Homebrew PCBs

Stefan Trethan wrote:
> Hi,
> 
> just want to let you know 5 minute epoxy glue is not really suitable for
> long term use in CuCl, even out of the wet above the etchant it's no good
> idea. Came apart after maybe a year, maybe even longer. Turns brown and
> soft.
> 
> Replaced with some plastic rivets "welded" in.
> 
> OTOH rubber seems to hold up well, although i was worried because some
> compatibility page said it might not.
> Wide rubber bands that provide the PCB clamping force, cut from a bicycle
> tire, look like new, if possible even better.
> 
> silicone is also just fine.
> 
> ST
> 

Interesting. I've had the "24hr" epoxy continuously immersed in CuCl for 
8+ months and I can't detect any physical change except that it has gone 
more yellow. But it went yellow in the first month, and hadn't changed 
further since. I think not all epoxy is the same. I've always avoided 
the 5 minute stuff, as it never set as hard or durable as the others. 
I'm using low viscosity epoxy (http://www.westsystem.com) sold for fiber 
glass work to glue/seal various items permanently immersed in 20% 
sulfuric acid copper plating solutions, and my CuCl etching tanks. No 
problems after 1 year. In other parts I've used a structural type 
adhesive non flowing gel epoxy and find it stands up equally well 
permanently immersed. The color changes to yellow over time.

Adam