Spraying - Conversion gun question - or is it me?

[Carl Beckett]

A question to those of you with more experience:

I have a conversion gun kit I purchased from grizzly H7671. Gravity fed with 1.4mm spray tip.

I am Spraying Target 6000 (I believe its the 6000... will confirm) - but also some polyurethane at times.

Here is the thing: I come from the world of automotive finishes/equipment on the one end. And on the other spectrum its the paint pumper sprayers for heavy latex/house paints.

These conversion guns dont have near the control or coverage that I get with the automotive guns. And the velocity is not all 'that low' (it says HVLP.... ?) Its all relative of course.

I guess I could go to a larger tip - or is it time to upgrade the equipment? The two things in particular is that I would like to control the amount of material more broadly (from not a lot, to more than I want - the automotive guns I can pretty much dispense any amount of fluid I want into the mix). And the second thing is the breadth of the swath. I see some woodworkings just spraying all over a piece in random motions. For automotive that would be a disaster. Instead we take single passes with some overlap, and for large horizontal surfaces at least like to cover 10" to 12" swaths at a time. The equipment I have is 6" on a good day.

Calibrate me - no doubt my expectations might be too much?

[John Coloccia]

If you try to apply 6000 like an automotive finish, you're going to be rewarded with a lot of blue haze and runs. That said, you have some really cheap guns there. A nice automotive gun will be $500+, and you payed $55 for two guns with two regulators. At this point, I would guess you're scraping the bottom of the barrel for spray guns and you might even do better with a cheap, harbor freight gun.

Anyhow, 6" about 6" away is roughly where I am when I'm spraying clear. A 10" pattern seems very wide.

[Carl Beckett]

Yes, for sure I have cheap guns.

But is it 'all' the gun as the issue. Or is it that the expectations are completely off (they are very different things) - I might spend a ton of $$ on fancy guns and be just as disappointed?

I have purchased cheap automotive guns and have had reasonable experiences with them. In that area, it is NOT all about which gun is used.

[John Coloccia]

Yes, for sure I have cheap guns.

But is it 'all' the gun as the issue. Or is it that the expectations are completely off (they are very different things) - I might spend a ton of $$ on fancy guns and be just as disappointed?

I have purchased cheap automotive guns and have had reasonable experiences with them. In that area, it is NOT all about which gun is used.

You may want to be a little more clear about what you're expecting vs what you're getting. Do you just want a larger pattern? Are you unhappy that the HVLP you have is causing tons of overspray? A better gun will certainly help with the over spray. As far as pattern, I usually have the air cap dialed back quite a bit to get my 6" pattern, and could go wider if I choose to, but somewhere around 6" seems about right. My personal experience is that I see a huge difference between a cheap gun and a nice gun. A cheap gun has very poor machining, is not accurate, has rough passages and generally ends up spray with a lot of turbulence and inconsistency. I've yet to find a cheap gun that lasts more than a couple of months without starting to leak and spit. A nice gun gives a well atomized, even pattern and will last a lifetime with reasonable care.

I'm not saying you should go buy an Iwata, but I think you're expecting too much out of $20 spray guns.

Where do you live in MA? If you're anywhere near the CT border, you can bring your gun down to my shop, and we can experiment with yours vs mine and you can see the difference for yourself. I'm just a bit east of Hartford.

[Carl Beckett]

Thanks John, Im in Harford regularly so one of these days......

The two things I want to see improvement on

First is the range of adjustability of the volume of fluid dispensed. And in a way combined with

Range of spray pattern.

These guns can go wider in spray pattern, but then are not able to push the volume of material needed at the wider pattern.

I dont really care much about overspray - again coming from higher pressure guns am used to overspray. (although as I type this its not entire true - of course I care about overspray - but thats not the issue). I used to run finishes through the automotive guns, but thought I would try out the conversion type.

These guns are not complete junk. Have been able to do a number of pieces with them. (I just dont always buy into the camp that a low price point product wont work - but sometimes that is true - and am trying to calibrate). Indeed a side by side would be a fascinating test.

[John TenEyck]

Carl, I'm a happy user of low cost guns. I don't use the word cheap, because that means low quality to me. The guns I have are low cost but still spray very well IMO, so they aren't cheap. But they are nothing special. They look pretty much just like those sold by Grizzly, Rockler, Woodcraft, and others. I've never sprayed EM-6000, or whatever you said you were spraying, but I've sprayed a lot of WB polyurethane clear coats, quite a bit of WB paint, and a lot of shellac as well. The key is to get the viscosity in the correct range for your gun. I also have a gravity feed HVLP conversion gun with a 1.4 mm orifice. It needs a Ford #4 viscosity of about 45 seconds to spray well. For the GF Hi Perf. Poly I often use, that means I have to add 10% water to get the viscosity down to that time. For the SW ProClassic paint I sometimes spray I have to add 18% water to spray it through my 1.8 mm gun. Your comment about lack of flow control suggests to me that the viscosity is too high, so I recommend you check that first. Once the viscosity is correct, the flow control valve should respond as you would expect. As for fan width, I really don't get more than about 8" of fan when 8" away from the work surface at max fan control, but that seems OK with me; at least the results are great which is the most important thing to me. BTW, for most things I run about 25 - 30 psi air inlet at the gun, maybe 20 for shellac and maybe a little higher for paint. I always shoot a burst at a piece of cardboard and adjust pressure, flow, and fan width to get a nice uniform elipse, before I spray the work.

Yes, I'd love to have a really high end gun, and if I made my living with one I'd have one or several. But you certainly don't need one to get great results. I've been using these guns for over three years, and have sprayed gallons of finish with them. They have always given me great results, never a problem, and are easy to clean and maintain. I would bet your gun will give you the results you are looking for once you get the viscosity and gun controls dialed in. Oh yeah, one last thought. Pull out that plastic filter under the cup and throw it away. It's far better to filter the finish through a cone filter. Then you know the finish is clean and won't plug up that little filter. Keep at it - you'll get there.

John

[Jason Roehl]

HVLP has nothing to do with velocity--the acronym stands for High Volume, Low Pressure, which means that the atomizing air is high volume, low pressure, but also that the fluid pressure is 10 PSI or lower, if using a pressurized fluid pot. That said, I rarely spray any heavier finish at 10 PSI or less of fluid pressure when using a pressure pot. I also try to avoid thinning my finishes any more than necessary, particularly waterborne. Instead, I don't worry about the atomization--what I look for is an even coat that doesn't run. If I can get away with a heavier coat, I do, because that means fewer coats. The only time you really have to worry about larger droplets is when you have a very fast-drying finish like true lacquer--you can end up with bad orange peel. However, waterborne finishes can have good leveling properties, so less atomization can be a good thing, while too much atomization may just mean more dry spray all over your piece.

Here's something else--there are many very good finishes in the woodworking world, but you said you come from the automotive finish world. Typical automotive paints cost $150/gallon and up, while many of the finishes discussed being sprayed here top out at $50-75/gallon. So you really can't expect the same performance in either application or durability...

[John Coloccia]

Just an FYI on the 6000 product, Jason. It's prone to bad orange peel with a poor gun setup, and it also takes on a bluish haze if you spray too heavily or too quickly between coats. The blue will eventually go away if you wait long enough, but with that product it's better not too spray a very heavy coat. It flashes off fairly quickly, though, so you can re-coat very quickly. I typically go about 30 minutes between coats (usually longer because I'm busy doing other things). Some people spray coats as few as 20 minutes apart.