[TheForge] OT - Mylar

[Ries Niemi]

On Friday, February 6, 2004, at 11:39 AM, Dave Brown wrote:

> This is a bit off topic, but there are so many people on this list of 
> varied talents and professions that I figure that there has to be 
> someone here familiar with Mylar.
>
> Can Mylar be shrink fit?  Think drum or pipe end here.  Can you shrink 
> fit Mylar over the pipe end and heat shrink the wrinkles out of it 
> where they form around the sides?
>
> Where would one get small sheet (say 18"sq) of Mylar?
>
> Dave Brown
> Heritage Smithing
> Green Bay, WI

Its been a while, but as I understand it, there are two types of 
plastic sheet- thermosets, which once they are formed, are not 
softenable and reshaped by heat, and thermoplastics, which can be.
Its my recollection that mylar is a thermoset.
But there are plenty of cheap plastic sheets that can be heat shrunk 
over a pipe end. I have had success in the past using a polystyrene, 
usually white, and various acylics, which can be optically clear. 
Butyrate works well too.
I used to have a quickie little vacuumformer that used some oven coils 
for heat, a vacuum cleaner motor for suction, and you could form up to 
1/16" thick plastic really easily.
My big milwaukee brand heat gun will get it hot enough to form.
I would look in the yellow pages for plastics- sheet strip and tube, 
and ask them what heat forms easily that is cheap. You may have to go 
as far as milwaukee- but it should be out there. Polystyrene or similar 
sheets should be 10 to 15 bucks for a big piece in 040 to 065 
thicknesses.
Not sure how easy it would be to get every wrinkle out- like in 
forging, the material has to go somewhere.

ries