Do I really need a spray booth?

[Mike King]

I'm going to start finishing my major project, an eight-legged writing desk shortly. The current plan is for BLO, wiped with 50-50 water/DNO while curing, after 72 hours spray Target ultra seal amber (with a drop or two of transtint bordeaux dye) followed by EM6000.

My question is given that all of the spraying will be done with waterborne finishes, do I really need to build a spray booth? Yes, I know it is pretty simple given the insulation booth described in Jeff Jewett's book, but the issue for me is more storage than anything else. Opinions?

Mike

[John TenEyck]

IMO a spray booth need not be hard to make, nor hard to store. Mine is nothing more than 6 mil plastic sheeting hung from nails in the floor joists. It takes 5 minutes to put up or take down, and stores on a shelf w/o taking up much space. What's most important is to contain and exhaust the overspray, for two reasons. One you don't want the over spray settling back onto your freshly sprayed finish. If it does it will leave a rough feel. Second, because I spray inside my basement shop, and would not want the chemicals wafting their way up into my living space. WB doesn't mean completely safe, although it does mean no risk of explosion. So, in any case, I have a large exhaust fan (my dust collector fan) hooked up at the far end of my temporary spray booth and it exhausts about 1200 CFM out a nearby window. No over spray, no smell.

By the way, what is DNO?

John

[John Coloccia]

Yes, you want a spray booth because:

1) you want a way to control dust
2) the chemicals are still nasty and you don't want to be breathing that if you can avoid it
3) you'll get over spray everywhere

But a non-explosion proof booth is so easy to make that there's really no good excuse not to. I have an explosion proof booth, and THAT is a royal pain to build and operate.

[Jim Tobias]

I would go to a furniture/appliance store(large items) and get a few large pieces of cardboard. Prop it up or stand it up behind the spray area. I think you will find about 80% of any overspray will be on the cardboard. Some will fall to the floor in the area in the form of white dust(it dries very quickly). I do have a JDS air cleaner in the overhead area and I put a cheap filter on the outside of it to catch the overspray that is drawn in. When done fold up the cardboard and either store or throw it out.
This is what I do in my shop after trying the spray booth route. I found it not worth the effort AS LONG AS YOU ARE USING WATERBORNE PRODUCTS.
I go outside to spray anything not waterborne.

Just my $.02

Jim

[Jim Becker]

I do not use a spray booth...I only spray water borne (usually EM6000) and very occasionally a quick coat of de-waxed shellac when I can have proper ventilation available. I use a central area in my shop for finishing so I have 360º access to the project while spraying, run my air filter to help collect the dry-spray fines that can get suspended in the are, wear a respirator and eye protection to keep those same fines out of my lungs and eyes and just make sure that the temperature is appropriate for finishing.

[Scott Holmes]

Question... What is the purpose of : "The current plan is for BLO, wiped with 50-50 water/DNO while curing"?

What is DNO?

All you will do is wet the surface with water, which will not help or harm; but may raise the grain. BLO should be wiped on, let set for a few minutes, then wiped dry; and allowed to cure overnight. Then you ultra seal then a couple coats of EM6000

NOW after the 2nd coat of EM6000 is the time to lightly sand the top coat. Then another coat and final sand if needed, then final coat.

[Mike King]

Denatured alcohol. This was the recommendation of Target to minimize adhesion problems of water borne finish over the BLO.

Mike

[Jamie Buxton]

Here's my take -- http://www.sawmillcreek.org/showthread.php?201498-HVLP-no-booth-needed-Pics&highlight=spray+booth

[John TenEyck]

Jim, I hope your shop is not connected to living space. You do not want the glycol ethers used in WB finishes hanging around to be breathed in later. As I mentioned, I use the fan of my dust collector as an exhaust fan. I just bypass the dust bags by running a hose from the back of my spray booth to the inlet side of the fan, and another hose from the outlet to a nearby window. I don't know why I didn't think of it years ago, but I've been using this arrangement now for about 3 years and it works great. No filters either, they just plug up. The over spray is dry by the time it hits the fan, so there is no buildup on it after spraying at least 15 gallons of finish, and the dry powder just gets blown outside. The fan moves at least 1200 cfm, but the temp in my shop doesn't change by a measurable amount even if I spray for an hour. There's just too much mass. The only precautions I take is to turn off the furnace because some of the make up air is coming down the chimney. If I had another window I would open it to provide an easier path for make up air. All in all, it's a simple, effective system for dealing with over spray and VOC's.

