Hulls made of HDPE

[jonr]

I found lots of references to flame treatment to prepare PE for gluing and apparently it works.

Here is one: http://www.jamestowndistributors.com...t+System+Epoxy

My understanding is that heat fusion is fully as strong as the original (for example, fusing pipes).

[jonr]

3M's DP-8005 is also reported to work well.

[yellow cat]

i was an Okoume/epoxy fan for building my catamaran, i found that the plywood 3 mm was easy to work with. this hdpe product is raising my interest. could i buy sheets of hdpe and laminate them with proper glue ? The finish and antifouling "paint" are also a question mark.

[rasorinc]

this guy is making boats out of it and light one too. 3M did develope a special for this stuff but I don't know the Number. I'll come back with a supplier posting. http://www.boulderboatworks.com/bbw_specifications.html

http://www.boulderboatworks.com/bbw_specifications.html

http://www.professionalplastics.com/...EXLMARINEBOARD and this one http://www.sdplastics.com/marine_board.html

[jonr]

I would think that where possible, heat fusing would be better than glue.

[powerabout]

Anyone have any news on Twintex, there are some beach cats built by Twin Cat in France at our club and they are all ( well ones exposed to the sun) looking like unpainted expoxy carbon parts in that the cloth has come to the surface so nice non skid finish now. They were smooth when they first arrived.
How would you fix this?
What kind of paint system?
Could you treat as per a plastic car bumper ( ppg dpx801?)
I have emailed owenscorning and waiting for a reply...

[Fanie]

I wonder if you have a PE hull that got damaged, if you could put it back in the roto mill and give it a 'new' treatment...

[powerabout]

the soft heavy roto moulded stuff can be welded successfully.
I used one as a tender on a dredge I worked on years ago and we crushed it and did all sorts of things to it.
They are very soft compared to later things like I described above which is close to your typical fibreglass weight but you cannot dent it with a sledge hammer with a full swing!

[yellowcat]

for a dingy, i plan to build a hovercraft, quite a program.
this high density polyet... could be of use. Flamability is a concern but there are treatments and add ons possible. Roxul insulation is one of them.
This hovercraft could even house my VW cabrio for beaching a car possibility. There are more reasons for that application, one of them is a <save the planet> reason for building less road infrastructures, i am working on a design for a hybrid elect/hydrogen/unleaded gas craft. of course the car engine's contributes to the <mothership catamaran>.

[grob]

Originally Posted by powerabout

Anyone have any news on Twintex, there are some beach cats built by Twin Cat in France at our club and they are all ( well ones exposed to the sun) looking like unpainted expoxy carbon parts in that the cloth has come to the surface so nice non skid finish now. They were smooth when they first arrived.

Don't know the answer to this, I made some hulls from twintex about 5 years ago, we left them with a natural finish i.e. no Gelcoat and they have also ended up the same way after 5 years exposure to the elements. I guess the answer is that they should have been gelcoated in the first place.

At the time my thinking was that a gelcoat on top of twintex would defeat the object of having a boat that was impact resistant.

Did the Twin Cat boats originally have a gelcoat finish?

Gareth

[powerabout]

No, they are actually molded with twintex plastic ( off white colour) with twintex cloth inside so I need to prime the twintex so we can paint one.
Clearly twintex doesnt really have UV resistance unlike gelcoat
Do you know what type of plastic twintex is?
Thanks

[yellowcat]

Originally Posted by grob

Yes rotomoulded HDPE is very strong but this is partly because it has so little stiffness that you have to use loads of it to match the stiffness of other materials like GRP, this makes it very heavy. Anything is strong when you use enough of it, the trick is to get high strength/stiffness and low weight. As John says Twintex goes along way toward acheiving that.

It also has the additional advantages:-

1. Impervious to water, unlike GRP which absorbes water through osmosis
2. Excellent resistance to abrasion, and impact resistance, better than GRP or HDPE.
4. High stiffness for its weight (same as GRP)
5. Easily recycled.
6. No Toxicity or emmisions.

The British Army use it for their landing craft and RIB's bacause of its toughness.

We have been using it for our multihull and we are very pleased with it.




Gareth
Warob Marine
www.fourhulls.com

This may be the product i will be working with, i plan to design an hovercraft dingy capable of carrying a small car.

[grob]

Originally Posted by powerabout

Do you know what type of plastic twintex is?
Thanks

Its a thermoformed Polypropylene see http://www.twintex.com/

Cheers