Structures

Scratchbuilding a Small Wooden Bridge

An Easy One-Night Project
  • Scale 6”x6” Guard Timber
  • Scale 8”x8” Ties
  • Scale 8”x18” Stringers
  • Grandt Line 1-1/2” Nut-Bolt-Washer

 

To begin, start with your plans and bill of materials close at hand. All of my lumber was cut to size with my Northwest Short Line Chopper and then sanded square.

Once all the wood is cut to length I use my razor saw and an X-Acto knife to add texture to my lumber. Now I want my bridge to have been in service for many years but still in working condition. With that, my weathering will be heavy. Really take care and pay attention to prototype wood, especially ties. Notice how the elements really punish the wood even if it is well maintained.

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Once you have the desired amount of texture, sand the wood with a fine sandpaper to remove any fuzz from the material. I really like to take as much care as possible to make sure my wood is as clean as I can get it. This will result in a more presentable model and photograph well.

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My son Jacob having fun helping with this project.

As I have stated in previous articles, my materials for weathering wood is India Ink, watercolors (burnt sienna and black), water and dirt. I use an aluminum container filled with just a little bit of water then add the India Ink (the amount of black ink is dependent on the level of weathering you want to achieve). The water colors I sometimes place on a plastic plate that I can add to areas of the model as needed.

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I brush on the water/ink mix and allow it to dry. Once dry, spots of fuzz that was missed in the initial sanding process is sanded off and I then continue adding coats of my dye mix allowing each coat to dry before the next one is added. This will tell me just how dark my wood is getting.

I do like to create sub-assemblies whenever possible. For me, it makes my projects a little more easy to handle. As you can see from the picture above, I have begun gluing the stringers together with small pieces of scrap wood I had in my junk drawer.

Now comes the fun part. As my final coat of wash is still wet, I brush on real dirt to my wood. I also use my finger in some spots to really smash the dirt into the grain and add more texture to the model. This will dry and then the access and larger pieces of dirt will be brushed off and sealed with a clear flat finish.

The dirt will also tie the colors together and add visual interest to your model. The results so far have been very realistic as you can see in the photo below (the ties are just placed on for the photo).

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I created a very rough drilling jig for my stringers by cutting 3 pieces of .40 styrene strips I made and measured the holes. Now I have a right (side one) and a left (side two) handed drilling jig.

I add my NBW castings and again add a light wash of India Ink followed by a dusting of dirt. This will add additional contrast to your raised details and the dirt will tie it all together.

Assembly

Most projects you will want to create a jig and place your ties into before gluing. This will insure all ties are perfectly spaces and aligned, however, since my little bridge has been in service form many years, I don’t want my ties to be perfect. I glued the ties down one-by-one but I did make sure the first tie was as square as I could get it. As I added the rest, I used a spacer, removed it just before my glue had set which moved the tie just enough.

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Now that my ties are all set in place, the guard timbers are next. I only added one coat of India Ink wash before I glued them to the ties. I am doing these a little different as I am going to add a heavier wash to simulate bits and pieces of debris that the train might pick up and hit the timbers.

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So I add the guard timbers to the model and add my NBW details.

Once added, I begin washing the die onto the timbers. Don’t worry about the ink getting onto the ties. Ties can fade slower in corners and the contrast will give your model a very realistic weathering effect.

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You can use your X-Acto blade to add
additional chips and scratches to your timbers
if you desire.

And there you have it. Now all you have to do is add the rail.

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