Spraying clear coat - gun,booth,etc....

[banderson]

My primary product is oak and cherry Vcarved signs (small). I have been brushing on Polyurethane but I like the finish better when sprayed. Unfortunately, when I first tried this with my low pressure (cheap) spray gun I purchased, my entire garage filled up with mist.

What are you guys using for spraying higher volume products in small shop situations? Oh- I can't afford a paint booth either......:)

[dlcw]

Bret,

I have things set up in my shop so I can set up a temporary "spray booth" using sheets of plastic. I have enough room that they roll up to the ceiling when not in use and I drop them down when I need the booth. I also built an exhaust fan system using 24" box fans and furnace filters.

At first I thought the non explosion proof fans would be a problem. But I read an article about this exact subject where a guy set up air sampling gauges inside his spray booth to determine how much volatile over-spray was in the air at several different locations. What he found out, through this scientific sampling system, was that by the time over-spray reached his exhaust fans, there was not enough explosive capability left in it to cause a problem. After reading that study, I determined that by the time my over-spray gets to my exhaust fans (which is further then his setup) the chances of explosion were slim to none. I also have a pedestal fan setup to move air into the spray area so that it pushes the over-spray towards the exhaust fan.

This setup keeps the over-spray going outside. Combine that with my two shop air cleaner set on HIGH, I don't have any problem in the shop after I spray. Even when I doing a whole kitchen of cabinet doors no problem. By the way, I use an HVLP sprayer system. I also use a Cricket spray gun and rattle cans of finish.

[banderson]

Does the fan provide enough draw with the filter on it to pull the overspray out? I purchased that kind of sprayer form Harbor Freight but it leaks all over my hand....guess you get what you pay for. How do you like the Criket?

[dlcw]

Bret,

The two fans provide plenty of airflow to keep the overspray out. If you are srpaying a lot, you will have to change the filters more often to keep the airflow up. I double up my filters to catch as much as possible before it goes out the door.

I use my Cricket all the time for oil finishes for my cedar signs and painting. I wouldn't use it to do fine furniture. For that I use a quality HVLP sprayer that I've had for over 10 years. I use it to spray poly (very infrequently), lacquer (infrequently), and conversion varnish (all the time - 5 gallons or so a week). Beautiful finishes.

[bcondon]

I plan to build a simple spray cabinet. I have a spray room but wanted to build a 4x4 cabinet and set on a table. The back will be slightly tilted (front and back) so I can run water down the face of the azek. There will be a okastic pipe with hiles drilled in it to distribute the water with a pump delivering about 5 GPM to the pipe. My Dad had one at his shop and with the water flowing all of the over spray is rinsed into a pail via a rain gutter. I was going to use cheese cloth to filter the paint out and the pump would send the
water from the pail back to the pipe...

I know my dad did not have it vented and I never saw overspray in the shop...

Anyone try this?

Thanks

Bob

[Ajcoholic]

I plan to build a simple spray cabinet. I have a spray room but wanted to build a 4x4 cabinet and set on a table. The back will be slightly tilted (front and back) so I can run water down the face of the azek. There will be a okastic pipe with hiles drilled in it to distribute the water with a pump delivering about 5 GPM to the pipe. My Dad had one at his shop and with the water flowing all of the over spray is rinsed into a pail via a rain gutter. I was going to use cheese cloth to filter the paint out and the pump would send the
water from the pail back to the pipe...

I know my dad did not have it vented and I never saw overspray in the shop...

Anyone try this?

Thanks

Bob

Bob,
I have worked with a wet booth before. The curtain of water removes the overspray from the air. However you have the large volume of water, once saturated, to deal with - that you cannot just dump down the drain. Disposing of the water is an issue.

You guys make me nervous. I spray a lot of catalyzed lacquer (conversion varnish to some) and I have a proper booth, etc. I cannot or would not spray what I do, without a proper engineered booth & fan system. And I exhaust about 30 feet above ground where the winds will disperse the fumes and not bother my neighbours.

Even a slim chance of a fire, or worse yet and explosion is too much risk for this guy (not to mention I get inspected by the insurance company, and health and safety and no way a cobbled up booth would pass muster)

[gerryv]

Several years ago I was in a shop where a fellow was using a roller apparatus that looked like one of those old fashioned porcelain stamp and envelope lickers, but bigger and wider. Kind of like a roller on an axle mounted such that the bottom of the roller was immersed in the finish in the partly filled well.

What surprised me was the quality of the finish compared to brushing for example, no need for spray protection and especially how quick it was.

