Can you use a hopper gun to spray finishing plaster?

Question

I'm intrigued by spray plastering. It seems that most people use machines like this, costing thousands, to spray finish plaster: http://www.pftplasteringmachines.com/product/pft-ritmo-plastering-machines.

Hopper guns (like this: http://www.all-wall.com/Categories/Drywall-Hopper-Guns/SharpShooter-20-Hopper.html) seem to be only used to apply textured finishes and external render.

Are hopper guns not suitable for applying finish plaster (provided you rule and trowel afterwards, obviously)? If not, why not?

Answer 1

No. A couple weeks ago when i was drywall mudding my room I thought of the idea, and i decided to try and find out immediately rather than ask the internet and wait. I don't recommend trying.

First there were immediate delivery problems, hand tools suddenly starts looking alot more practical. The plaster is far too thick & heavy for the gun to shoot. When it does shoot some, its random spurts of gobs and most of it didn't make it from the gun to the wall. I may have fared better if i had a conventional spray gun (high pressure low volume), i had a common low pressure high volume gun.

Second problem was nearly as immediate, and could make you cry. Paint guns are designed to use paint, that if you leave in the gun it doesn't dry and clog the gun in 20-30 minutes. Paint also has solvents that clear the gun for you if it did dry in the gun. Plaster sets in about 30, and there really isn't a solvent to make dried set plaster go away. So basically you have to mix, spray and clean it all out of the gun in 30 minutes, or you won't have a functional paint gun anymore. It didn't make me cry because I had a feeling my gun will break and i had one of those so-inexpensive-its-nearly-disposable harbor freight paint guns.

If you use a slower setting joint compound it wouldn't ruin the gun, but it won't spray on the wall like paint either.

IF you have a conventional high pressure, low volume paint gun though, maybe lots of pressure is all you need to make it work. Slower setting compound will give you ample time to clean it all out before it sets/dries.

Answer 2

Short answer would be no. This gun was meant for something completely different. Mortar has far bigger particles and I'm pretty the gun wouldn't work, or even if it would it would break down really soon. My advice is to do it manually, if there is something you need to do, if you are asking just out of curiosity I think I have answered :)

Answer 3

I've actually tried this with a cement-ish product. It wasn't plaster, but it had some lime and other stuff in it to chemically set up. Like python_starter mentioned, the larger particles cause an issue. First, they don't blow on that well, and second - you would definitely wear it through doing it consistently -

I've gone through one gun just in my own home improvement experiences. But... if you're just trying a one-shot deal, I'd say give it a try and see how it comes out!

Answer 4

What you really want is a proper plaster or stucco sprayer. But you also have to get a significantly more powerful air compressor than most people have in their garage.

"Use the wall sprayer with a 5 hp electric (220 volt), 6.5 hp gas compressor or larger." as per the product description. If you have an equipment/tool rental company nearby you can probably rent the air compressor.