I have only made a few eps/epoxy boards in the past (5), and there is one thing that has got me a bit confused. I keep getting inconsistent results from my epoxy resin when it kicks. I have been using the surf source SS 2000. I am always strict when it comes to my 2:1 ratio, and I always mix it well, and I always use clean mixing buckets & sticks. Sometimes it kicks as hard as a rock, and sometimes it kicks but not as hard as before (where you can push on the laminated board with your thumb and you can see it flex in a bit) and in some cases it won’t kick at all, it ends up like rubber cement. Lucky the rubber cement thing only happened once when doing some ding repair (what a pain in the ass). I have been looking around and can see that I am not the only one this is happening to. I’ve seen quite a few brand new epoxy boards (I’m not talking about the pop out epoxy sandwich constuction stuff, tuff lite, acme, etc.) in the shop with inconsistent hardnesses. You can sqeeze the rails and feel it give on some and not on others (same label, same basic shape). In my limited experience, it seems that it kicks harder in cooler temps, although that sucks because it takes hours to kick enough to continue working. Or is this inconsistency from crap resin? I want to make another eps/epoxy board in a few months and I want to try out your resin, hardner and additive F. I don’t want to end up with a mushy board. One more thing: if you use additive F when laminating, there is no need to skip sand your lamination before adding you sanding layer (hotcoat)? Do you have blanks in stock also, I typically like to get oversized blanks and cut some of the rocker out of them, but I can bring down a rocker template it you don’t stock blanks (I live in NSB). Thanks for any info.
I don’t generally like to discuss other peoples products but I will say this. In this area almost everyone was using, or at least trying, that product because it’s cheap. Now almost everyone has come back to our product. And yes, I did hear such things but I have no first hand knowlege that this is the case. You have more experience with that product than I do. As for blanks we accept custom rockers. Anything you want us to cut just bring it by.
I’ve used SurfSource epoxy 6 or 8 times now with excellent results. Its probably no coincidence that your worst problem with SurfSource epoxy came when you mixed only a small quantity. The SurfSource epoxy I have has extremely viscous resin and extremely thin hardener. For starters, thoroughly mixing liquids of such widely divergent viscosities is difficult, requiring lots of wiping and stirring… lots of opportunity for under-mixing, especially when mixing small quantities in relatively large containers. Next, as you said, mix ratios can be critical to epoxy setup. In the accepted sequence you add hardener to resin. You pour resin into a measuring container and dump it into your pail. The viscous epoxy resin thickly coats the measuring container as you pour the first quantity. Then you pour hardener into the measuring container, and dump it into your pail. Unless you clean your measuring container’s quantity of resin into your pail subsequent pours of hardener will only yield a portion of the required volume. If you use separate measuring containers for resin and hardener, failing to thoroughly empty the thick resin out of the measuring container will reverse the ratio error, resulting in too much hardener. Your mix ratio will be off, way off. For small epoxy volumes you might use a small flat measuring container, like a plastic spoon. The shape of such a device will accentuate the volume error caused by resin viscosity. Also, in small quantities, pouring the extremely runny hardener accurately can be almost impossible. Little splashes which represent only a 2% error in a 20 oz mix can represent a 20% error in a 2 oz mix. I’m saying you failed to mix thoroughly, or you got your mix ratios off.
I’ve been using resin research epoxy resin for about 20 years now…and I’ve try other resins and resin research has the best epoxy for surfboards AND AS FAR AS THE MIXING IF YOU MIX IT RIGHT 2-1 YOU WILL NEVER HAVE A PROBLEM…i’ve made over 5,000 epoxy boards…ET
Noodle may be right about divergent viscosities being a problem. We became aware of how important this issue was back in the production of our original formula 20 years ago. We found that decreasing the viscosity of the resin not only made it easier to get a thorough and correct mix but it also improved cloth wet out, adheision to the foam, lower resin ratios in the fabric and lighter finished board weight. Plus it made laminating a lot easier. And I’m pretty sure ET used some of our original 2 to 3 resin.
I bought a case of expired medical syringes that are precisely calibrated. I use these for measuring and haven’t had any problems with curing. Also, re: epoxy cure… I’ve read that cured epoxy softens when hot but if heated during the curing process, it has to get hotter before it gets soft. Epoxy cured at room temperature (or colder) doesn’t have to get very hot before it softens considerably.
