painting a base so it looks like concrete

What is the material you are intending to paint? I find the texture of the surface is as important as the colour if you're looking for realism.

When i'm simulating concrete i use a thin layer of mortar filler over the base material. This gives the same texture and colour as concrete and once it sets can be weathered to look like aged concrete.

I used styrene sheet one time, it turned out pretty good. It was for a 1/72 apron/ aircraft parking area, so it was just a flat slab really.

I cut the styrene to the size and shape I wanted, then cut expansion joints into it with a razor saw. Then I got out the liquid cement, whichever brand I had handy, and started stipling the cement onto the base with an old stiff brush. This gave it some texture, but not enough for what I had in mind. So I wrapped my finger in masking tape and sort of rolled it around in the still uncured glue. After the glue fully dries, I sanded the area lightly, knocking down and evening out the surface. It gave a pretty good looking texture with minimal work.

For the color, I started with a base coat of grey, just any neutral grey that I had on hand. After it dried to the touch, I added different shades of various other greys, some mixed with a bit of yellow to give it an aged look. Note: I was using an airbrush to do this, which allowed me  to apply the paint in a random, easy to control manner. 

After the concrete colors were dry, I went back into the expansion joints with a dark grey, think anthricite, almost black, to represent the tar. I also went in with a .5mm pencil and drew some random cracks around the surface. After all this was finished, I sprayed a light flat coat onto it to tie it all together. It looks pretty good, but unfortunately I don't have any pictures.

HTH

I just finished modeling a 1:1 bathroom, including using concrete backer board for the subfloor.   I have some cutoff scraps which I'm looking at using for concrete bases.  It is about 1/4 inch thick and has a 1-inch square pattern imbedded in the concrete.   They resemble expamsion joints.   It just needs to have some ramp lines painted and perhaps some POL stains and it will be good to go.

Check your local Lowes, Home Depot, or tile supply store.   A 3'x5' piece was less than 10 bucks.   It will not be all useable since there is also name brand writing cast into the sheet. 

I use a product called straw board which can be sourced very cheaply at any craft shop. I use a knitting needle to scribe in expansion joints between the slabs and use water colour paint to replicate the expansion joint material (canite).  A few applications of dliuted water colour for  oil and fuel stains and all looks good.

Cheers

Mike 

I cast in plaster. and then texture the surface. AFter that I use dilute washes of ivory black, raw umber, very very dilute burnt sienna, and sometimes some drybrushing with a dark grey. Concrete is not one colour its a wide variety and patches almost never match. I used an x-acto knife to score in the line and black cardboard to simulate the material in the expandsion gap.

This is a model of some newish concrete I recently modelled using the above techniques.

vespa boy wrote:

I cast in plaster. and then texture the surface. AFter that I use dilute washes of ivory black, raw umber, very very dilute burnt sienna, and sometimes some drybrushing with a dark grey. Concrete is not one colour its a wide variety and patches almost never match. I used an x-acto knife to score in the line and black cardboard to simulate the material in the expandsion gap. This is a model of some newish concrete I recently modelled using the above techniques.

what do you use to texture? I presume you wait until dry or close to dry {I would suspect the latter}

I use a material at work to deal with plaster called DURITE screen. We buy it in bulk but places like home depot sell it in small packages. I think the stuff when used up {it has a grit to it that rubs off, you can wet the durite and work your mold, with practice you can leave a babybottom smooth mold or part.} when it is grit free it might work as a camo net.

damp cotton material {a cloth diaper would be perfect} will remove the lines to leave a super smooth finish, I know that is NOT what we are looking for here, but if you ever need a smooth surface... {making a mold to reproduce a part may not work since the mold may change shape and or size during the process, I do freehand type molds for leg braces etc.} 

Has anyone tried dental plaster? A model railroad club I belonged to used the stuff for making mountains, tunnels, city streets, just about everything on the layout that wasn't track had a coat of dental plaster on it. Another thing you can use is plumber's putty. Spread either of these compounds out and level them up as you want then as it sets scribe in the construction joints and any cracks you might want in the finish. Paint with Model Masters old concrete and finish with a wash of alcohol and india ink. Wipe it with a cloth and it should be starting to look like old concrete. add a little grass or dirt to some of the cracks if you wish for extra interest.

The dental plaster we also used packed into homemade latex molds to simulate rock. This would be perfect for some dioramas. The detail is a lot harder to break than if made with plaster, you can hit it with a hammer.  

mpkev31b wrote:

why not just use real concreate? hell you can buy it at any lowes or home depot for cheap? and use it in small amounts? you get the " as real as it gets effect:

I agree that using concrete might not give the appropriate scale look, at least not used on its own.  I think you'd still want to apply some of the techniques for texturing that the others have posted here.

Great tips from everyone, too, BTW, I hope you don't mind if I borrow some to try.     I've only ever used the technique of using stiff cardboard, like the backing piece of a lined writing tablet, and that only for smooth, maintained surfaces, like an airport runway.

Regards,

Brad

On my model railroad dioramas I simply scribed styrene sheet plastic with an X-Acto knife then added a few cracks with the same blade and painted it with a concrete color of gray usually a light one. I would go back and weather it with a mix of alcohol and india ink which makes the lines pop out and gives it a little dirtier look. A bit of dry brushing and a coat of dullcote is about all it needs after that.

You can add a bit of interest by gluing little bits of ground foam in some cracks to simulate grass or weeds growing in them. 

the Baron wrote:

I agree that using concrete might not give the appropriate scale look, at least not used on its own.  I think you'd still want to apply some of the techniques for texturing that the others have posted here. Great tips from everyone, too, BTW, I hope you don't mind if I borrow some to try.     I've only ever used the technique of using stiff cardboard, like the backing piece of a lined writing tablet, and that only for smooth, maintained surfaces, like an airport runway. Regards, Brad

ya but useing the concrete as a base material,  of course you would probably have to use different techniques to make it look real to scale. thats what i was gettin at :)