Plastic Lumber (HDPE)

[Woodey]

I have a customer that purchased some 5½"x11½"X12' to 16'
Plastic Lumber Beams. HDPE (High Density Polyethylene) material.
It's Heavy 4-5 lbs. per board foot compared to
Pine at 2 lbs./ bf.
Oak 3.8 lbs./ bf.

He wants me re-saw the beams to 5½" x 10".

Has anyone ever re-sawed HDPE Plastic Lumber?
I'm wondering if the blade will heat up while cutting and melt the HDPE.

[Freedom6178]

I work in the plastics field. It might do just that tho not 100% sure. Use full flow on your coolent (water) and if you find its melting it you could try an airblast blowing directly at the blade in front of or at the cut. Otherwise I can't think of a better way to cut that material except with something like a hot knife.. Hope this helps.

[Chuck White]

I think it would saw ok as long as you keep the blade cool.

I thought the same thing as you did, last year I sawed some 4" styrofoam, but there were no issues.

[Jemclimber]

I too work with many different polymers and unfilled HDPE should be no problem cutting and keeping cool with proper water flow.
I've never seen it in that dimension, only pellets and sheet. Any idea what those beams were used for?  Just curious.

[tgalbraith]

Are you sure that these beams are solid???  A lot of them are hollow or skeletonized.  Just a thought. Might wand to check before you cut. I would think  you could drill a test hole.  Good luck.

[Cedarman]

Some of us have experience sawing logs with a hollow center.
MM had some pictures of cedar that were somewhat hollow.  At least on those the hole went to the end.

[drobertson]

I had one job back a few years ago, I sawed down 4" thick plastic, put two side by side  for a small machine shop.  It sawed out without issue,

[Woodey]

Jemclimber,
It will be used to replace a cypress beam walkway.
Part of the walkway is over a lake with a covered area.


The hard part will be getting the HDPE Beams On and Off the mill, they are 330 lbs. to 525 lbs. each, and he has over a 120 beams. 1650 Linear Feet to cut.

What is the best way and fair amount to charge for this type of job;
Linear Foot? Board Foot? By the hour? or for the job?

Thanks, Woodey

[beenthere]

Seems you best run a beam or two through the process before deciding a price. Otherwise you may paint yourself into a corner, and at the same time have an unhappy customer.

[Jemclimber]

I think Beenthere has good advice.

Since it's an unknown product, an hourly, plus blade cost might want to be considered.

[Woodey]

drobertson, When you cut the 4x4 did the shaving flow like sawdust?

I'm using a sawdust collector with my mill, do you think I will have a problem with the sawdust shavings produced from the HDPE beams?


What type of blade works best to cut the HDPE?

[drobertson]

Yes it sawed bout like wood, it did leave a little more frizzies on the cut exit,  can't really remember the blade, seems like it was a Cook's super sharp,

[21incher]

Plastic is not a very good conductor of heat so it may take a little extra water to keep the blade cool to avoid a melted burr on the exit side.

[drobertson]

I wish I knew , remembered the exact plastic, it was black, thinking it was some type of noryl, in any case, I have saw a pile on a verticle saw in the shop I worked in, it is a hair cloggy, but saws great, speeds of a wood saw are real close to what is needed this product. heat was not an issue on this one,  mainly clearance for the large sheets, but all was done, no issues, the post should pose no issues that I can see, but then again, who really knows, 

[Brucer]

I've cut HDPE on my table saw and machined it on my milling machine. No problem, except it can build up static and stick to stuff if the air is too dry.

You'll want your blades to be really sharp. Plastic tends to deform under pressure from the cutting edges. A dull blade will cause a lot more heat buildup than would be the case sawing wood.

[Freedom6178]

Dragging this back up.. Just wondering how did this job go? Was it possible?

[Dave Shepard]

I've never milled it on the mill, but it cuts with conventional wood working tools ok. I recently saw a park bench made with plastic lumber. I was glad to see that it, too, warped in the sun just like real wood. :D Now that's really going for authenticity. ;D