EPS Stringer!!

Hello all! Largely due to all of the EPS info in the archives, i have completed a few EPS Epoxy boards, with varying degrees of success. Since all of them have been 6’ and under, I have gone stringerless on each. The biggest challenge has been getting correct rocker lines and flow, since I have just been bending in rocker during glue up and then during shaping. It works well enough, and although I would like to start hot wiring the blanks, because of space and $$ constraints right now, I can’t. (My roomate and I shape, do all the graphics, and glass in our dorm room) So the glued up rocker tends to hold well enough, but on the last board we did, the time between shaping and glassing was longer than anticipated and the rocker line relaxed over and inch before glassing. So to solve this problem, and get more accurate rocker lines, I was thinking about adding a stringer to my blanks. I have read almost every post in the archives about adding stringers to EPS, but I don’t want to mess with wood because I can’t seem to find a good piece without having to plane it and whatnot, and I don’t want to do a horizontal glass stringer because the little RR Epoxy and cloth that I have is financially too important to use, haha.

So my proposal was to shape a stringer to the correct rocker line with EPS, and glue it in. I realize that EPS is not the strongest, but I figure that when vertical, it should at least be strong enough to hold the rocker in place until I can glass it. Basically i am substituting EPS for wood. I am not looking to add alot of strength or stiffness, just to keep my rocker true and keep it from relaxing before I can glass it.

Just for other info, #1 EPS foam from HD, using gorilla glue in the glue up, sub 6 foot board. What does everyone think?? Will it work, or am I wasting my time.

And a side note, the pink stuff from HD, I think it is XPS?? That seems like it would work best, and I read about people vac bagging with it in the archives, but if one were to use it just as a stringer, are there still delam concerns if it gets hot, ie in a car or whatever??

Thanks in advance!!

Shaping in your dorm room, haha, I hope I can do that when I go away…I would just go buy some cheap luan doorskin and cut the rocker lineout and glue that up as a stringer…prob better then eps…I dont seeing that working very well…good luck

I thought about that…looked at Home Depot today and I couldn’t seem to find wood that would work, where at HD would I find a luan doorskin?? I probably just walked right by it…thanks for the tip. If I do go the doorskin route, how much $$ are we talking for the stringer??

1/8" Luan is about $9 for a 4x8 sheet. Hard to get home like that, have them rip it into 2x8, it’s simple then. Plywood section, some have it, some start at 3/16".

Why don’t you just lay the styro blank on top of a surfboard that’s finished? Keeps the rocker.

You can also draw your rocker on the 1/8" ply and use a razor knife to cut it out, about 1/16", over size and sand to line. No power tools needed.

EPS on its edge won’t be any different than EPS laid flat, the cellular structure is the same. What that would get you, though, is a couple of glue ‘stringers’ that would add a lot of stiffness. If you cut a 1" wide piece of EPS for your stringer and glued it in with thick paper, like even grocery bags, on each side it would stiffen a lot with the glue and probably be all you need. Of course, 1/8" plywood would actually be easier, but the plain brown wrapper is just a hoot - and the rock-bottom cheap option. You could even do a brown bag stomp patch, it’ll saturate fine with epoxy and probably harden your glass job fine over the 1#…

Are you using homedepot EPS?? Multiple sheets? I’ve always wondered why not try a horizontal stringer if your glueing sheets together?

Yes, it is the HD EPS. I feel as though the horizontal stringer would be great, but like I said before, even though its just a few yards of additional cloth and a few ounces of epoxy, I was trying to conserve my materials since I can’t afford any more.

Benny, the brown paper bag option had me cracking up. That would be ideal, especially for a broke college kid!! I realize that the cellular construction of EPS is the same no matter whick way you turn it, I was just hoping that by adding a stringer, it would give the bent in rocker something to adhere to, just so it can’t bend back. Basically, like if I were to bend some rocker into an EPS sheet and then glue it to the wall of my dorm room with some gorilla glue, haha. Just so that it can’t spring back as much. I realize that its not the best option, but I had some extra EPS laying around, so I was trying to make do. Thanks for your tips, it was your original HD thread that got me started!

Aquafiend, thanks for the tip as well. It would be great to not have to use power tools, keep the neighbors happy since I do most of my work at the wee hours of the morning after class and homework. Although using the power tools is half the fun, haha. Seeing the look on my Resident Assistants face while I tried to explain to him that me power sanding a freshly glassed poly board in my dorm room at 3 am was in fact quite normal was priceless.

Lee, I looked thru the plywood section…when you said some have it, does that mean that some HD’s won’t stock it?? If that is the case, I’ll find another. Thanks!

If you’re shaping in a confined space, you can’t afford not to be hotwiring. They can be rigged together for almost nothing as far as material costs (heavy gauge guitar string is less than a buck)…I think mine ran me around 10$ including all wood, bolts, guitar string and tension wire for the bow. Have a look around the chemistry department for a variac. You’ll save yourself a heap of time cleaning and you won’t have to worry about pre-bending your sheets; just adhere them and use a profile template to cut the rocker out of your blank; if you’re cutting outline templates, a foil template is no more difficult; one on each side of your glued up sheets. Even better, glue them up on an old board with the desired rocker; already pre-bent once the adhesive is set; put your profile template on, hotwire your rockered blank, then draw up your outline and hotwire that too. Your rocker will be more or less set and you’ll have a completely square blank with square rails and no dust to clean. Hell, I’m hotwiring the railbands on my blank tonight! I’m finding the hotwire is more my friend than the planer with the lighter core materials.