HVLP Sprayer recommendation for Air Compressor

[David Ruhland]

I am looking for recommendations on an air compressor HVLP gun for spraying finish. I already have a water/oil separator installed in the line - I looked at the 3-m Accuspray and think this will be overkill? Home Depot has one that looks a lil promising. Any suggestions? I have an Earlex 6003 Sprayport System, but would like an air compressor gun as well. I am a weekend warrior woodworker, so use will be small.

https://www.homedepot.com/p/Husky-Gr...HVSG/203497641

[Jim Becker]

I've been quite happy with the Wagner HPLV conversion guns that I've owned for many years. They are reasonably priced, too. Gleem Paint is where I bought mine online.

[Patrick Chase]

Tangentially related, but: Has anybody tried the new Fuji compressor guns (LPX/MPX)?

[Marc Jeske]

No personal experience w this one - You may want to check it out.

Marc


http://www.gleempaint.com/hvcongunnew.html

[Mike Henderson]

I've had good experience with gravity feed guns. Better than the siphon guns I've used.

Mike

[Patrick Chase]

I've had good experience with gravity feed guns. Better than the siphon guns I've used.

Mike

Indeed. I've had good luck with pressurized siphon guns like 3M PPS and the Fuji T70, though.

[Marty R Schlosser]

Patrick,

Yes; I have both the MPX-30 and LX-20 models.

LX 20 small.jpg MPX spraying spindle small.jpg
MPX-30 (left photo) LX-20 (right photo)


IMG_8704.jpg
Specs of my compressor

They both perform extremely well, but you've got to have an adequate compressor as they need a lot of CFM. I'm currently running them with a Sanborn 30 gallon compressor, which if you look closely at the above photo you'll see it generates only 6.3 CFM at 40PSI, which is not quite up to Fuji's recommended 13.8CFM @ 36PSI. I've found that for my needs it works well enough, but I'm not doing production spraying and the 30 gallon tank holds enough for me to spray smaller pieces without the compressor kicking in. And when it kicks in and I'm still spraying it seems to keep up well enough. If I were doing this for a business, though, I'd invest in a much larger compressor and instal it in its own separate room and with excellent oil and water filtraton and of course piping throughout the shop.

The MPX-30, which is a LP (low pressure) gun (Fuji describes it as a mid-pressure gun) is similar to the LX-20, which is a HVLP conversion gun. Of the two, I'm most impressed with the MPX-30 and as you can see I've got their gravity fed model. I swapped out the 0 - 100 PSI gauge it came with for a 0 - 60PSI gauge to better see the pressure readings; the gun pressure is usually used at around the 8 - 12PSI range, and the space between pressure marks on the larger scale gauge made it difficult for me to see. A few PSI either way make a huge difference in performance, and each finish works best at different settings due to their viscosity and other features.

I own a Fuji 5-stage compressor and have their T-series, and the older GXP-C and touch-up gun. I find that I'm using the MPX-30 more than any other gun, but also like the convenience of turbine guns.

Sorry for the extra detail, but I though it'd help you out.

Tangentially related, but: Has anybody tried the new Fuji compressor guns (LPX/MPX)?

[Patrick Chase]

Yes; I have both the MPX-30 and LX-20 models.

They both perform extremely well, but you've got to have an adequate compressor as they need a lot of CFM. I'm currently running them with a Sanborn 30 gallon compressor, which if you look closely at the above photo you'll see it generates only 6.3 CFM at 40PSI, which is not quite up to Fuji's recommended 13.8CFM @ 36PSI. I've found that for my needs it works well enough, but I'm not doing production spraying and the 30 gallon tank holds enough for me to spray smaller pieces without the compressor kicking in. And when it kicks in and I'm still spraying it seems to keep up well enough. If I were doing this for a business, though, I'd invest in a much larger compressor and instal it in its own separate room and with excellent oil and water filtraton and of course piping throughout the shop.

I have a similarly-rated compressor and about the same amount of tankage downstream of it (the compressor has 15 gal at up to 200 psi, plus there's an outboard 10 gal tank at 150 psi). I'm also a hobbyist, not doing this as a business.

One thing to be aware of is that those lower-pressure CFM ratings are somewhat misleading, in that they simply tell you what the compressor can generate continously *at that pressure*. What happens in reality is that the compressor charges the tank at a much higher pressure (200 psi in the case of my compressor), and most compressors are geared/optimized their highest mass flow rate when working against high pressure. For example your compressor transfers twice as many molecules/pounds of air per minute at 90 psi and 5.5 cfm as it does at 40 psi and 6.3 cfm.

