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. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/cool.gif

[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 http://www.mandolincafe.net/iB_html/non-cgi/emoticons/coffee.gif

[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?

[sunburst]

Well, in the absence of responces to my flammability question, I got curious and did a small amount of research.
Heres something I found:MSDS for nitrocellulose (http://ptcl.chem.ox.ac.uk/MSDS/NI/nitrocellulose.html)

Don't know exactly how this relates to the dust and overspray in the finish booth, but thought inquiring minds might want to know.

[thistle3585]

In Indiana, you must have a sealed motor and starter, all lights must be sealed and rated for this application, you can't have any electrical outlets or switches within 20' of the opening of the spray booth, you need a fire rated paint cabinet to store you flammables, there is a CFM requirement in relation to the product that you are spraying and you need an enviromental permit, which may or may not include an exemption but you will be required to maintain a log of how many pounds of VOC's you put into the enviroment. Also, you can't wear a respirator unless you are certified by a doctor to have the lung capacity to use one. Unfortuanely, I learned all this after having just been visited by OSHA.

My suggestion, don't put one in your house. If you do, I would suggest you do plenty of research and get assistance from a qualified enviromental hygenist. A poorly designed unit can be just as, if not more, dangerous than none at all. This based on experience.

[Jim Hilburn]

It's good that we have a government to keep us safe from ourselves.

[Luthier]

Hmmmmm. #Horses to the right of me, cows in front,
and I have another neighbor that has (among other things) a rather large "watchpig". #Zoning is not a word that is understood here so aside from all safety precautions I choose to take for myself, I do not have a problem with outside authorities. #I am sure if I did this in a fulltime capacity and had employees, things would be different. #Gotta love livin in the sticks...LOL

Don

[Mando Medic]

And very well said Don. I moved a business to another city 5 years ago because when I origninally moved into a space and spent over $5K for my spray booth to comply with city standards, 7 years later they changed the standards and wanted me to upgrade to the tune of $15K. It was cheaper and wiser to move to a rural community.
I agree that sometimes we are just smothered by too much government in the areas of commerce.
Knowing how toxic and flammable lacquer and other products are that we use is very important. But beyond knowing that and knowing how to use and work with those products it think it's up to the individuals using them to use good judgement with them. You wouldn't test your shot gun out the back door at the neighbors garage, so why would you set up a flammable or noxious odor situation if you live in a high density area? You wouldn't. But I don't feel we need regulation or inspection to prevent it.
I have to have my business in town, in some center of commerce. I choose to not have a large spray booth any more because the personal health risks are too great and the cost of refinishing at prevailing shop rates has discouraged most refinishing and I don't want to cast my exhaust at my neighbors.
Are you aware of any scrubbing system that allows for the complete removal of noxius and flammable components of Nitro or Acrylics in a small capacity? And the cost? Kenc

[Dave Cohen]

John, the MSDS sheet which you looked up is only addressing the solids content of what we spray. To get an idea of how really bad the task is, look up the MSDS sheets for toluene, higher MW ketones like octyl nonyl ketone, and higher MW alcohols like octyl alcohol (IUPAC name is "octanol"). Those compounds are the components of the solvent mixture, which makes up 70% or more of what you spray, iirc. All of the solvent components are cns depressants, primary toxins, and either potential or outright carcinogens, etc., etc. They are also comparably flammable to the nitrocellulose polymer, with pretty low flash points in the vapor phase. Come to think of it, I don't know why in h___ I am still using the stuff.

[Luthier]

If you build it, they will come. #If you make it, they will buy it?

I like the stuff. #I like the results. #

Don

[thistle3585]

I don't want to get into a political discussion, but I walked away from my OSHA experience in a positive light. It was unfortunate how they arrived at my doorstep,but it was a positive and educational experience as I was WILLING to work with them. The OSHA laws are designed to protect my employees from injury, and myself from the associated claims and losses if my employees are injured. If I, as an employer, am uneducated about proper spray booth operation then so are my employees and we are all at risk.
Mandomedic made an excellent point with his shotgun metaphor. We each have a responsibility to conduct our ventures in a safe manner. A spray booth in a basement of a house scares me for more reasons than I could count. I would not encourage anyone to install one in their home. Why take the chance?
If you do want to spray laquers in your basement, then go with a waterbased product. At least then all you have to address is enviromental issues.

[Dave Wendler]

I always read the finishing issues threads with great interest...as this is probably the most harmful part of our construction process, particularly when the higher volatatility solvents are used.

I made a determination BEFORE I started my "electroCoustic" project that I would use WATERBORNE finishing...mostly for health reasons; and to a great degree, for environmently and fire related issues.

My current baseline product is a Parks Brothers waterborne polyurathene floor finish; I've been very pleased with it's workability and overall hardness once it's cured.

The biggest problem with most waterbornes is it's resistance to "flow out"...making your scuff sanding and finish sanding processes a bit harder....but with the advent of GREAT orbital sanders, this is really minimzed, once you learn how to work the material.