John

[Jim Tobias]

John,
Yes, my shop is separate (not connected ) with the house. I always wear a 3M 7500 mask with appropriate filters every time I walk in the shop.....even when I am not spraying or sanding. I have some allergy/sinus issues that requires me to do this 100% of the time.
I also make a point to spray the last thing before leaving the shop, leave the air cleaner on.
Jim

[Brian W Smith]

This is going to be a little hard to put into words because,most folks have preconceived notions that once set,is going to be hard to understand a different philosophy.

To start with,you're getting good posts above.A "booth" can be extremely fast/painless to put up.Google foo images of them.....look for the curtain wall style.Think shower curtain.

Dedicated fans and filters are expensive....as posted above however,you can utilize DC's.Google Grizzly's 3 HP dry spraybooth.....see any similarities?

But the above is all academic.The biggest benny of a spraybooth is space......unencumbered space.Which is possibly the cheapest component?The two things we'll never be without,a spraybooth and a loading dock........it's just space.

[John Coloccia]

re: fans
A cheap box fan would work very well. I think FastCap makes a breakdown plastic sheet booth. I've even seen them made out of PVC, or just a few pieces of hinged plywood. Life is very easy when you're spraying waterborne. :)

[John TenEyck]

Hi Jim. Actually, I was directing my comments to Jim Becker. Sorry for any confusion.

John

[Howard Acheson]

>>>> Denatured alcohol. This was the recommendation of Target to minimize adhesion problems of water borne finish over the BLO.

I've never heard of that process before. Be sure you understand what Target is saying. In addition, I strongly suggest you apply the finish to a sample surface to see how it goes. Never let your "money surfaces" be your learning curve. Only process to the actual surfaces once you are satisfied that your will get the results you want and expect.

Do you have much experience spraying finishes? Something like a desk presents problems.

[Mike King]

>>>> Denatured alcohol. This was the recommendation of Target to minimize adhesion problems of water borne finish over the BLO.

I've never heard of that process before. Be sure you understand what Target is saying. In addition, I strongly suggest you apply the finish to a sample surface to see how it goes. Never let your "money surfaces" be your learning curve. Only process to the actual surfaces once you are satisfied that your will get the results you want and expect.

Do you have much experience spraying finishes? Something like a desk presents problems.

see http://forum.targetcoatings.com/forum/viewtopic.php?t=1000

i have no experience with spraying finishes. I have 35 years of experience in woodworking. I did buy an exceptional HVLP system, the Apollo 1040vr with a 7500 gun. I'm in the middle of testing the finish schedule on scrap.

Mike

[John TenEyck]

see http://forum.targetcoatings.com/forum/viewtopic.php?t=1000

i have no experience with spraying finishes. I have 35 years of experience in woodworking. I did buy an exceptional HVLP system, the Apollo 1040vr with a 7500 gun. I'm in the middle of testing the finish schedule on scrap.

Mike

In my opinion, it would be far better to omit the water/DNA wipe and sanding, and spray a 1 - 2# cut of dewaxed, classic alcohol based shellac as a sealer over the "cured" BLO. This is a time tested recipe for sealing BLO and providing adhesion of subsequent topcoats. With no disrespect to Target, I think that recommendation has more to do with selling their products than anything else.

John

[Chris Padilla]

I spray shellac and Target EM6000 mostly and some dyes (and occasional latex) with my Apollo 1000 HVLP 4-stage turbine sprayer. I use the large cardboard box from our refrigerator cut and clamped together appropriately and propped on top of my workbench (MFT1080). I spray in my garage after a good blowing out (often need to blow out a couple times) and the cardboard folds up nicely to store behind the bench.

[John Coloccia]

I spray shellac and Target EM6000 mostly and some dyes (and occasional latex) with my Apollo 1000 HVLP 4-stage turbine sprayer. I use the large cardboard box from our refrigerator cut and clamped together appropriately and propped on top of my workbench (MFT1080). I spray in my garage after a good blowing out (often need to blow out a couple times) and the cardboard folds up nicely to store behind the bench.