Hi Mike, Long time no see. I use mid viscous epoxy for glassing and hotcoating in the summer. As what I have read from the web, it states epoxy turns into less viscous in hot temp, so I heat the resin (without hardener) for 5 minutes, the viscousity thereafter goes down, it makes the glassing job much more easy. The board turns into tack free within 4 hours. While glassing in the winter, it’s another story, I use a less viscousity resin. The problem just same as you have said, it kicks slowly, need one day or more to become tack free. Therefore I used plywood/eps foam to build an oven, using a 200 watt light bulb as the heating source, kept the temp between 30-33 degree C,baked the board for 6 hours. I find the oven is very helpful especially for the epoxy guy since the board takes few days to cure completely in room temp. Higher temp shortens the curing period. Besides, air entrapped in the less viscousity resin can escape easily. If you can’t get less visc resin, heat it before using it. I think your prob is the mixing ratio. When u pour the mid-high resin into the measure cup, then mix it in another container. Since the resin does not flow much, you may leave some resin in the measure cup, thus the ratio is not accurate. Regards, Crabie
There are mixing buckets available that you can pour both sides into and not have to have a bunch of mixing cups around that are inaccurate. We work straight out of those cups. They usually last about two or three batches of boards before we throw them out. They cost about 50 cents a peice. Heating resin can cause problems and does make for inconsistent results. Hot resin will cool rather rapidly when poured onto a cold blank. It will also bring the temperature of the blank up which can cause outgassing. Heat curing done on an uncured lamination can also cause outgassing from the foam. My best suggestion is to work in an area that is between 60 and 85 degrees. The cure speed of epoxy today, at least our, is much improved with the addition of our new faster curing hardener. This is available now and at 75º you can flip it in 3 hours. The softening John mentioned is a problem with epoxies that have low heat deflection temperatures. B staging can help increase HDT but instead we formulated ours to be quite high for a room temp. cure and have never seen that problem.
Thanks Greg, I have noticed the inconsistency of temp. What happen if I use a low viscous resin in glassing/hotcoating during the winter, then bake the board in the plywood oven? Since the 200w light bulb as the heating source, it gradually increase to 30-32 degree c, almost need 1 hour to achieve the temp. I m just a backstair builder and cant find a place with steady temp. Regards, Crabie
Good info Noodle. When I think about it, the problems I had with epoxy not setting hard was when I mixed small quantities. Thanks. regards, Håvard
You can buy papercups with volume marking in car paint shops up to the size of a good popcorn bucket. Greg, with your resin, are there no reason whatsoever to increase the temprature when a board cures? I’ve read that even the room temprature epoxies cure stronger at elevated tempratures. regards, Håvard
Every thermoset resin is improved by post curing. That includes polyester, epoxy and vinylester. Actually post curing urethane foam is very effective. The reason I don’t suggest using post cure more often is that it must be done correctly. The temperature must rise at the correct rate, it must be held for the correct amount of time and it must be the correct temperature at it’s peak. Most shops aren’t set up to do this correctly and because of this we have made our products so they don’t have to be post cured. That doesn’t mean they can’t be or that you won’t get a strength advantage if you do. On using an oven to help kick the resin initailly, I have seen this work but I prefer working in a room that is somewhat climate controlled. Keeping a small room between 60º and 85º isn’t that difficult and gives consistant quality results. If your going to heat cure B staging is the best way.
Thanks to all for the feedback. I use those mixing containers people use to mix gas and oil for two stroke engines (I just cut the top off of the container). It has all kinds of ratios on it and I add my resin and hardner to the container, mix and work from that. I think you might be right Noodle, my problem is probably with the variance in viscosity between the resin and hardner. That resin in certain temps is like melted plastic and the hardner is like water. I have seen guys use a mixer ( you know that thing you mix cake batter with ), to mix the batch up. It mixes it up but puts a lot of air in the batch. Thanks for the observations. Mr. Loehr, with additive F do I have to skip sand my lamination before putting down my sanding layer of resin? If so, what is the preferred method? I have heard of guys putting down extra layers of glass with the intention of sanding some of it off before hot coating or Buddah told me one time I could use a copper brush and soap & water to scuff the lamination. I have been using my DA sander with 100 grit paper?
Thanks to all for the feedback. I use those mixing containers people use to mix gas and oil for two stroke engines (I just cut the top off of the container). It has all kinds of ratios on it and I add my resin and hardner to the container, mix and work from that. I think you might be right Noodle, my problem is probably with the variance in viscosity between the resin and hardner. That resin in certain temps is like melted plastic and the hardner is like water. I have seen guys use a mixer ( you know that thing you mix cake batter with ), to mix the batch up. It mixes it up but puts a lot of air in the batch. Thanks for the observations. Mr. Loehr, with additive F do I have to skip sand my lamination before putting down my sanding layer of resin? If so, what is the preferred method? I have heard of guys putting down extra layers of glass with the intention of sanding some of it off before hot coating or Buddah told me one time I could use a copper brush and soap & water to scuff the lamination. I have been using my DA sander with 100 grit paper?
With Additive F it’s all up to you. You don’t have to sand between coats if you don’t want to. We usually do some sanding before hot coats so the finish is cleaner. Also hit the laps good so you can pop any bubbles there and then they fill with the hot coat. You guys are killing yourselves using products that make you work so much harder. WHY?