laminate schedule for e-glass, kevlar and PLascore

ducknut

Thanks for the reply. That layup schedule is one that seems more appropriate for my use. I had no clue that the Plascore might have different scrim options. I don't know what type I have but have contacted Luke the Sales Engineer to identify what I have already purchased. I have experience with epoxe and glass as well as vacuum bagging but definitely need to know if on bagging the panel will become many square feet of resin sucking straws.

 

Thanks for all the suggestions. Based on what I have read on the site I fabbed some test panels and could only punch through to the core one time in about 8 tries with: 2, 10 oz e-glass over 5 oz kevlar on 1/2" Plascore with "Veil and Film" (read resin barrier) with 2, 10 oz. e-glass on the back side. No chance to penetrate the 2-ply "inside" laminate layer. I vacuum bagged a sample of same and it sucked the extra resin away leaving a very strong and stiff panel. I will buy s-glass (8.9 oz) to further reduce weight and gain the 25 per cent advantage on strength and abrasion. This should be the most durable and one of the lightest Ausable River Boats around.

 

There will be some overlap with this thread and another site to which I belong. I have a concern about the Plascore laminate I tested. I used 1/2" polypro "veil with barrier" or the "film" discussed above and found after abusing the test panel I could quite easily pull the glass and kevlar layers away from the core. This was accomplished easier than I would have expected. It came away cleanly without removing any of the scrim from the PLascore. I did one with hand lay up and another with vacuum bag. The bagged one looked like the Kevlar and fiberglass cloth had been formed to a mold the separation was so complete. The RAKA tech said they only sell the "veil only" style because of the possibility that the limited penetration with "veil and barrier" can result in parting of the cloth and core. I used 2 layers of 10 oz. e-glass inside and 5 oz. of Kevlar and 2 layers of 10 oz. e-glass over it on the outside of the honeycomb. I wonder why not go back to 1/4" ply and less reinforcing fabric to eliminate the possibility of panel failure at the core fabric interface? I am in Traverse City, Michigan and may have some 3/4 and 1/2" panels available.

 

I guess my question is, are you peeling from the exposed edge of your test panels?

I'm not an engineer. Still, I would think that the resin won't ever actually bond with the core because the core itself is plastic. The idea is the entire vessel is glassed and completely enveloping the core leaving no exposed edges for peeling. The core material is there to create an I-beam like structure between the inner and outer layers of glass.

When I originally spoke to Rake about the problem I had with the Plascore, was the resin was flowing through the veil into the honeycomb cells. They at first didn't believe me. They said there should be a film between the two like NidaCore (which they used to sell). They grabbed a sample, put it in a pie tin and poured resin in it...it almost instantly went through it.

If you're bent on wood, they make a wood version of the honecomb core as well. However, it may be too rigid for some of the curves you're likely to make.

 

hardcoreducknut Thanks, you make an interesting point, yes I do need to be able to grasp the edge to get the ripping started. I first got onto this because I propped the test panel up on a 4x4 and stomped down on it very hard. This broke the inner 2 layers of 10 oz e-glass (in tension) and I took both halves now bound only by the other outer schedule (2-10 oz e-glass and 5 oz kevlar) and pulled the broken honeycomb away from the intact outer layer. Is this strong enough for what a boat might be asked to do? I don't know. If it was swamped in the river that water volume would generate tremendous forces. Maybe no composite would be enough. I am testing a ply panel today to see if the RAKA epoxy will bond to it more tenaciously because it can only penetrate the 1/20th of an inch or whatever the outer layer of 1/4" Merananti ply is. I have a kayak builder who states that only WEST epoxy is universally recognized as having an effective and reliable ability to bond to wood. It may be that I have never placed a composite in this sort of position before and I have unrealistic expectations?

 

Well, you might look at the fact that you broke through the sample by tension on the side without the kevlar. You might perform another test with kevlar in the layup of both sides. Then try it again. If you can't duplicate the results, take more extreme measures. Maybe strattle it between two cinder blocks and try a sledge hammer? An axe? I'd be interested in your findings.

I can say that my friend's plascore driftboats that he has built are tanks. He's been down some serious stuff in pursuit of trout without issue. Remember, he put untextured line-x on the outside of the bottom...