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Discussion Starter #1
I
Just built this 4' girder bridge from parts bought at Lowes. It is all plastic construction and once painted should hold up well outside.



Here's how I did it:
I started with 1 -8' piece of 1 1/2" plastic and 2 -8' by 3/4 pieces of plastic trim from the screen section



I cut some 1 1/2' tough board into 3" lengths and built a ladder



attached te 3/4" to top and bottom of ladder to form flange



then added styrene angles to create the plate effect glued with crazy glue



Here is the first load test with a 4' span. A little defection.


With a 2 foot span no deflection and it looks better.



anyone know what color I should paint it?
 

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Looks very nice.

For paint, either black or aluminum color would be good for the plate girder section. Maybe a natural stone (light grays) for the abutments.


Kind of like these:




 

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Bills, looks good! I was going to say that it looked a little thin for the height of the plate vs the length and weight of the locos. Do they sell the plastic higher then 1.5 inches??

I just pulled out an old enginerring book, and an E-45 load rating (1910 standards) for an 85 ft long deck girder, has the plate at 8.5ft high, so should be 1/10 the span of the deck. I can't find my other book, but I believe it states a general rule of thumb for more modern bridges with higher weight loads goes up to 1/7 and even 1/6 leght of deck to plate girder height.

-Ray
 

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Discussion Starter #4
I quess for 1910 standards I would be close at 1:29 scale using a 2 foot span. 1/6 would require a 12" span. I don't know if they have other sizes.
 

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Gents,


This was my Great-Uncle at work back in the early 1900's in Western Canada building bridges.

I swear that some of them are still standing... Lad on the left is my Great Uncle a one Richard Graham. He even had his own private car ...

I will indeed have a private car on my "GR&G" railroad...


gg




 

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I know where the stuff for the screen is in the store and where to find some stuff like tuff board and evergreen is easy enough ( not uv stable buy the way)


but where in the store did you find a 8 foot piece of 1 1/2 plastic .... or what is it used for in real life ?
 

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Discussion Starter #7
Scott
I found it at Lowes with all of the trim and molding stuff. tuff board is from home depot. I am going to try to build an 8' diameter curve from it.
 

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Looks nice. I going to do something similar on one of my bridges using Tufboard. I would think about reinforcing the CA (crazy glue) joints as CA is not known to hold up to outdoor moisture very well.
I would paint it with a coat of flat black primer then a coat of high heat bbq black paint. It gives a nice dusty black finish.

-Brian
 

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Discussion Starter #11
Low note
I have a lot oftuff board ladder too. All of it is elavated and I want a more realistic looking road bed I think I wiil paint it bsck.

 

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Discussion Starter #12
Mike
I am using Tite bond 2 which is an exterior wood glue. I wiii know if it works in a week after being outside
 

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Discussion Starter #15
I need to find a different glue. I have used pvc glue before and I will try it on these materials. I started making an 8' diameter curve, but the flanges did not bind to the PVC as well as with the 4' bridge. The tight bond is not binding to pvc well.
 

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I think I'd be tempted to use the plumber's glue for pvc pipes.
 

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Nice job on that bridge, it looks great ! You asked about a color for your bridge. I'm working on a bridge now, and I wanted something that would show up on the layout.



Bridge is 1/8" acrylic (plexiglass) strips on side are styrene. Used Weldon #4 and Weldon S16 for adhesive. Available at TAP Plastics. Two 1/'2" x 3/8" Aluminum channels underneath for support attached with Liquid Nails construction adhesive.

Best wishes, Joe
 
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