"Ancient" Asphalt

[Bexley]

I'd like to model some decaying asphalt for a diorama in 1:35 scale. There are plenty of methods for making relatively new or well-kept asphalt, but I want to model something that looks like it hasn't been repaved in thirty years- with the spidery cracks that have severely worn away. The primary difficulty I'm having is making that worn-away effect really old asphalt gets, where the individual pieces have rounded over and worn away around the cracks. My thought was to painstakingly scribe the cracks into tinted plaster which has been mixed with fine sand, then go over the cracks with an air eraser. However, I don't yet own an air eraser, and before I run out to buy one, I thought I'd see if anyone here has tried something like this before.

[eTraxx]

Interesting. How about if you poured a layer of plaster/sand the thickness you need. When set up break it/snap it. You could then round the edge with sandpaper etc and finally re-assemble like a jig-saw puzzle.

[Malachi Constant]

Bexley --

Check out the series of experiments Chuck did making slabs for his 1/24 diorama, starting here ...
http://www.finescalerr.com/smf/index.php?topic=446.105

Cheers,
Dallas

[Bexley]

eTraxx- The problem there is I'm looking at probably 800 (or more, that is just a guess) individual pieces- the area I'm looking to cover is about 4" by 5". I have used a similar method for medium-decay asphalt, but this stuff really needs to look destroyed. (The diorama is actually a post-apocalyptic Mad Max sort of setting, so the asphalt is really truly abandoned.) I had thought of laying a piece of cheesecloth into the form first, so that when I break it up, all the bits stay in position. This photo is close to what I'm looking to do, but the wear on the cracks would be far worse. I can't find a good reference pic- I'll have to take a trip up to the abandoned parking lot a few miles away with a camera to really show what I mean.



Dallas- I did see that. It is how I'm planning on doing the curbs and sidewalk, but the wear on asphalt looks much different.

Thanks to all for the input!

[eTraxx]

That looks like a really really bad 'crackle-paint'. Ok. Second suggestion. Take my first .. break up into manageable sizes, round edges a bit or not and glue back together. Then, buy crackle medium. That is used for faux furniture projects .. but .. I betcha you could get something similar using grays and blacks.

[Bexley]

Well, when I realized I would need an air eraser anyway to do the distressed concrete, I picked one up. I will photograph my test runs, and if I come up with something that looks good, I'll do an SBS on it.

Again, thanks for the help!

[eTraxx]

I may give it a try tomorrow .. you've got me interested .. and .. I picked an air-eraser up today myself at Harbor Freight

[Malachi Constant]

Bexley --

If you have some photos/links showing the effect you're trying to model, that might help produce some more suitable ideas ...

And, if you come up with a suitable approach in the meantime, post pix of that! 

Cheers,
Dallas

[eTraxx]

I was curious and experimented a bit. Poured a thin layer of plaster mix (2 parts plaster and 1 part Spectra Lock Sanded Grout (powder)). When it set I glued some wedding veil to the back with yellow glue. That way I could flex and crack it but it would stay attached (more or less). Colored with AI wash. White glue/water to lock in place. Painted gray acrylic, black acrylic wash, sprinkled brown dry tempera paint and scrubbed that into the cracks with a brush and tap water. Sprayed with matt. Not too bad for the first experiment. The car is a 1:48 Matchbox 1912 Simplex straight out of the box.

[Bexley]

That's mighty close to what I'm looking for. I've been too busy to experiment (or to drive over and get those reference photos)  but I hope to get a chance to play with some plaster tonight. (At least, I'd better, as the diorama is for a contest and I've only got three weeks left...)

[eTraxx]

I was trying for texture using the sanded grout mixed in with the plaster. Thing is .. that may have been better if I had used straight plaster. What I would have liked to get was the plaster to hold tightly onto the wedding veil material when flexed and cracked. Gauze might work also. Whatever .. so you can get the 'asphalt' to crack but remain in one piece.

[Bexley]

I get you. I had even mentioned above trying something similar, by pouring the plaster over a piece of cheesecloth, so that it would be imbedded in the bottom side.

I'm off to a good start, though. I mixed up some plaster, and added a generous squirt of Woodland Scenics black liquid pigment, giving me a nice medium gray. I also added several clumps of sand which I had sifted through a piece of window screen. (I used the batch that passed through the screen, not the stuff I sifted out.)  I poured this out onto a teflon cookie sheet. When the plaster was still soft and malleable, but had firmed up quite a bit, I used a piece of 50 grit sandpaper to press in a rough texture. The texture was a little too rough, though, so I used my finger to smooth it down a touch, and it came out looking really good. Once it was solid enough to remove the sheet I did so, and then began cracking it into small pieces. At this point, I'm not going to concern myself with the spidery patterns; I just want to test the basic idea. (Also, I appear to be out of cheesecloth, and I think to really get that fine texture I want, I'm going to need to be able to crumble it much more, and so I need that backing material.)

It looks really nice. The sand really gives the broken edges an asphalt texture. Also, the sand prevents the plaster from cracking in straight lines or gentle arcs, like it usually does. The cracks are crooked and look just like they do in teh road. I am optimistic, so long as I can find a way to wear down the edges to look like they've seen 150 years of exposure and a nuke or two.

(Sorry for the lack of photos- I went to take some, and discovered the camera battery was dead. It's charging now, and I will take photos before I begin the next step.)

[finescalerr]

Nice work! I'm looking forward to the next round of photos. -- Russ

[Ken Hamilton]

This is probably nowhere near the level of age you're looking for, but the technique
may be worth playing with....



My friend Narayan Khandekar mixes carborundum grit and white glue, spreads it on waxed paper
and freezes it in the freezer.  When hard, he peels it off the paper and breaks/cracks it and
applies it to the base. 

You might be able to add several layers to get your desired effect.  I suspect any appregate would
work (aluminum oxide powder, fine sand, etc.)
Just a thought.
Good luck.

[eTraxx]

Tried something different .....

1 - Poured a thin layer of plaster .. no coloring.
2 - When set laid a single layer of gauze
3 - Poured another thin layer of plaster
4 - let that set up and dry
5 - put the 'road' on a sponge and pressed all over to crack it
6 - Used Air Eraser to texture and erode the cracks
7 - Sprayed AI on both sides .. let dry
8 - Still had white in the cracks so used AppleBarrel Black Acrylic as a wash all over and down into the cracks. Let dry.
9 - Dry brushed FolkArt Steel Gray Acrylic

10 - on left third of road I brushed on Brown pastel powder (scraped from stick) then 'mopped' over with tap water


11 - center third left as was in step 9


12 - right third of road I brushed on Black pastel powder (again, scraped from stick) and 'mopped' over with tap water


.. and .. yes it's flexible .. no kidding!