Spray Booth

[fizch]

I am looking to buy a new house that has a detached garage that I plan to use for a new workshop. I would like to add a room or closet for finishing my projects. Should I build my own paint booth? What materials would I need? Should I buy a paint booth? Do they make them that small? Thanks for your help.

[rodger.]

I have researched this topic extensively, and came up with more questions than answers.  Here is what my research shows:

1. If you are spraying any solvent finish, forget about setting up a spray booth inside your home.  Between the cost of explosion proof fans, switches, and lights, it will cost a fortune.  This is not taking into account the other major hazards of atomizing finish near your family

2.  Garage seems to be the best bet, with collabsable walls

3.  A box fan is not enough for exhaust

So, I still spray in my backyard, though I hope someone has a good solution!

Check out Bob flexners book, and finewoodworking.com for some images and ideas.

Edited November 25, 2015 by Pug

[SawDustB]

For a quick and dirty spray booth, I've hung plastic drop sheets from the garage door track to create a mostly enclosed space for spraying. It worked pretty well, and blue tape along the bottom helps to prevent them blowing around from the air. I've only sprayed water based finish with it though. I don't think I'd be willing to do solvent based inside.

[fizch]

At this point, I have only sprayed stain, latex paint, and varnish through my hvlp. The only solvent has been paint thinner when I am cleaning it out. I wouldn't dare spray that in the booth. 

The garage that I am turning into a shop is detached and a long way from the house.

Edited November 28, 2015 by fizch

[Chris H]

Spray booths can be a little like dust collection.  You can get very good results from relatively solid DIY efforts.  However if you want perfect or near perfect, get ready to spend big $$. Below is my experience, and not meant to be a recommendation.  Everyone has to balance risks and rewards for themselves.  Know the value you get for your money hits diminishing returns pretty quickly.  

Sprays booths are really pretty simple, but can be very expensive in that simplicity.  Your goal should be perfection (air tight / balanced air flow), but even missing the mark by 15%-20% will be a huge upgrade.  The basics are that you need to move polluted air out, and only allow filtered air in.  There are lots of options, but unless you have a large budget and large space, I'd recommend going with a temporary booth of some kind.  This can be achieved pretty cheaply (~$250-$300) with some heavy plastic (go 6 mil +) some dimension lumber. The big $$ come from air management.  The rest is maybe $50-$100. 

1) Build two squares out of 2x4's, the size of the space (Mine was~ 8'x12').  One will be the floor weights (base) and one will be permanently attached to the ceiling or rafters of the garage(top).  

2) Drape the plastic from the ceiling to the floor fastening to the floor box, and ceiling box.  If you have extra, wrap around the top and bottom lumber a few rolls.  

3) Use vapor barrier tape on the corners (inside and out), and plastic off the top if the rafters are exposed.  This will create a simple air tight (ish) box that will serve as the booth. 

4) Simple zippers on tape can be bought for an entry way you cut.  These are used by re-modelers a lot.  Big box will have them. 

5) Add some i-hooks on the outside of the base 2x4 box.  Some bungees hooked into the i-hooks, and draped over the ceiling rafters will serve to hold it up on the ceiling out of the way when not used.  A pully system sync'd on all four corners would be cool, but I just made 4 trips up the ladder each time.  

Think big accordion.

Finally you have to figure out air flow.  Because your booth will not be 100% air tight, you can get away with a positive air flow system. You pump filtered air into the booth, and the positive pressure will push the polluted air out.  In a garage this can work, because you can open the garage up to let that polluted air escape outside.  The advantage here is your air pump can be outside, and doesn't contact with the polluted air.  Thus the "explosion proof" thing should not be an issue. (certainly operate at your own peril/risk here)

If you want to go a little safer, and consistent figure out your explosion proof exhaust solution and then an air-in solution (can just be a filtered whole in your barrier.  Air pressure in either case is your friend.  You likely don't need t pump in and out, as long as you are making sure the air in is filtered, and the air out, gets outside (the quicker the better). 

 

Sorry I don't have pictures.  I had this at my last house in a garage that was not a shop, just a regular car storage garage.  I  haven't bothered to re-setup at our new house, since the plan is to build a standalone shop in the spring.  I used a positive air system, but it wasn't perfect.  I bumped in air from outside (~300 CFM fan), filtered through a couple HEPA filters.  I hooked a hose up near the base to standard 4" exhaust pipe and would just run it outside.  It would get a little thick from time to time if I was spraying for long periods of time.  One big upside to spraying is that that is very rare to be in there a long time.  Big projects can be sprayed in 10-15 minutes tops in most cases, and then you just pump air in until it dries (also pretty quick).

 

This won't get you a professional spray booth, but it is effective. 

Edited November 29, 2015 by Chris H

[fizch]

Thanks Chris. That sounds pretty good. I do like the accordian idea with the pulleys to lift it up out of the way when not in use. That does give me a good idea on how to build the booth.

I guess I will need further clarification on the air flow. I am not sure how I would move air in and out.