RE: Lost Core Urethane Castings

From: Richard M. Harrington (
Date: Thu Aug 28 2003 - 18:51:56 EEST

Hi John,

If I understand you correctly, we have done this type of casting with a
water soluble wax. You can find the material from any investment wax
supplier. You will need to melt the material with a muriatic acid/water
solution. You will also need to dispose of the resulting sludge through
a hazardous material vendor.

Good luck and please call if you have any questions

Rick Harrington
Harrington Product Development Center
"Your partner in product development solutions"
1756 Tennessee Ave
Cincinnati, Ohio 45229-1202
Phone: 513.482.4702
Fax: 513.482.4709
Web Address:

-----Original Message-----
From: [] On
Behalf Of
Sent: Sunday, August 24, 2003 12:54 AM
Subject: Lost Core Urethane Castings

We are planning to make some flexible hollow urethane castings. The
interior volume of these parts will have significant undercuts in the
direction of draw, so a conventional permanent core for the molds won't
do the job.

Does anyone have any advice regarding possible core materials that can
witstand the moderate heat generated when urethane resin cures, yet can
be melted or dissolved out of the finished part?

We've thought about using the wax material that can be used in a
stratasys FDM system, but were concerned about the heat generated during
curing of the part. Also, we'd considered using the water-soluble
Styratasys support material, but we're not sure if we can "trick" the
system into creating a part that consists only of the support.

Any advice or ideas?

Thanks in advance


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