Responses: Vacuum forming hosiery

Responses: Vacuum forming hosiery

Thanks to all who responded. Below is my original post followed by the
responses. We have tried silicone spray and, as others have also reported,
still had the problem. There is some reason to believe that a lack of
moisture in the models could be contributing to the problem. Spraying the
model and/or hosiery lightly with water certainly seems like the simplest and
most harmless solution if it works.

Original Post:

Recently we have had a problem with plastic sticking to the hosiery we use in
vacuum forming, especially with our polypropylene AFO's. We are puzzled by
this as both the plastic and the hosiery are from sources we have used for
several years. The problem seems to have come from nowhere? I was wondering
if others have had this problem and may have discovered the cause and/or
solution. Any ideas or recommendations would be appreciated. I will post the
responses.

Responses:

You may try spraying your molds with silicone just prior to pulling, or
wetting the nylons slightly before pulling them on molds...  This has
worked for me in the past.
**************** 
 we have that problem if we do not use Baby powder or corn starch rubbed into
the nylon prior to pulling. We like corn starch over talc due to the lower
toxicity. We have not had problems since doing this.
***************
Your tech may not be impregnating the hosiery with enough silicone and may be
allowing the plastic to get too hot at too high a vacuum. Whenever this
happens you can use muratic acid to eat the hosiery away. you need to rinse
it off with thinner instead of water or else it will stain. Be careful about
the fumes!!
**************
Spray the nylon with silicone before you pull your plastic.  Be sure the area
is well ventilated.
**************
they sell a non-stick vacume forming hoses that we use, from durr fillauer.
they work very well, unless you use proflex plastic, and then you use a
powder puff on the residual mold and it works great!!! good luck!~!
***************
I have found that spray silicone sometimes causes
nylon to stick to the plastic during vacuum forming.
Try using only baby powder as a release agent on the
hosiery.  Usually works Ok
***************
We've had problems with copolymer sticking.  Similar situation.  I look
forward to your responses.
**************
We have had this problem. We use a spray bottle with water and spray the
cast and hosiery with the water just before applying the plastic. No idea
why it happens.
************
You are probably already aware of this, but Fillauer sells silicone
treated hosiery you may wish to try.  Polypro is usually too hot to use
nylon hose.  You can try sprinkling powder or corn starch on the polypro
to get it to stick or cotton stockinette.
*************
try wetting down your hose.this will not shock the plastic to bad.i think
this will solve the problem.
*************
I have had this same phenominon occur from time to time and in the past we
have traced it a mold moisture issue.

This is by no means a scientific thing, but moistening the mold before
pulling it seems to do the trick. Not wet! just not dry. Some times we heat
our molds to reduce plastic creap and I noticed that the molds that stayed in
the oven to long got realy dry and the panty hose actualy become embedded in
the plastic, no amountof silicone or powder solved the problem but a little
moisture did.

Hope this helps because that would mean I'm not crazy.
************
A few things come to mind;
1) Is the plastic and hose composition still the same?
2) Are you heating the plastic hotter than you were before?
You can try spraying silicone or sprinkling powder on the plastic this
will help act as a separator.
***********
I have been having the same problem recently. I am not sure of the cause.
Even spraying with silicone does not help. I would be interested to hear of
any solutions.
********
OK, same source, but a different shipment of plastic?  Maybe just a few
extra minutes in the oven?  Are you using talc or that messy but effective
silicone spray?  Have you failed to offer prayers to the vacuum-forming
gods?

The full moon was last night - maybe all will be well today...
*********
We have had this same problem. My techs use a slight coating of silicone
spray over the hose just before pulling their plastic and it seems to work
well for us, Good Luck!
*********
A little application of talcum powder doesnt hurt
********
I have encountered the same issue.  The nylons seem to be a little thicker
than previous times.  Use baby powder.  Either powder the high stick areas
(over pads or linings) or put a few nylons in a plastic bag with some powder
and shake and bake them.  This will eliminate the nylons inbedding your
plastic.
*********
Have you made any changes in your plaster mix?  Are the casts drier than
usual?
*********
Zens Hosiery.  Milwaukee, WI.  part no. AK-36-US is what we use.  Haven't
had a sticking problem ever.
*********
We use corn starch as a sepparator and have't had any problems.


Thanks again,
Eddie White, CP
Beacon Prosthetics and Orthotics
3911 New Bern Ave.
Raleigh NC 27610