# air compressors - how big for certain tasks?

**URL:** <https://boards.straightdope.com/t/air-compressors-how-big-for-certain-tasks/609779>\
**Category:** Factual Questions\
**Created:** [January 17, 2012, 7:41am UTC](https://boards.straightdope.com/t/air-compressors-how-big-for-certain-tasks/609779 "2012-01-17T07:41:01Z")\
**Posts on this page:** 2\
**Page:** 2

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**Author:** ![GTRtiger](https://avatars.discourse-cdn.com/v4/letter/g/c6cbf5/32.png) [@GTRtiger](https://boards.straightdope.com/u/GTRtiger)\
**Post date:** [February 27, 2013, 1:05pm UTC](https://boards.straightdope.com/t/air-compressors-how-big-for-certain-tasks/609779/21 "2013-02-27T13:05:54Z")

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> [@Machine\_Elf](#):
>
> Then you probably want the mid-size gun and a 10-15 CFM compressor, otherwise sandblasting will go very slowly.
> 
> However, the air leaving that coalescing filter will still be at something close to 100% relative humidity. When it squirts out of the sandlbasting gun, the pressure drop will cause cooling, and you’ll end up with condensation. That’s not good. So downstream of the coalescing filter, you’ll want a desiccator, like [McMaster part #5163K21.](http://www.mcmaster.com/#air-compressor-dryers/=g0q0y9) I have both of these items (filter and desiccator), and they work great. The desiccant beads, once saturated, can be dried in a 350-degree electric oven (not a gas oven; too humid) and reused indefinitely.

So would a [http://www.amazon.com/gp/product/B000ASG2R2/ref=ox\_sc\_act\_title\_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER](http://www.amazon.com/gp/product/B000ASG2R2/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER) work for sandblasting??? Thanks

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<div class="post-metadata">

**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\
**Post date:** [February 27, 2013, 1:56pm UTC](https://boards.straightdope.com/t/air-compressors-how-big-for-certain-tasks/609779/22 "2013-02-27T13:56:23Z")

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> [@GTRtiger](#):
>
> So would a [http://www.amazon.com/gp/product/B000ASG2R2/ref=ox\_sc\_act\_title\_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER](http://www.amazon.com/gp/product/B000ASG2R2/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER) work for sandblasting??? Thanks

The key is to size your accessories (blasting gun, impact wrench, etc.) appropriately for whatever flow rate you have available; in this case, the specs for that compressor claim 9 CFM, so you don’t want a sandblasting gun that is designed to work with more air than that. The flow rate will be too low, so it won’t pick up much sand, and the exit velocity won’t be very high.

check [here](http://www.tptools.com/Foot-Pedal-Operated-Power-Gun,1024.html?b=d*8026) for foot-switch-operated guns. Note that they have large, medium, and small verisons. If you’re going to buy that Hitachi compressor, you would want to select the small gun, designed for 4-8 CFM. It’l be suitable for smallish parts, items perhaps the size of a coffee cup.

For reference: My typical sandblasting job is ten steel bars, each one 3/4" square by 3 feet long. I have an 11-CFM compressor, and the medium-sized gun from the page I linked to above; with this setup, I can complete this job in about twenty minutes. With that as a benchmark, consider what sort of blasting work you expect to do, and size your gun/compressor accordingly.

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