I've used cardboard, and stapled some 1X3 to make a frame to mount a cheap box fan. I forget how I held in the fan, but it was nothing fancy. I may have just used C Clamps, actually.

[Howard Acheson]

>>>> i have no experience with spraying finishes

Then again, I strongly suggest you learn how to spray by testing on scrap wood or cardboard. A book titled Spray Finishing by Charron is also an excellent investment. Items like desks can be difficult to spray properly. Finish blows back when you try to spray interior areas. You need to think about how to spray certain surfaces or the finish can just Just loading up the gun and pulling the trigger will not give you good results.

[Jim Becker]

Jim, I hope your shop is not connected to living space.

My shop is in a separate, nearly dedicated building.

[Ethan Melad]

in my opinion, it would be far better to omit the water/DNA wipe and sanding, and spray a 1 - 2# cut of dewaxed, classic alcohol based shellac as a sealer over the "cured" BLO. This is a time tested recipe for sealing BLO and providing adhesion of subsequent topcoats.

For what its worth, i've been told by Target (and read anecdotal reports) that not all their products do so well over shellac. That would be my normal schedule as well, but per Target's recommendation I used their brand of sealer on my last piece and it worked fine. Doesn't look quite as nice as shellac, though.

[Paulh Tremblay]

I'm about to construct a paint booth for water bourne finishes in my basement. I think I will just hang plastic from the floor joists. The only tricky part is the fan. I have a nice window at the back of where the booth will go, but I don't want to just stick a fan in there because I will lose heat in the winter and make conditions too cold for spraying. I am thinking of using the same fan that vents a bathroom and running a hose through a fitted piece of wood in the window.

Any suggestions?

[John TenEyck]

Paul, I use my 1200 CFM dust collector fan to vent my temporary spray booth in my basement shop. I live near Niagara Falls and it gets pretty cold here most of the Winter. I can spray for at least an hour w/o the temp. changing more than 1 or 2 degrees. All the mass in my shop tempers the effect of the cold make up air. Unless your shop is tiny and has nothing in it I think you could expect something pretty similar. I used to use a smaller squirrel cage fan of around 400 CFM, but it didn't capture all the over spray like the 1200 CFM one does. I don't use any filters in front of the DC fan; they just clog up. Whatever goes into the fan is dry by the time it gets there so there's no build up on it and dry powder goes outside.

I spray WB and shellac ONLY.

John

[Earl Rumans]

Mike I am space limited, as my shop is in one bay of my garage. I made my spray booth by screwing hooks into the ceiling around the bay I park my wife's car in. I have some cloth drop cloths that I put grommets in, to match the hooks in the ceiling, and I just move the car outside, hang the cloths from the hooks and make the booth, when I am ready to spray something. I have a big plastic tarp that I put on the floor, to catch overspray and I have a carpet dryer style blower fan that I setup to exhaust the air out the bottom of the garage door. I used the cloth instead of plastic to keep the static electricity down. This setup has worked well for me and I only spray waterborne finishes.

[Paulh Tremblay]

Paul, I use my 1200 CFM dust collector fan to vent my temporary spray booth in my basement shop. I live near Niagara Falls and it gets pretty cold here most of the Winter. I can spray for at least an hour w/o the temp. changing more than 1 or 2 degrees. All the mass in my shop tempers the effect of the cold make up air. Unless your shop is tiny and has nothing in it I think you could expect something pretty similar. I used to use a smaller squirrel cage fan of around 400 CFM, but it didn't capture all the over spray like the 1200 CFM one does. I don't use any filters in front of the DC fan; they just clog up. Whatever goes into the fan is dry by the time it gets there so there's no build up on it and dry powder goes outside.

I spray WB and shellac ONLY.

John

The bathroom fan I bought only has a CFM of 60. I bought a piece of plexi glass to put in my window so I could vent the hose through it. I cracked the first piece when trying to use a knife for the hole. I went to the box store and bought a hole saw. I tested it on the cracked piece--no problem. I drilled the hole in my second piece, and it cracked too.

