Need help w/ finishing room. I’m building my dream shop and will have the luxury of a 12×12 finishing room. But I want to make sure I do it right. I’m looking for web sites that discuss ventilation, lighting, electricity, safety, etc., etc. If you know of any good, informational web sites, or articles in FWW going back to late 80’s, please let me know. Most of my finishes are hand applied oils and varnishes, but occassionally I spray either lacquer or paints.
Thanks for the help, Bill
Replies
I envy you. I need a finish room more than I need a work bench! Alas, I don't have the space for a dedicated finishing room. I suppose that you know the general needs and are looking for specifics, which I do not have. I do think that some degree of heating and cooling is importiant to preserve stored finish.
Mike
Thanks Mike. The heating and cooling are already in the plans. You're right about needing specifics. I've got all the equipment I'll use (compressor, regulators, spray guns, etc.) but I want to make sure I consider all the safety issues before I get too far down the road. Things like explosion proof switches and fans, special lighting, ventilation, etc. I've been going back through old issues of FWW from mid 80's on, but most address HOW TO apply a finish or the best HVLP sprayer. The only booth articles seem to address temporary setups using cardboard or plastic sheeting.
Thanks again. Bill
Bill- I am also setting up a finish room. I see that Grizzly has a new finish booth type fan with furnace filters set up in it. It is really just a table area with the fumes drawn away by the fan. Has anyone tried this product and/or is it something we could do with off the shelf items for less?? I think they wanted $1300 for it. Any thoughts??
Thanks
John
I'm in the process of setting up a finishing room in my shop, at least for the winter months. The book "Setting Up Shop" is helpful. I installed a chimney pipe when building the shop but decided against a wood stove so I'm using it as the exhaust vent (it works better when venting up, not sideways through a window). I plug it with a shaped piece of rigid insulation when not in use. I'm using clear poly over studs for the walls and have kept the lights and other electrical outside of the room. Any electrical components in the room need to be explosion proof. I framed an opening that fits a high end heater filter (available at home centers) and put ####fan blowing through the filter. If this doesn't exhaust fast enough, I'll have to buy an explosion proof fan and mount it on the pipe thimble at the ceiling.
All of the explosion proof components should be available at your local electrical supply house or Granger etc. but pay very close attention (or hire an commercial electrician) to the installation (fittings, conduits, etc are very particular in explosion proof applications). Think of it as a system, don't leave a weak link in the installation.
Let us know what you end up with,
Norse
Norse: Thanks for the reply. Sounds like you've done some research on the exhaust fan issue. That's one of my bigger concerns. I've got several "squirrel cage" fans laying around. My original thought was to put one of those in the attic above the finish room and vent it out through the eaves. I'd still like to do that but I don't know if the flamable fumes going through the fan could lead to an explosion or fire if they come in contact with the motor.
For air coming into the room, I'll cut an opening in the lower portion of an inside wall and insert two furnace type filters. This will keep dust out.
Please give me your thoughts on the "squirrel cage" idea. Do you think it would be safe?
Bill
When exhausting a finish room, DO NOT pull the air out of the room, push it. The vent should be exactly that, a vent. Use your fan to create a positive pressure in the room otherwise you will suck dirt in around the doors, under the sill plate etc.. If you opt to use an exhaust fan in the vent the CFM rating should be lower than the "makeup air" fan. Build your self a gage to check for positive pressure using 10' of 1/4" clear tubing. Mount it on the wall in a U shape about 1" wide with one end in the room and the other outside. Fill it 1/2 full with some colored water. The side inside the room should rise above the outside column. I used to build commercial spray booths
Joe Phillips
Plastics pay the bills, Woodworking keeps me sane!
Joe and Norse: Did you ever have one of those moments when you said, "Why didn't I think of that?" Both of you responded to my plea for help by suggesting I "push" the air in rather than "pulling" it out. I was so focused on an "exhaust" fan that I never thought about this approach. So let me see if I've got this right. And please let me know if I don't. That goes for anyone else reading this post. If you see a potential problem, please speak up.
I'll use a squirrel cage fan to blow air into the finish room along the lower portion of an interior wall. That air will be coming from the shop area, but I can build the fan into a box with furnace filters and clean the air before it gets into the finish room. I've done that with other squirrel cage fans.
To let the air/fumes/vapors out of the finish room, I'll put a duct in the attic leading outside through the eaves. I'll probably build a frame on the ceiling to hold another furnace filter to clean the air one more time before it leaves the room. It'll also be a good way to hold a piece of 1" thick styrofoam insulation when the fan is not in use.
Actually, this solves one more issue. When I open the door to leave the finish room, I won't have to worry about dirty air being sucked in and getting on my wet project. The positive pressure will push it away from the door.
Thanks again for all the responses. That's the great thing about this forum. When you need help, there's always someone out there with a better idea.
Bill
"I'll put a duct in the attic leading outside through the eaves."
When you write "eaves" I get a little worried that you mean to turn the duct and vent through the eave vents in the overhang of the roof. My advice is strongly to run the duct (well sealed) as straight up (vertical) as possible, cut a hole in the roof and extend the duct a foot or so with a weather cap (and flashings of course). A turn and in combination with a poorly sealed joint could lead to all the stinky stuff in your attic or worse.
As for the lights, you have too big of a room to light it from beyond so using IS lights, stitches would be the safe way to go. Remember to think of all this as a "system."
And yes, this forum is a wonderful place!
Norse
Anyone know of some good sources for IS type lighting and electrical switches?
Yep, I meant eaves, as in overhang of the roof. But you raise a good point. Going straight up through the roof will be better, and I have that option. Thanks again.
