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Anybody know sandblasting?

bradleyheathhays

NAXJA Forum User
Location
Lexington, KY
I'm trying to transition into commercial painting specializing in the horse farms around central KY and my first job involves taking down 11 heavy metal powder coated horse stall doors that have gotten somewhat rusted, sandblasting them then painting. I've done a lot of stuff but sandblasting isn't one of them. So I'm wondering just how does someone like me go about doing something like this. Do equipment rental places carry stuff like this? Other than handling the doors which I've got help for, is this blasting job something your average motivated joe can tackle?

Also, was wondering what'd be the best environment to get it done. The doors are installed in an all wood stable, and although a horse stall sounds like the ideal place to lean these gates up and blast away, I'd be afraid the wood wall behind it would disintegrate. There's another stable nearby that's made of cinder block which I imagine would make for a better staging area. These stalls are about 13 ft square which seems ideal for keeping the all the sand contained. I'm sure the wall would need repainting after everything was finished, but would a cinder block wall generally stand up to being hit with lots of sand?
 
I think I would go buy a portable sand blaster (something cheap like harbor freight if you don't plan to use it a lot).

Two things come to mind...

1. You need a ton of air....large compressor with a large tank. An air dryer is very helpful...wet sand doesn't spray well.

2. It will covet the entire area with sand. Do it out in a field or somewhere you don't have to cleanup afterwards.
 
This looks like a painful lesson to me...

Powder coating is an absolute *(female dog) to sandblast. This is going to be very time consuming.

Are these tube doors or sheet metal? If sheet metal you are also going to have to worry about distorting them with the sand blasting. The thinner they are the worse the situation. If tubing you just have 360 sides to sandblast.

John is correct about you needing a large air compressor. A pressure pot will work with a trailer mounted air compressor. You can probably rent an Ingersoll Rand or comparable from a rental yard. They will probably rent you the pressure pot too.

When it comes to media you get what you pay for. I would not bother with sand but would rather get at least garnet if not aluminum oxide. But I would also set up a temporary sanding booth and plan to recycle my media. Lay out a heavy tarp and build a floor and three walls with plywood and 2x4s (imagine a small racquetball court, perhaps 8' square). The bulk of your media should land within your booth and should be able to be shoveled up and reused. If you get lucky enough to get powder coating to come off in flakes you will need to filter your media through some sort of screen. 1/8" or 3/16" mesh should be reasonable.

Humidity is your enemy. Try to work during the part of the day when humidity is lowest. When your line plugs up you can often clear it by blocking the nozzle with your gloved hand and that will blow the line out back into the media.

You are going to get sand into every orifice of your body. Wear earplugs and a good mask. And be careful with where you aim the gun. I heard of a guy who died when he accidentally cut a major artery in his thigh. He bled out. Not a common mishap, but a danger that indicates the respect you need to show the equipment.

I have used a bunch of different types of sandblasting equipment over the years, most of it in commercial settings. From what I know of the right tools for the job I would simply take these doors to a commercial shop and have them sandblasted by someone who really has the right stuff. But I am betting that isn't an option on this job.

Best of luck.
 
Having owned and used sand blasters for 40 years, I have come to recommend a new method. You can get an adapter for a 3500psi pressure washer that mixes the blasting media in with the water at the nozzle. It cuts through the crap while not heating the substrate. It works great on fenders and panels. The nice thing is that you don't get all the dust. I blast while parked over grass. What is left is harmless and washes down into the soil.

There are companies that are doing this commercially such as Dustless Blasting.
 
Having owned and used sand blasters for 40 years, I have come to recommend a new method. You can get an adapter for a 3500psi pressure washer that mixes the blasting media in with the water at the nozzle. It cuts through the crap while not heating the substrate. It works great on fenders and panels. The nice thing is that you don't get all the dust. I blast while parked over grass. What is left is harmless and washes down into the soil.

There are companies that are doing this commercially such as Dustless Blasting.

Dustless Blasting uses glass beads. Very tiny glass beads from my research. I've actually looked into a set up to start doing it around here.

TO OP: powdercoat could be hard to get off with a sand blaster. I used a HF blaster and it was a pita to use. Was getting sand out my hair for days.
 
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Dustless Blasting uses glass beads. Very tiny glass beads from my research. I've actually looked into a set up to start doing it around here.

TO OP: powdercoat could be hard to get off with a sand blaster. I used a HF blaster and it was a pita to use. Was getting sand out my hair for days.

I'd stay away from HF. I've tried to use a couple different models and they weren't worth the powder to blow them off the curb.

I definitely think what Old Man had to say is worth pursuing. I may look into one myself. Damned roof rack!
 
It never hurts to coat everything with aircraft stripper a few hours before ultimately sandblasting. It will save a ton of time, air, and sand.

If the parts are easily removed and hauled around, you might get by cheaper by taking them to a commercial sandblaster. They have the big boy toys and can make short work of it.
 
If the parts are easily removed and hauled around, you might get by cheaper by taking them to a commercial sandblaster. They have the big boy toys and can make short work of it.
Though my rack is on the large size (Farm Boy) this is probably what I'll end up doing.
 
Now having discussed getting the old paint and rust off, be careful what you paint with. Horses in stalls get bored and commonly do what is called cribbing. They chew on everything, literally chewing railings made of wood down to nothing. They have even been known to strip paint from metal. Make sure what ever you paint with will not harm the animals if they chew it off and swallow it.

I might think about passivating the metal before painting. It will give you rust protection even if the paint gets chipped off.

If the stall floors are concrete, you might talk to the customer about epoxy coating the floors once they are clean and dry. Just add some traction additive such as silica sand to make them less slippery. It is so nice how they will just wash clean for years. It also dresses up a barn and will cut down the smell.
 
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