Question about using kevlar for top deck reenforcement

[Accessable]

Kevlar and epoxy resin is very tough, but as has been suggested, not very rigid.
I overcame this by laminating balsa wood "cross grained" i.e. I used 1/8" balsa and cut it into 1" X 1" square tiles.
No two adjacent tiles had their grains running in the same direction.
A final coat of epoxy resin seals the tiles.
Result: Very strong, very light and very rigid.
The balsa also adds buoyancy.

[Fella1340]

Sounds like it would be strong and a lot of work! I was thinking that will all this wonderful
technology we have there would be some kind of pre-fab material I could just use resin
and put it in. Its a really aqward place to work and I have back issues so I was hoping
to minimize my time working under there, you've got me thinking though!

[NativePaul]

I First used Aramid (kevlar is DuPoint's trademark and for price reasons I prefer Russian made Aramid) a long time ago, i found that it is a great product, stiffer and lighter than glass but I was trying yo use it without the right tools, I found that while you cant cut it effectively with scissors or a scalpel you can cut it with a fresh razor blade and a little patience, when I wan out of material I didn't buy any more again for many years as it is a pain to cut, I recently bought some kevlar shears and started using it again, with these you can cut it with ease and while they are not cheap I would recommend you factor a set into your budget unless you have a lot of patience.

The snowman turned me onto a product from Lantor called Soric, which is available in several different grades and thicknesses, it is a high tech replacement for coremat, it consists of dense foam hexagons which don't absorb resin surrounded by a honeycomb of thin absorbent fibres, as the hexagons displace resin the result is much lighter than coremat for the same thickness or much stiffer for the same weight it is more before resin is applied flexable as well, in fact flexability is its strongest suit and it is great for double curvatures.

End grain balsa is still the best thing (bar proper honeycomb, but I don't see that as workable on a home basis) for fairly flat areas, I made up some trial A4 sheets with different cores and skins, a 3mm Soric core is almost exactly the same weight as a quarter inch end grain balsa core, but because the skins are much further apart the balsa needs much lesser skins for the same thickness so is lighter and cheaper, when both had 200gsm carbon skins the balsa was almost unbendable at that size, with 200g glass it was still massivley stiffer than the carbon Soric, with 100gsm glass it was much stiffer, with 25gsm it was still much stiffer but broke when the carbon was still within limits, I don't have any but think 50gsm glass on 1/4"end grain balsa would be as strong and much stiffer than 3mm Soric or coremat and much lighter than coremat. It is not really suitable to double curves though unless they are big. End grain will follow curves much better than the cross grain mentioned above though, and is MASSIVELY stronger in compression which is what you need for a laminate core, it may seem even more of a hassle getting a balsa 1"x1" and sawing it into .25" squares and glueing them together, but you can buy sheets of it premade fairly cheaply in different thicknesses, although .25" is the thinnest I have found, it is commonly used for laminations in higher end boat hulls and wind turbine blades.

[Fella1340]

Thanks for all the information, the soric product you mentioned sound like a good idea.
I don't think I will go the balsa route. What you mentioned above sounds like the type of product I am
Looking for. I am going to look into it. Thanks again

[tiqueman]

I carbon and carbon kevlar all my boats hulls and have done most of the lids. I do not do the deck though, but I wrap the carbon up to it and slightly onto it in most cases. I run Futaba fast internal antennas. I think since Im not carboning the underside of the deck, it gets out. Most of my rx's sit in the back of the boat either under the back end of the hatch or under the rear deck of the boat. I was concerned with the first one I did after knowing signal wont get out of a carboned boat, but 7-ish boats are running without issue. Again tho, I don't do the deck.. See no reason to do so.

[Fella1340]

I plan on using cf for the entire hull section. i want it to look nice to but this boat needs a lot of
help in then stiffening up department, including some ribs to stiffen the top deck. its a beautifully
finished boat. it shocked the heck out of me when i saw what i was getting for $138, you a always
get what you pay for in the end. If its a 1/16" thick i would be surprised. the bottom is a heavier
layup and is very straight so that is very good news. The kevlar top deck is for the same reason,
rx and gps. I have some heavier weight fiberglass i may put in and then kevlar. I am still looking
into some of the suggestions above in regards to light weight honeycomb type design. I hope to
find something that is not $100 yard. whatever it takes though, I want this to be super nice. its
funny you replied tiqueman just now. I was just reading a pm you sent me when I first joined, good
advice indeed. strange timing thats for sure. I will have to make a decision soon. hopefully i will
be laying cf, kevlar and whatever else i decide in the next week or two. I practiced laying cf on a
R2 hobby hull i had built and it worked out well. one valuable lesson learned was to not walk away
from the job to quick. I thought i had all the extra resin worked out of the cloth, put down way to much
to start. I came back an hour later and the resin had pooled along the keel of the boat. over 1/8"
thick in places and i'm being generous to myself there. I should have said 1/4"! grind and sand and sand and sand some more. another 2 layer went in afte

[tiqueman]

Where's the hull from or did I miss that?

[Fella1340]

my computer is crazy. no capital letters and it just previewed and posted by itself!
so 2 more layers of cf went into that boat plus a bunch of cf sheet to get the hang of
cutting and drilling, laying up resin and all that other fun stuff. the boat got some good
money into it now! its an ok hull but hatch is awful. its getting a whole new power
plant to match its new status. I hate the look of it though, it may end up being used
as a target while we sit around taking pot shots at it. maybe a raffle of some kind to
go with it. or just redo the hatch. both are viable options

[Fella1340]

the hull is in my avatar photo. a couple of other guys have it. i keep going off topic and rambling on.
i wasn't going to post photos till i had a build thread going with real building going on. It's the same
hull alfa spirit has all decked out. fountain p1. mine is still in the primer it came in.

[tiqueman]

So was it just a random few built or is it still available? Seems like a cool project boat and friends keep yelling at me to get a mono. Lol

[Fella1340]

Technology is conspiring against me, moved to my phone and its dumping on me to.
Anyways, its a real nice boat, it comes finished in primer and the prep job is good enough to send straight to paint its that good. Who know what's under all the nice finish but it sure looks good. Nice scale details. The hatch vents had been filled on mine, alfa s wasn't so they may be in the process of closing the two banks of two vents on the deck. I have to fill mine in. The hull bottom is very straight and it has been somewhat reinforced but the entire rest of the boat is thin and flexible, needs stiffening all around. The hatch to hull fit is damm near perfect and sits perfectly level to the deck. You couldn't hang anything off the transom and run it the way it is. Very thin. Its not a true stepped hull as the two steps it has don't change the line of the keel. If that makes sense?? There are steps but they are not what you would consider to be true steps. That's the best I can do that. Shipping to Canada was steep due to size, about the same as the price of the boat. No surprises there. Incredibly well packages, almost like die cut sections of that nice foam perfectly hugging the body all around and over its length. It could have been kicked to Canada and survived. I can't will myself to get rid of the box!
His eBay name is okey_100 or something like that. Search eBay for 50"fountain p1 and it should pop up. Terrible pictures, I had seen it a dozen times online when looking and it wasn't till alfa and another member got them that I got to see them for what they were. Let me know if you have trouble finding it. It was also available as a finished boat on a website that I had trouble finding a second time. Search 50"fountain here for tons of pictures. I'm done, goodnight