My shrinkage problem did not look anything like what is in your photo.
"if its the foam to blame, then why do these problems not show up on the same blanks glassed with polyester resin?
Because its the resin. The only one with problems with all resins was th Ice9 Cane blanks."
well to be fair neither are to be blamed as they are merely ingredients of a recipe and those ingredients work perfectly in any number of combinations
I suggest that its actually the chefs fault for serving a meal and not having the recipe quite right.
imo as we enter a new age of board building with a whole range of new materials available. its up to the board builder to thoroughly test his combos of materials before marketing
I have made boards of both in polyester and epoxy that have dimpled exactly as in the picture. The polyester board I still have because it was returned and the epoxy with RR dimpled when curing in the back of a black suburban, which served me well as an oven on many other occasions. Both boards were made from urethane blanks from different manufacturers. Stuff happens all the time, and it is never fun when it does. When it does everybody likes to blame someone else. I understand that part completely, for something like this can ruin one’s reputation, that one worked so hard to achieve. It seems to happen to people more when they are starting to build boards, than those who have been building boards for years.
That it happened to me using both polyester and epoxy resins seems to indicate, the problem is on the foam side. I say that empirically, from the data I collected first-hand using the same experienced operator in both part failures, so the information is absolute for me. If you think I am going to post pictures, that will never happen.
At times making surfboards has been, at least for me, trying to control so many variables that can go wrong. When things go wrong, a little bit of experience normally finds a way to cover it up. Nevertheless, sometimes I lose, and it sucks, and I end up eating it.
After all the BS, of which there is so much, none of it matters when I am squaring of the bottom of a good one and my board is doing exactly what it was made for. The next best thing is seeing someone else laying it down on one of my boards, and folks that is about all it is about.
an all this time i was thinking it was for the money!
btw u make a good point huie
well in my opinion its a mater of being able to sort the wheat from the chaff’’
here in aus we have 3 foam makers that have been serving the industry well for a long time
and dont seem to have these prblms
from my observation a certain company had american shapers by the knackers
his demise led to a lot of cowboys and for the first time you are seeing some real good foam (surfblanks america)
**attemps at copying it can lead to all sorts of prblms ( just my thoughts’')
**
Now THAT’S pretty clear. Got it! Along with the problems come the benefits. In the US., even here in Cal. it is easier than ever to get blanks and all types of supplies. Never had that in “the cocoon”.
so it seems that multiple people on here have had shrinking problems with epoxy on various brands of PU blanks using Resin Research epoxy..... curious - has anyone seen these same problems using a different brand of epoxy on PU?
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so it seems that multiple people on here have had shrinking problems with epoxy on various brands of PU blanks using Resin Research epoxy..... curious - has anyone seen these same problems using a different brand of epoxy on PU?
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Ahhhh, yes Grasshoppa! Happened to a couple of boards I made about 8 or 9 years ago. Both Clark superblues, both glassed with Surf Source epoxy. It didn't happen right away, maybe a year and a half to two years, but both boards shrank considerably between the stringer and the bottom laps. Both boards spent lots of time in the back of pickups and both had solid color airbrush, one red and one blue. It didn't happen to the deckside, just the bottom, so I attributed it to sunlight and the owners not taking proper care of their sticks. I had no complaints from either guy as both boards lasted so long before it happened.
Grasshopper, i see some boards with this problem here in France. I don’t know wich PU foam it was but it wasn’t RR (no sell here at this time). I also see old Bufo boards when they were made with stingerless PU from surf foam (french brand of PU) vacum bag with there own german resin: dented like a golf ball ! But all boards were old and still surfable.
I do some compare test with PU (from south africa) and french EPS 1,5# industrial grade. PU is heavier, stronger: more weight before snap on flex test, less dent with same weight pressure test, and a bit more double stiffer. EPS max elongation before breaking is near the double, EPS return on pressure test: sponge effect.
I also do this test with 0,75#, 1#, 2#, 2,75# EPS, building and industrial grade. More EPS is heavier more it’s like PU for mecanical tests.
Sorry for my frenglish.
