Okay, I just glued up my 2" and 1" eps panels from the local builder’s store. I used Titebond III woodglue, supposedly waterproof and not as goopy as polyurethane glue.
I used 90% of the 32oz bottle to glue the two panels together…that’s nearly two pounds of glue that wouldn’t be there if they just made 3" thick panels. So here are my questions: How much glue did YOU use? Is hotwiring a billet of eps ultimately the way to go?
i’d say start over with 3m spray glue…it doesnt make shaping easy though…hw is the way to go if your budget allows
just use epoxy, use a trim roller or brush spread it out thin and evenly. Why would you use wood glue to glue up foam?? the 3m spray adhesive will eat through the foam don’t use that. Epoxy is an adhesive…the weight will be very minimal. If your that concerned about weight im guessing you want to make a bad ass shortie, you could do it with 2" of 1lb EPS…no glue up.(more bouyant) If you want to speed up cure time just line a carboard box with tin foil and then make an input for a hair drier. I actually did a quick glue up the other day where i wrapped the board in tin foil also… full cure in about an hour and fifteen minutes. To think I use to wait over night for that stuff…You should also put the rocker in while doing the glue up much easier this way.
Hotwiring is not the only way to go, its the cleanest, and easiest to get a good outline. however, you can use an electric turkey knife. If you go this route draw your outline on the foam cut about 1-2" outside the line, and don’t ever sand the outline…that can screw everything up…just true it up.
Why woodglue? Easy to spread, new waterproof type, nearly non toxic, zero smell, and…cheap. Besides, I wanted to save the RR for glassing the board.
I don’t think the epoxy would have gone on any thinner, as the culprit was all of those little striations that held the glue.
Yeah, thought about just making an ultra thin board out of a two inch panel, but at 210lbs that didn’t seem prudent. Maybe the extra float from lighter density would make it pencil out, but thought I’d try the lam method first.
Turkey knife! I feel a trip to the thrift store coming up.
So two pounds of glue is a shocker, eh? Okay…let’s see how it works.
I used about 12oz of white elmers glue…
link below gives the details and has post from others on how they glued up their eps blanks…
Remember, a lot of your glue weight evaporates.
the 3m spray adhesive will eat through the foam don’t use that.
3M™ Polystyrene Foam Insulation 78 Spray Adhesive [click to enlarge] Insulation 78 Spray Adhesive is a high solids, adjustable lace spray aerosol adhesive for bonding most types of insulation such as fiberglass, expanded polystyrene foam, and extruded polystyrene foam.
br - there are many ways to skin a cat…question everything…epoxy is best as far as overall strength, but only certain forces are in play and you can get away with less than the absolute best…im no expert but quite crafty with prob solving…so are a lot of others on this site
back to the spray…dont be a kook like the guy in the photo…USE A RESPIRATOR! full of nasties…i’ve used 77 too…light/medium dusting is all it takes
Used it on the first board and it separated.
Used it on the second board after properly preparing the two sheets (i.e. sanding them flat with 60 grit to take off the cook-off layer from manufacturing hotwire) and it worked fine. Abslutely no problems with shaping it either…no chunks…no hardspots.
And yeah, no question, if you can find it, hotwiring from a big billet will treat you better cause it’ll give you a much desired rocker table for vacuum techniques and you’ll be able to more or less have your rocker set rather than having to worry about always securing it while you do your lams. Question is, can you get it and do you have the space to store it…dry…
yea I was thinking about using that spray adhesive, could never find it in any store near me…haven’t ordered it yet. You’re easy balsa rails…you just use that for the foam wood glue up or do u also glue the wood together with it? I’ve also hear that those bonds arent trust worthy, I’ve always felt safer just using epoxy, I don’t think the weight gain is that significant, definatley under two lbs…I think Greg Loher recommends epoxy too if that helps…but yea the stuff is expensive I can see why you wouldnt want to use much of it…I think I used 1/2-1 cup for a 6’8 fish type board with the glue up…aslo I don’t know about putting in the rocker during glue up with a spray adhesive…have you had any luck with that?
I used about 1/2 of a 32oz Elmers, waited for several days for it to dry. It seemed dry, but when I turned the blank (3 - 1 inch Lowes EPS sheets) on its side & left it for a day the glue migrated down from the interior of the blank and oozed out the side/bottom. Glued the blank on its side to my work table.
When I was shaping it, the glue lines were a bit of a problem - much harder than the surrounding EPS when I was using my sanding block.
I think next time I’ll try a different glue or epoxy & use much less thatn I did this time.
A friend mentioned that his kid had noticed that his shop class had used some method to thermally fuse two pieces of eps together…is this likely? Guess I’ll have to go down to the garage with the heat gun…I feel a mishap coming.
As far as the glue evaporating most of it’s weight, (Wildy), maybe I’ll try weighing pre and post cured wood glue. I have a feeling that the insulating properties of eps might keep a lot of that moisture between the panels.
Glue it with epoxy (very little) and appply it with a small roller. Or better yet, get the right size billet to begin with. There are EPS manufaturers who will sell you billets literally all over the US and AUS. Hot wiring is easy and cheap to set up. And infinatly better in the end. For EPS availability look in the phone book under “insulation manufacturers” of look online at insulfoam.com or carpenter.com. There are many more companies as well. Central FL alone has five! LA has at least two! HI even has one… Great Pacific… I think?.
