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Modeling wood to replicate bridge supports

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Modeling wood to replicate bridge supports
Posted by reasearchhound on Thursday, December 15, 2022 11:48 AM

Thinking of using wood to create concrete bridge supports for a long span (using one 150' Central Valley truss bridge and 4 ME 85' deck girder spans) on an HO scale club layout. Because of the size (height) of the span, premade supports are sort of a last resort so wondering if any of you have successfully recreated the look of concrete over wooden items?

Have seen where pink foam has been successfully used this way, and that is also a possible way to go, but just wondering how wood can be made to look like concrete as well.

Thanks,

Dan

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Posted by Browneye on Thursday, December 15, 2022 12:03 PM

Slap some plaster on it and paint it. 

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Posted by NVSRR on Thursday, December 15, 2022 12:23 PM

I seam to recall an article about that very topic. Using wood for abutments, piers and such. Lots of sanding involved if I recall

 

shane

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An optimist sees the light at the end of the tunnel

A realist sees a frieght train

An engineer sees three idiots standing on the tracks stairing blankly in space

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Posted by reasearchhound on Thursday, December 15, 2022 1:04 PM

NVSRR

I seam to recall an article about that very topic. Using wood for abutments, piers and such. Lots of sanding involved if I recall

 

shane

 
Thanks Shane. Do you recall if it was here or in one of the hobby publications? Anyone having a link would be great!
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Posted by doctorwayne on Thursday, December 15, 2022 1:10 PM

I cast my own bridge supports using Durabond 90 patching plaster in homemade sheet styrene moulds...

...all of the moulds are upside-down when they're being filled, so that the same mould can be used to create different heights, depending on the terrain over which they'll be installed.
I've made all of my bridges as one-piece constructions so that any bridge can be removed from its' supports whenever it's necessary for adding scenery ("water/trees/and assorted ground cover") or simply to vacuum-off accumulated dust or scenic debris.

Some of the bridges are over finished portions of the layout, while some areas are still needing scenery, but all bridges are removable as single-piece items.

Here are a few photos...

These two need some "water" in that riverbed, plus a lot more trees and ground cover for the surrounding scenery...

This one was languishing in plaster gully for ages...

..but I finally got around to adding some scenery...

I do have a couple of areas on the layout where I conside the "scenery" pretty-well done...

...and an aerial view of the same area...

This view was taken before I attempted to create a water scene...

...and here's the same area after a flood of Durabond 90 and some paint showed-up...

Wayne

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Posted by selector on Thursday, December 15, 2022 1:15 PM

I had some bits of shortened 1/4" thick MDF that I used to craft spline roadbed about 16 years ago.  I cut those to length, and glued them atop one another (on edge) to craft bridge abutments.  I painted them up, and this is how they turned out:

On the current layout:

When I first made the ones shown above, on my former layout:

A second batch I made for a photo diorama:

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Posted by NVSRR on Thursday, December 15, 2022 1:18 PM

Could always use Wayne's idea and substitute actual Portland cement.  

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An optimist sees the light at the end of the tunnel

A realist sees a frieght train

An engineer sees three idiots standing on the tracks stairing blankly in space

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Posted by doctorwayne on Thursday, December 15, 2022 1:38 PM

NVSRR

Could always use Wayne's idea and substitute actual Portland cement.  

Yeah, although you might need stronger elastic bands to hold the moulds together when they're being filled.

I doubt that the majority of my moulds would be of use to anyone else, as it would be expensive to ship the larger ones...not because of the weight, but mainly because of their size.  Maybe a club layout nearby could use them, as my bridge-building days are done.  I'd guess too, that some of the oddly-shaped ones would be of little use to anyone.

Wayne

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Posted by jjdamnit on Thursday, December 15, 2022 1:48 PM

Hello All,

Both Krylon and Rust-Oleum make rattle can faux-stone texture paints.

Krylon makes a coarse and fine texture while Rust-Oleum only makes one "size" of texture- -it appears to be a coarse texture.

The Krylon fine texture only comes in three colors: Granite, Pebble, and Charcoal, while the coarse comes in Black-Granite, Charcoal Sand, Travertine Tan, Obsidian, and White Onyx.

Rust-Oleum is available in Mineral Brown, Sienna, Pebble, Bleached, Gray, Black Granite, and Granite. 

You could use one of these as a base texture and then apply the color of your choice as a final coat to get the finish you desire.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by dehusman on Thursday, December 15, 2022 2:27 PM

The key thing for using wood is hiding the grain.  That can vary depending on the type of wood and how promenent the grain is.

Basically it means numerous coats of sanding sealer or primer followed by sanding each coat.  If there is promenent grain, rubbing drywall compound or plaster over the wood and sanding when dry will fill large grain.

You can also use sheetrock or plaster board.  Easy to cut and sand, then scrape the paper off one side.  It can be laminated and the edges dressed with drywall compund and sanded.

Dave H. Painted side goes up. My website : wnbranch.com

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Posted by Track fiddler on Thursday, December 15, 2022 4:54 PM

Hi Dan

Some good ideas posted here.

You can make piers and abutments out of wood.  You just need a table saw with a 10-in blade.

The pier angles are 3°, same as an engineering shim.

First made some foam ones but didn't really like em.

A couple coats of plaster is probably good enough for a model replicating cement.

Here's a sled tool made from styrene.  Used it for pulling a skim coat to look like piers poured in board forms.  

Pulled some blanks for paint samples recently.  A bit too taupe, briar or something yet, decisions....

 

Give it a try.  They're kind of cool to make.

 

 

TF

 

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Posted by reasearchhound on Thursday, December 15, 2022 10:29 PM

Thanks for the great selection of ideas everyone. I like the idea of a plaster coat worked to give a concrete like texture. Looks like I have some experimenting to do.

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Posted by dknelson on Friday, December 16, 2022 10:12 AM

dehusman
The key thing for using wood is hiding the grain.  That can vary depending on the type of wood and how promenent the grain is. Basically it means numerous coats of sanding sealer or primer followed by sanding each coat.  If there is promenent grain, rubbing drywall compound or plaster over the wood and sanding when dry will fill large grain.

Beat me to it!  But this is what I was thinking - back in the day when Ambroid had some kits using wood to model ACF center flow hoppers and other metal prototypes, the secret to success was sanding sealer followed by careful smoothing with steel wool or finegrit sandpaper or emery cloth, in repeated steps, possibly a good many repeated steps.  But with care a high gloss finish without any trace of wood grain could be achieved.  A bridge abutment would be the same idea but you would not want the high gloss.  It's an old school idea to be sure.

I have used styrene and some Tamiya spray paints that have a very flat finish.  I have also used plaster castings from Monroe Models, and resin castings from Chooch.

Dave Nelson

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