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Basic sandblast setup?

Posted: Mon Feb 12, 2018 10:50 pm
by Bluesytone
What's the minimum setup that i can get away with to do sanblasting? I read all the threads that I could find and it sounds like I won't win any speed records but I can get away with a single stage compressor. I have one now, but it only puts out like 6.5cfm at 90psi. I typically avoid HF tools unless they are throw away items, but this might be a case where I can use them coupons...?

Re: Basic sandblast setup?

Posted: Mon Feb 12, 2018 11:42 pm
by DocAitch
I have seen nice sand blasts with smaller units than yours, it just takes more time waiting on the compressor to catch up. I am using a HF 60 gallon unit and an HF cabinet. My blasts are OK. I think that I am getting about 16CF per minute at 80 #, but am using a 1/2 “ line about 20 ft from the compressor.
I could get a higher pressure with a shorter, larger diameter line.
Both the compressor and cabinet were given to me by my brother.
DocAitch.

Re: Basic sandblast setup?

Posted: Tue Feb 13, 2018 1:34 am
by pipeguy
There's no way to get around this you need an 80gallon 5 or more hp that can deliver 22cfm at 90psi.that's the min.I Know people do it on a lot less but are they satisfied??Many are on a budget I get that too But to save money and spend it on enough to get by or just wait a bit longer and save the money to get something with
No regrets plus when you need more because you're frustrated that the stuff you have doesn't get you to the next level you got to save all that money again After being half a lifetime in the trades I have learned NEVER have tool regret :takethat:

Re: Basic sandblast setup?

Posted: Thu Feb 22, 2018 8:36 am
by Massis
I blasted my first pipe on a 2HP single stage compressor with a 100L (26gal) tank. It took 3 hours to get any level of detail in, of which 80+% of the time was simply waiting for the tank to fill up. Blast 10 seconds, wait 45seconds, rinse and repeat at infinitum.

For my own setup I ended up buying a 2 stage 5.5HP (4.2KW) compressor with a 270L (72gal) tank. I can blast for about 4-5 minutes straight at 8bar (115psi) without the compressor kicking in, and then I can simply continue blasting while the compressor kicks in and refills which takes a few minutes. Roughly speaking the compressor runs less than 50% of the time, but the most important thing is: I don't need to stop blasting.

Re: Basic sandblast setup?

Posted: Thu Feb 22, 2018 9:31 am
by Bluesytone
So it really comes down to how much time you want to wait. I suppose it also comes down to how much time you wait compared to how much time it takes to do hand rustication instead as an option.

Re: Basic sandblast setup?

Posted: Thu Feb 22, 2018 11:43 am
by Massis
Bluesytone wrote:So it really comes down to how much time you want to wait. I suppose it also comes down to how much time you wait compared to how much time it takes to do hand rustication instead as an option.
Yes and no.

A REALLY BIG compressor (70+gal, 5BPH +) means consistent airsupply and pressure and a compressor that won't wear out trying to keep up.
A decently big compressor (~50 gal, 3-4HP) means pretty consistent airsupply and pressure (although you might have to use a slightly lower psi or lower cfm nozzle) , but breaks are needed to keep your compressor below recommended running percentage (most are only made to run max 30 min/hour), especially if you want to do more than 1 pipe per session.
Any smaller compressor than that not only means actually waiting for pressure to build up again, but will also mean that:
1) your air pressure will drop significantly during blasting, so the first 5 seconds you blast at 110psi, the next at 105, 100,95,90 until your compressor can't keep up and
2) you need to interrupt your process to wait for the tank to fill up again.
Both those will result in uneven blasting, making it much harder to achieve a decent result.

Basicly, the tipping point is the amount of air you consume while blasting. If your compressor delivers more air than that, you can keep blasting, if it delivers less, you need to wait for it to catch up, but will possibly have to sacrifice some pressure as well.

Re: Basic sandblast setup?

