: Bill,

: I’m glad you enjoyed reading about the project. You are correct, the EPA
: concerns are one reason to use vacuum infusion, which limits worker
: exposure to the resin and solvents. In addition, the vacuum exhaust could
: be scrubbed to minimize the environmental impact to others.

: Another reason to use vacuum infusion is to offer better control over the
: resin content. With vacuum bagged wet lay-up, it is important to control
: the resin in some fashion, either by careful roller/squeegee work, or the
: use of wet-out machines that turn the work into a “wet-preg” exercise.
: With vacuum infusion, the resin content is controlled by the physics of
: the process in a way that is more consistent, reliable, and less work than
: what can be achieved with vacuum bagged wet lay-ups.

: Wet lay-up is less complicated, but I disagree that it’s easier, and it most
: definitely is more work because someone has to apply and squeegee a bunch
: of resin. I think one of Charlie’s cautions is that with wet lay-up, the
: wet-out and squeegee work is time consuming and not very forgiving. That
: is a valid concern. If one were to then vacuum bag a wet lay-up, there is
: additional time involved with getting the bag and other stuff on while the
: resin is kicking off, adding time to an already long and potentially
: hectic process. When I’m done laying a single layer of glass on a
: stripper, I’m ready for a break, not another layer (right Charlie?).

: But if one is going to vacuum bag a wet lay-up, then the difference in the
: materials required for resin infusion is trivial but the timeline changes
: completely. With resin infusion, a single person can take as long as they
: like to drape the fibers, apply release cloth and flow media, seal the
: bag, and check for leaks. I spread this out over many evenings after work,
: and could walk away or be interrupted at any time without consequence. So,
: in many respects resin infusion simplifies the process and creates a much
: more forgiving timeline in addition to offering better resin control
: compared to wet lay-ups.

: Sam

Hi Sam,

This is an interesting and unexpected topic

You're assuming that with a wet layup you'll use the same resin/hardener that's you would use for the vacuum infusion process. But that's not required. There are several resin/hardeners that have very extended layup times out there. Most though require a post cure. This isn't all the complicated nor necessarily expensive. Electric heater cores can be used with inexpensive thermostats for the heat and a foil/foam or foil/glass insulation box can be used to contain the heat for the post cure. With the oven/vacuum bag you can then also play with pre-pregs, thought the cost can get kinda silly. Still, with these methods you can achieve a seriously strong and light boat.

Vacuum infusion has a learning curve too, have seen several projets that ended up with incomplete boat parts where the resin didn't infuse as planned.

Either way, strip built is easier/cheaper.

Bill H.