Hey, I am sure everyone has seen them, they are used alot in parking lots during conventions, or at aggregate supply companies and mulch suppy companies. I can't find a picture of them anywhere, and I can not figure out how to model them. For those who can't place them they are about 3 foot tall and about 5-6 feet long and completly rectangular. How do I model them? Thanks, Mike
Have you seen the ones offered by BLMA?
Assuming you are not talking about Jersey barriers, or concrete vehicle stops (the BLMA stuff), are you talking about something like this? Is this image any closer (admittedly a wall of blocks) Or could you supply a picture closer to what you mean (I guess you would have to take a picture and post online)?
If it's just a rectangular concrete block (is there rebar sticking out the top acting as a handle so a forklift can manuever it - I think I've seen this), then maybe make a block out of styrene pieces, and rough up the edges a bit, and insert a section of wire for the rebar on the top, and paint - if you need a couple, either repeat, or make a mold out of the one styrene block, and cast a few more.
For whatever shape, I would get the prototype dimensions, make molds out of smooth-surface material and cast them in - gasp - concrete! Actually a moderately stiff mixture of 3 parts very fine sand to one part Portland cement. For objects with rebar cable anchors or 'handles' a little inventiveness with bent wire and spacer materials should produce the required results.
I expect to use the same technique and materials to fabricate large pre-cast concrete beams - an important flat car load for my prototype - and to 'pour' bridge abutments.
IMHO, nothing looks more like the material you're trying to model than that material.
Chuck (Modeling Central Japan in September, 1964)
tomikawaTT For whatever shape, I would get the prototype dimensions, make molds out of smooth-surface material and cast them in - gasp - concrete! Actually a moderately stiff mixture of 3 parts very fine sand to one part Portland cement. For objects with rebar cable anchors or 'handles' a little inventiveness with bent wire and spacer materials should produce the required results. I expect to use the same technique and materials to fabricate large pre-cast concrete beams - an important flat car load for my prototype - and to 'pour' bridge abutments. IMHO, nothing looks more like the material you're trying to model than that material. Chuck (Modeling Central Japan in September, 1964)
You also have to consider how well a material would scale down to your modelling scale. If you're going to "roll your own" so to speak, I'd recommend casting it/them with plaster or even spackle if it's not too thick. Most commercial manufacturers of a model that's supposed to be concrete will use either plastic or plaster. Actually portland cement, fine sand, and lime (to turn it white) is plaster, which you can buy in small quantities already mixed.
Sounds like the weights we use in our truck tests to simulate loads. Just a concrete scrap about 2' on a side and about 4' long. They weigh somewhere around 2000 lbs. When our source does it right, it has a centered "handle" of 3/4" rebar so we can lift them onto a tractor or trailer using a bridge crane in our garage. There's a pocket on the underside so they can be stacked one on top of another without crushing the handle. Last year, they skimped, used some real old 1/2" rebar. Handle on one snapped while about 3' off the ground, almost got a couple feet. We used to use 1000 lb cast steel blocks that were shaped so they could be interlocked, and had a couple hefty eyes cast in so a 3./4" pin could be used for lifting with the crane hook.
Why not just cut a number of scale 4' lengths from balsa or basswood roughly a scale 2' square, imbed a piece of 0.020" wire bent to about a 60 degree angle, paint it with artist's gesso, then a concrete grey paint? Paint the handle an dirty black or rust color. The gesso would give some texture, and could let yoiu work in some surface defects.