Rocks

[lieperjp]

So, we are doing a show soon and would like to have a rocky coastline in it. I was wondering how you guys make rocks that look like rocks but don't weigh like rocks. Solutions we've done in the past, (which, in my opinion, look fake - at least as done by us) are paper mache and styrofoam+knife+blow torch+paint. Neither of these methods are particularly good because both are messy, the result is fragile, and they LOOK like they were carved out of styrofoam or formed with paper mache. Plus, I'm not a fan of people burning styrofoam on my stage (fumes, fire hazard... really. I didn't come up with the idea.)

I did some searching (of course I would search) and found the many versions of VSSSD. Now, do you just lather it on a board or something, form, and let dry? What do you do? Since it's a coast line, rounded rocks are preffered over stucco type rocks. I'd like to do something better.

 

[scenerymaker]

Find your local urethane spray foam house insulation guy. When he starts a job, he will run some foam through the hoses before they start spraying. If he leaves the spray tip off, it comes out like shaving cream, into a pile as big as you want. If you tell him what you want, he might just make you some for free.

Another way is to make a 2x2 & chicken wire form, covered with newspaper, then spray-foamed. In either case you will have to paint the foam unless you like yellow rocks.

If you want lots of rocks, cut out irregular bit rounded shapes from 1/2" and 2" blue styrofoam, then glue them on 1/4" luan plywood with suitable structure behind it, leaving random gaps from 0 to 1" wide between the stones, then spray-foam the whole thing. The foam will build up on the rock faces but not so much in the cracks. You can even have him put extra foam on the bigger rocks to give it more dimension. Paint to suit, but be sure to ask him about the correct primer for his foam. For the first time, I had paint fall off in sheets on my last one because of no primer!

 

[Van]

Ah The many versions of VSSSD ! and now I have another one that I developed for making Birch trees for 3 Sisters ! I've had a lot of success with Scenic dope applied to carved foam. The biggest issue that I've run into, with rock in general, is whether or not the rocks have to be walked on. If they are strictly a scenic visual then you can get away with much flimsier materials such as a paper mache' covered armature covered with scenic dope. If you are looking for the more rounded "River Rock" type look, then I'd use one of the recipes that I've posted that does not include any, or at least very little, drywall compound as these recipes tend settle as they cure and leave a much smoother surface.

As to my new recipe for VSSSD: Fosters #3036 Lagging Compound for indoor use.
It's so much better and cheaper than Acrylic/latex caulk, well ok it's cheaper, and better for certain uses, the caulk base is still useful too.
Fosters is a latex based, water clean up compound used and carried by many insulation contractors. I got a very sweet deal from my local distributor. Making smooth rock would be, I think a good application for the Fosters 3036 base. I'll try and get the new recipe posted in the Wikki tonight.

BTW I've found that breaking pieces of Blue / pink foam leads to some really cool facets that look a lot like the rocks on our coastline here. but we have a pretty craggy coast line with a lot of volcanic Basalt and it younger than some of your smoother old coastlines.

 

[BrianWolfe]

There are many easy ways to make realistic faux rocks. Whether or not they look fake is dependent upon how skillful your sculptors are. From what you describe, a rocky coastline, we would make a simple wooden frame, apply forming wire, spray with insulation foam, carve to shape and then apply a hardcoat(probably urethane). The paint finish can make or break the final look. Fumes are not necessarily a problem. The foam can easily be carved with sawzalls, knives, grinders, cheese graters, sandpaper or any other cutting or grinding tool. One of my favorites is a foam plane made to carve down sprayed in insulation foam between studs.

 

[ship]

First show I ever worked on was what about 28 years ago was "Gidget goes Haiwian" We used scrap lumber, chicken wire and lots of paper mache. Years later and under the rock in running the smoke machine for .... forget the opera about a rat given it's English and I love it... or was it the opera "Hansel and Grettle"... I forget. It was about the same method but with muslin covering the rock this time. No mice eating the scenery at least. Years later still in now designing and making a hovel for "Riders to the Sea" and back to no budget or time it was back to the dutchman method and mice. Right after that it was Six Flags NY. I was working on at a scene shop and we were using like four foot square by six foot long blocks of foam we carved with chain saw and grinder chain saw blades for the rough cut and grinders, variable speed routers and belt sanders with sand paper wheels to hone and finish while wearing full face masks and EPA suites because the foam got everywhere. This in addition to attaching blocks of foam to framing than shaping the foam. Large project, mostly all foam for their believe it was Ukon area.

In the mean time I also did spray paint and torch burning of expanded polystyrine and extruded polystyrine (white dot foam verses the more dense colored stuff) for stuff like walls and rocks at times. Advantage of say doing a spray paint texture of the foam is if the spray paint is flat or primer, the foam is ready to take latex paint afterwards. Otherwise one has to prime or Jesso it in making a surface that will take and not as easily flake the paint. Dutchman and fabric coatings take paint much more easily on the other hand. Takes extra work with foam to prime it for painting before the work can start on making it look like a rock. On the other hand given a normal support structure for using dutchman or fabric covering, it takes a bit more work to make it look solid so the framing don't show thru.

Never tried spray foam, remember my Uncle's truck from way back when that got spray foamed and such foam had shaping of its surface when not between layers the size of packing peanuts that would take a lot of sanding and work to get looking natural if that's the result of the surface texture. Expect spray foam these days even from a can is a lot more dense given at times large bubbles that would have to be filled. Filled in around my garage door with spray foam and the bubbles and expansion was also larger or more empty pocket bubbled than easily shaped.

