Modeling concrete sidewalks - what paint color?

[Anonymous]

The best way to get a flat back on any mold is to create a plaster backup. With the master still in the mold, set it on a flat surface like styrene, glue a band of strips for a dam around the mold leaving a small clearance, and pour plaster, screeding it off (scrape a straight edge along the dam) and let it set. It helps to mark one edge of the mold and the backing so that correct orientation can be maintained.

With the mold set in the flat backing, any irregularities are eliminated.

[tcf511]

Postdog2 I actually have that and thought about using it but everything on the bottle just assumes that you are going to use it with their road system. Can you use it to paint styrene?

[Anonymous]

Well, if you prefer your concrete a little more on the light tan side, try Woodland Scenics Concrete Top Coat (they make Asphalt Top Coat, too).

[davekelly]

Mister Beasley,

Excellent idea. Gonna have to try that!!

[tcf511]

Thanks Redleader. I do have the expansion joints accounted. I guess I'll experiment with a few pieces and then take them into town and compare to the sidewalks there. Weathering with chalks can always help too.

[RedLeader]

Actually TCF511, the color of concrete depends on where youre located. This is due to the agrgates color. In some areas you will find an almost white concrete, because it uses limestone. In others parts it can aquire a dark almost bluish color since it uses volcanic or river stones as agrgate. In my region, concrete is very light grey with a yellowish hue to it. If you're modeling a specific region, I recomend to look at picture of local industries and roads, that will give you a reference so you may copy the color. Start with a white base and start adding black and yellow until you get the color. That's the way I did it. A very important note, is that you will never find pristine brand new looking concrete, less in curbs and sidewalks. Most of the concrete's color is given by weather and filth. So what I did, was to paint some pieces of styrene and started excercising my weathering skills, until I got what I wanted. For that I used weathering chalks and diluted ink. Remember that concrete slabs need expantion joints every certain distance, or it will crack due to temperature changes, since it is a very rigid material. (eg: you should have slabs for pavement larger than 5m x 5m).

[CNJ831]

QUOTE: Originally posted by ukguy

Mister Beasley : When you made the latex moulds how did you stop them from being so flexible and therefor make a flat casting. I tried to made a mould from a DPM wall section, I put on about 7 layers but it was still too flexible to make a good FLAT cast.[:(]
Any help would be appreciated.

Karl - Are you sandwiching in layers of gauze between applications of latex? In my experiece I don't think I've ever needed more than 3-5 applications of latex to form a reasonably sturdy mould. In my case, I've been using moulds roughly 4x6 inches in size to make stone wall sections out of plaster...DPM walls aren't much bigger than that.

With regard to the moulds laying flat, I suspect that too many layers of latex are the reason for the very uneven "back" of the mould. At 3-5 layers mine are almost flat.

CNJ831

[ukguy]

One sugestion I can offer regarding the backing and difficulty drying would be to drill small 'breath holes' in the styrene or other backing material, maybe this will assist in the drying of the sandwiched layer. Although thinking deeper into this solution maybe the latex near the breathe hole would dry thus sealing the breath holes back up [%-)] Its a tricky one.

Let me know how it works out and I'll do some experiments of my own and let you know.

Have fun & be safe
Karl.

[MisterBeasley]

Next time, I'm going to try making a "flat mold", and then joining that to the back of the real mold with the final layer of latex sandwiched in between. Given that I had trouble hardening the latex with a hard back, I give this only a 50-50 chance of working any better, but it's a cheap experiment.

[ukguy]

Thanks for the info Mister Beasley, sounds like I'm doing the same as you. I'll keep on keepin' on, and try some slight variations.

Have fun & be safe,
Karl.

[MisterBeasley]

I've made 3 molds so far, so I don't really consider myself an expert. Two of them came out pretty well, but one was a problem. I only used 4 coats, applied with an old crummy paintbrush. The problem mold was fine on the face, but the back was very uneven. I think this happened because I didn't pay much attention to the back surface as I was putting down layers, and I ended up with high and low spots. I suspect this is the same problem you're seeing.

I tried putting down a layer of latex on the back of the problem mold, and then pressing it flat with a piece of styrene. Unfortunately, when I did that I discovered that the latex wouldn't harden up at all. I guess it needs air. So, I took off the styrene and just smoothed the back as best I could. This gave me a mold that's acceptable for the application I've got, although it's far from perfect.

I'm using Woodland Scenics latex. This is a first for me, so I have no idea if I happen to have a really old bottle, and it's therefore very thick, or if this is the way it leaves the factory.

[ukguy]

Mister Beasley : When you made the latex moulds how did you stop them from being so flexible and therefor make a flat casting. I tried to made a mould from a DPM wall section, I put on about 7 layers but it was still too flexible to make a good FLAT cast.[:(]

Any help would be appreciated.

Karl.

[tcf511]

Thanks very much to all of you. I guess concrete is more gray than what I was thinking.

[MisterBeasley]

I've been using flat gray primer spray paint from Lowe's. On flat styrene, it looks too even, but on hydrocal it's pretty good. I took a single sheet of Evergreen "tile," which is about 1-cm squares, and made a latex mold from it. I then use that to make hydrocal castings, which look very good when sprayed with the primer. For some, I also use a thin India Ink wa***o bring out the highlights.

[Anonymous]

For old concrete ,I use aged concrete(pollyscale),with a bru***hen add washes of white,brown and finally alcohol/india ink wa***o highlight cracks, for new just about one drop of black to about a capful of white,basically a very pale gray.

[Anonymous]

Tamiya deck tan is what I use for concrete on models. Give it a try, it actually comes out sorta worn light gray. Drybrushing a little 50/50 mix of white and tan will help add an aged effect too.

[tcf511]

I'm using styrene to model concrete sidewalks and curbs. I tried using Floquil
concrete color in a spray can but it looks too gray to my eye. I live in the woods
and don't have any concrete readily available for comparison. Do any of you have
any magic color combinations? I have an airbrush available or would me more
than willing to brush it on as well. Thanks.