Rotational Moulding

[jamomac2]

Hi all,

I am a rotational moulder based in the Uk and wish to break into the boat market. I am very interested in possibly buying mould tools or contract moulding boats.
Please contact me if you can help or are interested in our service

[pistnbroke]

I am interested in rotomoulded boats because I have one from Fun -Yak ..so if you want to know how not to do it go look at there boats...
Welcome to the forum you will find many good people on here .

[jamomac2]

Thanks, i will look, I would be interested in producing boats but know very little of the kayak industry, We are taking delivery of a new machine in Feb 2012 with the capability of
producing Boat 5 mtrs long x 2.5 mtrs wide.

[Squidly-Diddly]

I'm a fan of larger SOT kayaks like AquaTerra Prism, Ocean Prowler15, Tarpoon 16, etc.

These boats become challenging to "King Kong"(carry overhead) and store.

How about a two piece big kayak where the haves could be stored standing up inside standard 8' high apartment(not to mention brought up stair or lift), or carried INSIDE a van or pickup with shell.

That would probably require a couple of aluminum poles to join the halves as roto material isn't stiff.


Another idea is boat design to also serve at a car-top storage box. I've seen a home-built plywood pram where the boat is the lid, but I was thinking of hull as the bin.

[Landlubber]

make a rain water tank too, always sell well...and if you like, water and fuel tanks for boats, with 1 1/2" threaded holes to suit whatever the owner requires. I designed such tanks for an Aussie company years ago and they are still made, private email me if you want the design details.

[pistnbroke]

also look at www.polycraft.com.au

[jamomac2]

Thanks for your help, i have some ideas, Has anyone got a rough idea on the cost for tooling or know of anyone with tools i could mould from.

Thanks

[Landlubber]

...tooling, you can easily make your own if you can weld OK...mine were made from mild steel, cheap and easy to do, though time consuming as they have to be perfect if you expect perfect copies (pf course0. The tanks cost less than $1200 all up to do, including about 8 threaded plugs for the outlets. One of the outlet plugs gets used to fill the mould with beads. The end results sell for $350 each (120 litre), so the costs have repaid many times over, and they are still as new.

...making a boat mould would be a slow process if you do it rounded, but a chined dinghy would be fairly cheap to make...think about the easiness of making the mould before getting too far involved

[Squidly-Diddly]

Does the "clam" need to be real nice and tight fitting so the resin doesn't leak out or is it 'self sealing' to an extent?

And how about 'mold release' or in that stuff naturally "easy release" as nothing seems to stick to it and it is tough and flexible?


WOuld this sort of hull be a tricky mold, where the hull is very flattened with small gap for foam between the skins?

I'm not understanding this Skin-foam-Skin roto process

[Landlubber]

Yes, make the edges as perfect as you can, but yes again, they are self sealing. You do not use any form of mould release, the pellets are slippery little suckers and they melt inside the mould as it is rotated. There is a percentage of shrink, thet is the natural release when it cools, never heard of one sticking, ever.

Flat surfaces (finished), need to be convex in the mould as they will settle, ask any rotomoulder what percentage of shrink the pellets you will be using have to be allowed for, mine were quite high, something like 2 to 5 %.