This is important because of what happens when we regulate from the high tank/hose pressure to the lower gun inlet pressure. Mass is conserved across the regulator, and mass_flow_rate is proportional to pressure*volume_flow_rate (ideal gas law). This means that If you send 90 psi from the tank at 5.5 cfm, and losslessly (no pressure drops) regulate down to 36 psi, then you could theoretically get 13.8 cfm. Of course there are parasitic pressure losses that I'm ignoring, such that the "gain" isn't as large as this math suggests, but it is nevertheless true that you can optimize flow rate at low pressure by using regulation to allow your compressor to charge a much higher-pressure tank. Your compressor isn't as far from Fuji's minimum as you might think.

The MPX-30, which is a LP (low pressure) gun (Fuji describes it as a mid-pressure gun) is similar to the LX-20, which is a HVLP conversion gun. Of the two, I'm most impressed with the MPX-30 and as you can see I've got their gravity fed model. I swapped out the 0 - 100 PSI gauge it came with for a 0 - 60PSI gauge to better see the pressure readings; the gun pressure is usually used at around the 8 - 12PSI range, and the space between pressure marks on the larger scale gauge made it difficult for me to see. A few PSI either way make a huge difference in performance, and each finish works best at different settings due to their viscosity and other features.

I own a Fuji 5-stage compressor and have their T-series, and the older GXP-C and touch-up gun. I find that I'm using the MPX-30 more than any other gun, but also like the convenience of turbine guns.

Sorry for the extra detail, but I though it'd help you out.

Thank you! Like you I have a 5-stage Fuji (Q5P) and both T-series guns, and was looking at the MPX-30 for convenience and maybe slightly expanded fluid compatibility due to higher pressure. I ordered a gravity version this week.

Do you happen to know which PPS adapter these new guns use?

[Patrick Chase]

Answering my own question:

Do you happen to know which PPS adapter these new guns use?

They appear to use the same adapters as the T-series guns: #18 for siphon, #2 for gravity.

[Patrick Chase]

Sorry about the double-question, but...

The MPX-30, which is a LP (low pressure) gun (Fuji describes it as a mid-pressure gun) is similar to the LX-20, which is a HVLP conversion gun. Of the two, I'm most impressed with the MPX-30 and as you can see I've got their gravity fed model. I swapped out the 0 - 100 PSI gauge it came with for a 0 - 60PSI gauge to better see the pressure readings; the gun pressure is usually used at around the 8 - 12PSI range, and the space between pressure marks on the larger scale gauge made it difficult for me to see. A few PSI either way make a huge difference in performance, and each finish works best at different settings due to their viscosity and other features.

The rated inlet pressure for the MPX-30 is 36 psi, though they don't state the resulting orifice pressure. Are you saying that you're regulating the input down so that it's producing 10 psi or less at the nozzle?

I guess I shouldn't be terribly surprised that that would work with at least some finishes. The fact that it lacks tank pressurization as in the T-series might limit how low you can ultimately go.

Sorry for the interrogation, just curious. I have an MPX-30 on order now :-)

[John TenEyck]

What led you to conclude the 3M Accuspray system is overkill? I don't own one but they look like a very well thought out system. Others have told me they spray great.

What is deficient about your Sprayport System? Are there certain materials you want to spray that it can't?

John

[David Ruhland]

What led you to conclude the 3M Accuspray system is overkill? I don't own one but they look like a very well thought out system. Others have told me they spray great.

What is deficient about your Sprayport System? Are there certain materials you want to spray that it can't?

John

nothing deficient about sprayport system... Love it so far! Would like to keep it “ pristine” by keeping it in my basement workshop...would like something similar compressor driven for the tractor workshop...

[John TenEyck]

nothing deficient about sprayport system... Love it so far! Would like to keep it “ pristine” by keeping it in my basement workshop...would like something similar compressor driven for the tractor workshop...

OK, then the Husky you linked to will probably meet your needs in the tractor workshop just fine.

John

[Mike Henderson]

One thing I'll add is that no matter what gun you buy, learn how to clean it well. If you don't clean it well after each use, it won't last long - or you'll have a major cleaning job to do on the hardened finish.

Mike

[Patrick Chase]

One thing I'll add is that no matter what gun you buy, learn how to clean it well. If you don't clean it well after each use, it won't last long - or you'll have a major cleaning job to do on the hardened finish.

For reactive finishes (varnish, water-base, etc) this is very true. You can get away with sloppier practices with evaporative finishes like lacquer and shellac, though