Repairing/filling EPS tear-outs

Hey all,

Searched archives for an answer on this, but nothing found yet. Glued up my first EPS blank (2#) using Gorilla Glue on the stringer. Made the mistake of laying a couple of 2x4s across the board to hold everything flat while curing and when the GG expanded it really glued the 2x4s to the blank on each side of the stringer. Needless to say in trying to get the 2x4s unstuck I got some tearouts in the foam by the stringer - the worst up to 1/2-inch deep. I made the blank about 1/4-inch too thick so when I sand/plane the blank some of the tearout depth will be removed, but I’ll still have some holes left to fill. My question is that if I seal w/ spackle, is it ok to just fill the deeper holes with spackle or will that be too weak? Should I use something else to fill?

thanks,

Jim

I would finish shaping and see how bad it is. If its not too bad I would just use the spackle. If they are still deep, I would try micro balloons and epoxy and mix it really thick. The tap water at my house turns the spackle yellow, but if I use the water out of my R/O its fine.

Jim, I’ve routed out areas that were too deep for spackle and gg’d foam back in. Works and looks great. I like doing that much better than heavy spackle.

Thanks guys. Both ideas sound very good. I’ll see how bad the holes look once I finish the shaping.

Jim

Next month I should have everything in place to start making my own EPS blanks. (back yard ,not for sale)

If you were to place wax paper onto the 2x4’s would it have prevented the problem?

What type of clamping system did you use to glue in the stringer. Photos ?

Did you use a wood stringer or PVC ?

If the tear outs are deeper than 1/4" I would repair with foam but I’m too new to the EPS process to give advise.

(All of the large dings that I do on traditional boards get new foam not filler)

Thanks for the post ,

Lots of people on Swaylocks interested in making their own 2# EPS blanks.

Ray

Share the stoke

Yep. Wax paper. That was my first thought as soon as I saw the glue foaming up. I didn’t know that the glue was going to do that.

I used four bar clamps and some 1x3 pine along the outside edge of the foam to set the jaws of the clamps against. That worked fine. For the stringer I used 3/16-inch luan plywood from Home Depot. The smell when I cut it reminded me of my first (cheap) guitar when I was a kid. I think next time I’ll try PVC or a solid wood because the center layer in the luan has a tendency to kind of crumble out in places when you plane it. It’s pretty soft stuff. 1/4-inch redwood bender board from the garden dept. might work well.

Making your own blank adds a lot of work to the whole process, but it was still fun to do. Sourcing the foam, getting it delivered, making rocker templates, making a hotwire cutter, hotwiring, gluing, etc. all took a fair amount of time and effort. On rocker templates alone I had to make several before I finally settled on one that was decent. Now I’ve got a homemade blank though and the next ones will be way easier having done it all once.

Good luck!

Jim

Blue tape & pipe clamps. Put your clamp pads on the outside edges so the clamps don’t crush the foam. I just use my masonite rocker/thickness templates as clamp pads - you don’t need to jam on the pressure like you do clamping wood. I now (like the 2nd & 3rd photos) cover the entire glue joints with blue tape. Its enough to stop the gorilla glue from oozing out in globs. It still oozes, but it goes flat under the tape and the planer takes it right off.

In order, you see 3 d-cell stringers, a redwood stringer, and no stringers - just 3 glue lines to stiffen a blank enough for shaping before bagging on skins (yes, that’s enough). The middle one looks crazy narrow, because that’s a 12’ board.



Hi Benny ,

Does it have to be blue Tape or will regular masking tape work ?

Your Photos are very helpful.

Ray

I like the blue just because it peels off without ripping into thousands of strips. The white tape is so shred-prone that every little blip where the GG hits the edge creates a tear point.

Attached pic shows my EPS blank glued and clamped. Note boards that I set on top to hold everything flat (the foam wanted to slide and shift slightly against the stringer while the glue was wet) as well as underneath plus the two little tip and tail areas that I clamped all stuck badly to the Gorilla Glue. Do not let this happen to you! Actually the damage to the foam wasn’t excessive. It’s just another thing to deal with now.