Getting core to stay in place while bagging

Dear builders,

We have a small dinghy building project and are looking for some best practices in working with core. Specifically, we are using a make mold with scored and skimmed 1/2 PET core. What is the best way to get the various core pieces to stay in place while we get the vacuum bagging set up over it? We are rolling on thickened resin to several layers of cured fiberglass, which is on top of gelcoat, before positioning the core with more thickened resin and a layer of glass mat. The pre-coat of thickened resin obviously makes the surface slick and unreceptive to a quickset epoxy or similar adhesive. Any tips on this would be appreciated.

Cheers,
Rich

 

I use plastic staples. The tool is expensive, but high payback in core construction using offcuts. The epoxy fills modest voids, but keep the cuts fairly close to be sure.

As far as thr core shifting on the table; you can hotglue tack foam hold ins and just cut them away with a multi tool.

I use an Omer 81P stapler and just the 1/4” staples. I usually staple both sides of any assembly. It works great if you need to have core inserts of varying density as well.

I keep all my offcuts that are 4 sq inches or more and rip them all to a standard dimension and build back panels for non-hull applications like cabin walls or cabinetry. The labor is a downside, but I hate to bin so much core. And if you have say 3 pieces of core 12x24; you can build back a panel of 12x72 or 36x24, so it really pays off. I usually tack the staples pretty close if the part is to be handled and I even sometimes shoot the ends. You do need to use care on large panels, but if it comes apart; you can also put it back together easily using the same holes or a couple new staples as needed.

I think I pad about $250 US for the stapler and a box of staples. Avoid or do not allow anyone to use the stapler on wet resin or with resin gloves.

 

We use spray adhesive to hold things together during infusion. I remember it is 3M but ask your supplier for the exact product type.