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Peter W. Johnson
12-05-1999, 06:02 PM
ORIGINAL POSTING

>Hello All,
>
>I am looking to make a mold out of foam to repeatably secure a subject's
>forearm in an apparatus. Are there any medical or other types of foams
that
>can be poured into a mold, the subject rests their arms in the mold, and
the
>foam cures fairly rapidly? I know the foam can get hot and you have to be
>careful not to burn the subject's arm. I'm interested in people sharing
>their experiences and the foams (manufacturer, part# etc.) they have
>used/recommend.
>
>I will post a summary to the group.


Thanks to all that responded to my posting, below is a summary of the
responses I received.

Based on what I have received, it appears using foam for impressions of body
parts is probably not too practical due to the risk for burning subjects as
the foam heats when it cures. It appears that there are several viable
substitutes (read below) one being Alginate. From what I understand
Alginate, is a material used for obtaining dental impressions, cures at
room temperature and is non-toxic. It can be obtained suppliers of dental
lab materials. Here's a web-site showing how to get an impression/cast the
arm using Alginate (http://www.bioweapons.com/castingHandsFeet.htm).
Another option is to use the Alginate or some other
material to get a light cast/impression (negative) of the arm and just place
the negative in some foam and let it cure. A few other viable options
posted below as well.

Thanks and Regards,
Pete

SUMMARY OF RESPONSES


From: JOSEPH HALE
Date: Thursday, December 02, 1999 6:29 AM
Subject: Re: Foam for molds/impressions of body parts?


>Pete,
>An alternative to using foam might be to use a technique that is used in
rehab to produce contoured seat cushions. Basically, this involves a "bean
bag" type cushion filled with small foam particles which the subject sits on
(or in your case, rests their arm on) and then the air is sucked out of the
cushion. The result is a fairly rigid contoured mold that can be reused by
releasing the vacuum. Unfortunately, I don't have any specifics about where
to obtain this product. You might checked with your local rehab or P&O
folks. Good luck!
>
>Joe
>
>
>Joseph E. Hale, Ph.D.
>Research Engineer
>Minneapolis Sports Medicine Center
>701 25th Avenue South
>Minneapolis, MN 55454 U.S.A.
>tel: 612-672-4749
>fax: 612-672-4560
>email: jhale1@fairview.org



From: Chuck Pell
Date: Wednesday, December 01, 1999 12:37 PM
Subject: Re: Foam for molds/impressions of body parts?


>BJB Enterprises in Tustin, CA
>(714 area code last time I checked)
>Ask about 2-part polyurethane pour foams
>TC-series are nice, fast
>Also: specify foam density (mass / unit volume)
>Also: specify flexible or hard foams
>
>The foams cure very fast
>They do get warm --- can be hot
>BJB knows methods and can help
>
>Latex troublesome for your app
>
>Best person to ask for there is Jill



From: Jenny Cooper
Date: Wednesday, December 01, 1999 11:51 AM
Subject: Foam for molds/impressions of body parts?


>
>Here is a non-technical non-detailed response to your inquiry...
>Check with an orthodic prosthetics person. I had some
>orthodics made a couple months ago and there was a
>sort of plastic that went into a toaster sort of machine
>and was used to take a mold of my foot. This was then
>used as the bottom of the orthodic itself. It hardened
>fairly quickly, and wasn't too hot.
>
>An orthodist could give you the details.
>Good luck.
>
>Jennifer Cooper


From: Rafael E. Bahamonde
Date: Wednesday, December 01, 1999 12:33 PM
Subject: RE: Foam for molds/impressions of body parts?


>To:Peter Johnson
>
>I worked with a company that produce a product called "Quickcast". It is a
>fiberglass and rubber knitted sleeve that is impregnated with a polymer.
>Heat for a hair dryer is applied to the sleeve and causes the polymer to
>soften and conform to the anatomical part. The company name is LANDEC
>Corp., 3603 Haven Avenue, Menlo Park CA 94025. I published an article in
the
>JAB that maybe helpful.
>
>Bahamonde.R. and Malone, K (1997) Biomechanical testing of materials used
in
>the construction of playing casts. Journal of Applied Biomechanics, 13(1),
>2-13.
>
>Rafael
>


-----Original Message-----
From: Ed Lemaire
Date: Wednesday, December 01, 1999 12:04 PM
Subject: Foam for molds/impressions of body parts? -Reply


>You could use alginate to make the negative model and then manufacture
>your restraining apparatus from the negative. Alginate cannot be used to
>restrain an arm but is does make a good impression. This would add
>more work to your project but it is not harmful for your subjects.
>
>Edward Lemaire, PhD
>Research Associate
>The Rehabilitation Centre
>(613) 737-7350 x5592
>


>Date: Thu, 2 Dec 1999 08:31:13 -0500
>From: Stephen Sprigle
>Subject: foams for molding
>
>the wheelchair seating and prosthetics worlds
>do a lot of molding around body parts
>
>for seats and backs, a 'foam-in-place' kit from =
>
>dynamic systems would siut your app
>704-683-3523
>this is a viso-elastic type foam used for support
>
>otto bock or other prosthetic foam would also work well-
>this is a very lightweight, rigid foam
>612-553-9464

One last suggestion which I accidentally deleteed was a bean bag like device
tied to a vacuum compressor where the bag could be evacuated of the air and
comfom to the body part.



=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Pete Johnson, Ph.D.
Ergonomic and Research Consulting
4756 University Village Place NE, Suite 373
Seattle WA 98105
Phone: 206.276.7525, Fax 206.328.5618
e-mail: Pete.Johnson@ErgoRsch.com
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

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