SevenSixTwo - InDIYana 2018 Coax Design

[KEtheredge87]

Hey Everyone,

Mid-day update for you. I have decided to stop at 6 coats of Arm-R-Seal, and things look pretty! Good shine to things, and even retained some of that reflective look after it dried. I don't have a recent picture of that, since I've been working on this next step... a poor man's down draft paint booth! In an effort to corral and exhaust as much of the isocyanide paint fumes as possible from my upcoming 2K spray can job, I put this together after a little research. It's a positive pressure setup, such that fresh air is pumped into the sealed booth by a box fan and filter at the top, while exhaust fumes and overspray should get drafted to the bottom and out another air filter on the rear. I've got this set to exhaust out the garage door, so I'll crack the garage door about 2 feet while I do the work.

I'll be finishing the construction of this tonight, and hopefully prepping and masking the cabinets for primer tomorrow. I actually ran out of duct tape last night making this (knew I should have grabbed more than one large roll!), so I'll hit the hardware store for more today.

Finally for now, there's also been an adjustment to my painting strategy. I became very concerned about using the rustoleum "automotive primer" on this project since I wasn't confident it would play nicely with the urethane 2K spray paint afterward. Instead, I've returned that to the hardware store and bought a larger can of lacquer based black primer/surfacer from an actual automotive paint store local to me. With it being lacquer base, it will cure much more quickly than the enamel stuff I've been using on the SuperBees project. This way I can prime the cabinets, let them sit for a day or so to fully shrink back the lacquer as it cures, then topcoat with the 2K urethane satin paint without fear of further shrinkage under the topcoat. I'm squeezing every last minute out of my project timeline, and I'm set to finish just under the wire. Good ol' Murphy's Law at work!

[xsilverjag]

Cool spray booth. Easy to take apart?

[KEtheredge87]

Cool spray booth. Easy to take apart?

Thanks sir! Yep, it should be easy to take apart. I didn't use any PVC cement for that reason alone. The whole design was napkin-sketch engineered last night. It's made from ten sticks of 10' long x 1/2" PVC pipe (maybe $15 at the hardware store) and some cheap 20x20x1 furnace air filters. The setup is a bit rickety, but its only got to hold up some lightweight plastic sheeting. It would be better if I used PVC cement, but I want to take this apart later and store it rather than scrap the whole thing.

Oh... and did I mention duct tape? Lots.. and Lots of duct tape! Can't have a positive pressure spray booth without a good seal.

[Kevin K.]

I've been thinking about building something like this for a while now. Mine needs to be something really easy to set up and break down since I can't leave it laying around after the weekend.

You know box fans don't have explosion proof motors in them, right. You're not the first nor will you be the last to do this in a garage but it's kinda dangerous. Be careful man and make sure your wife is home just in case someone needs to make that dreaded 911 call.

[marvin]

That's why he designed a positive pressure booth... The fan is on the intake side not the exhaust side so it shouldn't to see the fumes if he directs them out the garage door. Your concerns occurred to me as well.

[jhollander]

The first thing that will happen is Keith will kick the outlet filter out after it clogs, then remove the inlet filter then the whole set up could get trashed, well at least it did in my house.

[ugly woofer]

I have seen a guy spray pure lacquer thinner into a box fan....no flame, nothing at all except a clean motor.

[marvin]

I have seen a guy spray pure lacquer thinner into a box fan....no flame, nothing at all except a clean motor.

That doesn't mean it was an intelligent thing to do!

[Kevin K.]

That's why he designed a positive pressure booth... The fan is on the intake side not the exhaust side so it shouldn't to see the fumes if he directs them out the garage door. Your concerns occurred to me as well.

Marvin, not saying I've never tested my luck just like he's about to do. In fact, I use fans to exhaust the fumes out of the shop anytime there's airborne spray involved. I realize he's pushing air into the booth and not pulling, but for this to be perfectly safe, his exhaust system to get this stuff out of the garage is going to have to be air tight (not likely) otherwise his intake fan will eventually see the fumes. There's an element of danger in what he's about to do and the risk level goes up in smaller areas. Don't know what the odds are for something to happen in this situation (maybe really low), but I certainly don't regret the suggestion to have another person there (inside the house, not in the garage) in case of an emergency. Better safe than sorry.

[KEtheredge87]

Hi Guys,

I truly appreciate the concern! Here's what I know right now, and how it's working out in my head. I will say up front that I welcome more comments and suggestions. The better informed I am, the safer I can make this admittedly not-so-great situation.

