Opinions on HVLP systems - hobbiest use

[Rob Young]

I've begun experimenting with the use of HVLP for applying finishes. Right now my go-to is shellac. However I have also done just a little bit of experimenting with waterborne poly (Minwax Polycrylic because it was an experiment, the stuff is inexpensive and available at the hardware store up the street) and some exterior latex on patio furniture.

Right now I have a (very) low end 2-stage and so while it works just fine for shellac and pretty well for waterborne poly, latex paint requires thinning. Lots of thinning, I had to violate the "20% rule" on the can to get it spray reasonably well (1.8mm tip is largest I had, that's part of the problem).

Anyway, to the point, I plan to replace this system with something of 3 or 4 stages (maybe 5 but honestly, 8.5 to 9psi as you can get from a 4 stage seems sufficient for my needs).

Soliciting opinions on systems from:

Fuji -- MiniMite 4 w/ non-bleeder style gun
Apollo -- Eco 4 w/ non-bleeder style gun
Earlex 5500 (don't believe I get a choice on gun style, theirs is a bleeder???)
others?

Also, since the guns are pretty much universally pressurized designs now, advantages to top vs. bottom cup designs? Most of what I build isn't terribly large and so I think I might benefit more from the smaller (pressurized) gravity cup guns. Again, opinions on which cup design is better for which type of spraying work? Not planning to spray walls with latex, so not worried about cup capacity.

Opinions on accessories like needle/air cap kits, cleaning brushes, remote controls, gun stands, etc. too.

Thanks in advance! (edit to add preferences about gun style)

[jteneyck]

I have no advise relative to turbine units as I use conversion guns off my compressor, but I would recommend you look at the 3M PPS bottom cup system if that's an option with any of those guns. I have a large bottom cup system, about 1 L I think. The 3M PPS system allows you to spray at any angle. With both the cup and hose on the bottom of the gun I can turn the gun completely upside down to spray inside deep drawers, cabinets, etc. It's incredibly handy. You could do the same thing with the top mounted cup, but you can't get down into the drawer, etc. nearly as far before the top of the cup bottoms out. 1 L may sound like a lot of finish, but if you spray just one large cabinet or 8 or 10 large drawers you'll chew up a liter in no time.

The 3M PPS system also is incredibly easy to clean and you don't even have to clean out the cup if you don't want to, at least not for short term storage. You can just take the cup off the gun, insert an included plug in the top of the cup outlet and just clean the gun. Reattach the gun to the cup and you are spraying again immediately.

After using the 3M PPS system I never want to go back to the old school alternatives.

John

[Rob Young]

3M PPS -- interesting!

http://3mcollision.com/products/paint-ap...ion-system

[jteneyck]

Yes it is. And you don't have to throw out the liners and filter lids after only one use. I clean them out and reuse them; with the shellac and WB products I use they are very easy to clean. I must have reused some of them at least 10 times now without issue.

John

[Mr Eddie]

I think John is pointing you in the right direction. The PPS cup is so easy to use and cleanup is a snap. I bought an HVLP/PPS system after reading many of John's posts and seeing how well it worked and how versatile it is. It will spray anything from shellac to latex. I was very close to buying a turbine system but decided to buy a compressor and conversion gun after seeing the results John was able to achieve. Also, I took his advice and called Jeff Jewitt at Homestead Finishing and he set me up with the kit which contained the gun and three needles/nozzles. He also has the cleaning kit and the other bits and pieces you will need. Jeff is a good guy and will help you pick out what's best for your situation. It's worth your time to give him a call. I have not regretted my decision at all.

Lonnie

[JR1]

OK you've sold me. Does the 3M 16580 Accuspray Spray Gun System with Standard PPS work with a turbine?

[jteneyck]

JR1, I think that gun is for use with a compressor, but Jeff Jewitt sells several turbine guns with the 3M PPS cup system: Link So it's certainly possible to use the PPS system with a turbine unit. Whether or not it will work with the turbine you have, however, I don't know. Talk with Jeff, or contact 3M.

John

[Kansas City Fireslayer]

Rob,

I have the Earlex 5500 and I would have a hard time recommending it to a woodworker of your calibur. It sprays dyes and shellac just fine but that's where I pretty much draw the line. Even with thinning lacquer or enamels I struggle to get a finish I'm happy with despite my best efforts. Many are happy with the Earlex but they may not know what they don't know....or I don't know what they know! Nonetheless, it's an entry level sprayer, IMO. I compare the Earlex's finish to a Graco airless with a fine fine tip where you can get lots of volume, fine atomization, and no thinning required for any wood finish. You also get lots of waste and clean up though.

If you're going to buy a turbine unit I would only cry once and buy somthing really good if you're after top notch results. Otherwise I'd continue saving.

[BillN]

John, I've never used a gun mounted pressure cup, do you need a special regulator at the handle to bleed air into the cup?

I've used siphon feed and gravity guns and have a remote pot but missed out on these. Might have a use for one.

[jteneyck]

Bill, yes, there is a separate regulator for the cup. It's mounted to the gun inlet and has a range of about 0 - 10 psi. For most materials you set it at 5 psi and forget about it, but you can jack it up to around 7 psi for higher viscosity finishes. I think it has a pop off valve at about 9 psi. I used too use a mini gun regulator on the inlet of my gun, but with the need for the cup regulator I installed a separate gun regulator nearby and ran a 20 ft hose to the gun.

You can buy guns with a PPS cup on the bottom like I have or on top. Different size cups are available, too. And you can buy adapters to fit the PPS cup system to many existing guns, like maybe some of your pressure pot guns. For open work like painting cars I can see where a top mounted cup would be easier, but if you need to get inside something the bottom mounted cup is better, IMO, even though it seems counter intuitive. Being able to spray at any angle, including upside down, is a huge advantage. It's not as compact as a gun fed by a pressure pot, but cleanup is far, far easier and there is no finish lost in the lines, etc. that you have with a pressure pot. For a production operation using only a couple of products, sure, I'd go with a pressure pot system, probably several of them. But for someone like me who might only spray a pint of dye, then a quart of shellac, then the clear coats on a single cabinet, then paint the next day, all with one gun, the PPS system offers a lot of advantages.

Go to 3M's website and watch some of the video's on the PPS system, and their whole Accuspray system. They have an essentially plastic gun where you can throw away the nozzle when you are done. I almost bought one of them but ended up buying the Qualspray to avoid the recurring cost of the nozzles. But for a shop where time is money those guns make a lot of sense.

John