I'm interning at a shop, and trying to help them out in some process improvements. What you are doing in your spray rooms to control your quality and keep the pieces you spray contamination free and drying properly?
The AC in the room has broken since I started, and the wall unit is being used for the time being. Although it isn't keeping the temps down around 75 degrees, it's at least not 95 degrees. I know this could use improvement.
I had the idea of using a dehumidifier. When it rains, it effects the dry time greatly. The room isn't air tight - we basically just have a closed off room with a couple tables and a spray booth fan. We have some dust issues when we paint, and I think sanding and tacking in the spray room is the culprit.
From contributor Z:
Well, after looking at your company's website, I have a few suggestions. First of all, clean the shop out! That's right, move everything outside and clean it from top to bottom and then clean everything out before you bring it back in. That place looks like something you would see on one of the hoarders-buried-alive episodes. The dust particles are practically blotting out the photos. Just how big is this shop, and what kind of room do you have?
Wash your hands frequently. Instruct employees to do so. I treat my final sanded surfaces as if I were handling food.
It's okay to spray stuff down with WD40 and other lubricants, but be mindful of where it lands. Once again this is another good opportunity to wash your hands prior to handling wood that is to be finished.
When I need to clean all of the dust out of my shop, I stick a couple of box fans in the back door to exhaust, and another in a widow to bring air in. I start in a back corner and blow all the dust from one end of the shop to the other and eventually right outside. During this process I run my dust collector with all the blast gates open to help circulate air and pick up some dust. Wear a mask or a respirator when doing this! This takes me about an hour.
Install ambient air filtration as well. If you have fine dust settling all over the place on top of everything, you need to do a better job, either capturing it at the source or while it's still airborne.
If you're having dust contamination within your spray booth, your make up air system is not keeping up and your booth is sucking in dirty air from the rest of the shop.
As far as temperatures, consult the manufacturer of your finishing products as to the recommended temperature/humidity for application and drying. Much of this differs from product to product.
1. Remove/blow out all dust and sawdust, starting from one end of your shop to the other end. Keep the fans going and the dust storm moving in one direction - out! Repeat at a minimum of 3-4 times. Top of shop to bottom needs to be blown off.
2. Pick the perfect time to spray. If it's raining and your schedule permits, hold off the final coats until the moisture content drops per manufacturer's specs. (You'll never see perfect conditions.) If it's super hot, wait until the evening to spray finals.
3. Remember that constant wiping down of your woodwork will create a static charge to the piece and this will attract every single piece of garbage floating around, especially if you're spraying conversion varnish, etc. If you can't afford an air nozzle that dissipates static charges, you can use denatured alcohol as a good stop gap.
This list could go on and on! Just pay attention to where the contaminated air is coming from - in spray booths, it sneaks through cracks and small seams, etc. Unless you're spraying in a perfectly temperature controlled downdraft booth that has recirculating air that's been filtered, and air temp and moisture content is regulated, and you're wearing fresh Tyvek suits from head to shoes and testing the particulate fallout rate with a piece of 1'x1' black Plexiglas to see just how clean your booth is... You're gonna be prepping and cleaning constantly to fight for a consistent smooth finish. Or you could use pre-cat lacquer in a satin to dull sheen, have a fairly clean environment, and get away with murder by using a quick rub down after the finish has dried with the back of the sandpaper!
The short of it... Just know your coatings limitations, understand the environment and which direction the air is flowing from (start to spray from there). Keep the shop, your equipment, and your schedule clean and ready for the "didn't see that coming" things that finishers deal with day in and day out.