First, the exhaust should be ducted directly to the exterior. Like I said before, going up is better than sideways. If you put a fan in the room or duct, you need to put a filter in front of it or the blades will clog. This is why I'm more partial to the fan outside and blowing in. Even the little fumes you generate can be very explosive. Also, be sure to have some kind of control for the fan speed. There are some good explanations of positive pressure on the net under auto paint booths (but we're not painting cars or powder coating).
Try the squirrel cage outside of the filters.
Norse
Norse -
"First, the exhaust should be ducted directly to the exterior. Like I said before, going up is better than sideways."
Maybe I'm the wrong track. Will my idea of a downdraft not work? I understand the principle of positive pressure but not the updraft.
"Try the squirrel cage outside of the filters. "
My plan is to build a filter box around the squirrel cage and direct the air flow down through a pegboard suspended ceiling. Is this not a viable design?
Thanks for your assistance.
Ken
I'm no expert but it sounds like the down draft should work. I did a smoke test in mine and the only weak point is at the ceiling level where the exhaust duct protrudes below the drywall a few inches. Turning the fan to high, solved this. But watching the smoke rise straight up from anywhere in the room was telling. However, this was smoke, not fumes and there was nothing in the room except me (no work being finished, no air from the spray gun, etc.) I still have yet to put the room to a real test. Please let us know how yours worked, I'm very curious.
Norse
Ken: In my last shop I built two squirrel cage fan boxes just to filter and circulate the air. In both cases I used furnace filters. I found that they clogged up quickly and I had to change them often.
My point is, with your's up over your ceiling, you may want to plan for easy access to get up there and change the filters. I don't know what kind of head room you have up there, but crawling around to change the filters can be a pain in the posterior. The older I get, the more I think about convenience.
Also, with the filters overhead and out of sight, how often will you think about changing them. Out-of-sight, out-of mind. It's kinda like draining the tank on my air compressor. I know I should do it often, but I just don't think about it.
Just a thought.
Bill
Can any of you guys post a sketch of your positive pressure systems and the anticipated exhaust flow? I am currious as to the flow of exhaust air vertically with a positive pressure system. Sounds like a good concept.
Aaron
Just a little more about the electrical components: There are two kinds that are safe to use in this environment, explosion-proof (XP) and intrinsically-safe (IS). There are big differences and you need to know which you really need.
XP means that the part will contain an explosion inside it, so these are usually very heavy with lots of bolts etc., and they are expensive! But they do not prevent explosions, they just contain them.
IS means they are designed so they don't produce sparks, meaning they are safe to use in an explosive environment. This is normally what you would want to specify for you application, I think, especially for switches.
The point about positive pressure is very good! I was trying to figure out how to seal up the door, etc. and this solves the problem much more elegantly. Also it puts the fan motor outside the dangerous environment so it does not have to be IS or XP. Thanks! "Everything should be made as simple as possible, but no simpler." A. Einstein
http://www.albionworks.net
Thanks for the lesson on XP and IS. I had no idea there was a difference. Sounds like IS is definately the way to go.
Like you, I like the idea of positive pressure. It solves several problems.
Thanks again. Bill
I am in the process of building a similar setup. Although I have not completed it and put it to the test, I can tell you how I'm setting it up. Mine will also be 12 x 12 with 8' ceiling. It is under a mezzanine at one end of my shop. I'm building a box enclosure for the squirrel cage which will sit on top of the mezzanine. It has filters on all four sides. This will blow down into the finishing room through a suspended ceiling comprised of pegboard squares rather than typical ceiling tiles. My theory is that this will provide a downdraft similar to a commercial spray booth. I have double doors entering the booth which are weather stripped, and a louver exhaust on the back wall of the booth leaving the building which is also filtered. All of the lighting and electrical will be intrinsically safe. Compressor will be mounted on the mezzanine roof and piped in. I do have a concern about maintaining climate control in the rest of the shop, since that will be the source of my makeup air. However, since I am a small operation I plan to just open a shop window during the time I am using the booth. Will let you know if it works as planned when I'm done.
Ken McColly
Edited 1/18/2004 1:51:49 PM ET by Ken
Ken: sounds like we're on the same page. I kinda like the idea of putting the fan low down on an interior wall blowing into the finish room. I'll use a louvered vent to direct the air flow away from the center of the room where my work piece will be. With the exhaust in the ceiling, the air should flow around the room and exit through the vent in the ceiling. Hopefully, this will keep any particles in the room off my work.
With the fan above the ceiling blowing down into the room, are you concerned about dust getting on a wet workpiece?
As for lights and switch, looks like I definately need to go with IS. Someone else posted a question about where to get these. Any ideas?
Bill
Bill -
All of my makeup air will pass through filters before being blown down through the pegboard grid. My exhaust louver will be in the center of the rear wall, low to the floor. What I'm counting on is that the filtered makeup air will preclude any incoming dust, and the downdraft will quickly disperse what overspray I have. Like I say, I'm not finished with it yet, but that is the way I hope it will work. Time will tell........
IS certified electrical components are available from both Grainger and McMaster-Carr.
Ken
Edited 1/18/2004 8:30:12 PM ET by Ken
Bill,
Glad you started this thread. I just spent way to long with Penofin fumes in my workshop. Time to do something about the lack of ventilation.
Anybody have any rules of thumb as to how much cfm of air or positive pressure you need in a finishing room to clear the air?
Dirt Stirrer asked about how much cfm you need. In one of the past FWW articles I've been going through there was a formula. It suggested you need to exchange all the air in the room every 10-15 minutes. In my case the room is 12x12x10' high, giving me 1,440 cu. ft. of air space. If I divide this by 10 minutes, it gives me 144 cfm, meaning I need a fan capable of producing 144 cfm.
Does this sound right? Boy am I learning a lot from this thread. And I thought my poor old brain was already overwhelmed. :-)
Bill
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