I need to replace the headliner in my 75. My truck is basically a beater so I'm looking for a cheaper alternative than the plastic one. The cardboard looking ones still cost a little and will swell and get ruined again. I'm thinking about some kind of thin sheet plastic or similar that will bend enough but not take on moisture easily.

if your looking for something cheap why not do a sheet of dynomat.. will insulate the outside sound and can get it in a flat rubber mat.. would also leave you with a little extra headroom..

I used cardboard & carpet ,an haven't had no issues yet ,however that
stupid glue didn't stick!

I can take it off an reglue with better glue ,but just never got around!

http://s20.postimage.org/4e6p63d2x/pickup_001.jpg

I had heard about using foam board from an office supply store as the backer and then we added headliner material from a fabric store and it came out looking pretty nice.

Unfortunately the heat has caused it to shrink a bit and it is starting to come out of the trim so we'll be redoing it, probably with MDF.

This is what it looked like initially.

Another material I thought about using is coroplast(like they use for campaign signs). It's light, waterproof and easy to work with and in a few weeks there will be an abundant supply .

Might be worth a try.

What's left of the headliner you have now? I ask because if the current backer is usable and/or salvageable then a $20 can of spray glue + the standard headliner material that has been around forever now (the fuzzy stuff with a thin foam backing) would be a simple to install option. That material can be bought at fabric stores in a variety of colors and in the universe of upholstery materials go, it's quite inexpensive. Alternatively, if your backer is toast I've made them out of the heavy cardboard (nothing wrong with doubling up, it's only stronger) from appliance boxes which turned out to be ruff and tuff, however, that was before foam board was available, which sounds like an attractive option.

My existing one is so flimsy I barely got it out in one piece. Edges are so bad I will have a fun time even using it as a pattern.

I looked at foam insulation similar to what would go against a cement wall. I was thinking 1/2" would be an improvement if I could get it to stick. The backing I was considering a sheet of FRP but I've never used it for anything. I'm not sure about cutting and shaping it but it does seem to be flexible enough.

What's MDF?

Medium Density Fibreboard.

Thanks for the reply's. The MDF looks like a good alternative and cheap enough to try it without guilt!

Duncan beat me to it... MDF is the way to go. Made a headliner for my '74 when I had it with that. Turned out nice