3D background sealing

[prawn]

Hello,
Most threads I have seen regarding sealing 3d backgrounds point towards using epoxy. Where i live epoxy is not readily available and the few sources online that do sell them charge over $100 for small quantities! I was wondering if polyurethane varnish can be used instead. Im not trying to seal the background due to toxic substances beneath leaching out but rather to protect the background from deteriorating over time.
Any help is appreciated,
Prawn

 

[mgmine]

Is this the type of epoxy that you are talking about?
http://liquidglasscoating.com/1-quart-table-top-epoxy-resin/
It really depends on where you want to use the varnish. If using it outside than it wouldn't work and for underwater it defiantly won't work. For outside you would need spar varnish but even that can't be used under water.

 

[Meyer Jordan]

Most any clear marine coating will work. Check on-line.

 

[prawn]

Thank you that is what i was hoping for