1) The positive pressure setup is not perfect. In fact the biggest issue I have right now is needing to have an access door flap rather than 100% duct taping all the seams (can't seal myself inside or outside!) I did a few test runs tonight just blowing the fan into the booth, and the booth sure does inflate, but without a very particular attempt at securing the door flaps. Most of the pressure escapes there (back into the garage) instead of out the bottom filter. Strike 1.

2) Since the point of all this is to avoid fumes hitting any sparks from the motor, I'll need to start the fan before spraying anything and leave it running long after I am done to be 100% sure there's no danger. Although because of the door flap issue in #1, the instant I open the booth to leave it I will likely burp a bunch of fumes out as I try to exit quickly... which still defeats the point a bit. Strike 2.

3) While I don't know the exact ratios of fuel and air required to make this stuff ignite, the only real variable I have any control over is oxygen supply. That said, my goal would be to crack both garage door bays to about 2 feet off the ground to try and create a cross-draft in my garage. I realize this kind of defeats the purpose of trying to exhaust the fumes out of the garage, but if I can't control them burping out when I leave the booth, then the whole "exhausting out the garage" thing is already an exercise in futility. I figure cracking the bay doors will minimize the chances of wind blowing down my rickety little spraying booth, but still provide more fresh air to bias the air/fuel mix OUT of a suitable combustion range.

Another point that I think bears consideration is the amount of paint that I'll be using. At worst, it will be two 12oz cans of 2K spray paint, spread out over a couple hours. At best, I'll only need most of one can. If I had thought to spray an entire car's worth of 2K paints in my garage I would have immediately dismissed the idea as stupid. That level of painting is only getting done outside the garage where no fans are needed, or in a professional paint booth. This small amount of paint seems manageable.


Beyond all the careful consideration of the painting situation, Here's some photos of the cabinets stripped of their blue painters tape and decked out in some green automotive masking tape. I didn't trust the green frog tape to handle lacquer based primer and urethane 2K paint solvents without seeping paint underneath. I've got a bit more masking to do before it's all said and done, but I should be able to start spraying the black lacquer primer tomorrow evening.

[KEtheredge87]

The first thing that will happen is Keith will kick the outlet filter out after it clogs, then remove the inlet filter then the whole set up could get trashed, well at least it did in my house.

Ya know what John... I can totally see myself going all King Kong and tearing the building down if I got really mad at it! Heck, with as much duct tape as I needed, I may have no other choice but to kick out the filters!

[KEtheredge87]

Hi Guys... seems I have some thinking to do. I always knew you weren't supposed to breathe paint fumes, but the isocyanates used in these 2K paints seems absurdly nasty. I planned to use a 3M half face respirator with fresh cartridges when starting this job, but after reading 3M's own documentation on it, sounds like I wouldn't even know if my cartridges were bad and didn't block the chemicals. I do not want isocyanate sensitization and the associated asthma like symptoms if I screw this up... maybe 2K paints aren't for me.

[jhollander]

I've sprayed 2K but did it in an open 2-car garage with fan blowing the over spray out. Cars were parked down the street. Your surface area is not that great. Assuming you are using a HVLP you should not have a problem. There's no way I'd get in your plastic bag house, but with a turntable, a clear vinyl window and long gloves you might be able to make a paint cabinet with you on the outside.

[Kevin K.]

What's your weather like right now? Can you spray out in the yard? If it's warm enough and there's not to much wind, you've got just as good a chance of getting the paint on without debris as you do in the garage.

[KEtheredge87]

I've sprayed 2K but did it in an open 2-car garage with fan blowing the over spray out. Cars were parked down the street. Your surface area is not that great. Assuming you are using a HVLP you should not have a problem. There's no way I'd get in your plastic bag house, but with a turntable, a clear vinyl window and long gloves you might be able to make a paint cabinet with you on the outside.

Seriously John, Thank you for injecting a bit of humor into an otherwise serious topic! I've been trying to think my way through this all morning to come up with a cost-effective and safe solution (with no success, might I add.) Your "plastic bag house" comment gave me a good chuckle! Never thought about turning myself into the boy who lives in a bubble!

Getting back to the actual setup, I don't have a full HVLP setup yet (that's future plans). The Eastwood "2K aerospray" spray paints are marketed as having a fan pattern more like an HVLP spray gun. That fact, and the increased quality of the paint over what I can get at the hardware store, is what attracted me to those cans of paint. I do have a turntable and was planning to use it, but that does nothing for my fumes problem.

At the moment, I am considering going without paint on the MDF for the InDIYana meetup so I can be prepared. After that I can pull the drivers and revert to a gloss enamel spray paint from the hardware store. It's not my preferred option, but at least I won't need professional grade forced air respirators to feel safe.