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Sheer Rock Walls

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Sheer Rock Walls
Posted by jacon12 on Sunday, October 31, 2010 8:14 AM

I have an area on my layout that is in dire need of near vertical rock walls.  This area is part of the logging railroad in the mountains.  I've seen photos of this done using some type plaster or hydrocal, carved when it is still wet, at least I think that is how it is achieved.  I know that rock castings may have been interpersed here and there, but it looks as though most of it is done as described.  This area is made of foam and can be taken off the layout and laid on its side to make it easier to work on.  What I'm after is the naturally occurring rock cliffs found in mountainous areas, without using rock castings.

My questions

 1- what material is mostly used to do this 'rock' work ?

2- how is it mixed, thick, thicker etc.?

3- how long is the 'working' time before it dries?

4- any special treatment for the foam, prewetting maybe, beforehand?

5- problems to avoid?

I can't think of anything else to ask so if you have anything to add I'd appreciate it.  Photos would be great also!

Thanks,

Jarrell

 HO Scale DCC Modeler of 1950, give or take 30 years.
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Posted by Hamltnblue on Sunday, October 31, 2010 9:44 AM

Here's a pic of one I have in progress.  I just started painting it last night. There are molds availabe with different patterns from rock to brick etc. Just get some molding plaster or lightweight hydrocal and mix it to the consistency of toothpaste or a little wetter and put it on the mold. Then press the mold against the wall you are doing.  After about an hour the mold will pull off easily. Complete dry time is a day or 2 depending on humidity. 

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Posted by Hamltnblue on Sunday, October 31, 2010 9:50 AM

Another option are products like these from scenic express.  If mine don't turn out as planned I still might switch to one of these.  The ones on page 14 of this pdf are flexible and look pretty good.

http://www.scenicexpress.com/Cat_15_PDF/083-098%20Catalog%2008.pdf

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Posted by Phoebe Vet on Sunday, October 31, 2010 9:54 AM

I like Flexiwalls:

Dave

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Posted by jacon12 on Sunday, October 31, 2010 10:57 AM

Thanks fellas, but what I'm after is the naturally occurring rock cliff faces you find in steep mountainous areas, not the retaining walls.

Ya'll have some fine looking retaining walls though!!  I appreciate you trying to help me out!

Jarrell

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Posted by Geared Steam on Sunday, October 31, 2010 11:10 AM

Jarrell

These are made of rubber, and a little pricey.....but are excellent IMO. Hot glue into place, cut to fit, they come already colored, but you can add more to change the tint if desired.

http://www.cripplebush.net/santa-fe/santa-fe-category.htm

I have used them on my layout, they are great.

"The true sign of intelligence is not knowledge but imagination."-Albert Einstein

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Posted by yankee flyer on Sunday, October 31, 2010 11:25 AM

Jarrell

I like carved foam. Here are some walls I did when I first started out three years ago. I use a knife to cut in and flick out the piece. I think it gives a chipped finish.

 

IMG_0394a.jpg stone walls picture by Yankeeflyer

IMG_0393a.jpg stone walls 2 picture by Yankeeflyer

Just one of many ways to do a wall. I use the rock molds to make a wall that is eroded with the rocks emerging from sod or dirt bank.

Just a suggestion.

 P.S. To quote an unnamed sculptor, you just cut away everything that doesn't look like a rock face.Whistling

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Posted by Hamltnblue on Sunday, October 31, 2010 11:25 AM

They might have what you want. Check out their site. They have rock walls as well.

http://www.sceneryexpress.com/departments.asp?dept=1087

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Posted by Phoebe Vet on Sunday, October 31, 2010 11:38 AM

I have some of the flexirocks, too.  But I don't have any pictures of them handy.

Dave

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Posted by BATMAN on Sunday, October 31, 2010 11:57 AM

Here's one under construction. The colours are very bright because of the flash. They are much toned down in person. It's made out of Pink Salmon coloured foam. So far so good.

I am going to be making a deep canyon wall where I will use the face of the foam instead of stacking it. I will glue caulk chunks on it for contour. We'll see how that turns out. It will be about 30" deep. The thing about foam is, if you make a mistake or are just not happy with the result you can easily caulk chunks back on, or just carve a little more, or just start over.Cowboy

 

                                                                                 Brent

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Posted by Grampys Trains on Sunday, October 31, 2010 12:31 PM

Hi Jarrell: This rock wall was made using a combination of Sculptamold/ Gypsolite, worked with a small artist's trowel. I also used broken, layered ceiling tile for some of the wall for variety. DJ.

