4+4/4 vs 4/4 weight difference????

First post guys. This place seems like a wealth of information. I used the search function but was unable to find exactly what i was loking for. I think I have an idea of the answer to my question but just wanted to confirm with you smart gentlemen. 

My question is on say an average 6’ x 20"  shortboard what does a single layer of four oz glass and resin on the deck weigh VS. a double 4 top and resin? 

 

Im guessing a layer of glass on that size board is equal to about 1.5 yards of fiberglass so say 6oz for a layer of 4oz e cloth. so 6 ounces plus the weight of the extra resin which i have no earthly idea what that would be.

 

thanks for all the help

Hi Breiss, what did you figure it would take?

By the time you trim the cloth, spill resin on the floor, and cut any laps the precise numbers go out the window.

To get a goofball number for one isolated layer glass+resin, cloth weight times 2. This would be a hand layup 50/50 ratio.

Pros are ‘lighter and tighter’ so to speak maybe 60% glass to 40% resin. I am not a pro.

Initial lams take more resin, fill coats take less.

Ok so based on your info and for an APPROXIMATE number a professional glasser would have an approximate weight gain of 10oz for a board with double 4 deck instead of single 4. And a Joe Shmoe glasser would likely see a 12oz gain in weight between the two boards.

the more logical question would be a single 4 plus a partial layer (patch) vs. full double 4 deck.  doing it that way the weight difference will be a bit less. You really gotta beef up the underfoot area a bit…

Times two.

I just finished a 5’10 stringerless EPS epoxy 2x4 top and bottom (to get 16oz on the rails). 2.4kg.

A lot of my 4/4+4 boards come out similar or even weightier. The weight’s not in the cloth. It’s how much you let the cloth “float” in resin.