Anyone using 3M's PPS system or Accuspray gun?

[Kevin Nathanson]

I use both the gun and the PPS system on ALL my guns. To be clear, the PPS system will let ANY gravity feed gun spray upside down, as long as you bleed the air before starting to shoot. (Watch their videos, it's ridiculously easy...)

I love their gun too. There is really only one model of gun, although they have revised it over the years and there are a few of the older ones still in the channel. The tips/spray heads are what differs, but all the spray heads (1.2, 1.4, 1.8) fit the gun. I like the gun very much. I have three SATA guns as well, and as sacrilegious as this may be to gods of SATA, the 3M gun shoots just as well as they do, and is MUCH easier to clean, with the added benefit that I can just throw away a spray head that really gets gummy or temperamental to clean. They are designed to paint cars, which most would say is a higher order of performance than what is needed to spray wood finish.

K

[John TenEyck]

Thanks Kevin. I've watched several videos on the Accuspray PPS gun and it sure looks like a very well thought out system. Cleaning looks stupid simple. I'm curious why 3M calls it a primer gun, when it can be used to spray lots of products besides primer. Another website said the 1.8 mm tip is great for typically wood working clear coats, which makes me wonder whether the gravity feed gun will handle paint type products, say 80 seconds through a Ford #4 cup, or I need to go with the pressure assist gun. Time to call Jeff Jewitt on Monday to see what he thinks will best fit my needs.

John

[Bill Neely]

Hi John, I want to give you my take on the PPS using a 'gravity only' gun. With the medium cups about half way empty the cup starts to resist the crush and fluid delivery goes down - the fix for that, from what I was told on a forum is to bleed air into the cup thus forfeiting the ability to spray upside down from that point forward.

I'm definitely cantankerous but I can clean a gun easily enough so I gave up on them and use a small remote pot/w liner and a pressure feed gun. I'm happy with that for higher viscosity finishes.

[Kevin Nathanson]

Hi John, I want to give you my take on the PPS using a 'gravity only' gun. With the medium cups about half way empty the cup starts to resist the crush and fluid delivery goes down - the fix for that, from what I was told on a forum is to bleed air into the cup thus forfeiting the ability to spray upside down from that point forward.

I'm definitely cantankerous but I can clean a gun easily enough so I gave up on them and use a small remote pot/w liner and a pressure feed gun. I'm happy with that for higher viscosity finishes.

I've not experienced that problem, but wouldn't it only occur when spraying upside down for an extended period of time anyway? I'm pretty sure the 'gravity' part of gravity guns takes care of that issue otherwise.

Another nice thing about PPS is the ability to save material, especially if you have bled the cup as mentioned earlier. You can use the sealing caps to keep material for a LONG time, as it doesn't dry out when there is no air present in the container. Also, the PPS cap has a screen in it that acts as a fine filter to keep any contaminants and hardened material out of your gun too.

As far as the 3M gun being a primer gun, that is true with the 1.8 tip, as most automotive primers have hi-build fillers in them and need the bigger nozzle size. I shoot a lot of General Finishes poly (water-based) and I use the 1.4 nozzles for that, as 1.8 would be too much volume for that viscosity. Again, the gun itself is pretty agnostic, as all the 'adjustment' resides in the snap-on nozzle sets. The needle is the same for all nozzles.

K

[John TenEyck]

Thanks Bill and Kevin. At 100 seconds through a #4 cup I wonder if even the 2.0 mm orifice would work with the gravity flow gun. It won't at 1.8 mm with my conventional HVLP conversion gun; I can't really spray anything above about 60 seconds with it. This all leads me to wonder whether I need the pressure assist gravity gun. Ideally, I'd like to be able to shoot paint on the high viscosity side down to shellac on the low end with the same gun by changing the nozzle. I use a 1.4 mm orifice with shellac on my current gun, and it sprays fine, but I wonder if that's going to be too large with a pressurized cup, and that's the smallest nozzle they make for it (I think). It doesn't look like you can adjust the air pressure to the cup on the Accuspray gun that has the disposible nozzles. Can you block the pressure line and just use it like a gravity feed gun when you don't want air assist? What I don't know far exceeds what I do on this.