All this aggravation for a small fan that may not do anything. Should I give up on the small fan idea? You note that 400 CFM fan didn't even do everything you want. At work I expressed my skepticism that running a fan in a window for an hour in the winter wouldn't cool down my workshop, and my friends noted that since the fan blew out, it probably wouldn't cool things down too much (as you have already experienced!).

[John TenEyck]

The bathroom fan I bought only has a CFM of 60. I bought a piece of plexi glass to put in my window so I could vent the hose through it. I cracked the first piece when trying to use a knife for the hole. I went to the box store and bought a hole saw. I tested it on the cracked piece--no problem. I drilled the hole in my second piece, and it cracked too.

All this aggravation for a small fan that may not do anything. Should I give up on the small fan idea? You note that 400 CFM fan didn't even do everything you want. At work I expressed my skepticism that running a fan in a window for an hour in the winter wouldn't cool down my workshop, and my friends noted that since the fan blew out, it probably wouldn't cool things down too much (as you have already experienced!).

IMO, a 60 CFM fan is of no value unless the open area of your booth is only the size of a shoe box. Spray booths are designed for something like 100 fpm of velocity over the work to carry away over spray. For a booth with an open area of just 2 ft x 2 ft you need a fan with 400 cfm. The open area on my temporary booth is about 4 x 7', meaning my fan should be at least 2800 cfm. So even though my fan may seem large at 1200 cfm, it's not. I'm not sure I follow what your friends at work said about lowering the temp. in your shop. All I can say is that my 1200 cfm fan has minimal effect on the temp. of my shop even after spraying for an hour. Some of my makeup air comes down the chimney (I always turn off the furnace before spraying.), some comes from upstairs via the basement stairs. I think most comes down the chimney, but whatever might be coming from upstairs is already at 65 - 70 deg. If all of your makeup air were coming directly from outside, you might experience more drop in temp. than I have, but I still doubt it would be a problem unless you want to spray non stop for hours.

John

[Paulh Tremblay]

IMO, a 60 CFM fan is of no value unless the open area of your booth is only the size of a shoe box. Spray booths are designed for something like 100 fpm of velocity over the work to carry away over spray. For a booth with an open area of just 2 ft x 2 ft you need a fan with 400 cfm. The open area on my temporary booth is about 4 x 7', meaning my fan should be at least 2800 cfm. So even though my fan may seem large at 1200 cfm, it's not. I'm not sure I follow what your friends at work said about lowering the temp. in your shop. All I can say is that my 1200 cfm fan has minimal effect on the temp. of my shop even after spraying for an hour. Some of my makeup air comes down the chimney (I always turn off the furnace before spraying.), some comes from upstairs via the basement stairs. I think most comes down the chimney, but whatever might be coming from upstairs is already at 65 - 70 deg. If all of your makeup air were coming directly from outside, you might experience more drop in temp. than I have, but I still doubt it would be a problem unless you want to spray non stop for hours.

John

Thanks. That's really helpful. My friends at work were agreeing with you; they note that because the fan will be blowing out, it won't lower the temp of the shop.

Do you open up another window besides the one with the fan? I've read several places that you should, thought I don't think I have to.

[John TenEyck]

Thanks. That's really helpful. My friends at work were agreeing with you; they note that because the fan will be blowing out, it won't lower the temp of the shop.

Do you open up another window besides the one with the fan? I've read several places that you should, thought I don't think I have to.

That's kind of funny how your co-workers thought the temp. wouldn't change because the fan is blowing out. It doesn't matter if the fan is blowing out or blowing in. To blow out there has to be makeup air coming in. To blow in there has to be air leaving the house, somewhere. Same difference in terms of heat loss. In my case, I don't have another window in my shop that I can open, so the makeup air comes down the chimney, some probably leaks in under the sill plate, and some comes down the basement stairs from upstairs. If you have another window in your shop that you can open that would work. If not, you could open a window upstairs. The benefit of the using an upstairs window is that the air will be pre warmed as it makes its way to your shop so the temp. in the shop will drop more slowly than if you let outside air directly in through a basement window. The only way to find out what works best is to try it. In any case, you have to let makeup air in somewhere or the exhaust fan won't operate at its rated CFM. The tighter your house and the greater the CFM of your fan the more important it is.

John