You’re most likely leaving way too much resin in your lamination. The core+glassing schedule you describe should be noticeably lighter prior to hotcoating. Depending on the foam you’re using the blank may be soaking up excess resin if you haven’t sealed it prior to laminating.
Using epoxy requires a somewhat different glassing technique.
Yes, you are right I have noticed that… I need to seal the blank befor glassing it so the resin doesn’t soak in the foam. Mybe be this is making this problem, is not so lighter like I supose, before hot coating but I thought that would be lighter than a poly board in that scenario too. I was using 550cc with 2 4oz on the top. I think that depends on hte resin type (this ha a 4-1 relation with the hardener ) but is more or less what it’s taking to me.
What do you think?
Thanks for the response bro!
No, you don’t.
And it won’t make that big a difference, anyway. Resin doesn’t “soak in”, no matter which foam you’re using. You are probably loading too much resin in the glass and overdoing it with your hot coat, as well. Given the foam you use and the glass combo, your boards should be noticably lighter than a poly/poly board of the same shape.
I just glassed a 6’2 eps board 2x4oz on the bottom ,mixed up 520grm had issues with coloured tissue not laying flat folded it all back chucked the tissue finished the lam with about 100grm still in the pot.
What sort of blanks and epoxy are you using ?
I’m sealing my eps but its lowly insulation grade about 1- 1.25lb without sealing the epoxy just drains away
Ah Sammy…
If I lam a layer of Cerex sealing the blank, It takes about 200g of epoxy with 80g hardener to do a single layer of 4oz.
If I lam the same board without the Cerex layer, it takes about 320g of epoxy with 128g of hardener.
Where did the epoxy go? It soaked into all those little pours and holes in the un sealed blank.
My epoxy boards are 20% lighter than poly boards. Just the way it is. Could tell ya, but it’s all in the archives. Do the research and see the difference. I use way, way, way less epoxy when laminating a surfboard vs poly resin.
I’ve seen lots of guys that make very heavy epoxy boards. The problem is, is that they try to make them the same way as a poly board…and thats no bueno if you are trying to make a light board.
idea number one…
you need to sand more. remember epoxy is just the glue holding the fibergalss together, or filling the little pin holes… Sand it all off, just short of the fiberglass. 85% of the guys here don’t sand the board nearly enough.
sanding: meaning getting rid of excessive material…not getting rid of scratches.
Ah Resinhead…
Wet out table, vacuum bag. The epoxy you don’t put on is the epoxy you don’t sand off.
=)
That’s less than 5 oz of resin. I doubt anyone could feel the weight difference, even lifting it with one hand
No, it did not “Soak in”. It filled the crevices, nooks, and crannies in the foam. There’s a difference.
In most denser eps blanks, since 1,5#, fast curing surfboards epoxy don’t soak so much, but if you lam a bit dry it leaves pinholes, so cheater coat after lam or seal before. A shortboard 2# foam, 2x4-4 can weight about 2kg but will not be more durable than pu-pe same glass (about 2.5kg).
When I start with epoxy, a long time ago lol, I was disappointed with weight too. Every thing became better with training and faster resin. You use to much resin and I am with resinhead, you may not sand enough.
Eversurfer are those numbers with a wet out table? One layer how big a board?
Epoxy resin used in Boat construction seems to have more wight per volume then what resin used for building surfboards.
Yesterday I glass the bottom layer. I used only one 4oz layer with 400cc of resin ( 320 epoxy and 80 hardener ), the result was ok but I really expect that the surfboard would be lighter since is epoxy… I didn’t seal the hole blank since i’m testing the best result, and was pretty good the shape result I hade some little holes but no sooooooo much, next time i will seal it anyway. Do you think that if I seal the blank before I glass the board will I notice a big difference?
I understand that I have to use less resin in the glassing and in the hot coat, and I will aim that in this board. I’m taking extra care with this this time.
I’m really looking fordward to have a good result on this 
By the way… the amount that i’m using is for a 5 11 board with a shape of a HS Hypto Krypto.
Out of curiosity:
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400cc is a lot of epoxy for 1 layer of 4 oz glass on a board that small. Approximately how much ended up on the floor or left in the bucket?
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That’s a 4:1 mix ratio. What epoxy are you using? What is the gel time? What is the cure time?
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Did you seal the blank before glassing this time?
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What kind of scale do you have available? Could you weigh the blank before glassing to see how much weight it gained during that step?
Just a few thoughts.
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maybe 50/80cc more or less. Nothing left in the bucket
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The epoxy is the only that i can get in my country
, the gel time is 1.5 hs aprox, the cure time 12 hs. -
this time didn’t seal the blank. was very good, not much little holes in the foam but it has some…
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I couldn’t weight it… Will do it next time.
Do you think that the epoxy is not good? ,
Tonight I was suposed to hot coat the surfboard… hoy much do you think that should I need?
Your epoxy is too long to dry it’s go in blank. For a 4 oz on 5’11 fish I prep 250 gr of mix and i have some in bucket at the end. I seal my blank.
Yesterday I hot coat the bottom of the board, i used 210cc with mix, is this a good numer? I tried to use the less that I could do…
You foreign guy measurements, I had to go look at my bucket gradients…I use approx 10 oz…or 300 ml to glass the bottom of a 7’6" surfboard. My entire build of a 7’6" will use approximately 1000 ml of epoxy. That would be glassing, hot coat, fin boxes, and leash plug.
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get it onto the cloth…yes it might look not wetted out. but if epoxy touches cloth…It will wet out (I’ve used 5 min fast set epoxy on ding repair…and it wets cloth out just fine)
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let it sit. especially if you have a 1.5 hr work time.
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laminate, and pull off excess
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prep the laps so it looks like a finished board
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apply hotcoat with squeegee, and finish with stiff disposalbe brush
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sand hot coat off
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finish board with 2 part LP clear coat
This is what i do,I don’t know what else to tell you…keep at it…or, get some better epoxy?
jaja sorry bro! 
I’m in the other part of the world in Argentina!
Is the best Epoxy we can get…
I will try this! is a very good idea, I thought about it, but since everyone was telling that the best hotcoat was with the brush I didn’t want to change. I will use the squeegee toapply and then use the brush. Thenaks for the idea.
I think that the biggest mistake I have done was not to seal the blank… Our epoxy resin is not so good so I think I need more resin than normal. if I don’t seal the blank I will use much more than it is need it. My first hot coat was with 350/400 cc, and in the last I used 200, so is much better now and the weight has improved a lot!! since this blank didn’t have so much little holes and we used less resin trying to get a better result, I think that the weight problem has improved a little bit. I will still work in this issue… I will hot coat today the top, hope to get a good result.