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recycled plastic in leu of ply wood?

PostPosted: Fri Jul 23, 2010 9:32 pm
by eddie6775
Hi everyone, I wass trying to find a good source of siding when I stumbled across this link. The makers claim it's lite weight, durable and uv resistant.
It might be a good matrail to replace ALL the plywood! I wonder.....

http://www.stop-painting.com/bt-sheetplastic.html
:twisted:

PostPosted: Fri Jul 23, 2010 9:38 pm
by caseydog
Hmmmmm, seems like an interesting material. I built with 3/4 birch, and 120 pounds seems pretty heavy on that recycled plastic, but on the plus side, water is not an issue -- no delaminating.

Thanks for the food for thought. :thumbsup:

CD

PostPosted: Fri Jul 23, 2010 9:44 pm
by eddie6775
hey...nice trailer!..I'm designing a standie rite now, and the single biggest expence is the ply. I'm saving up now but dang....I'm thinking about that recycled stuff as a siding though. from what I've read here the frp needs paint to protect it. AND my local h.d. wants like $35 per sheet...so it's worth looking any way.

Plastic expansion

PostPosted: Fri Jul 23, 2010 10:08 pm
by eamarquardt
Not sure what you're looking at as far as what type of plastic it is but here is a recent string that might be relevant:

http://tnttt.com/viewto ... highlight=

Cheers,

Gus

PostPosted: Fri Jul 23, 2010 10:50 pm
by doug hodder
Might be an idea to find out what the expansion and contraction #'s are with it in temp. extremes if plastic only is your path. A lot of movement will make it difficult to make a "torsion" box for strength. Having worked in the sign industry for 15 years...plastic sheet goods can do a lot of wild things in the heat/cold and typically don't have a lot of rigidity to them...Just my opinion. Doug

PostPosted: Sat Jul 24, 2010 7:35 am
by eddie6775
hmmm... I had'nt thought of the problems with expantion and contraction yet. Good call! I'll have to investigate.

PostPosted: Sat Jul 24, 2010 9:48 am
by kennyrayandersen
also many plastics aren't very UV stable and go to crap in the sun.

PostPosted: Sat Jul 24, 2010 9:50 am
by Elmosaurus
Polyethylene is generally a semi flexible plastic. It's used in the construction of everything from milk cartons to kayaks.

Even with wall thicknesses of up to 1/4", I've had kayaks where you could put dents in the material. Yes, the dent pops right back out, but it's far from a 'rigid' surface.

Worse yet, bonding Polyethylene is very difficult. Basically, when you get a crack or gouge in a kayak, you have to 'weld' it back together using highly focused heat and additional poly sticks. I'm not even sure high grade silicone sealant/adhesives will stick to it. I've never tried using construction contact adhesive like Liquid Nails, but my guess is it wouldn't hold; the moment the material flexed, the adhesion would crack and release.

Since the majority of our 'torsion box' effect comes from a solid bond on all perimeter seams, I'm not sure you could get the same level of rigidity out of the torsion box since you'd, at best, only be able to fasten screws into your framing ever few inches. And even then, without a way to properly seal the screw holes and window/door/vent openings, water intrusion is probably inevitable.

:(


E.