Hello all, So I've been researching a lot on compressors and different types of painting set ups. Every time this question gets posed there's the "You need at least a 60 gallon compressor etc etc" camp and the "you can do it with a 3 gallon 1/3 hp compressor" camp. With that being said, I'm not buying a 1k+ setup and I'm not foolish enough to try with a pancake compressor. I'm trying to paint this 81' F150 gloss black and not expecting a showroom quality job, a rattle can job would look great compared to its current state and lets call this my paint gaining experience guinea pig. That being said I've done some looking into LVLP guns and think that the HF 21 or 26 gallon compressor coupled with a LVLP gun should work. I am not trying to paint the whole truck in 1 shot. Due to the amount of rust, I have 2 fenders and a cab sitting in my garage waiting to share the space with a door and bed I can find. I will only be able to salvage the hood and tailgate from my truck, so everything will be piece mail, fenders and doors one day, cab another, hood another etc. And again, not worried about variations in pigment etc from not shooting all at once. So the HF 21 gallon lubricated is 2.5hp - 5.8@40 & 4.7@90, the 26 gallon oilless is 1.8hp - 4@90 & 6@40. The gun I'm looking at is a Sprayvit SP-33500K and it's air consumption is 2.4 to 3.9@30. So the 26 gallon has a higher cfm rating@40 and larger air capacity but less hp but I'm thinking that's the right choice due to its higher cfm at lower psi to match the gun correct? Also, I plan on spraying in my garage, door sealed off, 2 fans blowing in 2 fans sucking out with filters with compressor outside and low VOC paint. All while painting in the middle of the day while the neighbors are at work and my wife and toddler are not at home, does that sound like a solid safe plan? Any insight/tips/tricks on this topic would be greatly appreciated (except for trying to convince me to buy the 60 gallon compressor lol), thank you all.

 

Ok, lets take the compressor to start.....

Forget the tank size for a minute and just focus on the compressor. the spec on the gun from amazon is..

Air consumption 2.4 to 3.9 CFM @ 30 PSI, Working pressure 28-45 PSI. Maximum pressure 60 PSI

So you need a compressor that is no less than 4 cfm @ 30 psi..... IMHO, the best and lest expensive way to get this is to purchase 2 HF compressors (wyed into each other)...
https://www.harborfreight.com/8-gallon-15-hp-150-psi-oil-free-portable-air-compressor-64294.html
or
https://www.harborfreight.com/6-gal-...sor-68149.html

To assit mitigating moisture (even though you will have a filter (but I'm assuming an inexpensive one), buy also an air tank like this.....

https://www.harborfreight.com/5-gallon-portable-air-tank-65594.html

So what this will all give you is this......you will meet the CFM demands, with the pancake style you will now have a reserve as well, but lastly, you will hang the tank in an elevated position (as heigh as you can get) as this will act as a secondary and very, very effective moisture containment system as water vapor does not like to travel upward and if it does, it will get trapped in the little tank.

Now for the garage. The hardners used in most all paints contains isocyinates….ie deadly toxins...that once they enter your body there will not even exit and rests within your liver, kidneys, bladder and spleen. So full encapsulating disposable suit and full face piece respirator is required. Ear and eyes are both direct depositories into the blood stream and must be protected....of course disposable gloves as well. The garage entrances doors (doors into the home), floors, etc, must be sealed with tape and the floors, walls, ceilings covered because...…. aside from limiting dust, these products will permeate the walls, as the paint dust dries, it can and will generate static electricity- enough to cause ignition source. These other ignition sources includes all light fixtures, wall outlets and light switches.....all must be taped off and sealed off as the spray vapor particulates are ignitable- and these flash fires are very, very ugly.

The fans an just not a good idea..... aside from their motors being ignition sources up or downwind, the fan blades themselves (unless made of brass), will produce static charge (significant) rubbing in contact with the air and /or dust paint particulates to cause ignition.

The plastic that you use should also be the fire resistive type (common item with suppliers), because even if you get a small spark, imaging standing inside of a plastic lined room that is now melting and burning on top of you.... not pretty.....and yes, I have seen events like this occur in both residential, commercial and even a school district (3rd degree burns on 2 employees working inside the illegal spray booth) who just didn't believe in the level of hazard that exists.

Just remember, without the area being sealed off, you have a real good probability of exposing (short & long term) not just yourself, but family, pets and neighbors for decades of very deadly toxins and carcinogens.

