Spray Gun

BlueChip · Post by **BlueChip** » Dec 28th, '07, 19:31

For a few months now i have been rolling and tipping small sail boats/row boats. (side job to make some money to go into the "Boat Fund")... and finally i have my air compressor up and running.

Question # 1: For spraying hulls what is a good spray gun to get.

Question #2: Is there one where i can switch spray sizes for different types of projects.

Question # 3: What SCFM should i have minimum for painting....

Thanks

Chris

DRIFTER31 · Post by **DRIFTER31** » Dec 29th, '07, 10:16

I paint cars for a living and have done a Bertram with Imoron as well. I would buy the Devilbliss GTI gun. I use one every day and it is fine for just about all paints. When you buy it usually they come with different tips and spray nozzels. A 2.0 tip will shoot perfectly. One note is that ALL spray guns are HVLP now high volume [cfm] low pressure. The guns need to be used with a big bore[3/8] hose and big bore quick connect couplings or they will NOT flow correctly. As to the cfm....The Devilbliss paper work will tell you how much it uses. The GTI gun is gravity fed with the cup at the top. It uses neat ziplock bags to line the cup with so the cup is a breeze to keep clean. After shooting just disconnect the air,flip the gun upside down and press trigger to let remaining fluid in gun fall into the ziplock and just pull the bag out and throw away . The only paint in the gun will be a tiny bit at the very bottom. Whateveyou do stay away from Sharpe guns and the big bore hoses and fittings are a must.

BlueChip · Post by **BlueChip** » Dec 29th, '07, 11:46

Any suggestions on where to get it.. i have found between 320 and 290$$ .. any place better?..

which model do you recomend...

Chris

CaptPatrick · Post by **CaptPatrick** » Dec 29th, '07, 12:09

I agree fully with Drifter in choosing the Devilbliss brand... However, my choice is the Finishline 3 Master Kit. You get a full range of tips & needles that will allow you to shoot from very thin to very thick liquids. This model isn't as easy to clean as the GTI, but for as much as $100 less & the full tip size range, it's possibly the best choice for a quality gun with a full liquid range.

Keep in mind that gravity cup guns are only good for about a quart of liquid. If you have a large job, such as a boat hull, you'll be re-filling the cup frequently. Most professional boat painters use pressure pots for larger jobs.

Drifter is also on target with the full size hoses and fittings, especially when the hose is longer than 10 feet from the compressor tank. Most lower priced compressors & tanks are fitted with 1/4" fittings, so for the best results, you might want to put an expansion tank or supply system between the compressor tank & your gun. 1/4" in, 3/8" out...

My shop air system is set up with 2 two stage compressors, one 80 gallon volume & one 30 gallon volume, both plumbed into a single supply line. The supply line is 2" PVC Pipe and stretches around 2/3 of the shop perimeter. Counting the 5 drops, a total of about 175 linear ft of 2" pipe. That gives me about an additional 57 gallons of air volume, for a total of about 167 gallons.

The compressor pressure is set for 110 psi kick out & 90 psi kick in. With all the volume of the pipe & tanks, that gives me about 22 cu ft of available air with a minum pressure of 90 psi. About the only tool that taxes my system is an air file and sanders.

Most single station HVLP spray equipment need a maximum of about 60 PSI @ 40 scfm, (1 cu ft = 7.5 gallons). Your compressor should be rated for, at the very least, 13 scfm @ 40 psi with 30 gallon minimum tank size. That's going to drop most of the Home Depot type portable compressors out of the running...

One final item to add is a pressure guage attached directly to the gun. Pressure at the tank & pressure at the gun can be signifficantly different. Pressure at the gun is what counts.

Br,

Patrick

BlueChip · Post by **BlueChip** » Dec 29th, '07, 14:31

Thank you both... the FinishLine is more in my price range...

Any places to buy them better than others?

My compressor is 60 gallons and will do 11.8 scfm @ 40psi and 10.3 scfm @ 90. .... Is that going to cut it? Or do i have an excuse to tell the wife i need a bigger better compressor?

Chris

CaptPatrick · Post by **CaptPatrick** » Dec 29th, '07, 14:53

Chris,

Your compressor might do OK by you as is... Just give it a try and see how how your techniques do with it. If you are working with a paint that can be applied a little more slowly the compressor may keep up. Adding another tank with 3/8" exit fittings will help too.

The link above seems like a pretty good deal. I'm even thinking about ordering that kit myself...

