On Wed, 25 Jun 2003 17:32:42 -0400, "Pat Brennan"
wrote in Message-Id: :

Larry,

I built mine for a couple hundred dollars years ago. I expect it has a
smaller HEPA filter than the one you quoted a price for -- I do not think I
paid more than 100 bucks last time I replaced it.

The filter in the JA-RO-CA Enterprises Flasking Hood is about 1-foot
by 2-feet.

I am sure it meets no
standards, but my contamination rate is very low.

That's what counts.

When selecting a blower it is critical to get one designed to operate at the
high static pressure required to get the air through the filter. Looking at
just the CFM is not enough.

How does one do that? The JA-RO-CA Enterprises Flasking Hood uses two
centrifugal blowers each mounted directly on an end of the motor
shaft. The motor is rated for continuous duty, but that doesn't
really address the issue of aerodynamic load on it.

Best deals I have seen on hoods are at state surplus auctions. Here in VA,
I see nice hoods (the open front workstation type) come up every couple of
months. They sell for very cheap money.

That sounds encouraging. I'm tempted to ask if you'd be willing to
act as my agent in procuring one for me. But the cost of
transcendental shipment might not make such an arrangement practical.

What's your feeling about the possibility of success in purchasing a
small HEPA room air filter unit, and adapting a hand-constructed
plexiglass hood to it for use in flasking small batches? They are
available for under $100 on eBay.

Pat
"Larry Dighera" wrote in message
.. .



Does anyone have any experience with or comments on this flasking
hood? http://www.jaroca.com/

There are three models, that retail for $1,072.50 to $1,122.50 each
(plus $88.00 shipping) for the Class 100 (99.97%.) units. The
brochure mentions that they meet or exceed the Federal Standard No.
209A which requires particle count not to exceed a total of 100
particles per CU. Ft. 0.5 microns and larger.

The blower puts out 200 CFM. The literature says, "Provides up to 75
FPM positive pressure to prevent airborne contaminants from entering
cabinet."

Some experts feel 100 FPM is appropriate air flow, not 75 FPM:
http://www.fungifun.com/flowhood/match.htm

Also offered is a filter-blower assembly (no hood) at $588.50 plus $?
shipping.

Replacement HEPA (High Efficiency Particulate Arresting) filters are $165.00
for the 99.97%, and $258.50 for the ULPA 99.99%, with prefilters
$66.00 per dozen.


It looks easy enough to construct one:

How to construct a hood:
http://www.fungifun.com/flowhood/

HEPA flitter sources:
http://www.hepafilters.com/CFS/filte...rance_sale.htm
http://www.filtersrx.com/sizes.asp?CAT=HEPHP9

Source for blowers:
http://www.grainger.com/Grainger/pro...mId=1611630999

http://www.surpluscenter.com/sort.as...t=1&keyword=EB
SA&catname=electric&UID=2003061222210572

Your thoughts?