Being able to switch from paint to clear on the same gun w/o having to worry about contamination is a real attraction. The price is also very attractive although I know over time the upfront savings will get eaten up by the required consummables. Still, I don't spray every day, maybe 3 or 4 days a month, so the ongoing costs shouldn't be very large.

More comments welcome. Thanks.

John

[Bill Neely]

John, Here's a link to a generic viscosity table with n/n sizes for gravity, suction and pressure feed guns. Presumably a pressure cup will function the same as a remote tank/cup as long as the pressure to the cup is adjustable.


http://homesteadfinishingproducts.co..._viscosity.pdf

[John TenEyck]

Thanks Bill. I printed out that chart when I started spraying about 6 years ago. The problem is it doesn't go any higher than 55 seconds, and I have some products I'd like to spray that are much higher. GF's White Poly, for example is around 65 seconds. Ok, that out to go through a 2.0 or 2.2 orifice on a gravity gun. But BM's Satin Impervo and SW's ProClassic are in the range of 100 KU, which converts to around 500 seconds #4 Ford cup, basically infinity. I've sprayed SW's product before with my 1.8 mm gravity gun, but had to dilute it 18% to get it down to around 60 seconds. It came out OK, but not as good as I would have liked. Clearly, those later products are intended to be sprayed with an airless unit, but I don't spray those products enough to justify buying one, nor do I think they will lay down as nice a finish as a well atomized one out of an HVLP gun. I could be wrong, however. Anyway, within HVLP technology the pressurized cup might allow me to spray those products w/o much thinning. The question then remains if that gun will still be able to spray low viscosity products well.

John

[Tom M King]

Skipping the discussion a bit, I've had a Graco airless sprayer for at least twenty years. I mainly used it for spraying walls in new houses I built, and sometimes exterior stuff. Also skipping talking about HVLP, but still use the Apollo. I bought one of the middle grade, second generation Graco air assisted airless rigs for finish spraying, and spraying thinner stuff. It worked great. My old airless gun finally wore out to the point that I needed to replace the gun even though the pump still works fine. I had an assortment of the Graco Fine Finish tips for the AAA, so I bought an airless gun that uses these tips. That gun changed the airless game.

It's not your Father's airless anymore. With the new gun and Fine Finish tips, you can turn the pressure way down from what you used to have to use, even with thicker coatings. I sold the AAA while I could still get most of what I paid for it. I can do as good a job with the airless now as I could with the AAA. If I didn't already have the HVLP for lacquers and such, it would have been a different story, but those two have everything on the market covered that I need to use.

I don't know if this does the OP any good at all, but just for what it's worth. I don't paint that often either, but when I do, I dislike it enough to want to get it over with in a hurry. Back when I was building new houses, I started out renting the airless rigs, but they were so poorly kept, that I bought my own rig. The pump still works as good as a new one, especially in its new life running at lower pressure.

[John TenEyck]

THanks Tom. Doesn't AAA and all but the hand held airless units use a separate pump and hoses between the pump and gun? If so, that's a lot of finish in those lines that has to be cleaned out every time. Sounds like a real pain for a small job. The 3M PPS cup approach is the exact opposite. Nearly no clean up nor wasted finish. I'm not against AAA or any other approach, but I want to minimize cleanup, wasted finish, and especially cross contamination.

John

[Tom M King]

I'd be tempted with the accuspray gun too if you already have a good source of dry air.

Yes, they have hoses. I think the one with the aaa was 1/8" x 25'. Smallest I have for the airless is 1/4" x 15' to longest is two 3/8 x 100' that I have put together for big roof jobs. I time what it takes to empty the lines, and push about 3/4 of that out with water before trashing the rest, so there is some loss. Yes, not what you'd want for a piece of furniture, but I use it for a set of cabinets. If I'm repainting an old set of cabinets, the good thing is there is no cleanup until the end. I take the tip and holder off the gun, and drop the gun in a bucket of water until tomorrow for the next coat. Commercial "saran" wrap covers the paint in the bucket. Since there is no air in the system, it doesn't set up. When I clean up in a city, I just run water through the gun to push out the left over finish down a running sink (only waterbourne stuff in cities), and leave Pump Armor in the rig. I wouldn't suggest airless one way or the other for smaller jobs than a kitchen full of cabinets.