Delamination Repair

I was wondering if anyone out there has tried to do a delam repair by simply drilling a few holes through the delam area and injecting resin. Then adding a "poor-man's" vacuum bag system of sand in trash bags to hold the delams down while the epoxy cures?

I have seen several posts about cutting out the delam area and adding new fiberglass etc.

But I also read somewhere (can't find the link now) about doing this epoxy injection and was just curious if anyone has tried it?

I've done something similar, except I slit the delam'ed 'glass and then peeled it back to expoxy it. I used a very thin epoxy - RR heated so that I could pour it under and let it run in as far as it would go.

Covered it with a black plastic garbage bag and buried it in a sand box I've seen surf repair shops along the beach dig a hole in the sand and bury the board to apply equal/even pressure.

I'm not sure about the injection, maybe if you got the epoxy hot and then shot it through a hypodermic needle or something similar?

I was also thinking of the 5 minute epoxy injection pens you can get at local hardware supply stores. the two parts of the epoxy are each in their own chamber. then there is a special needle you put on that mixes the epoxy as you inject...

Did your repair last?

The delam did stay together well. I had to filet it a bit to lay flat. It seemed the 'glass stretched or something and wouldn't lay smooth without some surgery. Then I painted the area to cover it up, lasted several seasons without issue. I did use RR and heated it so that it would flow easily. I really flooded the area pretty well. Not sure how it would work with the injection methodology.

i cut my delam off then brushed r/r on the foam then bagged it after that i just hot coated the area and its working fine , i got my g/friend to get some I/V needles 20 gauge from her work to use to inject air pockets on a board but i have not done so yet. i will probably predrill the board then inject it.

So I did the drill and inject method. My fix is not complete yet, but here are some photos.

My main issue was the main delam was pretty long, maybe 18 inches or so. After injecting (what seemed like a lot of epoxy) and putting on the sand bags, the sand bags just mad a wavy surface. With some more epoxy over the waves and some sanding I have it pretty smooth now.

If I were to do it over again I would have used 2" strips of 1/4 plywood instead of just a straight bag of sand. the wood would flex to match the board, and it would prevent the waves I ended up with...

I haven't taken it out for a ride yet as I am also replacing a set of probox boxes at the same time (post coming later on that one...)

First off the necessary supplies... Beer and a syringe


I had 4 total delams or blisters. Here are 2 side by side about the size of a silver dollar

Next was the big blister... in this picture it is difficult to get a feel for the size. there was a main blister that stuck up quite a ways, then further out from that you can feel that the fiberglass had pulled away from the foam...


In this picture you can see 3 of the blisters with the holes drilled. You can see the 2 small ones in the bottom of the pic, and the one big one at the top


Finally I weighed the entire thing down. Two 50lbs sand bags over the big blister, plust a crate of cast-iron cookware. On the two side by side I put One 50lbs bag of sand and 2 1/4" pieces of birch plywood. finally in the rear I just did some clamps and wood to fix that small delam.

Troy,
my board was black on the top deck and it delamed , so no more dark colors for me.

yea no more dark colors here either... need to head to the local fiberglass place today for a vent...

I forgot a pic of filling the big blister... you can see the syringe doing the fill, and epoxy coming out of the other hole at the same time...

Hey Troy,

Refresh my memory. Did you use EPS or XPS on that build? Was it Dow Blue or a generic white? If it was the white EPS, what density?

I did a quick check of your build thread and you used Dow Blue which is an XPS foam.



XPS has some significant issues when used for surfboard construction. The problem with extruded polystyrene is delamination. When XPS is manufactured a significant amount of blowing agent is trapped in the cells during production. Blowing agent expands under heat. That's what makes the production process work. The cells are created with blowing agent inside, then heated so that the foam expands into a shape/mold.

Compare that with EPS where 95% of the blowing agent is lost during the pre-expansion process. Then 95% of what's left of that 5% is lost in the molding or press cycle.

With urethane the chemicals are being changed during the polymerization process and you end up with only CO2 left in the cells. But with XPS the cells are left filled with blowing agent gases. When these cells are damaged, and the gas released is then heated, a delamination or bubble forms under the glass.

Further most XPS foams are copolymerized with polyethylene which NOTHING sticks to. This makes the delamination problem even worse.

I hate to discourage your repair, but even changing the color from dark to light or installing a vent (XPS is a closed cell foam) won't completely prevent future delaminations.

yep Styrofoam is bad, EPS polystzrene is good

Thank you for the feedback there. I figured this was the case, and I planned on sticking to riding this board in the mornings only when the sun isn't so hot

The reason I went this route to begin with was to learn. I have learned a lot, even at how to fix delams

Next board will be with a real surfboard blank.

Also black accumulate heat and help to melt wax etc.

There is some board from Channel Island I guess which i black but change its color with temperature towards white

I checked the heat level of my black board against my white one and the black was 30 degrees hotter after less then 10 min. in the sun.

Interesting