Sheet press

Trying to build a little tool that turns plastic into sheets. Very basic. Plastic is heated on a metal bed, another plate presses it into a sheet. Made a prototype of this before For some reason I made it of wood, which burned…so I stopped… Still think it has potential. Let’s try!

Step 1: Basic prototype. Making a little box that fits a heating element (from an old grill) the rest is made from some stuff laying around.

Hi Dave

I just found out about your projects today, really good stuff!

As to making flat sheet, I might have an easier way:

You could make a die for your extruder to create flat sheet. I worked for a company that did this with PVC material on a large scale, but it was just a large die on the end of the extruder and a winding mechanism. To be really precise on the thickness and width, you would need a motorized roller to pull it out of the extruder.

Hope that helps

Hi Jordan,

That’s something I’ve been looking at doing especially using an oven.

I don’t suppose you could attach a couple of photos? That would be super helpful 🙂

Thank you,


Hi Dave

We found great results and even heat by taking a sheet of steel with built up edges, filling this with plastic and putting it in an oven with a metal sheet on top (like a plastic sandwich) then we put this under a press we have built with a hydraulic ram. We have been using HDPE but found PP to not heat as evenly so needs longer in the oven on a slightly lower heat than normal. I think the oven works best for heating as it isn’t a direct heat, the heat itself is evenly distributed in the oven. However you are limited to about 38cm2

Hope that helps with your press!

Hi Dave,
I’m Sara!! Me and my boyfriend Raul moved last year on a tiny caribbean island that belongs to Nicaragua, Little Corn Island… This island is a true paradise, but have a big problem eliminating waste, particulary plastic bottle… So when we decided to build our house we came across the plastic bottle house project of Alfredo Santa Cruz from Argentina and decided to do the same… I dont know if you know the way he builds his houses, check
(easier if you look at it that to me to explain!!!)
Anyway… We realize that for us unfortunately use his sistem as it is is very difficult for two main reasons.
The first one is that Alfredo uses 2L bottles… We have only 0.5L bottles… And he connected the bottles to creat the bricks with screws… On for us is a double problem, first for the quantity (smaller bottles, means way more screws) and that where we will build is on an island, normal screws rust in no time, so should use screws that dont rust, that are very expensive…
It’s now months that I’m braining myself off for find another way to connect the bottles but stucking them in the same way… I was looking into a press and hot combination but I’m not an engineer and I couldntake up my mind about how to do it…
And then I found you and your project and really hope you can help me find a way…
My main question is if you think is possible to press the bottles without shred them… Essentially line them as Alfredo does but instead put them together with screw, put them in the oven and press them for obtain a panel… Then the panels become the wall…
I dont know if this make any sense to you, but with his sistem Alfredo already build almost 80 houses in poor comunities in South America, and I really would like to creat a version of his sistem that fits my island situation and help my community over there!

An idea to keep your colors strait: melt solid colors into sheets then cut into strips. Lie the strips in your preferred pattern and heat until they stick. This only theory, but I don’t see why it shouldn’t at least improve the result a little.

Still having difficulties heating up the plate equally, the middle keeps being hotter than the corners. Think I will need to rebuild it and use a better conductive plate like brass or copper with perhaps a few ribs on it to have ore heat absorption.

things get spacey

A test with mixing colors. First picture is before, second one after melting. Honestly I imagined something completely different coming out of here. its one big mess, however it does have some interesting details in there which might be worth exploring further.

i wanted to avoid making 2 heated sides, because it makes the machine building more difficult. But it does seems like you need it anyhow to get it molten accurate. Will do a few more test first though.

Video sounds interesting but doesn’t work… copyright block in my country…

What happens if you flip the whole carriage around, the case atop the elements. Should cook more evenly (?)

Another idea would be to mount it at an angle closing in both sides, like a waffle iron, then continually feeding pebbles till it fills up, should get rid of any air-issues as it sets bottom to top.

When its done you open the door like a fridge, and grab the plate ready to start anew.

Bits of oven-cookery yes yes yes!

Added an extra heating element to try and melt the entire surface (including corners). I know i know it looks like crap. It’s just for testing, promise!

Another test with less pressure applied to see if the movement of the plastic decreases. Aiming to keep the plastic in the same position as placed before melting. It definitely matters, Will do some more pressure test in this in the future. But first I want to find out how to get the corners melted as well.

Made some other test with some mixed colors. Melting goes well, 2 problems so far. The corners aren’t really molten properly, and the plastic is moving around when pressing, specially on the bottom/heated side. . It’s an interesting effect, but we should be able to control this

Made some first test today. Below the before and after picture. It doesn’t really seem happier.