Repost-Is An Exhaust Fan a Requirement for a Portable HVLP Booth, Spraying Water-based?

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Forum topic by gerrym526 posted 12-10-2009 06:34 PM 3374 views 0 times favorited 13 replies Add to Favorites Watch
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274 posts in 3774 days

12-10-2009 06:34 PM

Topic tags/keywords: finishing spray gun

Guys-this is a repost of this topic. Started it in the Safety forum, but this is probably the right place to get an answer.
Will be starting into spraying with an HVLP unit I recently purchased. In reviewing articles and videos on HVLP, the portable spray booth designs (usually big pieces of cardboard with duct tape) all had a cheap window box fan at the rear of the booth, covered with an inexpensive fiberglass furnace filter.
Here’s my issue-do I need the fan? I’ll be spraying only water based finishes and using a respirator with organic filters. I’ve rigged up a knock down setup of heavy shower curtains on wood closet rods to cover 3 sides of the spraying area. I’ll be using a heavy canvas drop cloth on the floor to keep finishes off the tile.
I can’t use a fan in my small basement shop without risking having any overspray it draws out end up on my stationary tools. Was told by the manufacturer of the HVLP unit (Apollo), that overspray with this turbine unit is minimal and shouldn’t be an issue like it is with a high pressure gun.
Am I OK without the fan, or do I need to wait until summer to use the HVLP with a fan-based spray booth in my garage.
It’s cold and snowy here in Chicago, and will be until April!
Thanks for the help.


-- Gerry

13 replies so far

View WayneC's profile


13753 posts in 4063 days

#1 posted 12-10-2009 09:45 PM


-- We must guard our enthusiasm as we would our life - James Krenov

View Ger21's profile


1074 posts in 3097 days

#2 posted 12-10-2009 11:01 PM

I spray waterbase in my garage with an old Wagner Finecoat. I don’t know about the Apollo, but my garage gets pretty filled with overspray. In the winter, As soon as I stop spraying, I open the doors for a few minutes to let the overspray out, then close it back up and turn the heat back on.

I don’t cover my table saw or other tools while spraying, though, as the overspray is not much different than normal wood dust. But the floor around the parts I’m spraying gets a lot of finish on it.

Not sure if any of this info helps you or not. If it were me, I’d probably use a fan and a filter. Better yet would be two fans. Also, I think the filters will clog up pretty quick, if you’re spraying a lot.

-- Gerry,

View lew's profile


12018 posts in 3721 days

#3 posted 12-10-2009 11:33 PM

I am not an expert, nor do I play one on TV.

Seems to me you have addressed the two main concerns of water based finishes. The respirator (and eye protection) should keep you body safe from the over spray/air born particles. The shower curtains will contain the same. I would add a forth side to your spray booth to completely enclose it and make sure the curtains are as close to the ceiling as possible to reduce the suspended particle escaping on natural air currents. The fan, although a nice touch, would not be necessary- IMO.

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View huff's profile


2828 posts in 3251 days

#4 posted 12-11-2009 12:03 AM

Jerry, The shower curtains will help contain the overspray and the respirator helps you. Even with an HVLP system, you will experience overspray. Usually a fan is used to pull the overspray from your spraying area and exhaust it outside, so unless you are setting your fan in front of an open window or door, there’s not much need to have it. If you use a fan, I do recommend you use a filter with it. Two reasons: one, it will collect a lot of the overspray, and not just blow it out the door or window, and second, it will keep a lot of the overspray out of the fan motor. You shouldn’t have a problem with overspray on your equipment, but like Ger21 said, you will get a lot of finish on the floor around where you are directly spraying. I usually put a piece of cardboard or plastic down first and have my project sitting on something to keep it off the floor. I’m too old to bend over that far! lol. Good luck.

-- John @

View SteveMI's profile


1092 posts in 3260 days

#5 posted 12-11-2009 12:51 AM

I paint in my garage, but use a dryer exhaust fan to move the overspray through a garage window. I push the window up and put a panel in with the flexible tube attaching to my paint tent. All of my painting is water base except occasional shellac.

Can you add a second exhaust from the basement like the clothes dryer? Flapper will close when not pushing air through.


View gerrym526's profile


274 posts in 3774 days

#6 posted 12-11-2009 06:40 AM

Thanks much for the info, it has been very helpful.
Steve-there’s no way I can add an exhaust fan to my shop without having to punch through a brick wall of the house. My shop has no windows, and the nearest window is across a hallway in the laundy room. I was a good idea however.
I will use the shower curtains, and painter drop cloth on the floor set up-should work fine until warm weather comes back, and I can move a portable spray booth to the garage.

-- Gerry

View BentheViking's profile


1782 posts in 2530 days

#7 posted 07-17-2013 01:50 AM

Glad I found this post. Trying to get ready to do some spraying next week. Will be spraying waterbased enamel in my garage and will set up some sorts of tarping/plastic possibly mounted to the garage door track (i want to keep the track and chain and motor free of overspray). I am thinking of keeping the openside right in front of the door so I can open it up and keep things well ventilated. Am I over or underthinking this?

-- It's made of wood. Real sturdy.--Chubbs Peterson

View firefighterontheside's profile


17948 posts in 1822 days

#8 posted 07-17-2013 02:22 AM

I think even in the basement you could still use a filter to take over spray out of the air. Maybe only turn fan on low so you don’t spread over spray too far.

-- Bill M. "People change, walnut doesn't" by Gene.

View NiteWalker's profile


2736 posts in 2543 days

#9 posted 07-17-2013 03:50 AM

I spray mostly waterbornes in my garage and I don’t tarp anything. The project goes on a cart in front of the open door for spraying; on the wall behind me I have a 20” box fan blowing fresh air inside. Works great.

-- He who dies with the most tools... dies with the emptiest wallet.

View joeyinsouthaustin's profile


1294 posts in 2038 days

#10 posted 07-17-2013 04:30 PM

Besides overspray… think about drying. A good, clean, gentle air movement is great for good curing. In all my smaller shops, the spray area was the curing area, this is where setting up the fan will also be important?? IMO

-- Who is John Galt?

View MrRon's profile


4718 posts in 3209 days

#11 posted 07-17-2013 06:23 PM

A fan is good to exhaust paint spray, BUT at the same time, that fan will be carrying airborne dust particles that can settle on your painted project. Try to keep the air flow as low as possible.

View NiteWalker's profile


2736 posts in 2543 days

#12 posted 07-17-2013 06:25 PM

IME, waterborn paint and clear coats dry so fast that the dust is rarely an issue except for humid days.

-- He who dies with the most tools... dies with the emptiest wallet.

View joeyinsouthaustin's profile


1294 posts in 2038 days

#13 posted 07-17-2013 08:28 PM

His fan, with the filter attached, is great for creating a light air flow, and if it is bringing air into the area, that is exhausted out, it is bringing in clean air. A positive pressure in the room will help keep particles from moving into the area. In open shop spraying, I have pointed my three filtered fans across pieces, to blow settling particles away from piece.

-- Who is John Galt?

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