I shaped a 2-lb. eps board with RR epoxy. I did a real lightweight spackle covering with dap fastnfinal. On a hot day last summer it began to develop two bubbles on the bottom, each about the size of a fist.
So, this is where it gets ugly. I cut the bubbles with an exacto knife and then cut out all the foam beneath the glass there. I glued a new piece of eps into the void that I created, shaped it down, and left it. When I returned, of course, the glue had exothermed and burned even bigger holes in the foam. Doh!
So I decided then to just apply dap fastnfinal to the hole in incremental layers to fill it. I glassed over this, hot coated, etc. The board looked fine. Until it delammed this weekend. The delams are in the same old spots and about the size of dinner plates.
Obviously I’ve done this wrong before. How to set it right? Thanks, C
My first board done that , you should have put vent valve in it after your first repair, i now use 3 lb. eps to build wakesurfers with no delam issues.
I’ve heard that, but the consensus, at least around here–I thought–was that vents aren’t really necessary unless it’s a) really hot or b) you’re at elevation. Since it doesn’t get really hot here at the coast and it wasn’t at elevation, I thought I would be fine without a vent.
Also, I’m curious as to why the delam has spread from the spackle. I suppose maybe it was already a bad bond in the area around the original delam and for some reason the introduction of heat or something caused further expansion. But it looks like a bubble, like something has off-gassed and is trapped.
I would just redo your original plan, but take time and prep the insert hole and the insert so that no epoxy pools will form, which should limit the exotherm, you dont want to use any more epoxy than you have to. Or you could use foaming PU glue like Gorilla Glue to attach your eps.
Keep in mind that even in moderate temperatures, direct sunlight can really bake a surface. I’ve seen some weird ass stuff happen to EPS when it reaches a certain temperature.
Was there a layer of beads still attached to the glass you removed? Maybe you received some funky foam that suffered from bead separation rather than a laminate failure?
Epoxy that cured at low temperature might be subject to softening at higher temperatures.
Was the board painted?
Any chance of moisture penetration via pinholes or cracks?
Yeah, given the history I think I’d vent that puppy.
Thanks for the replies. So John, you bring up a couple of good points. The board is dark grey on the bottom where the delam occurs and it was in direct sunlight.
So, for a plan. I will:
cut the raised glass and remove it.
check the spackle and see if it’s wet or loose and remove it.
reapply dap fastnfinal spackle to create a flat surface.
laminate a piece of glass over the whole thing, overlapping well past the exposed foam/spackle.
Pete C on here makes a Goretex ventplug. I have used them with great success. No need to remove or worse accidentally forgeting the plug. Look him up in the directory if you’re interested.
To fix that delam, cut out the glass using an abrasive wheel in a dremel. Once the foam is exposed, push in and compact any soft spots. Get some 2 lb density pour foam, put it in the voids, tape wax paper over it to hold it in, and let it go off. Sand it down, laminate a colored patch over it, hotcoat, feather the edges. Check your fin boxes for any separations or bulging around them. Expanding eps will try and push these out it if there was heating in the area. When the foam shrinks back down, it leaves voids and gaps between the lamination and boxes which can waterlog the board quite fast. Never try to bond in new foam into an eps repair with epoxy. Use poly foam and Gorilla glue or pour foam and you’ll avoid that melted mess.
the board that delamed had a black top deck and a light blue bottom , this board got 30 degrees hotter than a white board in 10 min. time . so i will never use dark colors again.
First problem, you used a spackle instead of sealing the EPS with a coating of epoxy resin, I can’t imagine the foam melting from putting in the foam patch, the fit must have been really sloppy to have that much resin pooling to create that much heat.
Eps, my motto, any color clear you want, we had Harbour EPS boards come back on Austin Foam, with the foam melted under the black Harbour laminate.
Before getting all cosmetic, you need to first figure out how to do the processes well, then branch out to trying color work
PeteC, why do I have to use pour foam? Why not spackle? (I’m not trying to be argumentative here, I used spackle last time and a lot of good it did me–just trying to understand.) Also, the fin boxes DID tweak. That’s amazing. I’ll PM you about the GoreTex vent.
JimtheG, I used a glue that was recommended to me at a boating store. Obviously I didn’t read the fine print or explain myself to the salesperson very well. It must have gotten really hot, which was exactly what I was trying to avoid. Not a mistake I will make again.
As far as getting the method right before experimenting, every board I do is an experiment and a learning experience. I shape approx. 2-3 boards per year and I will never be a good shaper as a result. The best thing for me about sways is the appreciation I’ve gained for a well built board. Your boards are some of the nicest I’ve seen. Thanks a lot for your input and take care,
Well here is another trick that might work. You could get some Resin-X and mix in some microballoons to fix the eaten away area if it is not too deep. I have recently been installing all my fin boxes with Resin-X and have not had any problems with it exotherming and eating foam away. If you just need to do this repair and don’t feel like buying a whole thing of Resin-X you could just borrow some of mine. I’m in OB so pretty close. PM if that works for you.
C-Slug, Spackle is not a good filler for repairs for a number of reasons. I use pour foam filling big holes, voids, etc in eps because there’s no heating. On a typical delam, once you cut out the glass there’s a gap between the original glass and the foam. I normally laminate layers of cloth (to edge of the cut, 8 oz) until it’s level, then laminate a larger patch past the cut. Since you had melted foam, I recommend the pour foam. Also be aware that all epoxies are not the same, particularly those from hardware/boating stores. Some of these will melt eps just like acetone, so always test on scrap foam first.
On the finboxes, I’m seeing more and more of this (maybe because I’m now looking). The only solution I have for now is to glass-over the boxes as much as possible so that the lamination will try and hold everything in as the eps expands. I’ve suspected problems with expanding-contracting eps for some time looking at how stringers tend to become more pronounced after time. At first I thought that it was just foam compression (like poly’s), but it happens on the bottom more than the deck.
That’s a really kind offer, thanks. I’ll let you know. I don’t have any pour foam and I’ve heard it’s pretty tough to mix properly so I’ve always avoided it but I really don’t want to fix ANOTHER delam. What a bummer, you know. Spend all that time on a board and then it’s like it’s never done. Peace, C
I glassed over the boxes and installed glass ons. I didn’t like the quad setup to begin with. Then I noticed some separation along the boxes and that did it.
One more question: should I stop surfin the board until I can fix the delam?
You can get pour foam in SD from: AeroMarine Products, 4128 Napier St, SD 92110 (877) 342-8860. $28 for a quart which lasts a long time. Mixing is very easy, 1:1 by volume. You have about 45 sec. after mixing to pour it, but the foaming action will fill all the cavities from the melted foam. It sticks very well to anything just like gorilla glue (almost the same stuff). All surftech factory repair places use this as well as Eva the BoardLady. Please visit her site for a more detailed discussion on repairing eps delams.