No fully cure epoxy is still skin sensitive. Only full cure epoxy should be sand. Post curing increase hardness and elongation to break of most epoxy resin. With all epoxy i go 12h at 45C before sanding.
Of course, but there are exceptions, like laps, and touchup of sand throughs.
One of my fondest memories is Greg pulling up to our factory in Atlantic Beach Fla.He would be driving this huge Dodge Power Wagon with 40 blanks crammed in it.He looked like a wildman.This was around 72’ or so.
Most of you know him as the epoxy guy but he was power shaping really sweet PU boards when Natural Art was king of the world.
Lemat, Dwight, I’m a big fan of both of you and I know it is hard not to jump in on these questions but if this is going to succeed, we need to let the guest answer the questions. Thanks for your understanding.
Hi Greg,
If you were glassing a dozen short boards a year for yourself and friends, I’m wondering what fibres you think would be the best at the current time?
Foam most often used being USblanks PU foam with a stringer (red or blue), which is what is available where we get them cut.
Kwik Kick resin.
Currently using a mixture of S glass and E glass, but keep looking and reading about all the alternatives.
Thinkin’ Mr. Loehr is in transit so don’t load him up too much, HA
Hi Surfteach. I’m a bit out of the loop on bead stock. Nova made the best about 10 years ago which still may be the case but don’t ask me what product number, it’s been a long time. As for block I use White Hot from ProWall which is right up the road here in AZ. I’ve heard that the place in Kingman also makes good stuff. The foam in CA has urban blowing agent emission restrictions on it so it’s not that good for boards. FL we use Imperial or Carpenter.
Hi G Daddy, sounds like your moving ahead with the bagging nicely. I do like Innegra between layers of fabric which has always seemed ideal. As for higher modulus patches that’s something that one of my board building mentors, Ted James of Fox Surfboards, used to swear by. I saw the results and I have to agree with what I saw. Couple of things about high modulus though, using it throughout the board can cause the laminate to be brittle which can cause failures. I’ve seen this in some of our earlier formulations. Also the modulus should follow the choice of fabric, high modulus fabric goes with high modulus resin, medium modulus fabric goes with a more medium modulus fabric and so on. And your suggestion of bi axial can be used to advantage as well. One other aspect is resin ratio, lower resin ration allows you to use a higher modulus resin because with more fabric content you are effectively lowering elongation.
A few out here are trying for optimum performance in crappie surf. So at the moment and I speak for myself only. Combinations of rocker, shape and the current “flat tucked edge” bottom is where we are at. So Cal.
Considering your FLA experience I humbly ask your take on bottoms that work in lesser conditions.
Mahalo
For the last year and a half we have produced high bio content resins, about 40%. When we looked at existing bio content resins most contained a percentage of epoxidized oils, tall oil mostly. These resins are characterized with low physical strength and quite low Tg. My opinion is that making a lower strength product in order to be “green” in not really “green.” So we were on the hunt for a better way which we found by using a glycerine based, bio deisel derivative, ECH in our chemistry. Using this method left us with exactly the same physicals as we’ve always had. Unfortunately after almost two years of production a very large European paint concern, Anzo Nobel, bought our suppliers entire production and we were phased out. So we went on the hunt for a new supplier and at this time we haven’t found one for our North American production. Our China facility is up and running with a replacement which gives us about 50% coverage. At this point well just continue to search until something comes online, it will and well once again be able to produce bio resins the right way.
Hi Barry, The new Ultra additive is an optical brightener that we can include in any of our resins. It is quite a bit brighter than anything we’ve made previously which seems to be a trend that some builders are following. It certainly makes brighter boards that any other brightening method. It also holds up very well lasting at least 300 hours in direct sunlight. This was a lot of work for something entirely cosmetic which suddenly seemd to have fallen on the shoulders of material suppliers. Oh well. As for post cure, the can have incredible result but unfortunately we are limited there by what our foam will take. But here’s a cool way of figuring post cure. Room temp epoxies cure in one week at 77F. Every 10F added cuts cure by 1/2. So 87 is 3.5 days, 97 1.75 days, 107 20 hours, 117 is 12 hours 127 is 5 hours, 137 is 2.5 hours and 147 is 1.25 hours. You can stop there because the foam won’t take any more. When you get above the 127 level your going to begin to see a much different animal than RT cure. Cross link density improves significantly so that your modulus and elongation both go up. To do this takes some equipment and some tests to get it exactly dialed in. To get an idea of what this is like wrap a piece of wet cloth around a soda can and heat at 150 for an hour or so. Then do one at room temp for a week. Demold each and compare.
Hi Dwight, a lot depends on the epoxy your using. It can also depend also on how chemical sensitive you are. And certainly a full cure will reduce the chemicals available that can cause some reaction. The chemicals don’t disappear from the epoxy they instead react within the chemistry instead of relating to your skin. Fully reacted resin is inert. But it takes a week at room temperature to achieve full cure. Before that there is still reactivity going on. All epoxies are not equal when it comes to sensitizing skin. Some may cause very significant problems, some cause almost none. I designed ours for me and my crew. It was very important to me to have the safest thing I could get.
Awhile back I ruffled some feathers when I said that working with Resin Research Kwik Kick in extreme heat (over 100 degrees f) I cut back a little on hardener, got a lecture about exact ratios, weakening the mix, etc. So is that a real no-no? I didn’t experience any strength issues that I noticed, but wanted to hear it from the source.
Hi Everysurfer, we have a low viscosity system, the Composite Pro System. It primarily for infusion, fabric intensive composites and fabrics that are difficult to wet. Look at our website resinresearch.net under composite pro. 2070 is probably where to start.
I don’t like doing that Huck, it does make the board yellow faster. Instead, laminate a side in two batches. Mix the first batch and do the stringer to one rail, finish that, mix the second batch and do the other side. No one ever did this in the polyester days because it didn’t work well but with epoxy this works great. I do 12 foot SUP’s in summer in Arizona no problem.
Cleanliness, I have fond memories of those good ole days too. Things were much simpler back then. Waves were better too.
Hoo-hoo, glad I asked, thanks!
Awhile back someone gave a tip for avoiding fish eyes on hot coat, thin cheater coat then apply the full hot coat when the cheater coat gels - haven’t had a chance to test it, is this a valid process in your opinion?
BTW, had a fun day of Golf with Ed Angulo, Steve Walden and Don Bowers today. At the 19th hole after a few beers we figured that together we had a total of 186 years of shaping experience. Damn we’re old.
You know, I’ve never really had fish eyes and could never figure what people were doing to get them, especially since Additive F. Then I found it. I buzz the laminate with some 100 or 80, then wipe off the dust with a paper towel or old t shirt and the hot coat the thing making sure you brush it out enough times to make it flow. That’s all there is to it. It’s the brushing that does the trick.
Newbie type question(s), if that’s OK?
With all your experience and knowledge, what tips or tricks would you give to someone moving from PE glassing to Epoxy?
What would you recommend for an inexperienced “backyarder” - Epoxy over PU or Epxoy over EPS / XPS?
Thanks for your time.