ORIGINAL POST
Hi List members-
Is there a technique of vacuum forming poly pro or polyethylene bivalve body jackets (not Kydex) where we don’t have to waste so much plastic? Now, we’re basically using enough plastic for two body jackets to make one!
Randy McFarland, CPO
Fullerton, CA
RESPONSES
If you are lining your TLSO’s with alimed or equivalent, don not cut off the waste section at the back but rather cut long rectangle windows out of the waste running down the edge of the bivalve join. Then buff down the alimed on the joining edge for a smooth edge of the foam and then mould plastic over the top. Plastic only needs to be big enough to reach to the foam waste at back of mould. Once the plastic has stuck to the foam this is now a sealed unit and vacuum is possible due the foam having been sealed together in the initial molding phase. The cut out window allows the piece to have a nice butt end to the foam as well as allows to have a nice overlapping flap for the plastic.
I hope this makes sense to you. Alan Bateman
IF you are vacuum forming an aliplast liner and you are able to get a good seal around your mould, leave it on the cast and carefully cut out a “window” around the area where you will want the anterior section. It must be done carefully so that you don’t cut your nylon or scratch the plastic. You then trim and finish the aliplast into the anterior opening of your orthosis. This should leave the plastic exposed around that opening. replace your finished aliplast into it’s spot and vac the anterior shell over it using the aliplast that is still wrapped around the superior, inferior and posterior aspects of the mould to keep the seal. If it is done correctly you would only need plastic large enough to cover the opening you made in the aliplast. This works just as well as vacuum forming an large piece of plastic but with much less work, and expense. It makes removal very simple as well. Gabriel
A technique that we have used for 26 years is fairly easy and simple and does not waste plastic. Lay the model to square up the supine portion.
Find the center line and quarter the circumference. This will make a half line on each side. Measure the plastic needed. Also, if you are using a liner trim it to fit the measured plastic.
Heat your plastic in the oven, lay down your liner, pick up your plastic and staple them on the half sides. Usually the plastic will layover the half line to have enough room to staple. Smooth out the plastic using silicone spray with thermal gloves over the iliac crests.
Doug
I think what you have here is the question-how much time and material you I want to put into this? You may be looking to save maybe between $10.00 to $20.00, mostly in labor and very little in materials. How much will it cost to investigate and field test a new method? Sometimes the devil you know is a good friend.
There are some materials such as sealing tapes (think caulk on a roll
here) That mold makers use to seal off sections of molds from resins etc. These may be a good place to start to seal off the part you don’t want to pull plastic over. Use your imagination and burn some plastic.
You will probably save money in the long run. I think it is possible to reduce your cost once you get things worked out.
Good Luck, Chris Beardsley, CPO
Sure, use aliplast. Seal the cast/mold with aliplast. Perforate the aliplast where you would like your plastic to be vacuum formed to and have at it! Instead of wasting plastic, you will be wasting aliplast which is cheaper.
Good luck, SSgt Matthew T. Hummel, ABC/BOC Orthotist Orthotic Lab, Keesler AFB
You can seal the back side of the mold off with Aliplast, instead of wrapping the Polypro all the way around.
Kevin Felton, CO, LO, FAAOP
Education Coordinator, Orthotics Department Texas Scottish Rite Hospital for Children
We pull one sheet ( usually modified) draping the plastic over the model to its lateral side. Then we cut the plastic off and glue firm foam to the posterior shell,( about an inch to an inch and a half in on the lateral trim lines) to act as a tongue between the posterior and anterior sections. You can vacuum form the firm foam then skive and glue into the model. Hope this helps. Mollie Matthews, CO