Br,

Patrick

JPRS51 · Post by **JPRS51** » Dec 29th, '07, 15:24

Check out eBay. Looks like you could get it for $217 with shipping and all.

http://cgi.ebay.com/ebaymotors/DeVILBIS ... enameZWDVW

Possibly lower by just placing a bid. Wait a day and see where the auction that is ending soon in this link ends up at. Currently at $151 at time of posting this...

http://search.ebay.com/search/search.dl ... 26fsoo%3D1

JPRS51 · Post by **JPRS51** » Dec 29th, '07, 15:29

Looks like you could even get a pretty good deal on the GTI gun on ebay. Maybe even close to $250 with 3 tips.

http://search.ebay.com/devilbiss-gti_W0 ... lissQ20gti

DRIFTER31 · Post by **DRIFTER31** » Dec 29th, '07, 18:50

Air consumption for the GTI is 15 SCFM at 10psi[at the air cap or inlet of the gun] I use a 6Hp upright compressor 80gl tank and use 15psi at the gun. Also like Capt Pat says use a gauge at the gun to be accurate and one of those spin on water seperator at the gun.Dont be folled by the low pressure used to spray. 15 cfm is a tremendos ammount of air volume.
I bought mine from Smart Shoppers 1-800-541-0399 current price on the GTI is 275.00 and includes 1.3 1.4 1.5 fluid tips air adjusting valve with gauge and gun holder. Gun part # isGTI620G.
If you want a cheaper gun Devilbliss has the PRI601G18 for 209.00 and is built on the same platform as the GTI. They call it a primer gun because of a 1.8 fluid tip but i would use it for thick paints such as automotive clears and Awlgrip etc. I shoot clear with a 2.0 tip which is bigger than the 1.8 If you want the GTI any size tip is available for 41.00

DRIFTER31 · Post by **DRIFTER31** » Dec 29th, '07, 18:57

One more thing ....you may have problems with a dry spray using tips smaller than 1.6 i would go 1.8 or 2.0 and when spraying do a 50% overlap on all your strokes. The Finish Line guns are nothing like the GTI series so beware of them they are more for shooting metallic colors with small tips designed to make the flakes lay uniform. Good Luck Troy

CaptPatrick · Post by **CaptPatrick** » Dec 29th, '07, 19:48

Troy,

I was thinking about buying the FinishLine for my gelcoat work using the 2.2 mm tip. Any thoughts? I'll also be shooting 2 part PPG in the not too distant future for the interior of Hancock's B31.

Br,

Patrick

DRIFTER31 · Post by **DRIFTER31** » Dec 29th, '07, 20:53

Hello Capt Pat...... I have never used the finish line gun but i have shot gelcoat through my primer guns 1.8 and i needed to thin it a good bit to make it flow. Results were ok but not great i had to sand and polish. I would use the biggest tip available. That 2 part PPG is fantastic. The same stuff as Imeron. You should be good with the 2.2 tip even with that product and as you know you could just adjust gun for less flow if needed. i once did my dads friends 25Bertram with Imeron white topsides and PPG 2 part Durethane on the sides in lt blue metallic. They broke down and a tugboat rubbed up against them and it took the paint off the steel rubrail and the Bertram was intact.
The boat was a 1962 25ft hardtop and when he bought it had twin 300Hp big valve 327Chevy engines with Muncie outdrives. the drives looked like 57Chevy fins on it. As a 12 yr old boy i liked nothing better than sitting on the fighting chair on top of the engine box while hearing those engines roar. That little boat hauled serious butt with 600+Hpand outdrives.Single engine speedboats were embaresed when they couldnt pass us with all the big pen senators in the rodholders.
PS- Do you think my 31Tiara express is harder to push than the 31Bertram with the same power? 210HP cummins. Walter uses 20x20x3 I am installing them now and need prop advice.It weighs 15000lbs loaded and is 12ft wide 16degree V with a huge 6-8in. reverse chine Thanks for the greatest site for boats yet. I am proud to be a member Troy

CaptPatrick · Post by **CaptPatrick** » Dec 29th, '07, 21:52

Troy,

I have to shoot gelcoat as a final finish occassionally and use a relatively cheap HVLP gun with a 2.2 tip. Even with that I have to thin, but have found that thinning is best done with Duretec Clear Additive, pretty much the same as Patch Coat. It's a crystal clear polyester resin that besides thinning the gelcoat, makes it harder, quicker cure, & almost no cured texture. When shooting gelcoat in molds I use a 6mm tip on a dump gun.

The Tiara is heavier but with the shallower dead rise should be similar to the B31 with 210s. I'll be calling my West Palm Beach machinist next week, I'll pick his brain about your props. He's been doing under water running gear for around 40 years & is real good at that sort of stuff.

Br,

Patrick

Raybo Marine NY · Post by **Raybo Marine NY** » Dec 30th, '07, 17:44

I had a GTI gun when it first came out, then converted it to a GTi millenium by changing the cap and tips.

Trust me when I say get thier GFG-670 gun instead, uses just about half the air and will outspray the GTI gun anyday.
Trust me on that one- and for those using the GTi, try the GFG-670 and see for yourself.

Its also sold complete with 3 tips and a regulator.
The main draw back about the GTI is its air consumption- it is THIRSTY for air.

The GFG670 transfers alot more material to the surface as well.

CaptPatrick · Post by **CaptPatrick** » Dec 30th, '07, 17:58

Robby,

Have you used the GFG-670 for gelcoat before? Looks like it doesn't have option for 2.0 or 2.2 tips...

