"Erik" wrote in message
...
In article ,
"Bob La Londe" wrote:

I finally decided to make a vacuum formed polystyrene cover for the
encoder
on the front of the big mill. Seems pretty straight forward. I've got
my
first vacuum box finished except for the port to put the vacuum hose in.
I
noticed a lot of the DIY guys make a hole for the smaller vacuum hose
even
though they have a full size shop vac with the big hose. Is there some
reason for that? Seems to me that the larger port for the larger hose
would
evacuate the box faster and form the plastic quicker before it cools. Am
I
missing something obvious?

(I have some PETG on the way to play with in case I don't like the way
polystyrene forms or holds up)

If this goes well, I have all kinds of ideas for vacuum forming...



I know little about vacuum forming, suggest running this by the folks
over at:

sci.polymers

There may be other plastics groups as well. Also, I've heard the model
airplane crowd now does a lot of vacuum forming.

As a kid I had one of those Mattel 'Vac-U-Form' things... made stuff
with it for years...

Good luck!

Erik

I went ahead and drilled it to fit my big hose for now. If I do much of it
I know I'll have to make two or three vacuum boxes anyway. It certainly has
plenty of hold for a simple suction test, but not doing any forming. I
couldn't lift a board off the box. I was able to lift a sheet of plastic,
but only because it would bend. I didn't make it particularly perfect
either. I am sure it leaks everywhere. LOL.

I posted over it sci.polymers too, but that group looks like its totally
over run by spam.