RE: Waterproofing SL part

From: RePliForm Info (
Date: Sat Oct 27 2001 - 19:57:57 EEST

I've done testing on water resistance of selected SL resins immersed in
water for up to 10 days and at temperatures that vary from 35 to 90 C.
(Sorry not the two years your looking for and I have not tested the 5210
resin.) Of the ones that I have tested (~5 so far), ALL absorb some water
but the rate is quite dependent on temperature of exposure, wall thickness
and how the material has been post processed. If you are running at below
40C there are two resins that did well, Ciba 5530 with a thermal post cure
to 160C and Somos 7120 with a thermal post cure to 120C. The Somos 7120 (TC
120) material gained about 2% weight over 10 days in a thin walled section
(2.5 mm) while the Ciba 5530 (TC 160) gained about 3%. Length change of
these materials was nearly identical at about 0.6% over this time period.
This is about 2-5x better than other resins tested. There was little change
in stiffness of these materials over this time. Thicker samples, 5 mm and
12.5 mm showed similar trends but the weight gain and dimensional changes
were much smaller. If the sample will be exposed to temperatures exceeding
60C, then the 5530 HT performs best.
One other thing you might want to consider is plating. Given the size and
depth of your holes you will likely need an electroless process. It should
be relatively easy to deposit .03 mm of metal over the surface and this may
provide a greatly improved moisture barrier.
Sean Wise
RePliForm Inc.
1583 Sulphur Spring Road, Suite 126
Baltimore, MD 21227
Phone 410 242-5110
Fax 530 325-4768
email: <>
URL: <>

-----Original Message-----
From: []On
Behalf Of Geir Gu­mundsson
Sent: Friday, October 26, 2001 8:22 AM
Subject: Waterproofing SL part

Dear list members,

I am looking for a method to make a SLA part waterproof.
The part is perforated with holes 1 mm in diameter and 5 ? 10 mm deep.
The part will be submerged in water to a pressure of 0,5 bar.
Water will flow through the holes and every 4 sec. the part will be lifted
out of the water. This process will continue around the clock for 2 years.
It is important that the part holds it strength and form during this test.

Do you know of any method or coating to make the surface of the part
and the surface of the small holes, waterproof? I am particularly
concern about the surface inside the hole, as lots of coatings have to
high viscosity to penetrate into the holes without blocking them.

Do you think resin like SL 5210 or any other "water-resistant" resin
could be used in this case without coating. That would of course be
the best solution.

Thanks in advance

Mr. Geir Gudmundsson
Project Manager - Production and Automation
Materials and Environmental Department
IceTec (Technological Inst. of Iceland)
112 ReykjavÝk
Tel: (+354) 570 7100; Direct: (+354) 570 7192
Mobile: (+354) 899 1832; Fax: (+354) 570 7111

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