Bridge building in balsa
- Thread starter Gavin Miller
- Start date
I wanted to disguise the hole with a highway overpass.
This would achieve two things. Allow road vehicle access to the industrial area on this module as well as cover the hole.
I have started building a highway overpass using balsa wood abutments and bridge supports (these will be clad with other material when the job is finished).
Here's the start:-
This would achieve two things. Allow road vehicle access to the industrial area on this module as well as cover the hole.
I have started building a highway overpass using balsa wood abutments and bridge supports (these will be clad with other material when the job is finished).
Here's the start:-
Attachments
This bridge has to be "purpose-built" for the location as it has to curve to mate with my curved backdrop.
I needed a material I could curve sideways and downwards at the same time (to form the incline on one side).
Balsa strips are ideal for this.
This photo shows balsa strips bent and pinned in place while my bridge design comes together "on the fly". he heh
I needed a material I could curve sideways and downwards at the same time (to form the incline on one side).
Balsa strips are ideal for this.
This photo shows balsa strips bent and pinned in place while my bridge design comes together "on the fly". he heh
Attachments
Well, after 30 minutes, this is as far as I have got.
But now I can at least see the "skeleton" of the desired final product. This is where balsa wood is just the most convenient modelling material. It is SO-O-O easy to work with (cut, glue, pin).
You can see the aeromodellers' "T" pins holding things together in this photo:-
(I'll post some more photos when I make some more progress)
But now I can at least see the "skeleton" of the desired final product. This is where balsa wood is just the most convenient modelling material. It is SO-O-O easy to work with (cut, glue, pin).
You can see the aeromodellers' "T" pins holding things together in this photo:-
(I'll post some more photos when I make some more progress)
Attachments
First the backdrop, now the balsa... Gavin, your work is quite fine and I personally thank you for your posts.
Thanks msh.
You might notice that my benchwork is also built out of balsa. This makes for super lightweight modules!!!
Balsa is actually quite strong. That's why aeromodellers use it!
Obviously if you king hit it or sit on your benchwork you will smash it, but how often do we sit on our benchwork?
My thoughts are - why do we use such H-E-A-V-Y material to build our benchwork when the only loads we intend to place on it will be no heavier than an N-scale train? (I use light weight foam for scenery).
As far as "above" the benchwork goes, well, my model bridge is never going to carry a load any greater than a few N-scale plastic vehicles so, even in balsa, it is "over-engineered"
I will cut and lay a styrene plastic road base/shoulder across the top of the balsa and use plastic Arnold highway railings to complete the bridge.
You might notice that my benchwork is also built out of balsa. This makes for super lightweight modules!!!
Balsa is actually quite strong. That's why aeromodellers use it!
Obviously if you king hit it or sit on your benchwork you will smash it, but how often do we sit on our benchwork?
My thoughts are - why do we use such H-E-A-V-Y material to build our benchwork when the only loads we intend to place on it will be no heavier than an N-scale train? (I use light weight foam for scenery).
As far as "above" the benchwork goes, well, my model bridge is never going to carry a load any greater than a few N-scale plastic vehicles so, even in balsa, it is "over-engineered"
I will cut and lay a styrene plastic road base/shoulder across the top of the balsa and use plastic Arnold highway railings to complete the bridge.
Great looking bridge idea! It goes to show, especially to me, that nothing is set in stone when building a layout and things can be added/changed even if they were not originally planned for. Thanks for the photos.
That looks great! I think designing the bridge to follow the backdrop curve helps the eye accept the illusion that the scenery goes on well beyond the bridge. Neatly done!
Ralph
Ralph
Some of the concrete has been "poured".
I used some mid-grey "German Board" (available from art stores) to cover the grain of the balsa and represent the "concrete" bridge abutments. I drew lines with a 2B pencil (then smudged a little with my finger) to represent the "pour" lines in the concrete.
I used some mid-grey "German Board" (available from art stores) to cover the grain of the balsa and represent the "concrete" bridge abutments. I drew lines with a 2B pencil (then smudged a little with my finger) to represent the "pour" lines in the concrete.
Attachments
Hi Gavin, I've been following your posts and have been intrigued with the layout construction from balsa wood. A lot of train modelers sell balsa short as a construction medium. As you have done, properly used it has great strength and you can do things with it that you cannot otherwise do with harder woods.
Unfortunately balsa has become rather expensive here in the US as most of the balsa sold here comes from South America (mainly Brazil) and the depleation of the forests and poor economys there have driven the price up. (I love to hear my airplane modeling buddies gripe!!
)
I was just curious as to where the balsa obtainable in AS. comes from....the Phillipines? or is it native to your part of the world?
Unfortunately balsa has become rather expensive here in the US as most of the balsa sold here comes from South America (mainly Brazil) and the depleation of the forests and poor economys there have driven the price up. (I love to hear my airplane modeling buddies gripe!!
)I was just curious as to where the balsa obtainable in AS. comes from....the Phillipines? or is it native to your part of the world?
Vic
I am not sure where we get it from (apart from the hobby shop haha). I presume Indonesia or the Phillipines. It is quite expensive here too if you want to complete a project using LOTS of it. But for my little bridge project, the 60 cent strips didn't break the bank!
I buy styrene sheet (for my roads, etc) from a plastics manufacturer by the metre - much cheaper than those little Evergreen sheets in the hobby store.
In this photo I have laid my bridge deck down onto a sheet of styrene so I can trace the curve of the bridge onto the plastic.
(You will note the four strips of balsa which form the bridge deck have been held in the correct curve by a batton of balsa temporarily pinned across them)
Next task will be to cut out the road section from the styrene sheet and paint it grey.
I am not sure where we get it from (apart from the hobby shop haha). I presume Indonesia or the Phillipines. It is quite expensive here too if you want to complete a project using LOTS of it. But for my little bridge project, the 60 cent strips didn't break the bank!
I buy styrene sheet (for my roads, etc) from a plastics manufacturer by the metre - much cheaper than those little Evergreen sheets in the hobby store.
In this photo I have laid my bridge deck down onto a sheet of styrene so I can trace the curve of the bridge onto the plastic.
(You will note the four strips of balsa which form the bridge deck have been held in the correct curve by a batton of balsa temporarily pinned across them)
Next task will be to cut out the road section from the styrene sheet and paint it grey.
Attachments
Hi Gavin and thanks for the information. Sometimes my curiosity "gets up" over the strangest things.
You might already know this...but if you wet balsa strips with Windex ( or any other amonia based window cleaner) they will bend even further then if dry. When they dry back out they will pretty much hold the curve bent into them.
You might already know this...but if you wet balsa strips with Windex ( or any other amonia based window cleaner) they will bend even further then if dry. When they dry back out they will pretty much hold the curve bent into them.
Hmmm ... no, I didn't know that, but this is sure a good project to try it out!
While my bridge "girders" are off the layout is a good time to give them a spray.
Thanks for the info.
Out with the Windex ...
While my bridge "girders" are off the layout is a good time to give them a spray.
Thanks for the info.
Out with the Windex ...
Yep, that's an old airplane building trick. Sometimes you have to bend balsa further than nature intended it too!!!