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HDPE sheet

190K views 713 replies 113 participants last post by  gunslingster 
#1 ·
Hello again, a simple project here this time, compared to the micarter (well sorta).

ok, so for those who have found this tutorial and not the micarta one, i'll repeat a few steps from that one.

HDPE is easy to find,

Font Rim Automotive tire Oval Automotive wheel system


as long as its got the number 2 in the triangle and or it has HDPE (sometimes PEHD) then its good for what we need.

hdpe melts (not burns or release fumes) at about 180 c.

this stuff can be easily singed at about 220 c i think from experience, although the inside would still be fine.

step one:

Wood Thumb Sculpture Composite material Bottle


take your bottle and cut it into pieces roughly 1-2 cm2 and collect. now i'm sure its wrong (knowing me prob by alot) but i think its weighing in at about 1.5grams per cm3 so you can roughly work out how much plastic you will need to collect by working out how big your mould is.

step two:

Automotive tire Automotive lighting Tread Motor vehicle Alloy wheel


putt all your HDPE into a metal bowl and place into an oven. switch oven to 190c and as with the micarta heat for about an hour checking twice and turning the bowl. this stuff is the consistency of toffee peeps, so dont think your going to be poring it anywhere! using a metal rod or butter knife etc pry the HDPE from the bowl and place into your mould.

step three:

HDPE when cooling wants to twist badly as different parts cool quicker, so i made a block moulder that i could dump the melted HDPE in and form it to a rough block and hold it there.

Wood Rectangle Composite material Gas Hardwood


here is the area for the plastic, it is contained by 2x2 cm wooden slats into a piece of ply with a side left open for a sliding push bar.

step four:

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once the plastic is sitting roughly inside the three sides of the rig, you can push the lid (peice of ply)

down and squash it then screw in place.

step five:

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use the push side to further squash the HDPE into the mould, and screw that in place.

and then leave to cool for around two hours before taking it out.

coloured pieces can be added into the mix before heating, or even layers of whole coloured plastic, or...... anything heat proof . anyway, hope that gave someone something to do :) Hand Gesture Finger Art Material property
Pink Red Material property Wood Magenta
 

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#11 ·
all plastic milk containers are HDPE. i once had an idea of cutting out the large flat sections and glueing them with epoxy to make a slab of material to cut into.

lexlow- ever consider trying the 5 gallon water bottles ? (unless im mistaken bout them being HDPE also)
 
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#13 ·
all plastic milk containers are HDPE. i once had an idea of cutting out the large flat sections and glueing them with epoxy to make a slab of material to cut into.

lexlow- ever consider trying the 5 gallon water bottles ? (unless im mistaken bout them being HDPE also)
i used a plant food container for part of a mix, it was HDPE but about 2mm thick, melted fine with the rest ;-) and no need to glue :)
 
#14 ·
So far I have acquired about 350g of HDPE, and that's just out of one bin. We drink a lot of milk and juice. Is this stuff infinitely re-meltable? Can I just keep re-using the off cuts when making a slingshot?

Also, according to wiki HDPE is 0.93-0.97 g/cm3
thanks for looking that on wiki, i didnt even think to bother as i knew someone would :)

and so far a few parts have been melted three times, also it did say somewhere that the property of this HDPE is that it can be used again and again.
 
#19 ·
This is a great idea ... I really love it. I know I have a reputation of being a scrounger, but this beats me combing second hand stores for old cutting boards!!!

Cheers .... Charles
i still do that lol. another source of good wood can come from pound stores, some of those wooden toys have a good amount of area, also they do epoxy :)
 
#20 ·
#22 ·
Do you think something like this would work?

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of course they have smooth surface plates as well.

It gets to the right temp, and I would imagine you could put pressure and form it as it melts. of course the possible issue is with ambient air isn't the same as in an oven. However they make cast iron griddles that I am sure you could put in the oven as well.

LGD
 
#26 ·
Here is my first attempt. It's a Bill Hays Patriot, still need to drill some holes etc. I was going to sand it back to get rid of all the lumps but thought it might be interesting like that so I stuck it on the router and am pretty happy with it. I might make a thicker one next time and sand out the rough surface. I cut it out on a scroll saw.

Loving this lexlow! This type of free reclamation/recycling and ending up with an awsome product is so satisfying!

The actual mass of HDPE in the slingshot itself is only about 100g-ish, the rest will just go back into the pot for re-melting so it doesn't really take too much to make these once you get started.

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I have to say, this stuff is bloody strong!
 
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