Temporary spray booth

Brian · 06-08-08, 08:01 PM

This one if for the DIY guys out there. We will be spraying paint sometime this summer and have already taken the class that Mark Worthington set up at PPG a little while ago. What I am considering now is any advice that someone with experience may have with setting up a spray booth in a two car garage. We'll likely be doing a knockdown with 2 bys and plastic sheeting, clean room tack cloth on the floor with positive ventilation to keep the air moving and dust out. And yes, we'll have man-rated breathing air to stop from breathing all of the nasties. What I am pondering now is to how illuminate the booth and if anyone has been sucessful with downdraft venting with one of these set ups. I saw the big fans at Home Depot this morning and the gears in my head began to turn.

Any thoughts appreciated.

Brian

Rick Muck- Mark IV · 06-08-08, 08:59 PM

Any lighting in the booth and any fans that draw air/fumes/nasties from the booth must be explosion-proof. You don't want to make that phone call to your insurance company as they will smile politely and then tell you to get stuffed!

If you are using clear plastic for the walls the lighting can be behind them.

Perhaps you could rent a proper booth from a local shop over the weekend when they closed?

Cliff Beer · 06-09-08, 02:46 AM

Brian, it sounds a bit unprofessional I know, but I've had very good result just simply painting outside in an open space on a warm day. If there's little or no wind, 75 degrees, not a lot of trees in proximity and some sunlight then you can do very nice work particularly if you paint panels rather than trying to paint the whole car at one time. Panels are easier to paint because you can wet out the whole panel and not have to worry too much about where you started and stopped as you're moving around the car. Similarly, overspray is easier to manage for the same reason. A BMW I had about 10 years ago was painted in this fashion by me and won a local car show award for best overall fit and finish!

Of course, the professional guys look at that approach as crude and inconsistent (and they're likely right) but some very nice results can be achieved when done carefully and there's no need to build a paint booth!

SpyderMike · 06-09-08, 03:23 AM

I have a paint booth I set up in my garage. I made with some 4 mil platic sheeting that I ran continuous around a plane I made (the wings are off). I stapled the sheeting beneath some thin strips of left over 1/8" thick melamine to the ceiling. I am not going with any additional ventilation. I have a HVLP system and will not be spraying much duration of three different colors (think WWII Navy scheme of white on bottom, gray in the middle and gray/blue on top). I won't be spraying much at a time, so I am going to wet the floor, step in an shoot a color. I have a forced air breathing system I will use.

Pretty simple - once I get done with the sanding.....

Malcolm · 06-09-08, 04:50 AM

Hi Brian

When I did some repaint on my front clip, we used clear decorating dust sheets from B&Q (Home Depot for you I think) and fixed them to the walls floor and ceiling with wooden battens. The lights were behind the plastic sheets just make sure they do not touch the plastic sheets in case they melt them. The compressor was outside and we used a big fan to extract air out. Made no allowance for putting air in but it seemed to find its way in as we did not create a vacuum! We just put the fan in the doorway. What we also did was to put in some heating to get the cubicle as warm as possible. It was very very warm in mid summer. I had a radiator from a central heating system so we jsut ran that full blast so again no major melting or flammable risk to the fumes or plastic sheeting. Oil filled radiators that are electric would be equivalent?

Once the paint job was done we just pulled it all down and threw away. We had very little leakage past the plastic sheeting. We taped up any weak areas. Thing to remember is that the extract fan will paint whatever is behind it so if this is in your garage, you had better put some protection onto the drive. Plastic sheeting weighed down at each corner should do it.

It is a temporary thing so no need to make it so pretty, just functional.

Brian · 06-09-08, 07:22 AM

Now the juices are flowing!
A tip we received at the PPG class was not to extract the air with a downstream fan, but to pressurize the booth with upstream fan(s). That way you are not sucking in every little piece of junk in the area, and the fans are not exposed to any fumes. The trick will be to get a lot of flow volume with very little velocity to keep the booth at a few psi higher than atmospheric pressure. I may have to craft up a diffuser of sorts. We'll be pushing the air into the woods behind the house. With respect to wetting the floor, we were advised to use the sticky mats from a clean room entrance as they capture everything.

We will be painting the car with basecoat clearcoar, HVLP in pieces. We'll do all of the alignment and plastic work with it assembled, key the pieces together and then take it apart to paint.

