Question for professional painters - Paint Booth liners

[wh500special 2,247]

So, I'm in the process of installing an automotive style, heated (180F max) paint booth at work.  It's now erected in the shop but is awaiting the ductwork, sprinklers, and utility hookups which will happen over the next two weeks.

 

I need to cover the inside of this thing with a peel-off coating before we commission it to keep the interior as new as possible.  Been looking at both the various adhesive films and the spray on coatings.  The rep who sold me the booth isn't crazy about the spray-on coatings but I'm not sure why.

 

Anyway, I'm sure there are body men out there or shop owners who use this stuff on this forum.  Anybody have any input as to which is the "better" booth liner?  Looks like the spray-on films are easier to apply and probably cheaper, but the plastic films and the 3M Dirt Trap stuff may be more durable. 

 

I shopped for paint booths for nearly two years.  This Garmat booth was certainly not the top in quality, but it gave us the best bang for the buck compared to everything else we considered...and there were many.  If we continue to expand our work to the current trends and plan, we'll be adding a bigger booth sometime in late 2023 or 2024.  Maybe I'll paint a tractor or two after work...

 

Thanks,

Steve

[squonk 41,939]

I would think the film liners would be easier to remove than a spray coating. Can't go wrong with 3M. Spray will get into crevices that wont be easy to get off.

 

Where is the filter rack on that and how big of a (BAF ) fan is that thing gonna use? 

Edited August 15, 2022 by squonk

[wh500special 2,247]

This is a "modified downdraft" booth with no floor pit.  So the incoming air filters are in the ceiling and the exhaust filtration is via a pair of vertical columns in each of the rear corners. Air is supposed to wash down over the parts from top to bottom then make its way out the rear of the booth through the filters.

 

This ought to be perfect for our needs since it's big enough for racks of small parts and can handle the occasional large item.  We paint military stuff, so we aren't after class-A automotive finishes so a true downdraft booth isn't necessary for our needs.

 

Filtered airflow is in the 13000 cfm range and there are two 7.5 hp blowers.  One brings air in, the other pushes it out.  They are squirrel cages.  Two stacks through the roof.  Blowers are controlled (VFD) to maintain the interior pressure at a predetermined setpoint.  I didn't know this, but spray booths operate at a very slight overpressure...I would have expected them to operate at a very slight vacuum.

 

Dimensions are approximately 24'x13'x10' (LxWxH).

 

Burner is 1M BTU/hr natural gas.  It can draw 100% outside air during spraying operations or can recirculate around 80% during the baking cycle.  It is direct-fired which is the normal convention for booths in the USA.  Only a few manufacturers offer indirect fired units at this time.  Indirect would have been my preference but I had to make budget concessions.

 

The eventual plan is to have a booth about twice as long and a bit taller and wider so we can paint ISO shipping containers. We can do them in this one, but just barely using a multi-step handling process.

 

Our painting contractors are killing us with their costs and leadtimes, so we decided to bring it in-house.   OSHA requirements essentially mean that if you're going to spray paint in a business setting you need to have a booth.  I started this project looking at much more simple open-front booths to meet the spirit of the regulation.  Then we crossed over into sucking all the heat out of the building in the winter venting the paint fumes so then I was adding make-up air furnaces.  When you hit that point it makes more sense to just enclose the booth and turn it into an oven.  The booth itself isn't horribly expensive, but the installation essentially doubles the investment.

 

Steve

[squonk 41,939]

You need over pressure to keep outside contaminates out of the booth when opening a door to it. Dirt or any airborne aerosols can ruin a paint job on anything. Your booth is the same principle of an isolation room in a hospital with pressure. If the patient had a highly contagious disease you run negative to keep it from spreading and the HEPA"s are supposed to take care of it. If the patient is immune compromised and you want to keep contaminates out, you run positive. Hope your VFD's are ABB and not those junk S flex Square D's. I applied for a HVAC job at a plant with clean rooms. 25 X 50 foot filter racks and who knows how many CFM.

 

Funny story about a paint booth. We had an older lady who owned a Chevy dealership and we had this old booth with just a big exhaust fan. She was outside wandering around one day and she sees "all this green snow" One of the body guys was removing the green masking paper from a car in the booth and was just tossing it aside. It got sucked into the fan and all of the "green snow " was getting blown all over the new cars! 

Edited August 15, 2022 by squonk

[wh500special 2,247]

Interesting feedback.  Thanks!

 

I haven't opened the control panel to see what kind of drives are in there, but I would expect mid-grade products in there at best.  I hadn't heard of the Square D drives being chronically bad, but that's kind of out of my swim lane.  Easy enough to replace if they die in the future.

 

I'm quite familiar with positive and negative pressure protection and isolation systems.  Our primary product line involves pressurized tents and shelters for shielding against chemical and biological warfare agents.  We run those with deeply filtered air and positive pressurization to keep the ugly buglies out.

 

We also make aircraft transportable isolation systems that run below atmospheric pressurization to provide a means of isolating infectious or contaminated people or assets from everybody else and so they don't have to scrap the airplane if they fly a contaminated cargo.  These are the military version of the hospital isolation rooms.  ALL of the patients the CDC and US military flew who had Ebola or Covid flew in our stuff (as an aside, once the military discovered that a $0.25 face mask was good enough to prevent transmission of covid they all but stopped using the super expensive, negative pressure isolation units to transport patients..)

 

What throws me about the paint booth is that I would have assumed that the primary focus would be to protect the booth from outward leakage to maintain good industrial hygiene.  Running it at a slight overpressure means they can leak vapors and mists into the shop environment.  But it's apparently quite close to neutral, so not a big deal.  Unless the filters are too clogged then you run the risk of blowing the doors open.

 

For our initial setup, I went ahead and ordered enough plastic film to cover the inside.  But I'm still up in the air on what to do long term.

 

I'm looking forward to having this thing going soon!

 

Steve

 

Steve

[Sarthurs01 891]

This is what I currently use in my booth. It’s a double booth that can easily fit 2 4door 8 foot bed tucks in, I’m spraying 6-10 jobs in it a day. It washes off with warm soapy water about every 3  months with filter changes every month. At my last place of employment I used 3M Dirt Trap, it’s a White fabric adhesive, worked well only painted 6-8 jobs a week there lasted about 6 months. We tried a clear adhesive film but it let dirt to fall off onto the jobs would not recommend that. Hope this helps! 

[squonk 41,939]

What throws me about the paint booth is that I would have assumed that the primary focus would be to protect the booth from outward leakage to maintain good industrial hygiene.

 

The primary goal of the paint booth manufacturers is the quality of the paint job. Not the environment the booth is in. Hence the positive pressure. It's your building. Set it up for negative pressure if you want. Should be able to program the drives to allow it 

[wh500special 2,247]

Paint booth rep referred me to the Dirt Trap.  Seems like a nice product but quite pricey.