Go to any big slaughter house and you can see this done.
The tool or nozzle has about a foot long hollow shank that is beveled like a regular hypodermic needle. They just stick it thru the hide along the hind legs and let er rip. In combination, they also use a wenching system to pull the loosened hide off with the help of skinners using sharp knives. Takes about one minute to get the hide off'n a big steer.
You will need a minimum of 100-150 lbs of air and a large volume tank.
The air method helps but there is still a lot of manual hand work to do.
I have done both deer and hogs this way. Works OK. Even though the compressor is in the barn I clean my animals in and it only takes a second I dont do it any more. Not enough benifit for me. On the hogs it seems the fat is in layers and you dont get a good separation of hide from the rest of it. It works better on deer but they are pretty easy anyway.
You can watch them blow up and see the separation I blew them up until a 100 pound deer looked like a 300 pound calf. Finally after limited success I turned one on until we all ran and it blew out. Still not all that, would have been a good video though.
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