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Old 09-10-08, 06:52PM   #1
Zedo
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Default HVLP gravity feed vs. traditional siphon feed spray gun- which is better ?

I'm posting this thread here because this forum gets a lot of hits, and I'd like an experienced answer from someone- I've done a good deal of painting in years past, just not recently- and always used a traditional siphon-feed gun, which I bought new and still have. The industry as a whole went to HVLP by what I am told, mostly due to emission laws outlawing the old siphon feed guns for commerical use. Just having one hanging on a nail in your shop can get you a stiff fine for hundreds or thousands of dollars. But private do-it-yourselfers at home can still use them.

when the HVLP guns first came out they were a real POS and didn't spray well. Mainly because they don't throw a lot of material at once. By what I read on the net, the HVLP gravity feed is more efficient and wastes less paint, but does not throw as much paint as an old siphon feed gun. I've watched a few guys use them and the first impression I get is, a gun with too little air pressure. But the guys that learn how to use them later say they save a lot of money on paint long term, by not wasting as much paint.

opinions ? for a driveway paint job, is it worth using an HVLP, or just stick to the tried and true Binks Model 7 type gun and its clones/copies. Mine is a Sharpe model 775 which today is an expensive gun (back in 1982 I only paid $125 for it). Even the old black plastic Binks model 7 sells used on Ebay for $150-200, and costs $360 new. The Binks model 7 with its huge spray nozzle head throws a giant spray pattern and covers a lot of area quick.

open to any info
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Old 09-10-08, 08:05PM   #2
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You've pretty much already answered your own questions. I have nothing to add.
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Old 09-10-08, 09:32PM   #3
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I asked my son...that's all he uses HVLP...but he sprays in a $100,000.00
spray both. Imported from Italy..Like you said it's the law they have to use them...he really likes his...it's a $400.00 gun. He says it's all in what your use to. But for what you want to do in the drive way...don't wast your money buying
a new gun...the results won't be any better.

He's done a ton of show cars..not because he's my son...but the kid is
on of the best. Specially with me as a critic....
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Old 09-10-08, 10:41PM   #4
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HVLP is the way to go, i like Sharpe. You can laydown more material with less pressure. I used to use Devilbiss and Binks siphon feeds in the 80's way before the Gravity feed HVLP's. it takes more air pressure and creates more overspray, of course. You get what you pay for when it comes to buying a gun,most cheap guns have a lot of plastic parts and the tips are not as good. If your a driveway painter then it doesn't matter.
Of course i don't have to tell you about breathing all of those nasty hardeners and clears that have isocyanates,get enough of it over the years and it will harden in your lungs,if you have asthma, you are screwed, best to use a paint room and outside air systems. Most hobbiests can't afford a $500+ gun,$600+ air filter system and $1000+ outside air.

With Laquer ,the thinners etc.. will get absorb through the skin and you can also breath in, and absorb lead. It gets in your blood stream and can cause brain damage,sorta like the spray cans everyone uses without reading labels.
No one can compete with Gachs son's 100,000 paint room.

Soo... doesn't that make you want to go out and paint.
But than again older house paint can be just as bad for lead content.

I knew Bob was licking house paint from the window sills.
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Old 09-10-08, 11:10PM   #5
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Old 09-10-08, 11:22PM   #6
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Quote:
Originally Posted by Gach View Post
I asked my son...that's all he uses HVLP...but he sprays in a $100,000.00
spray both. Imported from Italy..Like you said it's the law they have to use them...he really likes his...it's a $400.00 gun. He says it's all in what your use to. But for what you want to do in the drive way...don't wast your money buying
a new gun...the results won't be any better.

He's done a ton of show cars..not because he's my son...but the kid is
on of the best. Specially with me as a critic....
Lucky for him he didn't become an English teacher.
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Old 09-13-08, 09:23AM   #7
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I was watching someone paint with an HVLP and it seemed like he had to move way in close with the gun and paint very slowly to get the coverage . One of the advantages of a big siphon feed gun like a Binks Model 7, is the high pressure pushes the paint onto the sheetmetal and makes it flow. The key to a good paint job is no orange peel, anyone can paint a dry orange peel finish by keeping the gun too far away to avoid runs. My intuition is the only reason anyone uses HVLP is because it's the law for commercial shops- if not for that law, they'd be using siphon feed. I can't see any advantages to it other than saving material. But I guess a painter can get used to it.

