush (Binks and Iwata) that I use for headstocks or neck, but nothing large anymore, as it's just not worth the health risks or the space/heat requirements. Most folks won't pay the going rate for refinishes so why knock your self out.
I have a great Dayton explosion proof motor and fan for sale that handles 12,000 cfm if you want to setup a spray booth. However, for just a few instruments a year, I'd suggest french polish, or rattle can. There are alternatives.

[P Josey]

I built a spray booth modelled after one I saw in a Dan MacRostie instructional video. It's just made of plywood and is four sided but funnel shaped. The bottom is flat.It sits on my router table and I push it up against a window in my shop. The small end of the funnel is where the fan is located and fits right at the open window.The wide end is where I spray from. It's held together with screws and when I'm finished, I take it apart and put it in it's storage area. It works great and is no big deal. Just some plywood, a fan and a hook to hang the mando from.

[Steve Hinde]

So nar and sunburst, you can spray laquer down to what temperature? I live in northern Iowa where the temps stay below freezing from November to March. Doesn't the material freeze as soon as it is atomized out of the gun? I haven't tried it to see what happens.
I agree with the varnish on the mandos, but I prefer laquer on the guitars. I also want to see sprayed tinted laquer on the sunburst finishes.
My first 2 instruments, I sprayed the Stewmac laquer in my basement. Wasn't real pleased with the finish and the consistency of the spray pattern from the cans. Drove everybody out of the house until the fumes cleared too. The sealer was worse than the laquer. Probably lucky I didn't blow up the house.
And Mando Medic, how much for the fan?

[Mando Medic]

You know you can spray varnish too! It's not nearly as bad as lacquer for overspray and fumes. I would take $300 for the fan plus shipping. Kenc

[sunburst]

masamando,
I'll have to defer to nar on the lower limits of temperature for lacquer. I'm in Virginia, it never gets colder than about 20 below around here. And besides, I was spraying a catalized varnish in those days. The kind that Flatiron used to use in Montana in whatever weather they got.

You can't survive in temperatures that will freeze lacquer. You might have trouble with water based, but solvent based lacquer would have a freezing point lower than any weather on this planet.

Oh, and a little bragging here, I bought a Devilbis explosion-proof exhaust fan at an auction once for $5.00. They threw in a floor fan too.

[Mando Medic]

Wow! $5 bucks. You were really in the right place at the right time for sure. I bought this Dayton brand new 12 years ago and it set me back almost a grand. A friend of mine bought a squirrle cage exhaust system for his shop at a state auction for under $50 and mounted the motor outside the shop under the window because it was not explosion proof and he has had no problems with it. There's a deal everywhere if you look around.
I have sprayed lacquer down to 55 degrees, but below that, your gonna get a maybe job. I've done and I've seen it done colder than that, but it's not the way to go. Kenc

[Jim Hilburn]

I have one Stew-Mac finish video thet shows Don McRostie's shop which appears to be on a farm with chickens running around outside. He's spraying through an old box fan at the end of his funnel!

[nar]

Sunburst it may get to freezing for about aweek here in Western Canada during the winter, I just don't spray then. But I have sprayed many times in the high 30's.And as long as there is low humidity It hasn't been a problem for me.
Neil

[Luthier]

I know I'll get grief for this but I had to show you. I mounted my exhaust fan on a platform that rolls into the door opening of my shop. I just couldn't find it in me to put a hole in my wall. I can't even close the other door when this pup is turned on because there is so much suction. The fumes are gone in seconds.

Don

[sunburst]

Don, Now you've got me thinking about cutting another door in my shop!
How do you get that thing to hold still and stay in the doorway without tipping back into the room or moving across the floor like a wingless airplane?

[Luthier]

John, here is another pic to show the base. It is on rollers and it fits right into the door. As long as there is air coming in from somewhere, it stays put but I have seen that sucker do just like you said and roll back if there is no air that can be sucked through it.

[GaryM]

I saw one just like that go by me on the freeway yesterday

[Jim Hilburn]

Here's a shot inside of my booth. You may want to consider the hand-free holder I made. I attached a 3/8" eyebolt to a length of 3'4 emt. I then thread it into the endpin hole. I drill a 9/32" hole,which is smaller than the ebony endpins I use. I can put it into the holder either vertical, as it is here (with a tilt) or horizontal. I only do the back and face in the vertical ,and then you can orient it so gravity helps reduce the chance of sags.

[Jim Hilburn]

Also ,when I drew the plans for my shop, I had "spray booth" written on this room. Drew said "you don't want to submit that to the city". So the whole shop got called the "computer room".

[sunburst]

Jim, Looks like something that should work well.
The only thing I see that others might want to do differently is to use a smooth or slick surface material instead of the OSB.
The lacquer residue that builds up (flamable/ explosive) will be hard to clean off of that. You may have found that out already.
I've used tile board. It's masonite with a smooth surface sold at lumber stores to pannel bathrooms. It works OK, but next time I'm using sheet metal to pannel my computer room so I can clean it with solvent from time to time.

[Jim Hilburn]

Well, I get a powdery buildup of lacquer solids that vacuums right off. I basically used construction scrap to make it. I don't think that buildup is very flammable. The solvents are long gone.The only time there's a possibility of fire would be as you were spraying, and I can't imagine that happening unless you held up a match. Don't get me wrong, I'm all into safety. The fan is sparkless and explosion proof, and while not explosion proof, my lights are sealed and far from the spray. And I keep the surfaces clean.
Look at the shadow the mandolin is casting. Thats an HID light that really lets me see the spray as it's going on.

[sunburst]

The sealed lights are apparently pretty safe. Huss & Dalton (just over the mountain from here) actually got their spray room inspected and approved. Their lights are regular florescents, but they are in a sealed inclosure.
I find it easier to see when spraying if the light is from a single direction like yours instead of spread out like florescent light. Good choice!

The dried residue of nitrocellulose is pretty flamable. About like celluloid binding I think. Does anybody know the flamability of dried nitrocellulose? How carefull do we need to be with it?