Another backdrop question

Model Railroader Layouts and layout building
1

I am part way through expanding my existing layout and finally installing a backdrop for all of it. So far, one side and one end have a backdrop consisting of 1/4" Masonite supporting .060" white styrene sheets.

My question is, how do I fill and seal the joints between the styrene sheets so I can start the painting process? I think I read somewhere that I should use plastic putty but I’ll be darned if I can find any such thing at the hardware store. Any help will be appreciated.

2

the plastic putty is sold at the LHS…it’s also known as model aircraft putty or modeler’s putty…it comes in white, gray, and even one with a purple color…it’s sold in a tube much like the old testor’s model glue tube used to be…use it in a well ventilated area as it has toluline in it and the vapors are harmful if you breathe enough of it…apply it in the crack, let it dry, then sand it down smooth …chuck