Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml
Date: Tue, 28 Jan 2003 08:40:36 -0500
Message-ID: <redirect-2001484@logan.com>
From: Newlan2dl@aol.com
Subject: Re: [LML] Re: Equivalent foam from ACS....
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Divinycell H-80 is 5 lb/cubic foot and will pretty much double your 
compressive strength and modulus.  Do you know if they were using Rohacell 
then?  

Another option is to use ultralight density aerospace grade balsa core.  This 
is 4-5 lb/cu ft. density and is off the scale strength wise compared to 
foams.  I would specify the AL-600 coating also which helps prevent excessive 
resin absorbtion.  You will find that NOTHING beats balsa for toughness, 
compressive strength and high modulus.  It is still the standard for aircraft 
floor panels for airlines.  As an aside, the earliest failures in the floor 
panels were caused by women's high heels (remember when airline travel was 
glamorous and everyone got dressed to the nines?) and the food carts causing 
core shear failures. Balsa fixed that and has yet to be beaten.  It comes in 
all the standard thicknesses.  There were incredible loads placed on the end 
of a spike heel!  And if you have to sand a side after bonding you will 
remove the AL-600 coating so be sure to hot coat it with epoxy or whatever 
resin you are using.  This is to prevent excessive resin absorbtion which can 
lead to resin starvation in the fabric and incredibly low peel values.  Like 
you can peel it off with your fingers.

You can get it in small quantities of this balsa (from Baltek) at Fiberglass 
Hawaii in Watsonville, California near Santa Cruz.  They also have good 
prices on all kinds of fabrics and resins.  Probably anything you need 
materials wise plus gloves, mixing equipment, etc.  Sorry I don't have their 
number here with me, it's at the office.

And one fiberglassing tip of the day.  If you have to sand fiberglass or carb
on, (I find carbon itchier than glass), spread some barrier cream on your 
exposed skin before you start.  It washes off with water and prevents most of 
the dust from getting in your pores thus ALMOST eliminates itching.  
Available at hardware stores, one brand is "Liquid glove" but there are all 
kinds.  And most don't wash off in acetone or MEK.

Good building!

Dan Newland
Super ES