Finish spray guns and air brushes - created 05-07-2007
Kacoyannakis, Christ - 05/07/2007.14:54:20
Guest User
I am contemplating buying a spray gun system. I am not sure what is better for an HVLP system, syphon or gravity feed. Doe anybody have any ideas? I don't want to break the bank. Woodcraft has some all in one unit HVLP systems, are these any good?
Also, would an airbrush work (I am thinking this might be a lot smaller and cheaper, and produce less fumes than an HVLP sytem)? But since HVLP stands for High Volume, Low Pressure, I am not sure an airbrush would give enough output to apply a thick enough coat.
Thanks.
Do you already have a compressor?
In any event, HVLP produces less overspray(and waste) because the finish doesn't bounce off the object nearly as much, because of the low pressure.
I don't have a compressor. I am unsure if the units I saw at Woodcraft require a compressor or everything is included in the single unit.
What about the airbrush? Would that work or is it not enough volume?
An airbrush does not deliver a large enough spray pattern to apply an even coat on a guitar body.
Hi Christ,
Christ, Clay is right on, get a used compressor on craigslist (I got a Dayton Speedair for free). After struggling with siphon guns I'd steer you towards a gravity fed, high pressure touchup gun such as Harbor Freight's super cheap, (this month only!
Gravity feed are a lot easier to clean...
Thanks guys.
What is the difference between an HVLP sprayer and the high pressure gun mentioned?
For a start, HVLP stands for High Volume Low Pressure. Conventional guns are the oposite; low volume high pressure.
For this reason they require different air supplies. A compressor is normally used for conventional (for the high pressure), and a turbine (or conversion system) is used for HVLP (for the high volume).
Essentially the HVLP sprays a greater volume of material at a lower speed, so less material can bounce off the work piece, and it should flow out better if set up properly.
Turbines are usually quite expensive, especially when compared to a compressor, but are generally better quality in the budget range (remember that the budget range for HVLP will be many times the budget range of conventional systems).
I have heard some have a preferance for the conversion systems over turbines, but I am not sure as to their reasons. Anyone have this preferance?
A conversion HVLP system uses a normal air compressor. You get the advantage of an HVLP spray gun and an air compressor that can do many other things around the shop.
Any reason other than that Barry?
Compressors are cheepish, if you have one and a turbine as well, I assume the turbine would perform better for HVLP, correct?
Wrong. There are probably advantages of both, but the conversion guns give a better atomization of the finish. Also, the air does not come out hot which can make the lacquer dry too quickly.
I would not buy a cheap, disposable compressor. Get a cast iron, oil-lubricated unit made in the states, and you will be set for life.
The main difference seems to be price, the hvlp version of HF's touchup gun is 4-6 times the price of the conventional. What's nice about these bargain guns is that they are disposable/recyclable when they get clogged with something that won't clean up, like cured polyester resin...
The hot turbine air can be an asset when spraying in cold climates but the turbine guns have a totally different air-cap and won't work off of a traditional compressor or vis-versa.
I am assuming those all in one jobs I saw at Woodcraft are turbines. They seemed pretty "inexpensive". Are they any good?
How big of a compressor would I need for a conversion spray gun. I saw some little ones at Harbor Freight (probably disposable types because they were non oil cooled and only about a quarter the price of the turbines). Do I need high pressure or would something that small work?
There is no way we can tell you how good something is without being more specific.
The size of your compressor is determined by the volume needed by your spray gun. They are all different.
I recommend staying away from oil-less compressors.
I recommend staying away from oil-less compressors.
Why? (I was thinking of picking up a compressor.)
Small oilless compressors wear out after about a year of hard use. They are portable and can be often run when "unlevel" (pitched roof) which is their advantage. Also they don't put oil into the air they make. A good quality one will last much longer (forever) for "home" use.
My cheapie oil-less compressor's been a good friend for about 7-8 years now...
About my only complaint is noise.
The new generation of oil-less compressors and nail guns are almost lifetime tools - my old C-H oiless is 10 years old and was on contruction duty for much of that - have not touched it except to clean the air filter and dump the tank in the summer. I doubt I'll get to use a rebuild kit before one of the tanks rusts out, which might be another 10 or 15 years.
I like my Turbinaire HVLP, but if I had to do it again, I'd spend the same money on a 60 gallon, 10 SFCM@90 psi shop compressor (the Husky and Kobalt brands at Borg and Lowe's are good enough for what most one-person shops need) and a Sharpe FX100 and FX300 or Astro equivalent. Cat poly might be different, but Nitro and WB are just not that challenging, so dumping a truck payment on a SATA gun is not necessary (although they are nice, nice guns - especially the MJ-IV).
I use my compressor for lots of stuff other than finishing, so even if you bag the finishing stuff and send it out to Tony, you'll still have a very useful capability (enough go for air ROS, die grinders, drills, and other air pigs). Get a decent regulator/dryer set-up as well - for mini-guns, an inline desicant will do the job until you want to spend some bucks on a wall-hung model.
Oil-less compressors don't put oil into the air output but they do put in particles of the graphite valves that wear away.
I stand corrected on the longevity issue.
Barry:
Agreed - the older oil-less stuff was hit or miss. Still a good idea to go wet sump on large stationary machines with two stage compression. Good point on graphite and other stuff - a filter takes care of not only oil and water, but also all the junk that can come down the air line to your gun. Amazing how some folks will filter the paint but ignore the air.
Todd
Has anybody checked out the Earlex HVLP?
Google "earlex spray stations" : they are rather cheap turbine-based HVLP systems... they even show two resonator guitars in their web page as examples!!
Any feedback would be welcome, I'm still thinking about this instead of a compressor+gun.
Cheers
Have used: oil less compressor, Full size siphon feed (expensive and cheap), mini siphon feed, cheap full size gravity feed HVLP.
Staying with: Vertical Oiled compressor (longer life, quieter), Sata Minijet.
Thoughts: Cheap full size gravity feed HVLP (set up properly) has MUCH less overspray than expensive siphon conventional, but doesn't spray as well. For the home shop, I'll take the cheap HVLP and live with it. Then again. . .
HVLP Gravity feed conversion (Sata Minijet)
Pros: cheaper than turbine, can use existing compressor (needed to run the Micronizer on the Band Saw anyway), low overspray, easy to clean, excellent spray, ability to fine tune.
Cons: requires compressor (no big deal for me), you get what you pay for (so you gotta spend money), hard to fine tune.
Turbine (Fuji - my friend gave up his Sata Digital for this)
Pros: built for "true" HVLP, low overspray, excellent spray, fast setup.
Cons: very expensive for dual stage or higher, only comes in siphon feed (unless you get the "conversion" gravity feed, which still feeds through the bottom), can't use compressor for anything else (doesn't have one).
Bottom line? The $$$ you spend on spray equipment is inversely proportionate to the amount of time spent sanding your finish. Just my $.02.