Hey all... I've invested weeks learning some speaker finishing techniques, so thought I'd post a bit of what I learned here. Temporary paint booth idea: I converted a regular 10x10' spare bedroom into a temporary dust-free paint shop. Walls and floor lined with poly sheets. A cheap $20 box fan with a furnace filter duct-taped to the front hangs with $5 worth of bulk chain and S-hooks from the ceiling. It's used to pull floating dust nibs out of the air and away from wet polyurethane, and it also (as you can see) acts as an air cleaner. Even though I did this in winter with the window sealed throughout the project, the fan cleared the air of the bulk of paint fume smell within about 15 minutes. I would turn it on an hour or two prior to spraying to pull any dust out of the air (door and window closed), run it during the spraying procedure, and then shut it off about 15 minutes after finishing. I think this helped a lot as I got hardly a single speck of dust drying into any of the six speaker cabinets I've completed so far. Making sure the hot air furnace is off during the 30 wet film minutes helps too, with the overhead vent closed off... Here's a picture of the spray gun I used: Basically, my only message here is that you don't need to spend big money on an HVLP gun to get decent results, in my experience. Mine's a no-name $20 el cheapo unit I picked up as a close-out special at a place called Princess Auto (in Calgary, Canada). I bet any equivalent at places like Lowes would work great too. Bottom line is: no matter how careful you brush or roll on urethane, you can't beat a sprayed finished, and in my opinion it's even easier than brushing once you get the hang of it. Also, make yourself a carousel to spin the cabinet easily. Standing in one spot to catch all sides is much easier than requiring the space to be able to walk all around. I made one easily with a $5 "lazy susan" bearing between a couple scrap pieces of plywood. Also, get yourself something like Painter's Pyramids to prop the box up with. Having the bottom of the cabinet away from the table surface prevents uneven finish due to air turbulence there. These are even a good idea if you're brushing to get the bristles down to the bottom edge easier. Here's a pic of my carousel: One last paint booth tip I have is that I found using wax paper on the paint table a good idea. After several coats of dried urethane spray accumulating on the bare wood table I was using originally it would start to throw crud up into the wet finish due to air flow bouncing off the table. With the wax paper in place, I simply change it out with a fresh sheet prior to my final coat. I wish I could remember where I bought the roll, but it was five years ago. I think it was a hardwood flooring outlet and it was quite cheap for a huge 3' roll of the stuff.
Thanks radorod. I've never taken the time to make a booth. It's a good idea I think. And I like the furnace filter idea. I usually go outside, but there's a lot of pollen in the air right now (Vancouver Island). I have a gun from Princess Auto as well. Power Fist brand. Like you say, it's very good. To get noticeably better you gotta spend a lot of money to get a pressure pot and stuff.
General Finish's Enduro Var. If you want more detail you can read my post here: http://www.diysoundgroup.com/forum/index.php?topic=371.0
Hey Rado, I work in the automotive paint industry and thought I might suggest instead of hanging the fan from the ceiling take the fan put it in the window blowing out with the filter on the back and add a filter to the ceiling vent and turn the heat on. This will give you great airflow and will clean out the air rapidly. It will most likely speed up your dry time as well. Just as a suggestion, if you go to your local body shop supply store you can purchase just about any color you can imagine in base coat clear coat system, however I would recommend that you use an automotive primer as well. Most stores will sell as little as a pint of color and quarts of primer and clear coats. Also note that the automotive clear polyurethanes have excellent UV protection. The gun you have would work perfectly for the process too. And you can get cool paints that have special effects like pearlescent color shifts. Hope you found the information useful and interesting.
Thanks a lot for your suggestions. The window in that room doesn't open enough for my fan, unfortunately, but I love those ideas. At the time of those pictures it was 20 below zero outside, hence the idea of trying to clean the air with the window closed. Venting outdoors is the way to go, for sure! Thanks.