THere are those that will argue that waterbornes don't look as good as nitro...but I'll bet it sounds everybit as good. And, the paint companies are pretty much being required to develop these MUCH safer products...hell, I use a HVAC squirrel cage fan(ebay, $35 delivered!) in a basement window casing....works great...

So the material WILL be as good as any nitro finish in just a few years...and I'll know how to use it when that happens.

FWIW....shellac is pretty good, if labor instensive. It's also just about as safe as the waterbornes, particularly if you use natural ethanol to cut it.

[sunburst]

I use "pure grain" alcohol from the liquor store for my shellac. In his French polish presentation which I attended several years ago, Sergei de Jonge stood before us with his shellac and fractionated olive oil and said "I can eat anything I have here".
That's about as safe as you can get. It'll still burn, tho.

[onlyagibsonisgoodenuff]

Maybe you rent a corner of the local auto body shop's spray booth. You might even learn how to paint flames on the mando!

[Dave Cohen]

If you take a good look at any of Rolfe Gerhardt's mandolins, you have to admit that waterborne finishes can look every bit as good as nitro. The only problem is, Rolfe has jumped through a lot of hoops learning to use the waterbornes, and he has had to swallow the time and cost of doing a lot of refinishing of customers' mandolins with finish problems. Early on, he had several come back to him with severe cold checking. A coupla years ago, he discovered that his finish wouldn't stand up to shirtless playing at festivals when the (shirtless) player had sprayed himself with DEET (insect repellent, i.e., "Deep Woods Off"). That same finish was also acid catalyzed, so some players' perspiration was taking the finish off of the necks. The current finish that he is using seems to be a solution for at least some of those problems. But his experiences are the reason why I am still using nitro; I am waiting for some strong signs that most of the bugs have been worked out.

[Brookside]

Is there anything wrong with spraying outside provided the weather allows for it? Are the vapor police going to arrest me? Am I harming the birds/bunnies/rainforests/neighbors?

[sunburst]

Brookside, I must admit I have sprayed a few instruments outside. Birds don't seem to mind, it's the gnats that get curious and make an impression on the finish.
Keeping it clean is the only real problem if you live far enough out in the country and use a good respirator and other protection.

[crawdad]

When you spray outside, you soon learn about all the airborne dust, bugs and stray plant stuff blowing in the wind. Things you never saw before become really visible. It can be done, but a wet lacquer finish is sorta like flypaper!

[Mando Medic]

Don's )(Luthier) booth concept with the rolling fan and perhaps a spray booth attached or table I think is a good idea. It does beat going outside to spray. I've done that and have a couple of hilarious stories to share some other time.

[Mario Proulx]

You can spray outside when the weather permits. You can solve the bug and dust problme by simply placing a large cardboard box over the mandolin after you shoot. Place the box, then add a weight on it so the breeze, if any, won't blow it off. In 20-30 minutes, you can remove the box to let it breath a little, as the lacquer will have cured enough for dust to not become part of the finish.

As for heating a booth in the cold months, the best setup I've seen is to have an air intake into the room near the booth. When the exaust fan is on, the air being blown out needs to be replaced, right? So, instead of pulling cold air in from every nook and cranny(or an open door), the setup I saw was a large, 2 foot square duct that had no less than 4 radiators in it to heat the incoming air. The radiators are heated by a boiler system that also heated the rest of the shop. Worked like a charm! The tempaeratures don't dip but a few degrees, even in -20f temperatures.

Now, granted, most of us likely don't have 200,000 BTU boiler to help us out, but anyone could add a 40 gallon electric water heater close by. Add a circulating pump to move the water to the radiators, and crank the temp to high, and you've got a poor man's boiler system, perfect for short heating bursts like this.

[sunburst]

M. Proulx
Thanks for that excellent idea and answere to the original question of this thread.

[Luthier]

I would be curious to know what the car makers use for a finish. #
I know they have robots doing the spraying and I am sure they have to abide by very strict rules and operating procedures and regulations.

Don

[Jim Hilburn]

Mario, Welcome to the Cafe. I played one of your guitars last year and it was one of the finest I've ever heard.

[Darryl Wolfe]

I've done some silly things in the past..but they worked..like pitching a cheap tent in the backyard..wetting it down to quell any dust..and spraying inside. It became necessary on a white w/Chroma clearcoat Strat. I really haven't had any probs with nitroC outside as long as I pick the right day. (I live in a subdivision w/ large lots..located in the far outskirts of town

[Darryl Wolfe]

My dad has a nice spray booth out in his large unheated semifinished shed. Its the typical closet type deal with exhaust to the outside and sealed/filtered doors. When he needs to spray in cold weather he sets up one of those high powered tube style heat blowers just inside the door to the shed and lets the fan pull it thru the paint booth

[thistle3585]

Sorry Darryl, but the idea of an open flame combined with laquer sounds like a recipe for disater.
I once used a kerosene salamander, to heat my shop when the gas company was working on the gas line. I ended up having to strip and respray about 2 dozen products because of the airborne oil residue that came from the salamander contaminated the finish.

