Vacuum Bagging & Infusion

Everything that goes between your laminate and your pump: films and fabrics cut to the yard so one part costs one part's worth, flow media and tubing for resin infusion, and the tape that seals it all down. Every by-the-yard material comes in 1, 3, 5, 10 and 25 yard cuts or a full roll.

The order a bag goes together: peel ply straight onto the wet laminate, breather over the peel ply so vacuum reaches the whole part instead of just the area near the port, then bagging film over everything sealed to the mold with sealant tape. Add perforated release film between peel ply and breather to meter how much resin bleeds into the breather; without it, the breather soaks up resin straight through the peel ply.

Resin infusion uses the same bag. Flow media goes over the peel ply in place of breather, spiral tubing carries resin along the part, and semi-rigid feed line brings it in from the pot. The resin is pulled through dry glass under vacuum instead of rolled in by hand.

The part most first bags get wrong: there is no way to tell a sealed bag from a leaking bag the pump is keeping up with. They look and feel identical, and the second one lets go mid-cure. Close a valve between the bag and the pump, switch the pump off and watch a gauge on the bag side for five minutes before you mix resin. If the needle holds, the bag is sealed.

Pumps. We do not sell them, on purpose. A good HVAC vacuum pump costs about a hundred dollars and pulls deeper than pumps sold through composites channels for many times that. Buy the one you like. HVAC pumps have a 1/4 in SAE male flare inlet, so you need a female flare to hose barb adapter to meet 3/8 in vacuum hose.