Will be starting new project of sorts. I will be gluing up 12"x12"x18" 1lb eps blocks (free). The blank is for SUP build. for The glue will be either Gorilla, Foam Fusion or Styro Goo fast tac. My concern is being able to allow the degassing of the eps through the glue lines. I have read many posts of Frankenstein glue ups in the past but never a mention about this problem. My thought was to put 3- 1" tape lines on each block opposite one another and then roll the glue on. Prior to clamping blocks together I would pull the tape and align the blocks. The thought being that the air would have a migration point where the tape was. Past experience or thoughts much appreciated.
Hey PNWSB-
I prefer Gorilla Glue over 3M #78 Polystyrene glue for flexible/durable joints. I have not head of the other products.
Rather than tape them off, I just apply to one side and leave intentional ‘skippers’ towards the middle of the pieces…
I also drill stringers to allow airflow that way as well.
Done dozens of Frankenboards using EPS. Used all kinds of glues, and I think foaming Poly glue like Gorilla Glue is the best. I haven’t bothered with air migration. Make sure you scuff up the foam good. I’ve had 2 boards delam because I didn’t scuff the foam good, and the degassing caused a separation between the foam. It’s much harder to fix that than a delam between the foam and glass. I also didn’t have vents in these boards, so when I did a post cure of the glassing, the board turned into a balloon.
Gorilla Glue or epoxy are the best, but epoxy will make a harder glue line. Anything else will come part when you start shaping and put pressure on the foam. You don’t have to cover the whole surface with glue, I usually just run it down the center when I glue up small blocks. I try to keep the glue away from the area I know I need to shape. I did 2 boards with small pieces of foam perpendicular to the stringer and 1 with the foam running nose to tail.
LOVE that blank, brilliant recycling.
I hate throwing foam away…
Good job.
I should add that I use a single long 1.5" strip along the rail to make shaping the rails better. These blanks are cut narrower then I add the final piece after the outline is cut.
PNW/Shark,
This is rad. I am in the process of doing the same thing with an 8’10" Surf SUP build. I have ultra light EPS foam (made here in Japan for insulation less than 1 Lb for sure). I cut my runners out in the shape of the rocker and am using gorilla glue to glue them up into my blank. Shark I didn’t realize you didn’t cover the entire surface. That will save me a lot of glue. I purchased carbon for the rails and deck (due to the soft foam) and I will need to do HD inserts for plugs/handle. How are you guys doing foam inserts for fin plugs? I have a vented handle and I got one more vent to go up front just to make sure the blank doesn’t pop apart. I also got surf specific sparkle for filler for the eps… not sure if its worth it or not. I have never used spackle before but figured this crappy EPS may need it. I may start my own build thread but definitely following you on this build PNW!
Hi CWRun - It’s surprising how little glue it really takes… I’ve dabbed some glue on pieces and tried to break them after they cure. They hold surprisingly well. With a decent shell of a glass job, I suspect that a lot of internal glue is unnecessary. No worries at all regarding air flow. Your blank is looking good!
Thanks for posting those pics. I’ve seen you post them before and I lost that thread, it was driving me nuts.
If you look at the blank there’s a section of blue dow foam. It’s a heavier density and it’s there for fin box support. I also do this for a lot of the EPS builds. Balsa sticks about 1/2" wide maybe 4 to 5 inches long where the boxes will be.
One more comment…
The last 2 recycled foam boards I did were not covered with a wood skin. I can’t remember the glassing schedule, but I had a bunch of a heavier glass. It supposed to have been 8 or 9 oz, but it was a tight weave that needed to be wet out on both sides to saturate. I usually did 1 layer of the on the deck, plus 1 layer of 4 oz, and 1 layer on the bottom. Then I did a second 4oz layer on the bottom after the fin boxes were installed (after the first bottom lam). I just used up the last of that glass, so it’ll be normal 4 or 6 oz surfboard glass from now. Even with all that glass, these boards are very light. So far these 2 boards have held up OK. I used the first one a lot for about a month, and has some denting on the deck, not bad though. The second one has been used maybe a half dozen times. The spots I surf are a little too small right now for these to really shine, so I only use them if the waves are head high or bigger.
I’m doing 2 compsands now and I must say that they are way more hassle than shaping and just glassing foam.
Shark, thanks for the reply. My surf SUP tail looks almost exactly like the photo of your board above. Winged pin. Your input helps a lot. I don’t have access to the higher density Dow type foam here, i like the balsa idea! Im thinking about taking some pieces of old PU and using that for inserts as well… Basically just use what ever I have laying around. Im going to do a poor mans compsand and just use sheet plastic to pull the lam tight (I don’t have any vac gear). I would love to know your glass schedule on those boards. I currently have Carbon tape for the rails and I got a 5’ patch of carbon to go on the deck where my feet will be. Other than that I have 6 oz surfboard glass and some other 4 oz stuff floating around. I figure with foam this light I will have to put two layers on the bottom and two layers over the top of the carbon… Thoughts??
The logic I use for the perpendicular pieces is that they need a lot of force to move. They are glued into the foam and attached to the lam. May not look as pretty, but it’s solid.
Shark, really have liked your glue up posts. Was originally going to fiberglass my 1lb sup blank with 2oz w/ 2.5 cork then 6 on bottom. 2oz w/ 2.5 cork then 2- 6oz and deck patch if needed on deck. Started reading about innegra and might scrap the cork and go with it. 2oz w/3.5 innegra as sandwich and 6oz full wrap with rail cut. Top 2oz with the innegra then 2- 6oz. Don’t know how well innegra cuts but guess I will find out. Also picking up some 3# eps from a nearby mfg to use as a stringer instead of the 3 1/6" plwd I normally use.
I don’t know anything about the new high tech cloths. I’ve tried Bamboo fabric and texallium cloth about 10 years ago. If you do vac bag lamination, you could do a 3 layer glass in the bag and get a really strong but light shell. I met a couple of sailboard guys from Australia on Maui, and one of the guys made their boards. He told me that he only lams in a vac bag and he gets the skins really strong but light that way. Sailboard guys need extra strong decks with all the pounding they do landing airs.
If you’re used to working with plywood, it’s going to be stronger than any foam, but there will be a potential for the foam to get compressed along the stringer and break the glass open. For any future builds I do with 1lb EPS that has a stringer, I’m going to add at least one panel of balsa right over the stringer on the deck. I have 3" and 4" wide sheets of thin balsa.
Not trying to butt in… just to show how one company is doing a wooden compsand on their boards. I have heard good things regarding their durability.
http://star-board-sup.com/2017/technologies/#pine-tek-tab
Appreciate the link JM. Always enjoy the sharing of knowledge and open thought on Swaylocks.
for waves sup boards i use 2x6oz bottom and 19oz multiaxial glass on deck over 1,2lb foam stringerless. They seems to hold well. i would more go with cork sandwich thon innegra on deck.
Still wondering where all this light Cork is coming from
Amorim Corecork, comes in sheets as thin as 1.5mm. The challenge is finding a source, especially if you don’t want to buy a full roll.