Things go better with dessicant

From: Thomas Wilson [twilson@ms.cc.sunysb.edu]

Sent: Monday, April 02, 2001 1:24 PM

To: UNOLS RVTEC Maillist

Subject: Things go better with dessicant.

I noticed that I was running low on dessicant and was turned off by the
cost of indicating silica gel from Thomas Scientific et. al. so I did a
little research and located a distributor of for a wide range of ready
made dessicant packs. The ones I chose are "MiniPax" sorbent packets.
They contain 12 grams of indicating silica gel. The dessicant packaging
is uncoated Tyvek, which seals in the (toxic) silica dust and indicator,
but has a clear strip so you can quickly check the state of the dessicant.

The distributor sells these packs in a can of 140 pieces for $34.01 plus
shipping (P/N 40AG51). They take credit cards and don't mind an order for
one can. They are also a great source of knowledge - I gave them my
pressure case dimensions and they were happy to tell me how much dessicant
I needed for that volume of space.

Poly Lam Products Corp.
PO Box 1734
Williamsville NY 14231

Tel: 716-633-1977
T/F: 800-836-9648
Fax: 716-633-2007
attn: Joe Stallone or Deanna
www.polylam.com

No commercial connection, just thought I'd share what looks like a good
vendor. I'd say I've drilled holes in my last 10ml Nalgene bottle.

Best regards,
Tom Wilson

*************** NOTE NEW AREA CODE AND EMAIL ADDRESS IN SIG *************** Thomas C. Wilson / Ocean Instrument Lab / Marine Sciences State University of New York / Stony Brook NY 11794-5000 USA Tel: 631-632-8706 / FAX: 631-632-3124 or 8820 / thomas.wilson@sunysb.edu "Opinions expressed are not necessarily, etc. etc...."

Answers:

From: Dale Chayes [dale@ldeo.columbia.edu]

Sent: Tuesday, April 03, 2001 4:22 AM

To: UNOLS RVTEC Maillist

Subject: Re: Things go better with dessicant.

Thomas Wilson wrote:
>
> I noticed that I was running low on dessicant and was turned off by the
> cost of indicating silica gel from Thomas Scientific et. al. so I did a
> little research and located a distributor.....

Tom,

It's good to know that there is an alternate (less expensive) source.

For years, we've been drying the gel and re-using it. Is that still a
legal (and safe) option in the modern era?

-Dale

Dale Chayes
Senior Staff Associate
Lamont-Doherty Earth Observatory of Columbia University
V: 845-365-8434 F: 845-359-6940 E: dale@ldeo.columbia.edu

From: Thomas Wilson [twilson@ms.cc.sunysb.edu]

Sent: Tuesday, April 03, 2001 11:44 AM

To: Dale Chayes

Cc: UNOLS RVTEC Maillist

Subject: Re: Things go better with dessicant.

On Tue, 3 Apr 2001, Dale Chayes wrote:

> Thomas Wilson wrote:
> >
> > I noticed that I was running low on dessicant and was turned off by the
> > cost of indicating silica gel from Thomas Scientific et. al. so I did a
> > little research and located a distributor.....
>
> Tom,
>
> It's good to know that there is an alternate (less expensive) source.
>
> For years, we've been drying the gel and re-using it. Is that still a
> legal (and safe) option in the modern era?

Yes, according to my research. I even saw a couple of internet sites that
said the gel could be regenerated by repeated short (10-15 second)
heatings in a microwave oven. I think I prefer a conventional oven. The
problem with regenerating the Tyvek packs is that the regeneration
temperature of the gel is quite close to the melting temperature of Tyvek,
so regenerating the packs can weaken the envelope and lead to cracking and
spillage. As cheap as they are, I think I'm just going to use the packs
once and then cut them up and drop the dessicant into my bulk jar.

For those with time at sea and no whalebone for scrimshaw, my favorite
reusable dessicant container is a 10 ml Nalgene bottle. Take a Dremel
tool and a #60 PC board drill and drill a lot of holes in the body of the
bottle, then fill with silca gel and fasten inside your equipment with
cable ties and cable tie bases. The dessicant is visible and can be
poured out and replaced with regenerated dessicant as needed. WARNING!
Don't be seduced by translucent film cans - the tops pop off much too
easily, and silica gel in o-ring grease is a mess best avoided.

Another dessicant container (cheap and good for slipping into tight
spaces) is a plain paper envelope - just use tape to seal instead of
licking it!

Overall, silica gel appears to be a relatively nonhazardous substance.
Inhaling crushed silica gel should be avoided (just like any silica dust).
The cobalt chloride used as the blue/pink indicator has recently been
classed as a potential carcinogen by the European Union but has not been
banned.

An online MSDS for indicating silica gel:
http://www.geejaychemicals.co.uk/cobaltchloride.htm#SELF-INDICATING
(BLUE) SILICA GEL.

For those needing to dessicate BIG areas, bulk nonindicating silica gel is
sold for drying flowers (maybe even in your local craft shop). Note that
you can mix 10% indicating silica gel into the nonindicating gel and get
an indicating gel at a discount price. One source for large quantities of
nonindicating gel is:

http://www.desiccare.com/stores/showprod.cfm?&DID=14&ObjectGroup_ID=5&CATID=1

A 30 pound pail of nonindicating gel sells for $75.00

Tom Wilson