Scratch Building a Bridge

[Anonymous]

I've arrived at the point on my layout where Ive realized that I have to build a bridge before I can run the trains. The existing overpass of 1" foam over 3/4" plywood doesn't leave enough clearance for the train to pass underneath, but I'll have plenty of clearance once the bridge is built. It'll be just under 16" long, and on a slight curve. The bridge will be straight, but wide enough to accomodate the curved track in it, just like the big boys would do. The bridge is this long because the track below it curves as well.

I've got a book on bridges, designs, changes in designs over time, etc., and I've settled on building a wooden truss through bridge. It's not completely prototypical for the stuff I'll be running, but I figure it'll be easier to mimic a wooden bridge than a steel bridge, and besides, it's my layout and I'll build whatever I think looks good, right? I figure I've got a RR running on the cheap, and until the bridge can no longer pack the weight, we'll keep the wood until we HAVE TO upgrade it to steel, right?

Questions for the group:

1. How would I model the bolts on the top of the steel suspension rods? I'll be using piano wire for the rod, but need to have a "big nut and washer" on the end of the rod. Suggestions? I'll be painting the piano wire a rusty brown / black.

2. How would you fini***he wood? My book says that the older bridges weathered to gray, whereas the "new" bridges were treated with creosote and weathered to a gray / brown.

3. Should I fini***he wood before or after I assemble it?

Any suggestions you'd give would be appreciated.

Mark in Utah

[Adelie]

I'll take a cut at #2 and #3, Mark. I'm going to wind up modeling steel bridges, but I do have a couple of small wooden trestles. I fini***hem with plain old Minwax. My own preference is black (they call it ebony, I think), Go to their web site, because I'm sure they have a gray/black color.

Fini***he wood before assembling the bridge. The reason is that whatever glue you use, if it "slops over" will seal in the finish. If it "slops over" unfinished wood, the stain will not cover that part very well.

[hminky]

I found a rather odd ball approach to weathered wood, I paint it white and stain the paint. It works after assembly:



It also works on styrene.



The three boards on the left are styrene the others are wood.

I have a web article at:

http://www.pacificcoastairlinerr.com/weathered_wood/

Thank you if you visit
Harold

[egmurphy]

I agree with finishing the wood before assembly.

Someone makes nut/washer castings, just for applications like this. I can't remember who right this minute, but give me a chance to look.


(Edit) Looks like Campbell Scale Models makes one, here's a link to the Walther's listing for them, unfortunately showing out of stock. Try your LHS.
http://www.walthers.com/exec/productinfo/200-925


Regards

Ed

[Anonymous]

hminky,

Your method of weathering the wood is good because it's not sensitive to the absorbtion of the paint or stain by the wood. It makes it look like the older un-treated wood that's been weathered. It works really good!

I'm wondering if I could do something similar to make a weathered creosote look to it, by using more of the darker paint (a richer mix) that has a few drops of brown paint and black ink mixed together.

Anyone else try to make a weathered creosote look?

Mark in Utah

[chateauricher]

Mark,

It would be helpful to know what scale you're working in.

[hminky]

QUOTE: Your method of weathering the wood is good because it's not sensitive to the absorbtion of the paint or stain by the wood. It makes it look like the older un-treated wood that's been weathered. It works really good!

I'm wondering if I could do something similar to make a weathered creosote look to it, by using more of the darker paint (a richer mix) that has a few drops of brown paint and black ink mixed together.

I am sure the white paint can be stained everyway possible. I developed the method making styrene look like wood. I just tried it on wood and it worked great. The problem with staining wood is the wood adds an uncontrollable color to the staining. My method still has the wood texture but makes the color controllable.
I model the 1870's so have not went into the creosote look. I am sure it can be attained.

Harold

[JohnT14808]

QUOTE: Originally posted by mark_in_utah
Anyone else try to make a weathered creosote look?