Br,

Patrick

Raybo Marine NY · Post by **Raybo Marine NY** » Dec 30th, '07, 18:09

personally I think one would be a fool to use a expensive spray gun for gelcoat.

For that I use Astro guns, you can get thiers with a 2.0, I also use a 1.4

having had gel kick off in my gun before it would hurt to be scraping an expensive gun out. Not like you can benefit from good atomization or a large spray pattern when spraying thick coatings like that.

On another note- for a touchups I use a small cheap astro siphon feed gun that has a rather large 1.4 tip, it can spray gelcoat for touch ups and put out ALOT of material- its cheap too, less then $50. That little bastard can even spray non-skid with no problem.

For spraying smaller parts like window frames and such and for paint touch ups I use a Devilbiss SRiW gun, it can spray up to a amazing 8" fan with thinner coatings, with imron it can spray almost 6" fan, and it also puts out ALOT of material- you actually have to be carefull the first few times you use it. The gun's parts are all stainless steel so its also good for waterborne paints.

JohnD · Post by **JohnD** » Dec 30th, '07, 21:44

I'm not sure If I want to be a painter or not, but at $15-20k quotes for painting my topsides I may just give it a try. What the heck I can always sand it off if it doesnt turn out.

When researching some of the suggestions list here I see something called an LVLP from ASTRO. It's suppose to use less air than HVLP guns??

I've got a pancake compressor and would like to start out small repating portions of the topside. Starting with the flybrige helm and doghouse, then moving to the cockpit. I was going to give rolling and tipping a try but after doing my bilge I don't care for that method.

Any thoughts on the LVLP or some of the less expensive paint guns?

Thanks,
JohnD

Harry Babb · Post by **Harry Babb** » Dec 30th, '07, 23:37

I have a Binks 2000 that I have used for years to paint fabrications and equipment.

My setup includes a pressure pot. Several years ago I had to spray inorganic zinc primer. This stuff is pretty thick and I had to purchase a Graco gun with a big nozzle. I think the tip diameter on the Graco is about .1" Compared to the Binks it looks like the barrel of a 44 Mag

I have always liked my Binks but have never painted anything with broad areas like the side of a boat.

What do you guys think about Binks????? I really would like your feed back.........I intend to use it to do major painting during my current repower project.

Harry

Raybo Marine NY · Post by **Raybo Marine NY** » Dec 31st, '07, 08:22

Binks 2000 was a great gun, I dont know if they are really making it anymore, they were bought out by Devilbiss.

a LVLP gun is along the lines of the newer tech guns like the GFG670 gun I mentioned.

John D- you are being quoted for the prep work which takes the time, start out working on something smaller and see if its something you can live with before tearing into your boat. If you want to save some money with a pro doing it take the boat apart and put it back together.

DRIFTER31 · Post by **DRIFTER31** » Dec 31st, '07, 11:06

Capt Pat is right they dont make the tips bigger than 1.8 for the 670Devilbliss. I have the GTI Millenium and it does consume alot of air and with a large surface like a boat it may challenge even 6hp 60gl. tanks. I agree on not using an expensive gun for gelcoat. I myself use a cheap Astro gun for gelcoat and primers.
The old Binks gun was fantastic in its day but now paints are a little thicker and they dont seem to spray good out of older guns. I bucked going to HVLP guns forever till i tried one with the big bore air hose. Some cheap guns shoot great and some shoot crappy so its hard for the beginner painter to know if its him or the gun. Thats why for great results i suggest a great gun.
Painting your own boat is not that hard if you are patient and understand how to prep it corectly. Prepwork is 75% of the job. The actual spraying part is very easy. Knowing what grit to sand with and what primer/sealer is key To the guy that has never painted before i would say read a " how to" book on the subject first just to understand the fundamentals and practice a little on a similar vertical surface.

Raybo Marine NY · Post by **Raybo Marine NY** » Dec 31st, '07, 17:47

I dont think I have ever needed a 2.2 tip, even a 2.0 is a handfull.
Spraying thick coatings with that 2.0 they tend to wrinkle because the coating is so thick and it comes out with such a narrow spray pattern.

I would caution a person just starting to paint to stay away from anything larger then a 1.8
Gelcoat is forgiving, but paints and primers if put on too thick all at once will not cure properly.

Rickysa · Post by **Rickysa** » Jan 2nd, '08, 11:27

DRIFTER31 wrote:
Painting your own boat is not that hard if you are patient and understand how to prep it corectly. Prepwork is 75% of the job. The actual spraying part is very easy. Knowing what grit to sand with and what primer/sealer is key To the guy that has never painted before i would say read a " how to" book on the subject first just to understand the fundamentals and practice a little on a similar vertical surface.

Any recommendations on books, or a quick outline on prepping?

I've just purchased a compressor and paint gun + blaster are on the horizon (for a '53 chevy pickup project...but I'd like to repaint an outboard I have)

Rick

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