Cleaning DuPont Somos(R) 7100 parts

From: MICHELLE P WYATT 328-8537 (
Date: Tue Feb 10 1998 - 20:46:36 EET

Dear Ingrid,
Isopropyl alcohol, used by itself, will not clean parts made from the DuPont
Somos 7100 Series. There are several other solvents available that will clean
the parts, including TPM which can then be followed by a rinse in isopropyl
alcohol (primarily to remove the TPM from the part and thus eliminating some of
the smell, not to further remove any remaining resin).

We have found another solvent, however, that we believe works better than TPM as
(although we have not yet been able to scientifically prove it) and that is
propylene carbonate. Propylene carbonate is relatively safe as far as chemicals
are concerned, has little to no odor, and appears to last longer than TPM.
Another neat trick is that parts will float in it because the density of
propylene carbonate is higher than the cured resin. The only potential drawback
(that we have found so far) is that it is slightly more expensive than TPM. You
can purchase propylene carbonate from Huntsmen Chemicals at 1-800-662-0924 (or
706-643-4637). For a five gallon container (50 lbs) the price is $4.63/lb.
There may be less expensive sources out there...If you want to purchase it in
larger quantities, the price substantially drops.

To summarize, when we clean parts in house, we rinse the part in propylene
carbonate and then rinse it in isopropyl alcohol, dry it and place it in the
PCA. Propylene carbonate can be substituted for TPM or a few other solvents.
I would be pleased to discuss this with anyone who would like further
information. I am also hoping to discuss this further at 3DSNASUG during the
break out session hosted by Beth Israelnaim on post-processing. I believe that
a more comprehensive paper on this has also been accepted for publication by
Prototyping International for this year's Annual Review.

Don't hesitate to contact me if you have further questions.

Michelle P. Wyatt
Technical Marketing Engineer
DuPont Somos
Two Penn's Way, Suite 401
New Castle, DE 19720 USA
Tel: 302-328-8537
Fax: 302-328-5693

For more information about the rp-ml, see

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