[Darryl Wolfe]

Thistle..Dad's quite careful..I think the heater is electric and none of the fumes from the booth come back out into the room where the heater is. The exhauster is on an outside wall in the booth and he sprays with the filterd door closed..seems safe...not?

[thistle3585]

Actually, the heater being used DURING spraying is a secondary concern. I see the primary risk being the use of the heater after spraying while the instrument is curing. The fumes from the drying process are more dangerous in the prescence of a heat source.

[Darryl Wolfe]

ah...good point....however, I forgot to mention..he uses only Fullerplast on his reso guitars. Likely far less a concern. Remind me not to use it for Nitro http://www.mandolincafe.net/iB_html/non-cgi/emoticons/laugh.gif

[sunburst]

Darryl, Has he got an old private stash of Fullerplast? Pre-Lawsuit?
I used to spray that stuff. It had great working charasteristics.

BTW, it releases far less VOCs than lacquer while it's curing, but flamable none the less.

[Darryl Wolfe]

I think he does. I know he had to change vendors or something a while back. He's been using it for years

you can email him at;

resoport@bellsouth.net

He's in Davidson, NC

[sunburst]

I believe I met him at Galax a good many years ago. He was pretty suprised I knew what Fullerplast was.

[Darryl Wolfe]

Yep..he goes about every year..he thought "he discovered Fullerplast" on his own. He gets great results..maybe a bit too much body for a mando. It seem a bit like Dupont Chromaclear to me. I use that almost exclusively on electrics and auto's

[sunburst]

I've sprayed it on about 7 or 8 mandos. Kept thin, it's hard to tell from nitro.

[Steve Hinde]

Hey Guys,
Great responses. I like the idea of the water heater radiators. May even put pipes in a thin concrete floor for continued heat in the room. Will have to do something like this. I could probably use a small central heating unit in the duct too. Same idea as an air make-up system for a commercial spray booth. Maybe even a motel room heater unit that's electric. Would provide a filter and generate heat along with air conditioning in the summer. Put it through the wall of a small room in the garage and exaust with an explosion-proof fan. What do you think? Anybody seen anything like this?

Steve

[Luthier]

No matter what the air temperature is in the "spray location", you can count on the fact that it will be removed due to the ventilation and air movement produced from the exhaust fan. #This means the ideal way to do this is to heat the air being drawn in from outside the spray area during the winter and vice versa in the summer. #This, however, cannot always be achieved. #Humidity will blush lacquer without a retarder added in the summer. #As long as it is not teeth chattering cold, it is ok to spray in the winter.
Once again geographical location comes into play.
The times that I have spent in the industrial sector in a spray booth, I can tell you that it was an enclosed room with filters all around, it was all OSHA approved, and I never stepped foot into any booth without my resperator. #Whether we do what we do as a vocation, a hobby, or a profession, it is important to try to take as many precautions as possible so we can "live long and prosper."

(This is the first time I have heard of "Fullerplast" too)

Don

[Spencer]

I haven't seen anybody mention the use of a heat exchanger to heat the incoming air. It wouldn't be quite as effective as using a heater, but should help to keep the air temperature from getting too low while spraying, and could eliminate the need for a heater. If anybody is interested, I could help with sizing, as I had a lot of heat transfer courses in college.

I also worked for years next to an explosion expert, and saw some scary examples. You want to be real careful with these vapors. Dave Cohen has already pointed out what nasty stuff is in a lot of solvents.

Spencer

[Mario Proulx]

I haven't seen anybody mention the use of a heat exchanger to heat the incoming air.

Ummmm, what I described was indeed an air exchanger, only on a magnitude suitable to heat the incoming air sufficiently. Because all of the air in the room that the booth is in will be evacuated within seconds of the blower running, the air that is coming back in needs to be pre-heated. Yes, in many climates this is unecessary, but in some, and I think the original poster was in one, it is a reality.

Blushing in this case will not be a problem, since the incoming air will be rather dry.

But, all of this assumes a real spray booth with a real exaust system. A little box with a fan at the back doesn't count as a booth, at this point.

[Spencer]

M. Proloux, my apologies, you're correct, that is a heat exchanger you described. What I should have said was a regnerator (I don't want to get into a semantics discussion). The idea is to heat the cold incoming air with the warm outgoing air. If the process is efficient enough, then it would not be necessary to add external heating, giving one less thing to mess with, kind of a passive system. As I said, this would not be 100 percent efficient, but should be possible to make it good enough to keep the temperature at an acceptable level while spraying. Of course, with a heater you can choose the temperature if it is big enough. Hope this is clearer.

Spencer

[sunburst]

Spencer,
I wouldn't say it couldn't be done, but you have to consider that the outgoing air is full of VOCs, sticky lacquer overspray and stuff. You want it out with an unrestricted path to the outside.
That would complicate the situation. If the system worked perfectly the incoming air would be clean, any leaks and you're bringing VOCs, lacquer mist, etc. back in.
If the lacquer mist dries and accumulates in the system, you've got nitrocellulose solid in there and that's the stuff in the MSDS in my earlier post. (flamable explosive).