My customer wants to frame an antique dress more than 100 years old. It is made of a very heavy material and consists of a maroon velvet embellished top, skirt and underskirt. Finished size will probably be about 60x30. The customer wants to do the mounting down with a combination of stitching and velcro. She will do this herself. She wants me to provide the mounting board which I am to cover with a heavy, damask type fabric. The look is to be Victorian. The board will need to be quite heavy to hold the weight and to stand up to the mounting process. My first thought was to adhere two sheets of foam board to make a 1/4 board. However, from past experience, I suspect this board will warp badly. Fitting it into the frame will straighten this somewhat but I am still concerned about its viability especially since the customer will be handling it before I get to the fitting stage. Anyone have any ideas on a more rigid board, not too thick because of the frame depth limitation, through which stitching can be done?