"Ancient" Asphalt

[Malachi Constant]

Neato-cool ... and I suppose since it's so flexible, it could be laid over a rough surface if desired to give more of a Mad Max disaster setting ... and chunks broken out completely, etc.  Nice work!

Cheers,
Dallas

[eTraxx]

Thanks Dallas. Couple additional thoughts ..

1. You don't have to crack the road up like I did. That was just to test the method. It pulled up 'crackless' .. ha.

2. I used an Air Eraser to texture the surface. I did that across the road surface and to erode the cracks. I'm thinking .. if I put down a layer of sandpaper .. and poured the plaster over that you would have instant texture!!

3. This is pretty easy and you can see how flexible it is. Seems to me .. that you could pour your roads (simple forms of stripwood, clay etc.) .. distress them as much or little as you wish .. paint, stain etc. all on the workbench. Then, simply pick up the strip and glue wherever you wish. Note that as flexible as it is, it will conform to the layout contours.

#3 means .. you could 'detail' your road on the work bench .. spin it as needed .. do all sorts of 'hooah' things .. then place it wherever. Seems to me that would beat the heck out of trying to create a road at arms length on the layout. The more I think about it ... the cooler that last bit is.

[Bexley]

Man, I love this forum.

I'm glad to see the gauze idea works. I think the only thing I might try different is to mix sand into the top layer of plaster. The cracks look too... like broken china. Too straight. The sand seems to cause cracks to run in crooked lines. (Though, without the sand, I think that'll be a great way to model a dried cracked lake bed, as the cracking looks spot on.)

I have the day off tomorrow, so I hope to get a good test run in. (And photos! I promise!)

[finescalerr]

Now THAT is COOL! -- Russ

[eTraxx]

<snip> .. I think the only thing I might try different is to mix sand into the top layer of plaster. The cracks look too... like broken china. Too straight. The sand seems to cause cracks to run in crooked lines. (Though, without the sand, I think that'll be a great way to model a dried cracked lake bed, as the cracking looks spot on.) ... <snip>

I'll have to try that. Seems reasonable that adding sand would cause the plaster to fracture in random directions. The thing to watch out for is proportions of sand/plaster. Need to keep notes on that as to the results. Enough to make the random fractures but not so much that the plaster won't bind everything together.

I want to try using sandpaper for the bottom of the 'form' to create texture and combine that with your sand idea.

[Bexley]

I would think that the sandpaper might bond to the plaster, though. (Or not- won't know until it's tried.) I pressed the sand paper into the top when the plaster was mostly set but still a bit soft, and that worked pretty well.

Also- no reference photos. I went up to the lot today to take pictures, only to find it had been bulldozed. Maybe for the better, though- I also noticed when I got there that the lot was part of the outskirts of an Army reserve base and a munitions storage facility. Loitering about the edges of such a place taking photos might not have been wise.

[Bexley]

Gauze test number one is setting up right now. I think I may have mixed the plaster too thin, and didn't add enough sand. (I was low on the sifted sand, and forgot to bring some home from work. I thought I had enough, but I think it was too little.) But we'll see.





This was from my first test. I didn't continue messing with it, as the plaster was too thick (3/16") and I wanted to try a test with gauze. But it did show me I was on the right track. This was the plaster, mixed with some sand that had been sifted out using fiberglass window screen, and some Woodland Scenics black liquid pigment. I should note that in this photo, the plaster is still somewhat damp, and it lightened up considerably after drying out. But the cracking is about what I'm looking for, though the pieces are much bigger than I'd like. (The two squarish pieces in the center are about 1/2" by 1/2".) After it had set up a bit, I pressed the surface with 50 grit sandpaper. I smoothed it down somewhat wth my finger, as it was a little too rough.






The gauze, soaked in the plaster and pigment mix, spread out on a cookie sheet. I added the sand after doing the gauze part, to make impregnating the gauze easier.






And the layer of plaster/pigment/sand. I spread it to about .080 thick, give or take. Once this has set up a bit, I will press the surface with sandpaper.

[Bexley]

Here is the sheet of plaster, textured, dried, and cracked. There is actually a lot more cracking, but since the gauze backing holds the pieces in place, many of the cracks all but disappear when the sheet is laid flat.





Here it is bent a little, to show off the cracking better. I don't think I will be able to get what I'd really like, as some of the smallest pieces would be 2" by 3" in real life, and getting this plaster to crack into pieces that are .057" by .086" is likely not going to happen. But it does give me very much the effect I'm going for. Either later tonight or tomorrow, I will go at the cracks with an air eraser and see what I can do.

My overall hope is that having all the pieces stay connected like this means I can lay it over colored Celluclay, and have the pieces not only keep their positions relative to each other, but conform to the surface of the Celluclay. (Of course, most roads, crown aside, are fairly flat. But my goal is a very old weathered destroyed road, where the roadbed under the asphalt has deteriorated.) My big concern is the gauze showing where the erosion is most prominent, but I think that the exposed fibers can be worked into the Celluclay and become invisible.

My other plan is to pour this using a form, sort of. As I want the road to be flush against a concrete curb, I intend to use either some basswood or a piece of styrene as a form to get one straight edge, which would be glued up against the curb. I also want to embed a manhole cover. I think I will have to glue the cover to the gauze first, then pour around the cover.

My biggest concern at this point is that the Celluclay, covered with "asphalt," curbs, and concrete sidewalk sections, will take weeks to dry- weeks I don't have. I may have to go with plaster as a base.

[Malachi Constant]

Hmm ... might not be the exact effect you have/had in mind, but dang that looks good!

Looking forward to the updates ...

Cheers,
Dallas

[marklayton]

I like the effect in that last photo - the pavement is cracked to a degree that makes sense.  Looks like a parking lot that has been in use for 30 years without resurfacing.  Thanks for posting the tutorial!  IMHO, some of the earlier examples in this thread were just too extreme, looking more like cracked hardpan in the desert than aged asphalt.

Mark Layton

[Bexley]

Here is the plaster after eating away at the cracks with an air eraser. I also rubbed in some ground up dark gray pastels, to make them stand out more. I'm very happy with the effect. I think the only thing I will really change is using the sandpaper to texture the plaster. When I rubbed in the pastels, the texture picked it up in a weird way and leads to the speckling. Other than that, though, I think I've worked out what I need to do. When I do the real thing, I'll probably use a lot more variation in the pastel/pigment colors as well as some washes. I'll probably also remove some of the little chunks entirely.

[finescalerr]

Looks quite good. Congratulations. -- Russ

[lab-dad]

Great experiment, great SBS.
A win win for all of us!
-Marty

[Frederic Testard]

Very nice result, thanks for sharing all this research process.

[Malachi Constant]

Ya know, Bexley, that last shot looks like a really boring photo of an old busted up street ...

(Rather than someone just trying to "model" an old street ... so ... WOW!  nicely done)