I don't know if this was something that was available commercially or was shop built but it sure worked. I'm assuming the fellow had a good feel for if, when and how much thinning was required.

Anyone else seen one of these? Maybe it could do the trick?

[gene]

Bret
turn down the air pressure and up the paint mixture . I spray a lot of clear lacquer with the harbor freight guns 15.00 and you can tune them to where there is almost no mist . 40 to 45lbs MAX air pressure . also make sure that the viscosity of your finish is correct , not to thick ( orange peel look) or too thin ( runs)

[bcondon]

I am currently spaying "mostly" with latex but do use some clear lacquer.

His system was commercially made, held 5 gal of water which was used over and over again and had a 5G/M pump which is quite a bit of water.

Again, Thanks!
Bob

[banderson]

Thanks guys. More to think about here than I thought.

[cabnet636]

I make all my new employees watch this just to insure we have all seen it,, I believe taughton press (fine woodworking) has one called spray basics

well worth owning

http://www.amazon.com/Spray-Finishing-Simple-Step---Step/dp/1600850928/ref=sr_1_4?ie=UTF8&qid=1354824740&sr=8-4&keywords=spray+basics


http://www.finewoodworking.com/how-to/video/introduction-to-spray-finishing.aspx

[beacon14]

If your insurance company saw you spraying with plastic sheeting hanging from the ceiling they would have a fit. I was in a shop that was in half a building, and had hung plastic sheet from the ceiling to the top of the dividing wall between the two halves of the building to keep the heat on our side. During our annual inspection that was one of the biggest problems they flagged. Yes the likelihood of a fire is low, but if some of that plastic is involved it would spread quick and the whole building could go up in smoke.

[Bob Eustace]

Bret I hve had to fight a vapor fire and believe me its no fun and very, very scarey. Why not think about using water base finish? These have improved out of sight and you will be impressed. Try not to be put off by the milky appearance when stirring clear as it goes away. The main advantage isno nastu VOC,s. another altrnative is Minwax wipe on polyurethane. Yes it does take 6 coats to get a brilliant shine but many fine woodworkers use it.

[banderson]

The water based finsih sounds real good. I just looked at the Minwax web sight. Can anybody recommend a specific product that they use? Most of what I make is small (9x2) to large (30 x 6) vcarved signs in oak and cherry. I stain with minwax products and then apply a coat of poly.

[stumpgrinder]

While investigating if we really needed a hood I came across a story of an individual who had lost part of their shop due to fire. When the insurance company came in, they saw a make shift hood with plastic curtains in the un-burnt area of the shop and turned down the claim even though the spray area was not responsible for the fire. I believe it was an electical fire on the far side of the shop. We ended up buying an explosion proof, open bench hood for around $1500 shipped. The only reason we have it is because we spray a shellac sealer on our instruments. Each spray session lasts ony about 30 seconds and I'm positive that there is no way we would blow up, but better safe than sorry right! For our clear coats we use a product called KTM-SV. It is a water based varnish that has been giving us excellent results. Here are some pictures of two mandolins, one with the satin finish, the other with gloss. You can order it in all levels of sheen directly from Grafted Coatings.

[cabnet636]

I operate a booth with which is both Sprinkler and has a self contained fire suppression system, I would never advocate a paper or plastic solution, anyone who has ever had a flash fire knows you do not get a second chance to fix a first mistake on this.

[Bob Eustace]

The water based finsih sounds real good. I just looked at the Minwax web sight. Can anybody recommend a specific product that they use? Most of what I make is small (9x2) to large (30 x 6) vcarved signs in oak and cherry. I stain with minwax products and then apply a coat of poly.

Bret in Australia its just called Minwax Wipe on Polyurethane in gloss or semi. Tin is rectangular and $29 a litre. Lots of application data on U tube. For Aussies reading this unbelievably you can now get it at Bunnings!

[banderson]

thanks guys for the good input. still processing and deciding what to do.

[chunkstyle]

Hey Bret,
Like some others, I've gone with water base and eliminated the risk of explosion. Sherwin Williams KemAqua for tinted laquers, ML Cambell's Aqualante, Target coatings, etc. There's quite a bit of discussion about these coatings on the woodweb.
Aside from the occasional Danish oil application, I've never had to use anything but water base for my small cabinet shop.
My spray booth is a hole in the wall with a louvered fan stuck in it. In front of the fan I've stretched a roll of filter media designed for water based finishes. I've gotten the filter media thru Chemco. Good luck.
Tim