Hopefully I'm in the right thread. I'm using a tow behind air compressor as my main compressor 1966 Chicago pneumatics 85cfm and 100 psi to 120 psi. I've been sand blasting with it and I've been getting horrible pressure drops so I've done a lot of research, just seeing if this set up I'm about to do sounds about right. So I'm gonna be running 1 1/4 main loop with 3/4 leg drops 1 to a blast cabinet then 2 other ones to hose reels. I was wondering if this is totally over kill and unnecessary. "I might try doing sand blasting on the side also as a side job" and then next topic freaking filters I think I gotta get filters that handle the psi and cfm output of my compressor right ?? And does anyone have any recommendations for inline filters.
Air compressor lines and filter suggestions
- Thread starter jmoser87
- Start date
Firebrick43
Well-known member
You have given no definition as to what blasting cabinet you have and it’s required cfm is.
3/4 pipe is only flow around 30 cfm, no where near 85 the compressor can out put
If your blasting for money you are going to want your blaster to be as fast as possible so it should be running at least half of the cfm that your compressor can output.
3/4 pipe is only flow around 30 cfm, no where near 85 the compressor can out put
If your blasting for money you are going to want your blaster to be as fast as possible so it should be running at least half of the cfm that your compressor can output.
To say 3/4" pipe will "only flow 30 cfm" is absolutely untrue under almost any circumstances, even though you would need to actually define the circumstances (at what pressure, length of pipe, etc.) before making such a statement in the first place.
Why on earth would you say that?
How much pipe (length) are we talking about? Also, what is your blast gun's rated consumption, and at what pressures are you blasting?
Firebrick43
Well-known member
Pressure loss charts, that is why I would say that.
To directly quote the OP
Pipe, fittings, connections, ect all add friction. Above 30 ish cfm friction starts to climb. If the OP is blasting for profit then even if he isn't using 50 or 60 cfm plus currently he more than likely will want to in the future. At both my local big box store and plumbing supply store 1" pipe is only 6 and 7 dollars respectively more than 3/4 pipe for a 21' length.
IMHO that is worth it to use it for the blast drop. It only cost a little more to go first class. To have to upgrade in the future will cost much more and be three times the work.
Blast rate consumption is I believe 6 cfm to 29 cfm it's a harbor freight blaster. Minimum I either do 90 or 100 psi. And length I'm not entirely sure yet. My garage is 25ft W X 40ft L. I was thinking maybe just doing a 25x 25 loop, just so it's a square loop, so 100 feet atleast. I really don't need it to be that big, I'll only be using like half the garage for sandblasting. But 2 sides of the loop is gonna be 25 feet for sure. If that makes sense
. I also gotta think about the way I should plumb it also should I go compressor to my 500 propane air tank to my condenser, or compressor then condenser then tank. I haven't really seen any threads on anyone talking about running plumbing or about air filtration for a set up like I'm doing yet. Thanks for responding btw.
. I also gotta think about the way I should plumb it also should I go compressor to my 500 propane air tank to my condenser, or compressor then condenser then tank. I haven't really seen any threads on anyone talking about running plumbing or about air filtration for a set up like I'm doing yet. Thanks for responding btw.Jswain
Well-known member
That chart is pressure drop for 100ft of pipe, with your loop being 1.250" and if you do a full loop your basically doubling the flow then it's just a short drop of 3/4" to the cabinet. That would flow way more then enough, easily.
I have seen the blast charts yes I
Yeah I seen the blast charts I also didn't really take intp consideration about the loss of pressure or velocity of the air from the fittings also. I was thinking the main 1 1/4 piping would be in a loop, so air would be trapped in there or building up while I am not constantly using it. Obviously the compressor is gonna be able to keep supplying me with more air than I use even when I am blasting. Sorry at Work right now I'm sure my typing and sentences are gonna be all messed up trying to explain stuff to you guysPressure loss charts, that is why I would say that.
To directly quote the OP
Pipe, fittings, connections, ect all add friction. Above 30 ish cfm friction starts to climb. If the OP is blasting for profit then even if he isn't using 50 or 60 cfm plus currently he more than likely will want to in the future. At both my local big box store and plumbing supply store 1" pipe is only 6 and 7 dollars respectively more than 3/4 pipe for a 21' length.
IMHO that is worth it to use it for the blast drop. It only cost a little more to go first class. To have to upgrade in the future will cost much more and be three times the work.
Oh ok from the first couple of comments I thought I needed bigger drops. I'm still new to this stuff and still working out the kinks on this old compressor with no manual which *****.
Jswain
Well-known member
How do you have it currently setup to be having pressure drop problems?
The piping is **** I had there already with my DeWalt 60 gallon so I knew I have to change it up just wasn't sure about piping. I just kinda recently got this tow behind and was just dealing with the pressure drop till now.
3/8 mostly
Jswain
Well-known member
Ahh yeah, your new setup will be a huge improvement
So 1 1/14 main and 3/4 drop or 1 inch drop?
According to the chart above, you would only see a 2.1 psi pressure drop at 50 cfm and 100 psi with 100' of 3/4" pipe. I'd say that's plenty good.
I kinda understand the chart but wouldn't it be less I'll have far more in the 1 1/4 for the look part the 3/4 drops are just to go where I need the air at. I wouldn't need no 100 ft of 3/4 I'll probably need about 30 to 40 ft of it depending how high I wanna have the 1 1/14 stuff off the ground. Maybe I should have posted a picture
That's my point. You won't have anywhere near 100' of 3/4" pipe so you'll experience even less than the already nominal amount of loss in the chart.
Jswain
Well-known member
3/4 drop will be fine.