**
I like RR - I use it all the time
I also like US blanks - use them all them time
They both make great products. I dont use them together however. Greg says that using the 'blue' RR will eliminate these problems.......I still havent tried it.....use UV inhibitor, put a polyester gloss coat on it, etc......lots of solutions.......still funky results are showing up, not worth it
Surfblanks makes a great product also - I shaped one up when I had some time in Aust. - light & strong - good stuff - would like to get my hands on some of it over here....
so it seems that multiple people on here have had shrinking problems
with epoxy on various brands of PU blanks using Resin Research
epoxy…
this is the point i have tred to make puting all urathane in the one box just shows a lack of understanding?
well when clark was still going strong, RR was being pushed heavily on this site to use with Clark blanks for a superior product. So giving it a whirl, boards turned out great but 6 months to a year down the road - shrinking problems. after talking with greg on this site, after all the hyping up, it became apparent that there were shrinking problems with the lighter density blanks and you needed to have an extra additive (UV inhibitor) added to the resin or you eventually get the shrinking problems with the heavier density blanks also.
so i have had my share of pu/epoxy boards shrivel up over time. others on this site have apparently had similar experience with multiple brands of pu foam and epoxy resin. great that you have found a combo that works. i agree surfblanks makes a great product. but so does US - if you glass em with polyester, they can last a really long time and do not shrivel up! but i am hesitant to glass em with epoxy - maybe the new blue RR will do the trick? others claim they have used this type of PU with epoxy and additives and other tricks to great success. apparently the surfblanks and epoxy is a combo that works together also. i havent tried those combinations. my experience was with clark and clear RR. they shriveled so after that i have done PU with PE and EPS with Epoxy. i am weary to trust the new latest and greatest will solve all the problems after hearing the hype before the true results were shown once before. I will probably give them a go with some personal boards at some point and let you know how it works out.
of course not all pu blanks are the same just as not all epoxys are the same not all eps is the same. i dont know why you keep blaming the foam - the foam from my expierence is good foam - works great with polyester - no problems there. the epoxy is also great - works awesome with eps. its does not appear to be the foam or the resin at fault but the combination of the two.
Maybe I got lucky, but I’ve done U S Blanks red with epoxy, and no problems other than the blank tearing a little more than I’d like when planing.
Difference in epoxy vs. polyester is the polyester gets pressure dings, and stress fractures, where epoxy dents with no glass shattering or fracturing. Could it be Surfdings overshaping theory?
I have seen epoxy wrinkle if oversanded with dull paper, and too much pressure - result of too much heat build up.
So the trade off is shrinking with epoxy or crushing and glass fractures from polyester.
Certain places on the blank have not reacted properly in one way or another and are reacting to one of the chemicals in epoxy. This is also a problem with ResinX as well I believe which is why it is not recommended for use with foam from certain PU manufacturers?
It’s pretty simple. Certain parts of the blank react, other parts don’t. If it was epoxy the whole blank would react. It’s not the sun as I have had this happen to boards that haven’t even seen the light of day. That leaves the foam as the culprit.
Perhaps a better idea would be to list which PU manufacturers people have had this issue with? Mine is South Coast. Never had this issue with Bennetts.
huie - thanks for the insight. there may be some misunderstanding but trying to figure things out with help from others on this site. apparently my problems were due to a missing ingredient (UV inhibitor). But to me, if it was known the foam/resin combo being pushed needed an extra component, why would it not be included in the product???? I think it was being pushed first and tested second. that experience makes it hard for me to put much stock in the shiny new 'cure all' package until it has been out there for a while. hoping to let others be the guinea pigs this time........still keeping an ear to the ground
Certain parts of the blank react, other parts don't. It's not the sun as I have had this happen to boards that haven't even seen the light of day.
i dont think this is the same problem that is being discussed here. soft spots as you describe are the foam problem and can happen without even glassing them. but the shriveling of a blank glassed with epoxy is evident on the WHOLE board and it happens over time in the sun and heat. this is with a blank that would be perfectly stable unglassed or glassed with polyester resin.