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Trey Gibson
Posted: Dec 22, 2006 08:30 AM
Air Requirements
I am trying to figure out if our rig has enough air to run a scarfer.

How much air does the proportioner take (gun, stick pumps)?

Also, these scarfers use about 21-23cfm what is the minimum amount of compressor that could run above equipment and scarfer?
Posted: Dec 22, 2006 04:19 PM
realize compressors typically tell you "cfm displacement" not "cfm free-air"...you want to know the free-air number(cfm at working pressure)...
a 5 hp compressor will deliver about 19 cfm free air at 100psi,,,less at 140psi,,,even less at 175psi
a 7.5hp compressor will deliver about 25 cfm free air at 175psi,,slightly more at 140psi...
a true 10 hp compressor will deliver about 34cfm at 175psi...you can get another 2-4cfm out of it by lowering pressure to 140psi...(set your psi to the lowest working pressure,,its easier on your machine)so lets say 35cfm for sake of discussion...so lets add it up
drum pumpsx2 estimate 15cfm
air purge gun(trigger & purge)estimate 4cfm
(air stirrers are air hogs like scarfers..est 15cfm)
so we are getting right up there with just the processing of material....
my air scarfer is a valuable tool and i couldnt do closed cell with out it,,(well i could but it would be a big pia)and though i dont know its cfm requirement,,,i can tell you it takes a boat load of air,,and i always estimated consumption at 18-20cfm.....we notice line drop trying to get out there beyond 150ft and have started to add larger diameter hose for the first few lengths to the house...we notice line drop even more when it is cold..also you cant have enough air tanks,,this is "reserve"...less cycleing,,less heat,,less moisture...
next rig will be a 20hp rotary screw minimum,,,and maybe even 25hp if $$allows..

will look for cfm rateings and post if i find and if time allows

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