If I was to cover a deck of an 8’6" mal with a patterned cotton cloth under the glass laminate, any idea on how much extra epoxy resin it would use and would I gain any strength from the cotton fabric?
just weigh the fabric … as a general rule itll soak 6 times it weight in resin … it does add strength , the best way to get strength out of it is sandwich it between 2 layers …
its not as strong as glass , so the sandwich helps get the most out of it …
you could turn a 6x6 oz deck into a 4x fabric x 4 oz , would get similar results weight and strength wise …you can just put it underneath everything as the bottom layer but because it wont have as good a tensile strength, youll lose a tad of overall strength , but its easier to work , all the loose strands are a nightmare , so depending on what your chasing cosmetics or strength , if its cosmetics then do a tape up , put the fabric down first , let it gel off and blade to trim , then glass over it , you wont have any strand drama …
hey mike !! have you got a digital camera ???
i was gonna do a thread on sandwich construction , but coz there is a number of ways of achieving similar things , i was wondering if you may contribute as well coz i know you do slightly different techniques at the rails …
regards
BERT
Thanks Bert …like your drag car! yep I do have a digital camera Ive tied a few different ways for rails from using a solid end grain similar to the way you do rails to wrapping a various kinds of sandwhich materials around the rails. Let me know what sort of pics you want.
Back to the material I was going to do it for cosmetic reasons and was hoping to get some strength out of the extra weight of the resin and cloth, 6 x is a lot of resin I was thinking of bagging it with the glass and trying to get a 1 to 1 ratio. I can see by sandwiching it I’ll gain the strength of it’s thickness in the sandwich, Just wondered percentage wise how it would compare on its own as a laminate as compared to a glass laminate in stiffness and compression.
Bert,wow, I always new that cotton/polyester used a lot of resin, but that’s a lot of extra weight! I quit using 2 layers of glass over fabric, substituting the fabric as one layer of glass. It doesn’t shatter and is more flexible than glass, I don’t remember the boards denting worse than others?
yea jim , i suppose it does depend on the weight of the fabric , if a customer goes and gets his own fabric , i always ask them to get fine cotton or rayon …
i once had a customer bring me this real heavy fabric , i reckon coarse hessian would have sucked less resin …
hey mike the fabric does work as a laminate as glass would in a bag set up , ive got one order at the moment , for a pvc board , using fabric top and bottom to hide it , combined with a balsa /cedar rail laminate …
i find by itself on the outside it works , as long as you dont hit it with the sander , most times i have minimum at least a 2 oz over the top as a buffer zone …
i personally reckon cotton doesnt have quite the same strength as its equivilent weight in glass , but like jim said it doesnt shatter as easy is more flexible , but can rip easier when really loaded …
it does get stronger with less resin …
i know that sounds like a paradox , but any brittleness to the laminate and the failure of the resin will initiate the fabric to tear , so using a vac will get better results because you give the job more overall flex with lower resin content …
jim! would you normally use fabric then 1 layer of 6oz ???
when bluejuice asked the question , i presumed he was talking about the deck?
in experiments ive done …
epoxy in combination with keritin based fibres is the strongest , and cellulose fabrics come a close second …
the price is quite reasonable as well in comparison to fibreglass…
regards
BERT
I used 6 & 7.5 in single layers over fabric and I have seen some great prints, but it was like they were upolstery fabric and would have sucked up gallons of resin. Greg Loher was talking to me about using percale bed sheets to laminate with epoxy as a non fiberglass alternative
my very first board was done with an old cotton bed sheet when i was 12 …
it did work , but my glassing skills werent developed yet and i left it floating on the resin , it ended up cracking in most of the places where the resin was more pooled …
i keep saying i want to do a whole board with no fibreglass , but somehow i never seem to go through with it and always end up using a combo of both …
the biggest drama is hitting the weave , i think thats why i always at least do a 2oz over …
jim!! have you got a digital camera ???
ive heard various glowing comments about your work , i read about shell fins and inlays , the first thing that came to mind was , wow this guy must be a real artist …
id like to see some of your work …
regards
BERT
Well, an industrial artist, I am not what one would call a portrait artist, but I did have an art scholarship to the to the University of Hawaii, but my dad deemed it to far from them “if something happened” and back the a man wasn’t a man until 21 years of age. Cleanlines can attest to the authority my old man carried!
I try to look at what can go wrong first, then go about it in the most scientific/intelligent manner to come out with the desired results, that combined with the luck of the draw on having been in the right places at the right time. Not to say I haven’t been bit on the ass many times! We supposidly learn by our mistakes and have I ever made mine. Cleanlines and I were bannished from anything more than the front desk of Inter-Island and Surfboards Hawaii, we wanted to see/know the how’s, why’s of surfboard building, but in 62’-63’ factories didn’t let anyone into the inner sanctum to view the secret society of the surfboard craftsman. With that, we learned from trial and error, lots of error, had our noses rubbed in it by our peers. It’s like being picked on by the bully, eventually you stand on your own two feet and fight back with a vengance. My fight was to learn how to build boards that if picked up by the “pros”, would be marveled at.
Being 15-16 years old, with no money, no car, little experience, resourcefullness was our only tool. I had started gluing up my own blanks and one day while dump diving at the Hickam AFB landfill, I found the packing crate from helicopter blades, it was 1x8" by ? western cedar, but it was shy of the length for a stringer, I did a shiplap joint on it and soon the school had cartoons of that board with shiplaps all over the stringer very visible in the drawings and being offered in a drawing of a fictitional surf movie. Sort of a laughing stock of the school. Well the laughers are fat, dead, don’t surf or own surfboards anymore, but Cleanlines and I are still plugging away, as broke as surfboard craftsmen can be, but I love what I do and still try to make everyone like it was my very own. Oh I bought a new scanner, but the damn thing won’t install! So pics are still on hold
I will be using the cloth to cover the ugly colour of the divinycell, I bought some samples of materials and have laminated them today I noticed the whites became clearer and the dark colours became darker. I also sprayed white primer on half the divinycell before laminating as part of my experiment that I’ll be pulling apart in a few days. I hear we may be able to get hold of corecell here in WA, It’s cream in colour so should be easier to disguise with material.
here check out these pics of a board that came in recently for repair …
its from N Z …
eps , divinicell , sprayed over , then glassed with polyester … the glassing with poly was the only bad point , other than that a nice sandwich board …
the customer got it secondhand , he didnt even know it was a sandwich board …
when i pointed out what it was , he said , " wow! i wondered why it was so light?"
at first glance it looked just like a conventional board …
regards
BERT
