TEPIC or a new polyethylene panel or ???

[kengrome]

An Australian came to my shop the other day and he showed me a piece of 8mm thick plastic material that came in sheets like plywood. He said he thought it was made of polyethylene but I have my doubts ...

This material was white and opaque and appeared to be too stiff and not 'slippery' enough to be polyethylene. It was also lighter than the HDPE I've seen before, yet heavier than a piece of aluminum honeycomb panel of the same size ... and it felt heavier than the Meranti plywood I've been using of the same thickness. It was scratch resistant and uniform color and texture throughout.

He said it was a new material and he was possibly going to use it to finish the inside of his proposed new 60' catamaran. This material does not look laminated, instead it appears to be completely uniforn in texture and appearance throughout its entire thickness. It was very smooth on both faces and even the edges look like they could be planed or sanded to be as smooth as the faces.

The truth is, it reminded me a lot of Dupont Corian -- but it was MUCH lighter -- yet it still seemed to be a lot stiffer than it should have been if it were made only of polyethylene. This made me think that perhaps some other ingredients are mixed in with the polyethylene and maybe that's why it seems so stiff.

I just read some info about another relatively new material called TEPIC that may have similar characteristics when produced as sheets, but I cannot find anything online to suggest that TEPIC is a commercial product yet, so the sample I saw the other day is probably something else.

The thing is, this material impressed me enough with its apparent stiffness that I immediately thought of using it as a replacement for plywood in small boat hulls. But I don't know where to find it because I missed my chance to ask about its brand name or where to get it, and therefore I'm hoping someone here can give me some thoughts on where I might to find such a material.

If you're aware of any synthetic materials (new or otherwise) that have the characteristics I've described herein, can you please suggest a URL so I can try to locate a source?

Actually I am interested in any synthetic sheet materials that might effectively substitute for plywood. I know there are plenty of lightweight core materials available for composite sandwich construction these days, but that's not what I'm after. I'm really looking for a synthetic sheet material that can stand alone as a decent hull material, much like plywood can ...

[AndrewK]

Kenneth
I have seen product same as you describe at a local plastics workshop, I was told it was expanded PVC. If I can remember correctly it was made by GE, apparently it is common and there are other producers.

[kengrome]

Hello AndrewK,

If the material you've seen is the same material my potential customer brought me then perhaps he mistakenly called it "polyethylene" since PVC is "polyvinyl chloride" ... but it is good to learn that it is a commercial product and readily available.

I will do some research into "expanded PVC" and GE's product line to see if I can come up with more info. Thanks for your help!

[Guest625101138]

Klegecell is expanded PVC. It has been around for a long time.
http://www.matweb.com/search/GetMatl...&tn=Klegecell®

What you describe does not sound like expanded PVC but I have only used the low density stuff for core. I am told it is not as good as Corecell but I have not compared the properties. I can get Klegecell from a local distributor but have to have Corecell delivered and not worth the effort for the small quantities I use.

Rick W

[Herman]

Foam cores are a complete other chapter.

Klegecell is cross linked PVC foam, stiffer then Core-Cell, but also less damage tolerant. Don't worry too much, though. Millions of boats have been made and are made with this material. Same goes for windmill blades.

About the sheet you had: It could be foamed PVC. Different then Klegecell, Airex and others, more a mixture between PVC plastic and some air bubbles. Vikuplast and Kömacel are brand names. Perhaps you can find something with those terms.

[kengrome]

Hi guys,

I think it's some kind of expanded or foamed PVC. I can't tell from the info on any websites because I don't have the sample here any more, and even if I did it's pretty hard to know the character of a material from a picture.

One thing I know is that I couldn't see any tiny air bubbles when I looked at it up close, so if they are there (and they must be given the somewhat light weight of the material) they are probably microscopic or close to it.

I was thinking about experimenting with it as a possible hull material without any glass/epoxy sheathing, but if all these products are available yet no one is using them as hull material they obviously are not appropriate except perhaps as a core.

Or maybe as the hull of a small dinghy ...

[AndrewK]

I still think the material is an expanded PVC, linear rather than cross linked.
The only thing it is being used for in boat building that I know of is where high density inserts are required under deck hardware, industrial plastic being cheaper than marine.
Two reasons why you can not see the cell structure, surface is smooth finished and it usualy is a much higher denisty than the 80kg foam.
Have a look at the below, this is just one version of the product.
http://www.laserlite.com.au/commercial/vymaruPVC.asp

[kengrome]

AndrewK, the guy who showed me his sample is from Australia so maybe that Vymar material in your link is the same stuff. Sounds like it.