I painted with a 2 qt. pressure feed Binks gun one time, that was a real winner. It threw a tremendous amount of material in one pass. The guy I borrowed it from used to be employed as a painter refurbishing diesel locomotive trains, and used it on the job. I was painting backsides of patch panels with 2-part epoxy/hardener, and handling one panel got a big thumbprint in the backside of panel before it dried- one pass with that gun filled in the thumbprint so that it was not even visible !
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Old 09-13-08, 02:12PM   #8
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Quote:
Originally Posted by Zedo View Post
The key to a good paint job is no orange peel, anyone can paint a dry orange peel finish by keeping the gun too far away to !
There is always orange peel on every paint job, with the cars that they bake in the booth it flattens out really good, but there is still some peel. Personally im a stickler and wet sand and polish all my cars till the finish is like glass.
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Old 09-13-08, 03:19PM   #9
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Nice Fireball!
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Old 09-13-08, 07:59PM   #10
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Quote:
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There is always orange peel on every paint job, with the cars that they bake in the booth it flattens out really good, but there is still some peel. Personally im a stickler and wet sand and polish all my cars till the finish is like glass.

I agree, no base/clear job is going to be perfect right out of the gun- the basic premise with these base/clear jobs now is, you are going to wet sand/compound them just like lacquer in the old days- the nice thing is the paint gets super hard really fast with the urethane catalyst so you can compound it within a few days of painting it, if not the next day- personally I'd always wait at least a week to buff anything, call me old fashioned

the real test for a painter in the "old days" was being able to spray a synthetic enamel or acrylic enamel job and get a high gloss finish with no runs and minimal orange peel, right out of the Binks model 7 gun- without clear, using color only- that separated the men from the boys, and saved a
s-hitload of time to get a high gloss finish- because the alternative was 12 coats of straight lacquer and days of wet sanding/compounding/polishing- but you only got ONE crack at straight enamel- if you had runs or dirt in it, they were there for good, or a very long time until it hardened- then "maybe" they'd wet sand/buff out 6 months later. The only time I saw these old timers use clear was if they were painting METALLIC, in that case the clear sealed the metallic so it would not oxidize- otherwise, they didn't use clear. The early clears were not all that good, and had a tendency to dry up, crack, peel, and come off in sheets like cellophane ! How many 1980's GM cars have you seen going down the road with peeled clear- tons of them. The really experienced guys could remove most of an enamel run with a paper towel or special clean rag by absorbing the run and then painting over it quickly before the entire paint job dried- the end result looked better than an ugly run- there was lot of tricks

base/clear urethane takes all the guesswork out, no matter how runny or dry it may look, you can sand it with 220-400-600-1200, then wheel it out like glass- urethane is bulletproof

age old saying- behind every good painter, is an even better wet sander/buffer. Anything can be wet sanded in steps of finer grade paper, then compounded, polished, sealed, then hand waxed. One time someone left a paint thinner rag on the hood of a car we were selling overnight- next day it left a big round spot on the paint- I compounded it repeatedly- and eventually it all came out- by removing layers of paint- that was a GM lacquer job- the OEM GM paint was very, very good for not having clear on it

one thing I noticed, if you have a very clean booth to spray in, using a retarder really gets any paint flowing nicely and flattens it out

urethane is very long lasting and tough, but nothing has as deep a shine as STRAIGHT LACQUER- the problem with lacquer is, it dies out and the sun dries it, and eventually from buffing the car runs out of paint to buff.
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Old 09-14-08, 09:03AM   #11
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Quote:
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It's all about how much money they can make of the consumer. Most of the paint jobs are payed by insurance companies. Those BC/CC paint jobs can go to hell just like other types of paints. I can show you a 15 year old enamel paint job that look real good and it was color sanded and buffed years after the paint was first put on. Metalics is where you can run into problems. Use a BC/CC for metalics, other wise use a single stage paint. It always comes down to cutting and buffing for the best finish.


what I see lately though, is the trend to put clear on everything- even straight color with no metallics
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Old 09-18-08, 08:44AM   #12
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You don't need to put clear on a solid color single stage paint. In AZ the clear would just end up coming off years down the road. With a solid color single stage paint, the clear can't come off so that is one less thing that can go wrong.