I completely agree with Greg. I did 2 boards with glued-up blanks and then found 5" & 6" thick slabs for everything since then. Hotwiring is faster, easier, cleaner, did I mention cleaner?
One thing is the length. I build mostly longboards so I want blanks around 10’. My local EPS guy has up to 8’ only. I start by having the foam guy rip the 4’ x 8’ sheet to 1’ wide 8’ strips. Easier to hotwire & add stringers that way, not to mention put inside my Subaru.
Once I get home, its no trouble to cut 2’ off two of the strips and add them to 2 more to make 10’ 'ers. Gorilla Glue is da kine. It dries fast - 3 hours. It cures with water, not air, so the insulating properties of EPS don’t mess with the set up. I spray the ends of the billets with a little mister, smear GG on one side, and hold it together with blue tape. Couldn’t be easier.
And oh yeah, the 2 extra 6’ x 12"
pieces make a really nice fish blank. Can make 2 fish blanks if I use a
6" thick billet and keep the rocker down…so for one $84 sheet of 6"
thick EPS I can make 2 6’ fish and a 10’ log…
Epoxy T-88 Glue or Regular Epoxy with some Qcell filler No significant weight gain and pretty strong.
1" glued to 2" taped using that stretch packing film to a board I want to copy the rocker from.
You can even shape the bottom contours on the EPS sheet that will be on the bottom while it is still a flat piece of EPS on a flat table (easy) then glue everything up. You could at that point even bag the bottom lam on while setting the rocker all at the same time. You do need to shave everything down afterwards which is the messy part Benny talks about. The hotwire is cleaner in that perspective, But I think this is a little less wasteful as I’m only throwing away the outline cutoffs. The next dat cut the plastiuc off and you’re ready to start shaping… $14.00 for a Lowes 2"x4’x8" and $20 for a HD 1"X4’X8’ for 2 boards no incluiding the $28 for the 1mmx4’x8’ Bamboo if you want to go that route. But Benny’s foam is better at 2lbs… This is less than 1lb density stuff…
Here’s a day’s work of templating and glue ups… Sitting in my shaping bay…
Here’s the rockers I’m grabbing Mandala, Merrick, French, Parmenter
Here’s the bunch stacked on my junky racks
And here’s the stringer… I cut out a planshape 1-2" narrower than the outline out of this stuff and glue it in between the two slabs. Acts as a stiffener, internal spring and horizontal stringer… Still needs to be tested.
You can put the same stuff on the out side as well… This stuff epoxied becomes stiff as steel and as sharp on the 1mm edges as razor wire.
Peter I had a block of 1 1/2 lb.EPS 10’ by 24" by 24". Shipped to my door in Aloha for about $ 170.00.From Insulfoam in Kent Wash.I’ll get 5 to 6 boards out of it. I did a Home Depot board this winter. To much time spent on the blank. So I’ll be hot wiring. If you need the number let me know. Gordon
Oneula, the blocks of foam I get are 1# density. I haven’t tried any in 2# yet…
Hey Gordon, thanks for the info. I had the Isulfoam thing figured out awhile back, but wanted to try the Benny method of ultra cheap and whatever was available locally. But six blanks out of one billet…that’s $28 per blank. Not bad. Did the billet arrive in decent shape? How’s the bead size and uniformity?
My ten gram puddle of glue has lost two grams of weight so far, after being partially dried in the toaster oven. I’ll venture a guess that final weigh out will be four grams. So my nearly two pounds of glue will hopefully evaporate to less than a pound.
If you’re in Canada, at least western Canada, Plasti-Fab is the company you want for EPS billets. www.plastifab.com.
I just picked up three 8’ x 2’ x 6" 2lb blocks at $38 (Can) each. They have a minimum order of $100 at the plant I got it from, but I figure its still worth it, considering that for $31 I could’ve gotten the same dimension 1.5 lb, green tinted foam at Home Depot that I would’ve had to glue up. I’ll gladly pay an extra 7 bucks for a blank thats heavier density, is nice and white, and I don’t have to glue up. It feels a lot more solid than the home depot stuff, but it hotwires just as nice as the cheaper stuff.
Now, where to get stringer material…
For stringer material you can use PVC which you can get from sign supply companies. Look in the yellow pages under “signs - materials and supplys”. Comes in 4x8 sheets or 4x10 sheets for long boards. Use either 2 or 3 mil material. Costs between 20 and 30 a sheet. Enough to do about a dozen boards. Makes nice template material too. You can cut it with a razor knife.
There are some good veneers that can be used as well. Check for that in the achives. There are also some wood shops around that will cut custom stringers out of wood stock. I’ve had this done and it isn’t as expensive as you’d think. Poplar works well as does bass wood. Spuce and Western Red Cedar too. You can find wood shops under woodwork in the yellow pages.
You can also get balsa in sheets from a local hobby shop. Comes in many thicknesses and is generally available in 6" x 3 or 4 foot sheets. Glue up multiple staggered layers and then after the resin sets you have a solid sheet. Then cut the rocker template.
For the center cut, draw a line down the center of your blank and cut it with a jig saw or hot wire. Then use the factory cut outsides as your blank center. In other words, switch the sides.