Posted: Thu Feb 22, 2018 11:48 am
by sandahlpipe
5HP 2-Stage (2 stage pumps air into a chamber and then pumps from the chamber into the tank. It lets the PSI go up higher) and 80 gallon tank is a great way to go. I had a 30 gallon unit to start and it would take me an hour to even get a texture on the pipe, let alone a decent blast. And there's a hard limit on how deep and craggy is even possible with such a small unit.

There are a few other variables such as the blast gun you use, the nozzle diameter (affects the CFM consumption of the gun) and the type of media. But it's far better to buy an adequate machine than to sit there for hours of blasting, wishing you had bought the bigger machine. Just rusticate till you can invest in the right machine.

Also, I was afraid to buy used for a compressor, because I didn't understand how they worked. They're actually fairly simple, and you can get them used for 1/3 the price of new if you watch craigslist or facebook marketplace.

Re: Basic sandblast setup?

Posted: Thu Feb 22, 2018 12:10 pm
by Bluesytone
Thanks guys, this is all very helpful... for me and for others as well. I've read on here in other threads there is also an option of a pressure tank or something along those lines to help keep adequate pressure built up for smaller compressors? Is that a legit option? I dont mind investing in the right tools, but I'm very limited on workspace in my shop so that's a compromise as well. I'm currently working with a small band saw, variable speed small jet lathe, 7x10 metal lathe, 1x42 belt sander and a bench buffer motor setup as a french wheel. I've also got dust collection setup. My hope is to find a good deal on a bigger metal lathe and replace the smaller wood and metal lathes. All that said, there's not a lot of room left for a compressor and a blast box so I need to be strategic about it.

Re: Basic sandblast setup?

Posted: Thu Feb 22, 2018 12:24 pm
by sandahlpipe
You can use a pressure pot, but that's not a substitute for an adequately-sized compressor. The 80 gallon compressor doesn't take up that much more floor space than a 30 gallon. It will require a 220V circuit, though. I don't know what your shop situation is, but you can also put the compressor in a different room/shop/shed and run the air hose into your work area for the blast cabinet if that's an option. Compressors are extremely noisy and if you're working next to it, you'll want ear protection. I built a closet for my dust collector and air compressor and put sound-dampening insulation in the walls, so I can blast and still listen to music.

But the bottom line is don't try to skimp on the compressor. Sandblasting is about the most demanding operation you can do with a compressor.

Re: Basic sandblast setup?

Posted: Thu Feb 22, 2018 12:28 pm
by Bluesytone
I've got 230 running to my shop heater so I can sort that out. And come to think of it, I got a concrete slap right outside my shop back door where the house A/C unit lives so I could put it out there and make a cover for it to keep out the rain/snow and run a nozzle through the wall.

Re: Basic sandblast setup?

Posted: Thu Feb 22, 2018 4:12 pm
by sandahlpipe
Another tip is to get anti-vibration pads to put under the feet of the compressor. Putting it outside and covered should work, as long as it doesn't get too cold. Also, leave yourself enough room to get underneath the unit to access the drain. You'll want to drain it after each session.

Re: Basic sandblast setup?

Posted: Fri Feb 23, 2018 11:22 am
by Massis
sandahlpipe wrote:You can use a pressure pot, but that's not a substitute for an adequately-sized compressor. The 80 gallon compressor doesn't take up that much more floor space than a 30 gallon. It will require a 220V circuit, though. I don't know what your shop situation is, but you can also put the compressor in a different room/shop/shed and run the air hose into your work area for the blast cabinet if that's an option. Compressors are extremely noisy and if you're working next to it, you'll want ear protection. I built a closet for my dust collector and air compressor and put sound-dampening insulation in the walls, so I can blast and still listen to music.

But the bottom line is don't try to skimp on the compressor. Sandblasting is about the most demanding operation you can do with a compressor.
floorspace depends on the model. Vertical ones are near impossible to find over here. Mine is a horizontal one which takes up about 8-10sqft...