I just had a really strange “snapping” of my board on the second day. As this is my 7. board and it happened so fast it must have been a mistake in glassing, cause the wave won’t snap a board, only the rocks and there isno proof for hitting a rock on the whole board.
It’s XPS foam, 2 x 6 oz top and bottom glassed with epoxy, so pretty strong for a 5’5. Glassing temperature was fine and the curetimes like on all my other boards. I’m mixing with a digital kitchen scale and a calculator so mixing ratio should also be fine. The line that you can see is glueline that I made to glue the two foam parts together.
The bottom and foam isn’t damaged and in the middle of the rail the breakage line stops.
I surfed the whole day with it and it didn’t get worse. I think I’ll cut out the broken part and reglass it.
Have you seen this and perhaps know what I’ve done wrong?
Im guessing that the flex point just in front of your front foot
caused delam crease (typical with that type of foam) and in turn kind of
got a flexing whiplash affect from the wave which first slacked the top
to loosen the lam, and then flexed the other way, causing a sudden
tightening of the glass in that area.
Ive seen the same thing on
boards that come in for repair that have started with a top crease that
is not really visible to the naked eye without really looking close and 9
times out of 10, it snaps there. Sounds like you just had bad luck on
that one.
This is just my best educated guess based on not being
able to see the board in my hands. Be careful when using that foam. (it
looks to be that blue type?) it didn’t work in the 50s and now is
no different I’m sure. (remember, the definition of insanity is to do the
same thing over and over, but expect different results LOL) That foam is notorious for off-gassing and it usually spreads along the surface between the foam and lam layer.
That's what you called a buckle. Next time put a stringer in it or use more glass. Pretty simple. or maybe it was because:
What's up with the foam glue up going wrong way? Don't tell me it was a homemade blank??
Next time buy a good blank, glass it up the same way, and it probably won't break..i say probably, because they all break.
I don't mean to be completely rude...So I'll just be kind of rude. it looks like your glassing skills are something to be desired. I see lots of dry patches and strange areas. next time do a more solid glass job and your problems will be minimized.
No I’m serious resinhead, this is my 7th board with homemade XPS blanks, the first one that causes trouble and I won’t ever buy a traditional blank. I’m riversurfing, so my boards allways hit stone walls and I would have to repair after every 2-3 sessions. So I use XPS and don’t care about small dings.
I guess your dry spots are the ones on the second picture? Thats not “glassing skill” that was the stone wall scratching off the hotcoat and damaging the weave a bit. But yes I’m sure my glassing is really bad compared to the most guys here and I’m pretty sure I messed up glassing to cause this problem, but what is the question?
Well I’m already glassing 2 x 6 oz on top and bottom… Doing more would be too much.
salty the gasing out sounds possible, but I thought this wouldn’t happen with Extruded closed-cell polystyrene foam? Only when its open-celled?
You’ve got a lot of glass on that one, but I think a stringer would be helpful on the next one. It sounds like you are in some extreme conditions. Sounds like fun conditions, but I’m sure you must plan for repairs. Anyway, I’ve found good stringer material fairly cheap at home depot. I would suggest redwood. This advice since you are making your own blanks.
Another option would be making a timberflex board. I’ve heard those are very hard to buckle. You’ve already made 7; why not 8?
Fix this one of course, and ride the thing into the ground first.
Yes timber flex is the way to go. Also, any ding on the rail will give the board a point of failure. Guys always say...why did my board buckle. well any rail ding will be the weak link in the rail strength. Presure on a clean railed board will distribute presure through the entire board. A ding rail will be the weak spot, and the focal point of faliure. This also goes for sketchy glass jobs, or sand throught.
Keep your rails ding free, or patched.
Also...River surfing. I think you forgot to mention that in the initial post. WTF, river surfing. Heck I'd probably double the glass you got going on there?
Parick, use diolen between glass layers, it’ll give you tougness for low price. It’s what they use for low price fiber kayak. If you have more money use kevlar (vacuum bagging) even better impact resistance. I do a deck with 2oz kevlar under 1,5 balsa and 4oz Sglass over on 2lb EPS, absolutly no ding or foot prints after 1 year of surf, we can hit it with a rubber hammer it’s do nothing !.
Yes,there
is potential for off gasing in both types of foam epoxy combo, but with
eps, a vent can be added Android the gas can build up throuout evenly.
Now with xps, being closed cell, gasses have nowhere to go but the layer
between the glass and the foam, pushing them appart. This, coupled with
the fact that xps wont soak in any resin, it is even easier for lam to
peel away.
Here is what i recomend, in my humble opinion;
1 add some sort of stringer or wood venere bottom.
2 make sure you leave shaped blank with deepish sanding lines in the liniar direction to add bite for glass. ( I say liniar because its purely asthetics. of course, bi-directional would be better but?)
3 experiment with scraps to find the best bond
With no expert in this area, so if anyone out there can chime in on the
subject, it would be great. I just know from my experience to steer
clear of certain combonations of materials, however, Im a huge fan of
experimentation. Just do it with scraps first, and not with time
invested projects.
I break alot of boards and your buckle looks like it failed and didn’t flex the same around your glue line. ----The pressure built up around the glueline. Butting two pieces of foam strait together is a bad idea try angling your seams. And sometimes stuff just happens but stringers-skins help–wood is good.
Today I cut out the broken part and reglassed it. In the middle of the board it looked like the resin didn’t really stick to the blank.
@lemat I’ve played around with carbon and kevlar a bit, also made one board with this rails and I think I’ll go on testing it if I can’t figure out how to fix my problem.
@salty I wanna go on with stringerless boards and tryingto solve the problem. But if the next board also fails I’ll try a stringer.
I also did some research and perhaps scratching up the blank can help me a lot. I think this blank was the first one I finished with 200# sand paper and the ones before were only done with 60#. I’ll try the bi-directional scratches, asthetic isn’t a point for my own boards, the just have to be solid and be fast.
Next week will be testing time with some scratches.
@lavarat Your way of glueing the pieces together looks way better than mine. I’ll also give it a try. After thinking about straight is really the worst idea for flex.
Thx, you are allways a good inspiration.Shaping and surfing without swaylocks would never be the fun I have at the moment.
200 grit is way too high! I have rarely heard of going over 80 in most cases in poly blanks. although I give a once over with 15o grit on a foam pad to blend everything at the end of my shaping, I also know that the resin soakes into the poly blank for a good bite.
you should never go over 60grit on that foam in my opinion.
Stingerless is fine most times, and I have made many that way, but I use EPS, seal it and usually either a carbon or carbon/Kevlar hybrid cloth, or wood veneer on the bottom to get a nice spring and flex pattern to the board. Otherwise, it feels mushy and lifeless. Of course, I dont know if it matters on river waves, but I think it would. Of course, if you go the wood route, you should use a vacuum to adhere the layer on the blank before glassing. I also install vent just in case. mainly for piece of mind or if its in a hot car or traveling by plane etc. Also, if the vent is near the tail it can be used to drain off water, should i punch a hole in it for some reason. (yet to do that! lol knock on wood)
Im trying to upload a schematic I did for you, but it gets marked as spam by the Swaylock uploader for some reason. Maybe I can email it when I get a chance
LOL) That foam is notorious for off-gassing and it usually spreads along the surface between the foam and lam layer.
