hotwire glue ups

I’ve just made a couple of sets of masonite templates. I have two blocks of 12" wide foam and am ready to hotwire.

A couple of options:

  1. hotwire each half of the board separately then glue together

  2. place the two foam blocks together and hotwire both halves at the same time – glue together after cut

  3. glue the blocks together — then hotwire both halves at the same

I’m leaning towards #2 because I’m concerned about cutting the hotwire through the glue…

You guys who’ve done this before - what is your recommendation?


Hey Smedman… I’d say 2 or 3.

The only problem I’d have with 2 is clamping the two halves together and keeping them steady/not moving.

And with #3, the hot wire should have no problem with PU glue (GG) if it’s applied very thin.


ps - I’ll keep your suggestion in mind for the balsaComp class. Let me know what other dates might work for you.

cut both halves

put one side on a flat bench or the floor

glue on the stringer to one half using weights and 5 minute epoxy

clamps are a waste of time if your joint is good

let the glue set

apply glue to the other side of the stringer and put the other blank on top

hold inplace or use weights

do not use big gobs of epoxy or you will get runs

a thin smear is all it takes

this was made over a year ago and was my first normal eps board

board is still mint and found a happy owner who rates it high

partly cuz it was only 150bucks

but mostly cuz its strong and goes good

triple 6 deck and double 6 bottom with patches for the fins

Hey silly, good timing there. I’m just at this stage with some blanks I’ve cut from a block.

Q. With the 5min epoxy do you have to have a really smooth cut for the stringer to stick to? I figured on using Gorilla glue to fill some of the beady gapage (roughness) in the foam, but can’t find Gorilla glue anywhere near me. (No gorillas to stick it with I suppose).

heya jase

i wouldnt use an expanding glue or you will need to clamp it

the stringer material i use is planed and thickness sanded

but my next one i may just use pvc

i just smear it on a reasonable amount but not so much as it drips and blobs

put it on the stringer and the stick the stringer to one side of the blank

i just hold it in place and havea couple of weights (block plane)

five minutes later you putting glue on the other side of the stringer and sticking the other half on

your shaping the board 5 minutes later

maybe a waterproof wood glue would be

but then you waiting ages

a good industrial 5 min epoxy cant be beat


cheers bud! It’s the 5 min epoxy for me then (I still can’t find any gorilla shite).

hey silly,

(quick hijack of my own thread)

when people talk about PVC stringers - are you talking about a similar material to the PVC baseboards that are used in home construction – here in US at home improvement stores you can buy various thicknesses of white PVC trim to finish out a room in your home – wood is also used, but PVC is cheaper and lighter - is this the PVC everyone refers to? thanks!

go with option 1 like silly says, less hassle and only 10 extra mins to cut twice. I use sumo glue instead of epoxy or gorilla, it is PU glue but does not expand as much as gorilla and is white and sands out easily, unlike epoxy. sumo is made by locktite, not sure if it is avail in US or NZ.

PVC foam is generally Komatex or Sintra, it is used by sign makers.


I vote for option 1 as well. You’ll cut the EPS twice as fast, so it won’t be like double the work to cut two halves. You’ll get a better result with your rocker templates only 12" apart - less wire wobble or crown.

On 10’ boards, I can’t get the whole thing done with 5 min epoxy. But I agree that, as much as I like pu glue, this isn’t the right application for it, since it expands & presses everything apart right where you want it to be tight.

The same stores that carry 5 minute epoxy usually have a 30 minute version that’s packaged the same & everything. That would be my recommendation… no need to stress yourself out. You can do both halves at once, since you’re gluing the stringer to a factory edge.

I think this is the pvc that’s used. It is used by sign and display makers and comes in sheets of various thickness.