finally someone who's willing to admit that- clear is a 2 edged sword !

no, you don't need clear on single stage- but you'll be wet sanding/buffing/compounding/waxing that single stage to get it flat and shiny, just like working a lacquer job. So much for modern technology, we're right back in the 1950's, but with a different paint system. Given, the urethanes hold up better than the old enamels or lacquers- but urethanes are not bulletproof either.

yes, the clear will come off any aftermarket paint job- even the metallics ! Esp. is the car is stored outside. Sun and acid rain do it in.

yes, I realize you don't "have to" put clear on single stage solid color- but everyone does ! It makes it look shinier at first. But the car has to be garaged, because like you said, acid rain and sun bakes that clear off ! Then is looks like a desert sprouted up on the hood.

There was black basecoat/clearcoat paint job on my Firebird at one time, acrylic enamel w/hardener- painted in 1980's- it looked great- until the clear started coming off in sheets ! That was the last time I paid anyone to paint a car for me- never again. The high dollar paint jobs are simply not worth it on a daily driver car stored outside. Wasted effort, wasted money, they don't last more than 5 years at best.

bottom line- no matter WHAT they paint it with, it's not going to last ! In 5 years it will need another paint job- with the acid rain and brutally hot summer sun baking it off. Truth be told, nothing holds up like a cared-for factory paint job. The GM paint job on my GTP is holding up great- and it's been sitting outside now for 14 years. But even GM had base/clear adhesion problems in the 1980's, remember ? A few of those cars are still running around, they look like baked lizards going down the road- with all the clear and basecoat falling off.

IMHO there's only one paint that is truly bulletproof, if you have the balls to spray it and get it on you- Imron. Now it's common knowledge how deadly Imron is to the painter- so you need a body suit and dedicated air supply to spray it. But that is a truly bulletproof paint. People put it on airplanes- and clean the paint with lacquer thinner on a rag !
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Old 09-18-08, 12:21PM   #13
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IMHO there's only one paint that is truly bulletproof, if you have the balls to spray it and get it on you- Imron. Now it's common knowledge how deadly Imron is to the painter- so you need a body suit and dedicated air supply to spray it. But that is a truly bulletproof paint. People put it on airplanes- and clean the paint with lacquer thinner on a rag !

Imron had a smell like no other paint too, smells like something died in the can. It doesn't cut and rub very well either, so lay it on smooth.
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Old 09-18-08, 09:41PM   #14
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I was in the local discount tool/hardware store today and saw those Taiwan HVLP and siphon feed paint guns. A siphon gun w/no drip cup is $20- a spare no drip cut is $9- the gravity HVLP is $40 I believe.

I passed on them- I have a good Sharpe Model 75 siphon gun with 3 air caps, for #8, #10, and Clear Coat. Depending on what cap is used it will throw an 11"-12" pattern. I bought it 25 years ago for $100 and kept it clean and it never needed a thing. It still works fine. They are out of production now, replaced by the Model 775.

The Kellogg gun is a Binks Model 7 copy and therefore will throw a slightly larger pattern than the Sharpe, and more paint to with its larger tip. I'm going to give it a try with some primer first. I like a gun that moves fast and throws a lot of paint, nothing worse than having to "wait" for the gun and have to move slow so the paint can get on the car.

If I was in the market for a brand new gun, I'd get a 2 qt. pressure pot- they throw a huge volume of paint and the job gets done quicker- and will paint at any angle without going dry. I was also thinking about a gravity feed conventional gun too, non-HVLP, but that cup on top just looks top heavy and would obscure the painter's viewww somewhat. They just look cumbersome to me.

It's funny those Taiwan guns are so cheap. They are virtually not worth cleaning at that price. I've had to clean a few old guns that had caked on lead-based enamel and lacquer inside them, from previous owners simply not cleaning them properly and leaving paint in them- that stuff is hard to get off- even after being soaked in paint stripper or thinner, the entire paint cup and gun body submerged in cleaner- that lead paint had to be scrubbed off with a small wire brush, and air cap/tips cleaned with fine 400 sandpaper !
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Old 09-20-08, 03:21PM   #15
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