So I had a broken rudder. I glued it back together with some g flex west system epoxy.I knew I should should glassthewhole thing but i struggled to imagine doing a nice job on piece with do many sharp edges. Finally came up with a cheap vacuum bag set up. I covered the rudder with epoxy and then lasted up the glass the best I could andthen just flooded it.I then took plastic wrap and wrapped the whole thing tight.then poked holes all over it with little pins then wrapped an old towel around all of that.Finally put the whole thing in a sturdy big recycling bag and hooked the shop vac up to it. Had to leave the shop vac run until the resin set up butthe results were outstanding. Will be for sure using this method again in the future
This works pretty good, though shop vac's don't live long under continuous load. Another cheap trick is to use those storage bags, that you use a vacuum to suck out the air and flatten an over size sweeter, so it'll fit in a drawer. The valve to these units can be transferred to another plastic bag and taped in place or you can just buy big storage bags. If you have a good seal, they'll hold the vacuum well enough for a cure.
I love that idea. My vacuum got so hot I was using the exhaust side to blow hot air on the rudder to help it set up faster...and it did lol vacuum/blowdryer.
You should let a minimum air flow to maintain vacuum efficiency.
Do it Making a small hole somewhere in the pipe.
Triphase motor are brushless, but they are normaly used in industrial vacs above 4-5 kw, using the other types you surely wear brushes.
Another thing to verify is that you are using a model that can sucks liquids, because in these types the motor is cooled by a separate flow instead of the vacuum flow that in this use is quite null with the consequence of overheating...
Concerning noise, I have no advice...
Gianluigi