need advice on innegra

I’ve been building a couple of boards this summer in an attempt to build a durable but light longboard. Inspired by Dwight’s thread on wet out tables, I was able to build a couple of boards, vacuum bagging veneer decks and nylon and cork around the bottom and rails and they are strong, but they weigh around 18 pounds. The board I’m in the process of building now, I’m trying for more like 13 or 14 pounds. It’s a 9 ft 6 in eps 1.5 lb blank that I hand lammed a layer of 4 oz top and bottom and then vacuumed on a .023 veneer deck with another layer of 4 oz under that. The blank weighed 4 lbs 8 ozs, then with the layer top and bottom, 6 lbs 4 ozs, and then with the veneer, 7 lbs 13 ozs. At this point I was just goin to ad a couple layers more of 4 oz and call it good though I know the bottom at least, will flex when pressed on. I have some innegra around from a past build and though it was a bitch to wrap the rails with, I thought I might try it again on this board and not try to wrap the rails. So my question is what is the best way to apply the innegra to the existing glass and keep it light. I’m wondering if I were to squeegee resin onto the board, lay on the innegra. then wet out a layer of 4 onz on the table, put that on top and bag it , would that be enough resin to hold it together or do I need to saturate the innegra. When I used it in the past, I layed it on the board like a layer of glass and then poured a ton of resin on it, thinking the excess would be pulled out under vacuum but that added a lot of weight. Any advice here would be much appreciated.

By the way, I don’t have enough points to respond to my thread. If I did, I would respond to Huck’s over fifty thread, and tell him, hell, I didn’t even start surfing until I was fifty.

Edit, thanks for the responses. I’m using greenroom resin. I probably wasn’t very clear in describing what I meant by stiff. I was thinking of the skins impact strength, hence the innegra which I thought acts kind of like a core between the glass layers and is tough to break through when impacted. A lot of friends who surf two weeks a year use my boards and they get a lot of abuse. This one board though, I’m reseving for myself, figure it can be a bit more delicate.

Hi Mitaman,

What kind of resin do you use? You could definately save weight by using a very low viscosity epoxy resin with ultra long pot life [the slowest hardener you can find] in combination with a proper vacuum bag set up.

Adding Innegra afterwards sound a bit painful. Besides, i doubt it helps a lot strength wise. you would be better off in my opinion

by vacuuming 1 strip or 2 strips of veneer on the bottom with regular glass, then hand glass over it. Is it a stringerless shape? If with stringers, add the 2 strips a bit outside the centre stringer.

Cheers

If you’re looking for stiffness in a stringerless blank go with a uni-directional carbon strip on the bottom or VectorNET.

Innegra is for impact (ding) resistance and does not have the tensile advantage of carbon fiber.

I’ve only used innegra on a few boards, but I had good results from wetting out the innegra as dry as I could and then laying a dry piece of fiberglass over that before putting the board under vacuum.  The vacuum doesn’t pull a lot of resin out but it will pull enough out to wet out the fiberglass cap.  IMO, aside from adequately wetting out the innegra, adding more resin beyond that just adds more weight.  

The veneer probably adds all the stiffness you need.  In conjunction with the rest of your glassing schedule I think the innegra will inhibit any failures at the rail under normal loads.  That stuff is tough.  

Are you using perf ply and bleeder cloth? If the resin is not too hard the pref with bleeder over it should suck out any extra resin and pack all of it down as tight as possible. as wouter says maybe you need longer curing resin so you can get it in the bag and still get it to flow into the bleeder. It should be no matter how much resin you aply the vacuum should suck out all the extra into the bleeder (too much if you run more than about 8lbs. vacuum).