Hello,

I am planning on doing an infusion of a 5’5” x 20” surfboard. The board itself is made out of xps foam. I plan on doing the whole thing at once. I’m a little worried about the foam twisting while under vacuum. I’m thinking my solution to this is to do a hand layup of carbon rails (basically just around the perimeter of the foam). In my mind this will prevent the foam from distorting while under vacuum.

The epoxy I’m using has a viscosity of 350 and a working life of 40 minutes. The working life is what I’m concerned about. My plan to combat this is to pull vacuum from the wide point on both rails. I will then have spiral tubing running the length of the board on the deck and bottom with a resin feed line in each. I have no idea if this is a good idea or not but with only 40 minutes working time, it makes sense to me.

As for the lay up, it’s an xps foam core followed by 4 oz E cloth fiberglass, 2mm lantor soric lrc, 4 oz E cloth, peel ply, then bag. There will be spots along the rails were there is no soric, these spots will have flow mesh on top of the peel ply. I made a diagram of what I’m planning.

This will be my first go with infusion. Am I on the right track or will my ideas not work? Any input is more than welcome.

Thanks.

I'd be really concerned about infusing that for a few reasons:

Is the XPS foam strong enough to withstand vacuum?  Warping and crushing (especially corners) will be a thing if it is less than 2lb density - maybe even if its more.  I think your idea of a hand layup around the perimeter is a really good one - it will protect the edges from crushing and give you something to land the core on.  If you use glass, cut strips so the fibers are running +/-45 degrees to the perimeter - this will conform really well but you may have to wet it out on painters plastic to keep it together.

350cps epoxy is pretty thick to infuse that in the time you have.  The Soric LRC is not an ideal flow media compared to mesh on the surface - so it may be slow.

I would be very worried about running the Soric too close to the edge.  It won't go around a tight corner gracefully and it will want so bad to wrinkle.  I'd hold it back 25mm from the edge and do that radius as a second bagged or hand laid operation - or use some extra glass.  The spiral wrap will push into the foam unless you keep it well clear in a pleat and covered with peel ply - so only the peel ply makes contact with the surface.  On the inlet side, you can scrunch it down to meet the surface and then pull it back up before the resin starts to gel.  

I'm not meaning to be a downer but this is a really complicated first infusion project!  It could work, but it would be a lot of work! Why are you choosing infusion instead of hand laying glass as is usually done with surfboards?

Good luck!

Thanks for the reply this is exactly the info I was hoping for! I’ve done a ton of hand lay ups on surfboards. The reason for the infusion is really because of the Soric. With surfboards, xps foam has a lot of delam issues. A lot of the delam issues seem to be caused by pressure dents from feet. On xps, the bond of the resin to foam is much weaker than the glass itself, so the foam gets compressed and the glass springs back causing a delam. I’m hoping the Soric prevents this by preventing pressure dents in the first place. And honestly it just sounded like a fun project, and if the idea works it has tons of potential.

I was planning on cutting the Soric to fit both the deck and bottom just to the point where the carbon tape comes up the rails. This should prevent it from wrinkling.

I really want to put my resin inlets on both sides of the board in the center with spiral tubing running the length. I feel that’s my best shot at getting a full infusion, with vacuum being pulled on the both sides at the center point.

I think maybe when I hand lay the carbon tape on the rails, I could run a narrow strip of 4 oz e cloth down the middle on both sides. This is where my spiral tubing will be. Would it also be a good idea to run spiral tubing around the perimeter from my vacuum lines?

Sounds like I should also use the flow mesh on the whole board.

This is an experiment , and if it fails, it fails. But I would like to give myself the best chance I can at being successful with it.

I went through with the infusion. I made some mistakes and learned a lot. I was having trouble getting the bag to seal with my vacuum line along the rails, so I put it on where my second resin line was going to be. I ended up with spiral tubing running the length of the top as the resin line, and spiral tubing running the length of the bottom as the vacuum line. Resin and vacuum ports were centered on these lines. What ended up happening was I basically had a freeway of epoxy from my inlet to the vacuum line. Epoxy reaches the vacuum line well before the board was fully infused. This caused me to waste quite a bit of epoxy as I had to mix and add more several times. The other problem i ran into, I used hardware store T fittings for my vacuum and infusion line...they were hard plastic and did compress the foam a little underneath them. The spiral tubing did not compress it much at all. I still have to finish sand the board, but I’m already planning my next one. I may use coremat and flow mesh instead of soric, or maybe even innegra. I’m just messing around with different composites for surfboards trying to find one that’s a winner.

+x

 

Daveym - 12/28/2019 4:24:27 PM

Nice board!! I'm trying to make an infusion shortboard aswell using carbon fiber. Do you have any past experiences using EPS foam? Is it too weak and does it absorbe too much resin?

+x

 

ruben booth - 6/6/2020 3:57:21 PM

+x

 

Daveym - 12/28/2019 4:24:27 PM

Nice board!! I'm trying to make an infusion shortboard aswell using carbon fiber. Do you have any past experiences using EPS foam? Is it too weak and does it absorbe too much resin?

If you use eps you have to seal it extremely well or it will pull in way too much resin and be very heavy.