 

Beechkid,
So I was actually able to get an older campbell hausfeld 2hp 20 gallon 7.8 cfm@40psi, 6.3 cfm@90psi compressor off craigslist and am planning on adding the hf 11 gallon reserve tank. I definitely have adequate air consumption for the gun and will have a big enough supply for what I'm doing. Now for the spray booth. I was thinking about getting a portable garage from hf (https://www.harborfreight.com/10-ft-...age-62860.html) and this 8" ventilator (https://www.harborfreight.com/8-inch...tor-97762.html) and fully enclosed motor exhaust fan ( ) The exhaust fan is rated higher than the ventilator so it should in theory create a negative chamber. I'll be wearing a full face respirator and Tyvek suit and have the family be away on the weekends I spray. Add filters on inlet side and outlet side of fan/exhaust. With the amount of air passing through it I'm not so concerned about all the equipment being certified as "explosion proof" enclosed motors and vapor proof will suffice.
Does this sound like a halfway decent plan to you?

 

I have a Husky 30 gallon I got from, Home Depot for $300 and it worked great to paint my truck, never ran out of air. I probably could have done it with a 20 gallon compressor.

 

Also I used a 12x20 canopy with enclosures to paint it in.

 

Very nice! What kind of gun did you use? Also, what was your air flow set up for the tent?

 

It was a Kobalt gravity feed HVLP from Lowe's. I didn't really have an airflow setup in the tent, I just wore a respirator. I had a large fan in the garage to pull anything out that got outside of the tent.

 

In general yes, with the following recommendations....the tent material produces static electricity....it absolutely needs to be grounded. The fans are "death traps" as far as ignition sources go...… if they are within 10' of those particulates, it is close enough to cause ignition and create a flash fire (upwind or downwind).....I'm not kidding on this....forget the fans!!!!!!!!!!

 

How would you go about grounding the tent material? How is the fan blowing in going to cause a flash fire? I don't see how there's a chance of flash fire unless I feed the exhaust into the supply air creating a loop or have such a bad leak in the tent that it is spilling fumes into the direction of the supply air 2" away. See attached drawing and let me know what you think, I just don't see how this setup could go wrong.

 

How would you go about grounding the tent material?


Through use of standard bonding then grounding practices... much more than I can begin to go into here but readily available on the internet...

How is the fan blowing in going to cause a flash fire?
very simple..... generic type fans while pushing air away from them also create a venture type effect......easily seen with smoke. Also, the paint particulates will float outside of your "booth" and remain airborne for a while..... that is why all switches, etc. located within 15 feet of a real spray booth opening (sealed doors, sealed windows, etc.) MUST be rated Class 1 Division 1 electrical....past that area/zone, they can now be reduced to Class 1 Division 2 electrical (still explosion proof, but of a lesser degree)

See attached drawing and let me know what you think, I just don't see how this setup could go wrong.

More than enough illustrated on your drawing to validate what I am saying.... but let me give you a bit of more insight on the hazards of static electricity.....

Without proper, verified bonding & grounding, the re-routing/reverse of a single static charge will result in a fire or explosion (if it reaches a container or airborne particulates which become flammable because of their micro-size or when paint dust dries...it becomes highly potential for ignition)- this evens happens in cars... when do to a design flaw (such as in the 1990’s) when GM experienced 2 fuel tank fires in their 2 newest “high mpg” cars because a single static charge was generated during re-fueling, the charge exited the vehicle tank but the newly designed low resistance tires prohibited the charge from “finding the ground” and returned to the vehicles fuel tank. Back in the 70’s (IIRR), the USAF also experience this with a 747 in Texas, causing a fire in one fuel tank and explosion in the center fuel tank which was almost empty.

 

Y'all are making this more complicated than it needs to be.

 

Not even close...…. I am a state certified and nationally recognized instructor specifically in the storage, transfer and application of flammable and combustible products, with 30+ years experience in this specific field and have also "Been the one" who has had the responsibility of "picking up the pieces" cause by these types of oversights.

 

I didn't do half of the stuff you are telling the OP to do, and I didn't have a problem. Sure anything could happen, you could get killed in a car wreck tomorrow, I don't live my life worrying about what could happen. The setup the OP posted a would work fine, this isn't rocket science, you just have to take some precautions and use common sense.

 

Also when properly adjusted you don't get that much overspray from an HVLP it's nothing like an HPLV gun.

 

I really thought you were going to post about how you've been pulling my leg this whole time. You've listed 3 very singular events in history, I think this topic can be laid to rest now.