Re: Exactomer

Date: Thu Feb 01 1996 - 05:13:36 EET

Thomas Himmer wrote concerning Exactomer:

>Do you know what is behind this fruity smell? I guess not.
>I am also not allergic to Exactomer, but we use a respiratory
>protection mask for post-processing. We have heard, there is
>a higher risk of sensitivity (compared to SOMOS 3100).
>Also you can add filters which protect from TPM, Aceton, etc.

When working with ANY rp material (liquid, powder, filament, other ) and/or
solvent (TPM, Isopropanol, etc) it is highly advisable to use appropriate
safety equipment for skin, eye and respiratory protection. Just look at the
MSDS for each chemical/compound and you'll find most all have acute affects
if ingested, inhaled or exposed to skin (contact dermititis, etc).

A person may have an allergic reaction at the initial contact with a foreign
substance, or develop a sensitivity over repeated exposures. I was (and still
am) sensitive to Ciba Epoxies (SL5170 and SL5180) from the start, but I have
developed/acquired techniques to work with these materials without exposure.
 Included are eye, skin and respiratory protection as well as shop practices
to keep the chemicals where they should be. Discipline is the key to
success; establish safe practices and maintain them.

Switching to Exactomer was an attempt to attain the performance of epoxy
resins with reduced risk to allergic responses to epoxy. However, Exactomer
5201AR differs in process characteristics from Ciba's SL5180 so much I went
back to epoxy. Not to say I will not look again for alternative materials.
 In ANY CASE, working directly with SLA materials requires protective
equipment, whoever you are. Otherwise, one is only gambling one's own health
and probably won't have a job for long (employers are not tolerant regarding
unsafe work habits).

Although in passing by an SLA500 running with Exactomer, I can't help but
take notice to the fruity aroma, significantly different than epoxies or
acrylates. No, I do not know the components creating the aroma, but I do
agree an organic vapor respirator will remove the smell as well as those of
solvents. Moreover, a total facility/process design including HVAC, filters,
personal safety and hygiene is the broader solution.

Best regards.

Steve Deak
Hasbro Toy Group
Cincinnati, Ohio USA

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