.....'core mat' [or whatever other name[s] it goes by worldwide !]
have [m]any of you guys you used it ?
i like the look of the Futures and the FCS ones i've seen , some have a 'foam-core-like' appearance ...
so , of course , i'm keen to buy this stuff ......and have a go at making some !!
the american , Will, at my local supplies place said it's good , because 'it can be dyed , tinted, pigmented , sprayed' ....so , there 'should' be some interesting effects available , i reckon ! [i'm thinking the one posted above was a tint job]
anyway, i eagerly await people's practical feedback / experiences of using this material....
Hi Chip, they are referred to as RTM (resin transfer molding). In most cases it is a molding process that involves the use of an insert (coremat in the picture above) which can be many different things. Fiberglass is placed into the mold, then your insert, then more glass. There is an injection port where resin is fed into the mold, and then it is usually pressurized or vacuumed to remove all of the bubbles. Once the mold is re-opened and the fin pops out..you'll have a flashing that can be quckly sanded off and you have your fin. The resin can be tinted or opaqued. This process is difficult to do consistently and requires skill and knowledge of the mold and molding process. The end result is a molded fiberglass fin, that is usually lighter than a traditional hand lay-up depending on how thick your insert is (which takes the place of x amount of glass and resin that would be in it's place otherwise). The big benefits are obviously weight, and of course you get a consistent foil shape over and over and basically eliminate the foiling process which cuts down on waste since your not foiling away layers and layers of glass and resin. The only people that I know of doing any production with this process outside of china is Greg Trotter at Soar fins in Terrigal NSW and Probox Larry at Fibreglass fin co. with the Aerocor fins. As mentioned it's a tricky process especially when it comes to getting out all of the bubbles so they are often opaqued or painted to hide them. The chinese have the process pretty dialed and do most of their production with tinted resin where you see the insert clearly. The better factories there do them with little to no visible bubbles. I am not completely knowledgeable on the process so that's the best I can explain it. Maybe Larry will chime in and correct me if I've explained anything wrong. Cheers Jim
thanks for the feedback , Jim ! good to hear from you mate ! [ I read your comments on fins in the Surfers Journal article with interest , too !!]
'Probox Larry' , and others ...do you have anything else to add , please ??
I'll hand lay up mine , but hopefully , 'should' be able to cut down on at least HALF the layers of fibreglass cloth , so as you say , less wastage in terms of foiling away excess layers
yes , knowaloha , i've tried foam core too , i'll give it a go again , i'm sure [i had a problem with the tab snapping on the one set of sideys i made ....]
well, been a while between drinks , on THIS thread , at least , anyway ! [ I'll post it here , instead , as I couldn't find my original "thanks huie !" thread ..."search" ? .... gone wrong ! :(
Here, finally , is the result of using the coremat / 'soric' , that 'Huie' sent me a while ago .
I put two layers of [clear] 4oz down , then the 'soric' , then about ? 28 ? more [these ones were ] red tinted layers of 4oz , in the end . I was wanting to make two side fins out of it . To match three commercial glass-on fins , that I had found on a thrown away snapped board , last winter here [august ...in west oz !] . THANKS , to whoever throws their board away , with fins still attached ! [.... yewwww ! I SCORED !! :) ]
Anyway , here are some photos .....
alongside one of the three re-tabbed glassons I found ...
in the walden ...
I think that I may need to seal the edges [and base ] , where the cutting and foiling exposed the 'soric' ...I'm hoping just a brush on of resin [?gloss coat ?] could suffice ?
I’ve been doing hand layups with coremat. There are some cool bits to working with it, an some pains in the ass.
Yes you can reduce the number of layers of fiberglass, but with the 2mm coremat I have worked with it’s no where close to half. You don’t want to jump into the 4mm stuff since it will start poking out when you’re foiling.
Air bubbles at the edge of the coremat are a pain in the ass. I just laid up a fin using roving at the edge of the coremat to help that and it worked. Although the woven roving that I pulled my roving from is pretty stiff and kind of tricky to get to stick when I wanted, although it completley solved the air bubbles. Might try the next ones with layering tiny strips of 6oz fabric at the edge.
Visually (looking at the contour of the layers) hand foiling your “top side” (the side of the fin that was not on the glass panel during layup) can be tricky. This is because how the coremat creates a “lump” in the panel, with the FB layering over it. Have yet to foil the fin with the roving at the edge and but hopin the smoother “lump” helps somewhat.
4… The coremat creates a stiffer fin than just a pure fiberglass layup. Once I’ve mastered hand laying up it I want to try puttin selective patches of it in.
Can I feel the difference in the coremat versus plain fiberglass? Definitely since the coremat provides a lot less flex. What I want to try is how much flex difference you’d get in orrienting all of your cloth layers in the same direction versus alternating the angle every layer.
Do you have any photos of the finished fins , please ? I’d be keen to see other homemade 'coremat ’ / ?“soric”? fins …
The stuff I bought was like blotting paper thickness. Inlaying two layers , it was pretty THICK, and soaked up a LOT of resin , to laminate it fully. Whereas , the "soric’’ , that ‘Huie’ sent , was thinner and easier to work with and , from memory , I inlaid only ONE layer in the panel.
The stuff I have is 2mm. I know they make the soric and some coremat in everything from 1mm to 10mm. I might get pictures tonight as school hasn’t given me much time to toil over foiling fins.
But here is my first experiment layed up. All of them but the bottom right corner are 10 layers deep with 10 layers bellow the coremat. The bottom right is 15 layers deep with 5 layers below it.
it was made with 8 layers of fiberglass and coremat honeycomp,
i don’t like this construction because there are no enough force with the deslamination , that’s why i’m gonna try rtm to obtain a low level of deslamination between layers, and reduce the micro air bubbles arround the coremat
sientistblank, i will try tyo put a thin strip ob 6Oz in front of the coremat to reduce the bubbles this weekend, i will inform you of my progress.
i like this forum because there are a lot of knowledge about this
All of them but the bottom right corner are 10 layers deep with 10 layers bellow the coremat. The bottom right is 15 layers deep with 5 layers below it.