I am looking for the processes people have used in laying up prepreg material in the glassing of a board. The factors in getting it to adhere strongly to the foam, a pre coat still wet before the prepreg? How do you get a vacuum bag around a tacky board? One side at a time, or both? I am doing a seinior project on this subject. Informatiom on prepregs pertaining to surfboards is not as common as that for aero-industry, just got turned on to this site today, looking forward to discussing and learning some good things. Dont know exactly how the system works but the mail is at , thaks
I thought prepreg fabric was impregnated with resin and that the fabric was fairly stiff, like a semicured fabric. In the snowboard industy it’s laid up in a mold under pressure and then heat is applied to soften the resin to bond it to the underlaying material and ultimatly cure the resin when it reaches a certain temprature. Atleast that how I recall what I’ve read about it. The advantages is that the optimal resin to glass ratio is achived so you get maximum strength to weight ratio. For a surfboard however I would consider it very impractical and much more expensive then regular laminating. For more information about prepregs check http://www.spsystems.com/prod-prepregs.htm regards, Håvard
Prepregs do have problems when used with foams. You have to have significant resin transference when dealing with foam and prepregs just don’t do this well. Coating the blank prior would help but at that point your just adding steps and weight and hand layup is still easier and more effective. I have done some projects with Florida Tech using prepregs and like Havard said and from what I’ve seen I don’t think they’re applicable at this time to surfboards.
Way to many issues to cover here but: 1) Storage of prepregs require a large freezer. Expensive. 2) Now we are talking heat cure, So now you need an oven that can cure at about 200 F to 250 F. Expensive 3) Adhesive films will be needed (or as Greg put it, pre-coating foam with wet resin.) In snowboards, some of the larger companies have adopted the use of prepregs to save labor costs. However most of these boards have terrible adhesion to the core, causing the laminate to peel up rather easily compaired to a board made with wet resin because they are not using adhesive films. You need 2 to 5 mil gap for good adhesion hence the adhesive film. 4) Vacuum bag materials are not cheap! Yeah plastic film from Home Depot can work for low cost bagging. 5) Rocker table will be needed. It is amazing how much pressure a vacuum bag has. Jono