I would be interested if any one living in more extreme climes tries this method and any resulting outcome.
Ok here we go. The girder work is from 25mm Fascia trim. Its available in 5 metre length from UVPC window suppliers for only £5.
I used just over 2 bits for this bridge. I went looking for an alternative to styrene products like Plastitruct and Evergreen cos it's expensive once you start using a lot of it, also this is stronger than styrene. The real boon is that this stuff is designed to be stuck together with CA In this case I used the very low viscosity "pink" flash glue. It sticks in about 30 secs and after 5 mins or so So its quick and easy, in short this is all you need.
I got the Mesh from an aquatic shop, its used to separate big an baby fish so the latter don't get eaten. he top bit is left at 25mm angle, the bottom bit is cut lengthways so its about 13 by 13mm. You can use a pair of compasses pressed against the edge of the angle to score a line along it. Do this 3 times and them cut with a heavy razor knife, such as a Stanley or similar. Use this method to make the uprights also.
The 12mm flat strip you can then score in half lengthways, 3 times should do it. Take care not to go right through though. These will form the diagonal braces,cut them to the desired length and then fold them to a right angle and glue from top corner to opposite corner of the uprights. Lastly cut some of the 12mm flat strip in half to make trim for the edge of the deck. Spray the whole lot with a rattle can of matt black or grey or what ever you want and add the track. Knock up a couple of abutments out of the same stuff with some brass contacts and you are there.
There was at the time I made this bridge in Oct 2008 a great deal of skepticism about CA standing up long term outside. I believe their still is. I have to tell you when I tried to separate two pieces of the angle I glued in error it broke the angle and the joint held. The bridge is a good as the day it was built, despite some extreme (from a UK perspective) weather conditions over 2009-10.
I am not getting into the "metal is better than plastic" this is just a simple alternative for those people that have limited resources in order that they may try something for themselves. Click on the tiles for a larger picture.