The shops up here won't rent booths or shoot paint on cars that they have not prepared. I'm sure they don't think it's worth the hassle, and we'd need to be in and out a dozen times to finish the job.

I won't cath up to Scott with his Tornado, but hopefully will be on the road this year, sans a few pieces.

Brian

David S. · 06-09-08, 08:36 AM

Brian,
Most of the problems spraying in your garage is dirt. You also want to have dry air to your cup gun. I would suggest an air pig or small tank in line with your compressor with air dryer or some type of filter for moisture. I would also suggest wetting the floor of the area that you are spraying in this also keeps the dust down. As for surface preperation Chix Tackcloth I-6117-G these are blue and do not use beeswax so they do not leave residue. There is also a Chix surface prep cloth 8809 these may be brown or white and are like a scott towel but are lint free. You can mix up a batch of 40% Naptha or(isopropinale alcohol)and 60% DI water(deionized water) to wipe the part down before you paint. Also use the same air that you spray with to blow the part off. I would suspend the part in the air with metal hooks or chains from the rafters if you can. Get yourself some of those cheap blue nitrate gloves and wear them when you do the finale prep. If you follow these steps you should get an excellent finish.
Dave

MReid · 06-09-08, 09:33 AM

When I painted my coupe in the garage, we installed a furnace air filter in the window and sealed squirrel cage fans under the garage door. I cleaned all the dust and spider webs out and wet the floor down just before spraying. A friend found these blowers in a dumpster (skip for my UK friends) behind a school that was being refurbished:

I didn't use any plastic and we already had significant lighting in the garage. Be careful with regular plastic sheeting. Paint won't stick to it and over a bit of time, will flake off and fall onto your freshly painted car! Here are a few more pics:

Mark Worthington · 06-09-08, 12:58 PM

Hi Brian. It's been a while since you've been to my place as I've upgraded my shop by hanging a 6-mil polyethelyene sheet barrier down the middle of the garage with a roll-up "window" between the front of the car and my workbench. It really helps control the dust when I do sanding, and I'll be able to use it when I spray. I've also significantly upgraded the lighting - I bought a bunch of high-efficiency T2 ballasts at Wal-Mart and wired them up. Think "operating room" bright. I also bought an air dryer from Harbor Freight ($300) and plumbed my shop with 3/4" galvenized steel pipe so I have ample volume of nice, dry air. Problem is that there isn't a huge amount of room between the car and the walls of my "paint booth" now, and that means I'll have to be real careful with the air hose.

A while ago I built a paint booth out of 2x3 lumber and 6-mil poly with two fans with AC filters taped to them with the intent of temporarily attaching it to the exterior of my garage. I might still use it to buy more space.

The main problem here in New England is the relatively narrow window of opportunity during which you can paint your car. Last week it was in the 50s - too cold. Now it's 95 degrees with high humidity - too hot. There's also a metric shitload of pollen and debris in the air right now. So really, we have a window during the months of July, August and September, as long as it doesn't rain or get too hot or too cold. Don't you just love New England?

MReid · 06-09-08, 02:47 PM

Oops, pictures were blocked at work:

Blowers found at school:

Filters in window, floor wet down, compressor in other room, and ready to paint:

View from the outside:

Let the painting begin:

Big-Foot · 06-10-08, 09:48 AM

Done more than a few driveway and garage jobs.. I think a couple key things of importance are;
1) Start ventilation well in advance of the actual painting to ensure fumes don't build up.
2) Correct (for the paint being used) breathing aparatus.
3) A way to get out without jeopardising your work.

kiwi ka · 06-11-08, 06:19 AM

More ideas on the same theme, I work for Hirepool so big fans were no problem, went to a dress fabrics shop and bought some thin micro fibre not unlike a duvee liner about 10 mm thick and staple it in the door way with the fan sucking thru that. Air found its own way in and the over spray stuck to the fabric. I used a proper mask twin organic filter 3000 series and can still read rite and remeba 3 years later. The garage was lined with drop sheets that acted as great static attractants for any over spray and or dust whilst the floor underwent a few changes in color, grey,black,white and then orange top coat. Finnaly a nice new coat of grey floor paint hid it all. No over spray was found outside.
Cheers