Still though foam is fast to shape I believe but takes extra time to prime, typical rocks are faster to be ready to paint but take extra time to shape and cover. Overall, spent many years in being stupid as a caution. Can't walk by white foam these days without a lung remembered rememberence of not wearing a mask or doing so in a well ventilated area. CPVC's in the air I believe it is ain't a good thing. At the shop proper stuff, off work for the night, just a small wall I was carving.

 

[thatactorguy]

Find your local urethane spray foam house insulation guy.

If you want lots of rocks, cut out irregular bit rounded shapes from 1/2" and 2" blue styrofoam

We were able to happen upon three large cardboard boxes (18"x18"x36") of purged urethane spray foam. We made a headstone and "dirt" base out of some of it before the ED decided it was in the way, didn't know what we would ever do with it again, and threw it away. Many of us hoped that he hurt his back whilst tossing it in the dumpster That stuff isn't cheap...

Had to make a couple of quick rocks for Nunsense II and used the 2" blueboard method you described, using Liquid Nails to hold the pieces together. We didn't have time to cover the seams between the pieces, but with paint and distance, they worked well enough for the 20 seconds they were on stage. We still have them, which is good, considering I'm about to direct that show at another theatre

We used scrap lumber, chicken wire and lots of paper mache....It was about the same method but with muslin covering the rock this time. No mice eating the scenery at least.

Advantage of say doing a spray paint texture of the foam is if the spray paint is flat or primer, the foam is ready to take latex paint afterwards. Otherwise one has to prime or Jesso it in making a surface that will take and not as easily flake the paint. Dutchman and fabric coatings take paint much more easily on the other hand.

Expect spray foam these days even from a can is a lot more dense given at times large bubbles that would have to be filled. Filled in around my garage door with spray foam and the bubbles and expansion was also larger or more empty pocket bubbled than easily shaped.

Can't walk by white foam these days without a lung remembered rememberence of not wearing a mask or doing so in a well ventilated area. CPVC's in the air I believe it is ain't a good thing. At the shop proper stuff, off work for the night, just a small wall I was carving.

We made a huge tree trunk and branch for Secret Garden out of lumber, chicken wire, and paper mache, got it out a few months later for another show, and discovered the mice had gotten to it first. Oops, lol.

My experience working with foam (pinkboard/blueboard, EPS) is if you use spraypaint without first using a primer coat of latex, the foam melts like crazy. Discovered this quite by accident and subsequently killed the foam I had taken so much time to carefully shape, but have also learned to use it to my advantage on a couple of pieces.

Muslin/1x4 framing is definitely a good choice. Lightweight, and does indeed take paint easily, but as Ship noted, be careful when forming the frame, lest the telltale lumber or chicken wire show through.

I wasn't involved with this particular production, but somebody used that expanding foam in a can to make tree bark on 2'x12' sauna tubes. I imagine that was an expensive way to go, took forever to paint, but it did look fantastic!

Seems like it's either formaldehyde or cyanide that's released in the air when blue/pink board is burned. I don't think it's so much so with EPS, but proper ventilation and masks are definitely a must!!

But I think I'm preaching to the choir here...

 

[jessamarie6]

As another coating option for the foam I've always loved the look of Jaxan. It's a spreadable rubberized coating (originally a roofing compound), it takes paint really well and is incredibly durable. BMI and rosebrand both carry it I know, but at one point I had the direct number of the manufacturer and I'll post it back here if I can find it.

 

[dewalt827]

Did a show a few years back where we needed lots of craggy looking things, moon rocks basically, and we used carved styrofoam covered in a thin coat of Quikcrete and then painted them, it turned out the best of any of the rocks I have done so far.

The method of dutchman over chicken wire is lighter and usually easier to deal with though and the result is not that bad in my opinion.

 

[ship]

The Quikcrete / Cement or morter coating is very curious and a great idea. Did you have to move the scenery during the show in only question about it portability and did any flake? Did you pre-prime the surface?

Ah Jexan, something like that I believe was used on the roller coaster set.

Wonder if a coating if even flame proofing of not dutchman but paper meche' can be done, say flame proofing the exposed non-painted inside surfaces might keep the mice away?

Next option not mentioned might be of fiberglass molds and similar types of shape forming methods. Find a real life wall or mound you want to reproduce and cast it with a fiberglass shape and or a few layers of glued muslen. Once dry it holds its shape and all a question of support for it afterwards. This would be very light and strong and as long as the proper release method were found for the natual or carved setting of the above reproduced as a mold, it might work out well and be very strong.

Fiberglass of course very strong but a few layers of muslin can be almost as strong when glued. Might be a way to go.

 

[BrianWolfe]

One of the companies we work with did make fiberglass copies of real rocks for a Jeep commercial. Here is a link to the whole process:
Beyond Design, Inc. - Display & Themed Environments - NY Auto Show Jeep Liberty Rocks
It works but it is heavy, dangerous and expensiveto cast such monsters.

We also used the concrete coating for many projects. We used the stuff made for fake brick and stone facings on a house. It came with a special powergrip additive that made it stick really well to whatever substrate we used. It looks great but is very heavy. For scenery I prefer to use a sand paint for the same kind of fine texture. For a heavy texture you can take wall board compound and use a jiffy mixer to stir in saw dust. Put the mixture on with a trowel. As it starts to dry you can do all sorts of nice texturing. It paints easily and holds up pretty well. You can also add latex paint so that when it scratches it is not white. It is also very inexpensive.