I also am building a creosote stained trestle and have the construction 99% done, with only one bulwark remaining to go. I used diluted india ink (suggested by a forum member) in a 40 drops of ink in 1/4 cup of isopropyl alcohol ratio. When wet, it looks dark, but lightens up to a pukish grey. Over time, however, the trestle has aged ( only phrase I can think of) a bit and really looks good now. I did stain all of my wood pieces prior to construction. I was also careful with white glue application and I used a LOT of q-tips to clean up any glue blobs during construction.

I am to the point of starting to plan how to install the trestle on the layout. I have to coordinate with another club member as this trestle leads to his project area (mining camp area) and he and I need to be on the same page. I foresee some gouging away of old scenery and supporting terrain for the track on either side of where the trestle will be installed. Then I can do any touchup needed on the trestle bends and stringers. Once installed on the layout I will place the final diagonal stress timbers from bent to bent. {I noted in one of the Turtle Creek articles in MR that when the trestle was installed, they had a devil of a time getting the "ground" formed around the bents, because of the bracing on the bents and the tight spacing. Hopefully, leaving the diagonals off until the last will help me get the trestle installed without major hassles.}

[Anonymous]

I'm modeling in HO, and the parameters have changed some, as well as my plans. Let me explain....

The bridge is now about 22" long after better measuring the required span length. After the scenery is added it MAY end up being longer or connected to a trestle on one end.

The minimum internal bridge width is almost 4 1/2" to allow for the curve in the track. Extending the bridge into the potential trestle area will not significantly add to the bridge width.

I can still build a wooden bridge and keep it prototypical, as the largest wooden train bridge was about 150', and was a Howe.

For now I substituted a piece of 1/2" OSB for the bridge to keep the track laying going. I'll continue with the construction work, and this will allow me to better formulate the bridge design to match what I finally build for the layout.

I still want to fully think this through, as this bridge will be right at eye level when you first enter the room, and I want to be SURE and get it right.

Mark in Utah

[GMTRacing]

Of course at 22'"you are right on the size of Walthers two track steel truss bridge so you may be able to be lazy after all and just kit bash. J.R.

[Anonymous]

Mark:

You can get N/B/W, that is: "nut bolt and washer" in various sizes and designs. Try the Walthers site online.

For wood bridges I have found an alcohol ink wa***o be the best way to go...Dilute india ink or sepia ink with alcohol about 20 parts alcohol to 1 part ink. There is no hard and fast rule here so use your "artistic license". I prefer the alcohol from the hardware store to rubbing alcohol as it has much less water to raise the grain of wood. I use various grades of sand paper, a distressing brush and old jewlers saw blades to roughen the wood stock before staining. I stain the stock before cutting and touch it up as necessary, mainly as a time saver. In prototype practice the wood was creosoted when the bridge was (usually) prefabricated offsite. As mentioned, the longer a structure was in the weather the more the sun bleached it. You may want to simulate some replacement elements by having them darker as an accent. Dont forget to do a bit of "rusting"detail to the metal parts and include a bird nest or two as "added points of interest" for the sharp eyed among your critics/visitors.

Good Luck and have fun.

Randy

[jacon12]

QUOTE: Originally posted by hminky

I found a rather odd ball approach to weathered wood, I paint it white and stain the paint. It works after assembly:



It also works on styrene.



The three boards on the left are styrene the others are wood.

I have a web article at:

http://www.pacificcoastairlinerr.com/weathered_wood/

Thank you if you visit
Harold

Harold, what a great tutorial on weathering wood! Thanks for putting it together. I've got it book marked.
Jarrell

[Anonymous]

GREAT TUTORIAL! Thanks for sharing it with us!

[Anonymous]

I use ZIG KURECOLOR permanent Alcohol based ink pens to colour timber structuires. The pens have fine and broad tips. They come in a variety of shades. I have the Cool Grey and Green Grey and have found that you can vary the shade by adding additional coats to darken it up.

Campbels and Grant Line are the two companies that I am aware of that produce detail bits for structures but I have not used either so am unable to comment.

I can't work out how to post pictures to the site to show the end result. If you are interested I can forward to your e-mail.