# How to make HDPE sheet with a cake pan method



## Can-Opener

Here is the first part of three videos on how to make a slingshot in HDPE. This one show how I make the HDPE sheet in a cake pan.


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## Poiema

Fascinating process. Definitely worth watching. I'm just amazed at how much planning and hours of work goes into this. Thanks again for taking the time to share all of this. Really nice to see how you've perfected this process.


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## leon13

Thanks for a noter super cool video tutorial it's really fun to see the progress and it looks al so easy what you do thanks again 
Cheers


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## sharp eye

Thank you for posting, very good and useful tutorial.


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## Btoon84

You rock CO thanks for taking the time dude. :bowdown:


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## Urban Fisher

Thanks so much for posting this C-O!!! Great info for sure!

It's funny when I started learning with this stuff, avoiding bubbles was my main concern...now it seems bubbles are a wanted thing...LOL!!!


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## Kerry Cornelius

Thanks for sharing! What temp did you melt your plastic at. When I melt HDPE it acts differently. It may be because of the temperature.


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## Can-Opener

Kerry Cornelius said:


> Thanks for sharing! What temp did you melt your plastic at. When I melt HDPE it acts differently. It may be because of the temperature.


400 Fahrenheit also it is a convection oven I was using


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## Kerry Cornelius

Can-Opener said:


> Kerry Cornelius said:
> 
> 
> 
> Thanks for sharing! What temp did you melt your plastic at. When I melt HDPE it acts differently. It may be because of the temperature.
> 
> 
> 
> 400 Fahrenheit also it is a convection oven I was using
Click to expand...

Thank you. That explains a lot.


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## Beanflip

Can-Opener said:


> Kerry Cornelius said:
> 
> 
> 
> Thanks for sharing! What temp did you melt your plastic at. When I melt HDPE it acts differently. It may be because of the temperature.
> 
> 
> 
> 400 Fahrenheit also it is a convection oven I was using
Click to expand...

Is convection vital? I have used a toaster oven at a lower temp and the surface gets a lot more browning than what I see in your video.


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## sharp eye

Can a portable planer tool be used to finish the HDPE blanks? Thanks.


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## Urban Fisher

sharp eye said:


> Can a portable planer tool be used to finish the HDPE blanks? Thanks.


Not sure on the answer to this one, but I gotta admit not many of us have a planer like that...though wish I did! 

However, how I do mine...I cut out the slingshot first, then I use an ordital sander and just sand the crap out of both sides (top and bottom) until it's smooth like it went through a planer. After sanding I can get it nice and flat (I put it on a flat surface to see just how flat I'm getting it) and then finish with finer sandpaper to get a nice smooth finish.


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## sharp eye

Urban Fisher said:


> sharp eye said:
> 
> 
> 
> Can a portable planer tool be used to finish the HDPE blanks? Thanks.
> 
> 
> 
> Not sure on the answer to this one, but I gotta admit not many of us have a planer like that...though wish I did!
> 
> However, how I do mine...I cut out the slingshot first, then I use an ordital sander and just sand the crap out of both sides (top and bottom) until it's smooth like it went through a planer. After sanding I can get it nice and flat (I put it on a flat surface to see just how flat I'm getting it) and then finish with finer sandpaper to get a nice smooth finish.
Click to expand...

Sounds like a good option for getting the HDPE surface flat and smooth finish.


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## JonM

Crap, now I have to find a convection toaster oven :wave:


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## tinbird

The company I work for is in the piping industry (mining, civil, etc) our specialty is fusing hdpe pipe. the fusing equipment has a heater plate that heats to 425 F and then hydraulic rams butt the two ends, under pressure. length of heating, heat soak and cool down vary due to pipe wall thickness, pipe diameter and of course ambient temperatures. Once the pipe is fused, the wall will typically break before the fuse would.

The ends are 'faced' smooth and square with a rotating head that has 3 carbide cutter blades so that there is a perfect union at the seam.

I say all this to recommend trying a true 425 F temp, heat it and then compress it once the temp is reached and give it about 45 minutes to cool slowly to ensure good 'fusing' of the material.


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## hainfelder

thanks for the "*opening-up-the-bubbles*" explained at 08:50 in the video

until now i just poked them open with a little stitch which still left some sores on the surface - really opening them up is different. Recommend this part of the vid for everybody.

Also the "*air-bubbles-make-nice-swirls-when-travelling-through-the-material*" is really a finding ...

@can-opener: any reasons why you did open up another thread?


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## hainfelder

Beanflip said:


> Is convection vital? I have used a toaster oven at a lower temp and the surface gets a lot more browning than what I see in your video.


Toaster ovens tend to have the heating elements very close to the surface of the HDPE and have high ratios of radiant heat - so they burn the surface more easy. This is why your cheese toast (its a toaster oven) in there gets this nice crusty surface ... maybe try to make a kind of shielding against the radiant heat in the oven.



JonM said:


> Crap, now I have to find a convection toaster oven :wave:


Convection ovens (as in circulating air ovens) normally heat the air and then pass the heated air around in the oven with a ventilator, so the heat distribution is more even and the ratio of radiant heat is quite low.

It´s up to Can-Opener what he means by "convection oven" ... in the vid it looks like a classic toaster oven with infrared heating elements.


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