Responses to Fabrication AFO's

Responses to Fabrication AFO's

Skewes, Ed

5/9/2007

Thank you to all that responded.

 It is always fascinating to see the variety of suggestions.

 Ed Skewes CPO

 

 

 

Hi Ed

 

I've done what you describe many, many times. Instead of placing the 2
plastic pieces on top of one another I heat them separately. Once hot, I
apply the 1/2 piece onto the cast, then apply the larger sheet. What I
found happened in the layer in the oven method was areas where the
plastic heated unevenly and/or air being trapped as the plastic heated.
Placing the 1/2 strip first then the larger sheet yields good results.
I haven't had one delaminate yet. If you're concerned about the strip
moving a bit of glue attached to the stockingette keeps it in place as
the larger sheet is applied. As for heating the cast, we don't do that
anymore as, in our case, it didn't seem to be the cause of the problem.

 

Good luck!

 

Cameron

 

Hello Ed,

 

We often wrap our casts ina large and water tight plastic bag and then
submerge them in a bucket of hot water while the plastic is heating up.
When the time is right we take the cast out, prep it in the vacuum jig
and then wrap it with towels to keep it warm for the few remaining
minutes until its go time. This saves room and mess in the oven.

 

Hope this helps,

 

James Little B.Sc., C.P.(c)

 

1. i use inverted Y shaped strip, so that it overlaps heel bilateral;
very strong

2. you can set an infrared light with reflector next to mold, warming up
specific area

3. you can use heat retaining boot placed on top of pull, to prevent
rapid cooling of plastic resulting in different temp gradiant

4. roughning plastic strip on the side that goes against the pull helps
bonding; some techs put glue on it, usually polyadhisive.

i.lesko, lcpo

 

Are you fabricating the AFO completely out of Copoly? Have you tried a
coploy strut and use polypro as the main brace material?

 

Lifestyle P&O

Jeff Hoerner CPO

 

 

What you describe sounds alot like a design we use called a Plastic
Reinforced energy storage AFO or Chevron AFO. This uses poly-pro
reinfocement laminated together with the colene AFO section. We heat
the 2 pieces separately and then place the hot poly pro on the cast (
already set up with 1 nylon over the entire cast and another full nylon
rolled up over the toes and around the metheads) once the poly pro is
in place you quickly pull the 2nd nylon over the hot poly pro and drape
the entire cast with the colene (a little barge glue helps to keep the
poly-pro from sliding around).

  The nylon between the poly-pro and colene acts as a wick and insures
there are no air bubbles and a very solid connection between the 2
plastics. I have never seen one split. We don't heat ours but
sometimes we paint them to seal a wet cast for a quick molding.

 

At Chedoke Hospital in Hamilton Ontario Canada they are doing alot of
research with this design - The energy return aspect of it is really
impressive!! It may be worthwhile to contact them and find out more. I
use this design constantly and am still surprised by it. I can send you
their contact info if you want.

 

Cheryl Lewis BSc(HK), CO(c)

 

I've done these a couple of different ways. If the plastic and the strut
are separating, it is a bonding issue. It sounds like air is being
trapped between the strut and the AFO. I've had great success by heating
the strut on the tray next to the plastic for the AFO section, not
layered. The key to my success is in the set up.

 

1) I mark on the cast where I want the placement of the strut.

 

2) After I cover the positive with the nylon I leave enough additional
nylon to pull back down over the mold. I then put a drop of superglue
near the top and bottom of where the strut is to be placed and put small
nails in the mold and snip them off to the length of about a 1/16. I
put the drops of superglue on the nylon so that there is no run in the
nylon when I put in the nails in the mold.

 

3) When the plastic is ready I place the strut on the positive so that
the nails grip the strut and prevent it from shifting. I quickly pull
the remaining nylon down over the mold and tie it off. There is plenty
of working time as long as the plastic is adequately heated.

 

4)The plastic is then vacuumed over the mold and all the air is removed
from between the strut and AFO section forming a solid bond.

 

I have also tried this without pulling a nylon over the strut but air
would usually get trapped between the strut and AFO plastic. I hope this
info is helpful.

 

Best Regards,

Bradford Baker, C.O., C.Ped.

 

Make sure your mold is a dry as possible.

 

David Mitchell, CPO

 

Good Morning,

>

> In an attempt to reinforce a child's thermoplastic AFO ...

>

Ed, we place the reinforcements on the outside of the plastic after the
vacuum pulls it into the model but before it starts to cool at all. If
the plastic is not the same thickness we usually preheat which ever is
thicker. After the device is cut off the model, the reinforcement is
blended into the base plastic by sanding and buffing with the Tycro
cones. We us one of the PDQ ovens and have not had to preheat the
model. Terry

 

 

Ed - We always warm the cast, have been for the last five years or so. I
put the cast in the oven at the same time as the plastic, set timer for
ten minutes then pull out cast and prepare it while plastic continues to
cook. Makes a big difference. I've been pulling plastic for 18 years and
just started warming cast in the last five years. Seems you can teach an
old dog new tricks.

 Best wishes, C Long RTO

 



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