polyethilene

[zgubidani]

is there anybody with experiance with that kind of material...I think that PE is best choice for home-made boat solution

[apex1]

Welcome here,

did you make the whole boat from PE?

[zgubidani]

this is not my boat, I have visit this little workshop in zagreb(Croatia-Europe)and now I want try to do something like this alone...Yes the hole boat is form PE, and this guy has make a good job with PE boats (start price is 5.000 E)

[gonzo]

The downsides are: heavy weight and dull finish . The good points: it can be rotomolded and welded, and it really takes a lot of abuse.

[apex1]

For the tube ok, but for the hull, I would recommend a much stronger and lighter way of construction. Wood, Alu, even GRP gives you a better boat.
And welding PE is not as easy as it seems to be! For amateur building there are better methods.

[Fanie]

As Gonzo indicated, heavier than glass, PE is very wear resistant, difficult to repair, trust me, a real bugger to do. Nothing glues to it, whatever you add needs to be bolted, screwed or rivited. Scrapes and other physical damages remains visible, you cannot paint over it. Black and other dark colours last in the sun, be carefull of lighter colours. Black is friggin hot.

Truely a stunning material BUT it would be a choice further down the list for boat building. Considering the relative low cost and ease with which one can build an everlasting fiberglass boat vs high cost working with PE I would reconsider. Roto moulding is expensive for the first, after that relative less costly if you make lots of them. I'm surprised to see such a big hull if that was roto moulded !

[gonzo]

There is a company in the USA in North Carolina that rotomoulds speedboats of up to 21 feet. They have the largest rotomold machine in the world. They run great, but the finish looks nice for about two uses, then starts scratching. The hulls are foam filled, which allows for a thinner skin and also makes them unsinkeable.

[pamarine]

Originally Posted by gonzo

There is a company in the USA in North Carolina that rotomoulds speedboats of up to 21 feet. They have the largest rotomold machine in the world. They run great, but the finish looks nice for about two uses, then starts scratching. The hulls are foam filled, which allows for a thinner skin and also makes them unsinkeable.

Actually up to 23 feet now

It's called Triumph Boats, it's a subsidiary of GenMar Holdings, a very large boat manufacturer in the US. I own a 17 foot model. they use LLDPE for the Hull, which, coupled with good engineering, ends up giving a lighter boat than a comparable fiberglass boat. And the boats take a hell of a beating. They are easily repaired via plastic welding, which most folks are comfortable doing. They require significantly less maintenance than a Fiberglass boat as well.

But as a 1-off building method PE ain't the way to do it. The finished boat will be heavy and expensive compared to other, more traditional methods.

I think you would be better off with a cold-molded boat or traditional GRP hull.

[zgubidani]

that could look just fine...I'm mean, for tubes I can use PE pipes with outer RC layer (Resistance to Crack - in yelow, blue or green color), problem is with plates..they are all black)...here is one example where investor want to combined PE with INOX

[Steve W]

As others have pointed out it is heavy and is not structurally stiff in sheet form,another downside is that it has very high thermal expansion which may or may not be a problem in the finished product but being aware of it while building. Contrary to popular belief it is glueable with proper preparation and on this i know what i am talking about, i used be the engineer for a snowboard manufacturing company in Taiwan back in the late 1990s,of course the running base material is UHMWPE and in all our destruction testing the bond strength of the epoxy/glass bottom laminate to the PE base was always the strongest bond.
Steve.

[pamarine]

It is most definitely gluable, basically you are chemically welding the material, so care must be used to select the correct compatible adhesive.

[Steve W]

Actually to glue it with epoxy it is all in the surface prep,you have to alter the surface tension,making it wettable,to achieve this you sand it to get rid of all gloss,i like to use about 80 grit,if you go much coarser you have a harder time getting it all,much finer and you dont have enough tooth,so far its just the same as prepping any other shiny material,the next step is to flame treat it ,you can use a propane torch and wave it over the faying surface using the corona of the flame,the edge of the blue part,obviously you need to move the torch fairly smartly,you need to develop a feel for it on a piece of scrap.Now you just glue it like anything else,dont do the corona treating too far in advance of glueing. Really ,any material that you want to glue needs to be prepped properly,if you wanted to epoxy something to the hood of your car which you regularly wax it aint going to stick but if you,remove the wax with solvent and paper towels,then sand it and wash it off,now,if you pour water on it,
instead of beading up it thoroughly wets the surface you have sucessfully altered the surface tension,dry it off and its glueable.
Steve.

[pamarine]

Originally Posted by Steve W

Actually to glue it with epoxy it is all in the surface prep,you have to alter the surface tension,making it wettable,to achieve this you sand it to get rid of all gloss,i like to use about 80 grit,if you go much coarser you have a harder time getting it all,much finer and you dont have enough tooth,so far its just the same as prepping any other shiny material,the next step is to flame treat it ,you can use a propane torch and wave it over the faying surface using the corona of the flame,the edge of the blue part,obviously you need to move the torch fairly smartly,you need to develop a feel for it on a piece of scrap.Now you just glue it like anything else,dont do the corona treating too far in advance of glueing. Really ,any material that you want to glue needs to be prepped properly,if you wanted to epoxy something to the hood of your car which you regularly wax it aint going to stick but if you,remove the wax with solvent and paper towels,then sand it and wash it off,now,if you pour water on it,
instead of beading up it thoroughly wets the surface you have sucessfully altered the surface tension,dry it off and its glueable.
Steve.

I use the method you are describing to adhere decals to PE but the few times I tried it to bond two pieces of PE the joint failed prematurely. It could definitely have been an error on my part, but with such a technique it seems error will be easy. Welding either via Heat or Chemical seems to me to be the surer methods for the amatuer.

[Steve W]

Originally Posted by pamarine

I use the method you are describing to adhere decals to PE but the few times I tried it to bond two pieces of PE the joint failed prematurely. It could definitely have been an error on my part, but with such a technique it seems error will be easy. Welding either via Heat or Chemical seems to me to be the surer methods for the amatuer.

If you have ever skied or snowboarded? this is how the uhmwpe bases are prepped for bonding,followed by reverse screen printing with 2 part epoxy screen printing ink followed by the epoxy glass laminate which is actually bonded to the ink,the adhesion is exceptional.However i should point out that the epoxies used are formulated for press molding at about 100 degrees c,the weak link is the bond to the wood or foam core,the core fails.As you try to bond thicker PE to PE there are probably better adhesives.I use snowboard base material for all sorts of things in boatbuilding, ie,the rudder in a drum trunk and the keel trunk of my sons 24ft ULDB are lined with it.
Steve.

[Jimbo1490]

Originally Posted by Steve W

Contrary to popular belief it is glueable with proper preparation and on this i know what i am talking about, i used be the engineer for a snowboard manufacturing company in Taiwan back in the late 1990s,of course the running base material is UHMWPE and in all our destruction testing the bond strength of the epoxy/glass bottom laminate to the PE base was always the strongest bond.
Steve.

I concur on this. 3M has 'Off The Shelf' solutions for creating structural bonds on PE and PP. This tech used to be trade secret and only a few companies (mostly makers of loudspeaker drivers; especially woofers since the PP cones are bonded to both the voice coil and the rubber or foam surround) knew how to do. Now you just pick up the phone and order the right glue.

Jimbo