[ATM] Moisture resistant baffles

["Jim Miller" <jim@jtmiller.com>]

I did some work last fall on improving my baffling but haven't had time to 
implement it after some experiments nor put the info on my website. I 
thought I'd just pass it along now for those interested.

I've been using black plastic corrugated sign board (CSB) (one brand is 
coroplast) for much of my baffling and attached it with industrial strength 
Velcro. CSB has good stiffness but can bend if periodically slit along the 
corrugations which makes it useful for implementing curves. CSB is 
lightweight and impervious to moisture. It also isn't sharp when cut which 
makes it unlikely to cut you in the dark. You can find CSB in the US at any 
home improvement, office supply, sign shop or plastic supplier. It's pretty 
cheap. Lastly when finished for the night it can be removed and laid flat 
for storage if necessary. I put mine in my chart case.

I found the surface a bit too shiny for my tastes, however, and sought to 
apply some flocking material to make it less reflective. My previous 
experience with paper backed flocking materials showed they work at first 
but when exposed to heavy dew tend to fail at the paper interface. John 
Sherman from the ATM list suggested Fidelio velvet from JoAnns fabric store 
as a very dead choice. Since it is a polyester fabric it won't be affected 
by dew like paper backed flocking.

After buying some I was then left with attaching it to the surface of the 
CSB. If you've every used CSB you know that not much sticks to it. 
Fortunately the industrial strength velcro sticks very well however. After 
doing a bunch of tests of various adhesives I found nothing that would stick 
well to CSB and be easy to apply to the fabric. So I decided to go to a two 
adhesive system as follows.

First wash the CSB in soap and water to remove the mold release. Next rough 
up the surface with ordinary sandpaper and remove the dust created. Thin 
some GOOP (home improvement stores in the US) with Toluol (home improvement 
stores) until it is a syrup consistency. Paint the thinned GOOP on roughened 
surface and allow to dry overnight.

Next layout your fabric and paint the backside with Weldbond glue. Lay the 
fabric on the GOOP-primed surface, smooth out without stretching the fabric 
and let dry.

I've found this combo will resist separating to the point of destroying the 
fabric when doing a pull test.

Hope this is useful for someone else.

jtm 

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