Need Help with My Killjoy Raygun Build

[kingcamero]

I need urgent help. I have been trying recently to make a replica Killjoy raygun from My Chemical Romance's music videos (My Chemical Romance - "Na Na Na" (Official Music Video) - YouTube)

and I think I came pretty close with the picture that is attached to this post...
It is made out of foamboard and posterboard.. I knew that spraypaint would dissolve the foamboard so I thought it would be a great idea to cover it in resin to hopefully spraypaint it later.
Well it turns out the resin dissolves the foam also, so I need help!! What can I do to still get the effects of the resin that wont dissolve the foam? Cause I have two more of these that I have to send out this Sunday for Christmas gifts.

 

[kingcamero]

I have attached close up pictures of what the gun looks like after the resin compared to close ups of what it looks like with out, so hopefully someone can tell me what went wrong and help me find a solution.

 

[Birdie]

I'm pretty sure if you spraypainted them with acrylic paints they wouldn't melt. I'm not really up on working with foam, but it may be you'd get a better result with polyeurethane resin over polyester, if that's what you are using.

The guns look like mods of old Sega lightguns to me.

 

[kingcamero]

Ok thanks! Yeah I was using a polyester based resin it was just the generic one I found at Lowe's, so I bet that was the issue.. And I didnt know that they have spray acrylic paints where do you get those?

 

[Birdie]

Ok thanks! Yeah I was using a polyester based resin it was just the generic one I found at Lowe's, so I bet that was the issue.. And I didnt know that they have spray acrylic paints where do you get those?

Well, I don't live in the US, but you could try checking out your local hobby store for Tamiya's range, pretty sure you'd be safe with them

 

[HmHinkle]

I did the same thing and covered the foam in a thin layer of wood filler. I then made a mold of the gun in silicone and made a resin casting. Looks just like the real McCoy.