Received: from opus.hpl.hp.com (opus-fddi.hpl.hp.com) by jr.hpl.hp.com with ESMTP (1.37.109.24/15.5+ECS 3.3+HPL1.1) id AA148284767; Tue, 15 Sep 1998 14:26:07 -0700 Return-Path: <hangtime@elnino.engr.sgi.com-DeleteThis> Received: from hplms26.hpl.hp.com by opus.hpl.hp.com with ESMTP (1.37.109.24/15.5+ECS 3.3+HPL1.1) id AA181434762; Tue, 15 Sep 1998 14:26:02 -0700 Received: from deliverator.sgi.com (deliverator.sgi.com [204.94.214.10]) by hplms26.hpl.hp.com (8.8.6/8.8.6 HPLabs Relay) with ESMTP id OAA07431 for <wind_talk@opus.hpl.hp.com-DeleteThis>; Tue, 15 Sep 1998 14:26:01 -0700 (PDT) Received: from odin.corp.sgi.com (odin.corp.sgi.com [192.26.51.194]) by deliverator.sgi.com (980309.SGI.8.8.8-aspam-6.2/980310.SGI-aspam) via SMTP id OAA12757 for <@deliverator.sgi.com:wind_talk@opus.hpl.hp.com-DeleteThis>; Tue, 15 Sep 1998 14:20:33 -0700 (PDT) mail_from (hangtime@elnino.engr.sgi.com-DeleteThis) Received: from sgi.sgi.com by odin.corp.sgi.com via ESMTP (951211.SGI.8.6.12.PATCH1502/951211.SGI) for <@relay.sgi.com:wind_talk@opus.hpl.hp.com-DeleteThis> id OAA14842; Tue, 15 Sep 1998 14:22:05 -0700 Received: from cthulhu.engr.sgi.com (cthulhu.engr.sgi.com [192.26.80.2]) by sgi.sgi.com (980327.SGI.8.8.8-aspam/980304.SGI-aspam: SGI does not authorize the use of its proprietary systems or networks for unsolicited or bulk email from the Internet.) via ESMTP id OAA07667 for <@sgi.engr.sgi.com:wind_talk@opus.hpl.hp.com-DeleteThis>; Tue, 15 Sep 1998 14:22:04 -0700 (PDT) mail_from (hangtime@elnino.engr.sgi.com-DeleteThis) Received: from elnino.engr.sgi.com (elnino.engr.sgi.com [198.29.104.45]) by cthulhu.engr.sgi.com (980427.SGI.8.8.8/970903.SGI.AUTOCF) via SMTP id OAA46303 for <@cthulhu.engr.sgi.com:wind_talk@opus.hpl.hp.com-DeleteThis>; Tue, 15 Sep 1998 14:22:04 -0700 (PDT) mail_from (hangtime@elnino.engr.sgi.com-DeleteThis) Received: (from hangtime@localhost) by elnino.engr.sgi.com (950413.SGI.8.6.12/960327.SGI.AUTOCF) id OAA03813 for wind_talk@opus.hpl.hp.com-DeleteThis; Tue, 15 Sep 1998 14:22:03 -0700 From: "Chris Rowe" <hangtime@elnino.engr.sgi.com-DeleteThis> Message-Id: <9809151422.ZM3811@elnino.engr.sgi.com-DeleteThis> Date: Tue, 15 Sep 1998 14:22:03 -0700 In-Reply-To: "Brad James" <bjames@exponent.com-DeleteThis> "Vacuum Drying" (Sep 15, 12:12pm) References: <n1306261805.58069@faamail.fail.com-DeleteThis> X-Mailer: Z-Mail (3.2.3 08feb96 MediaMail) To: wind_talk@opus.hpl.hp.com-DeleteThis Subject: Re: Vacuum Drying Content-Type: text/plain; charset=us-ascii
Brad, vacuum drying sounds like a cool plan. But getting the board down to 1/3
of an atmosphere sounds dangerous. From the little board-building experience I
have with styrofoam core boards like you're talking about, I can offer a little
advice:
A "full pull" of one atmosphere will crush a board down to 3/4 its
original size, caving in the bottom and flat parts of the deck.
Getting to 1/3 atmosphere is right at the edge where the styrofoam
can't
take it alone, so the skin takes a lot of the load from the vacuum, and
at that point you are risking damage by crushing and buckling.
Because the concave bottom shape went out of fashion years ago, I would suggest
trying to never go below 1/2 of an atmosphere. I'll never take one of mine
below 2/3 if I can help it. Maybe use a combo of heat and vacuum? Trust me,
it really blows (pardon the un-pun) to leave a board under vacuum, go for
pizza, then return two hours later to find a broken, shrivelled remnant of what
used to be a 1500-dollar slalom board.
Of course, all this only applies if you are vacuum bagging it, or sucking
directly from the nozzle of the board. If you put the thing in a
depressurization chamber or autoclave, then pressure won't destroy the board no
matter how high or low it gets because it will equalize inside and out. I was
just guessing you don't have a chamber because otherwise it wouldn't matter
what kind of vent plug the board has.
Rock on,
Chris.
-- Chris Rowe Silicon Graphics, ASD Product Design 650-933-8732 -----------------------
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