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Posted by larak on Sunday, October 31, 2010 3:26 PM

 

Maybe these will help a little Jarrell,

Real rock below, structolite and castings above;

Carved Foam:

 

Structolite and plaster castings:

Structolite and real stone:

Pure structolite:

More foam (I couldn't find the shot I wanted to post but this gives you some idea.)

As you can tell, I like a variety of techniques but structolite is my friend

 

Karl.

 

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Posted by ARTHILL on Sunday, October 31, 2010 5:21 PM

I like carved foam

http://i12.photobucket.com/albums/a235/ARTHILL/SublimeCut1.jpg

This is plaster casts, The stones are carved foam

This is broken ceiling tile

If you think you have it right, your standards are too low. my photos http://s12.photobucket.com/albums/a235/ARTHILL/ Art
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Posted by A. Wallace on Sunday, October 31, 2010 5:40 PM

Sheer rock walls would necessarily be granite or basalt, as natural erosion and weathering in nature would create slopes of boulders and pebbles at the base. You might want to consider leaving space for warning fences (wire fences that falling rock, boulders, etc would break and set red signals). In  any even, unless you are a sculptor of advanced ability, you could not carve rock to match the real thing. Therefore, I suggest you get some liquid latex and go looking for real rocks that provide scale rock faces. Apply a couple of coats of latex at the site, (unless the rock is small enough to bring home: I have a garden full now), and peal off. Place cheesecloth on the back side, and apply several more coats of latex. This will help pervent the mold from cracking later.

     I recommend Hydrocal B-11, based of 30 years experience with it. It should be mixed to a thick soup consistency, and applied to the mold, then pressed into place. I use screen wire for the base instead of foam, as it allows more room behind for other tracks. To this, I apply 2-ply kitchen towleing cut into 4" squares, and dipped in thin-soup Hydrocal. When dry, it should be misted with water to assure the hydrocal in the mold will adhere when pressed against it.

     Coloring may be done with Acrylic paints, thinned to "washes". Raw Umber, Burnt Umber, Yellow, Black, and other browns, plus Red should provide enough different shades. (Be very sparing with the red, a toothpick-end worth will cause an amazing change in the color of your mix). If you have strata in your mold, consider brushing it with a slightly different color from adjacent areas, I recommend coloring with brushes instead of spraying, as it allows better control of color placement

     One consideration: If your track goes through "cuts", they would probably be better done as sloping dirt, as cutting through granite rocks would be expensive for a logging  road.  Some of my home-road work can be seen at www.freewebs.com/awwallace. I hope this helps.

 

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Posted by MisterBeasley on Sunday, October 31, 2010 7:26 PM

These are made using Bragdon Foam, from www.bragdonent.com.  I used one of the Bragdon molds, too.

The foam is a 2-part mixture.  It sets up pretty quickly, but can be softened and re-shaped with a hair dryer.  It's easy to cut with a knife.  There is a bit of a learning curve, but once you've actually used it, you may decide it's the way to go for those "signature" spots on your layout where only the best will do.  The basic starter kit comes with instructions, and they will help you through it via e-mail if you have questions.

 

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Posted by jacon12 on Sunday, October 31, 2010 9:36 PM

Wow, thanks for all the suggestions and pictures everybody.  I'm just going to have to make up my mind which method I want to use and go for it.  If it don't come out good, I'll rip it out and start over again.

Jarrell

 HO Scale DCC Modeler of 1950, give or take 30 years.
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Posted by Don Z on Monday, November 1, 2010 12:22 PM

Jarrell,

I'll second the motion for Bragdon molds. The level of detail in the molds is wonderful...these photos are raw castings I made using 2 different Bragdon molds.

I used white art plaster to cast them, letting the mix set up to the consistency of pancake batter before pouring into the mold. The mold can be applied to the scenery while still wet if desired, allowing the mold to follow the contours of the scenery base. I let the mix set in the mold for about 2-3 minutes before applying to the terrain I was working on.

Don Z.

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Posted by jacon12 on Monday, November 1, 2010 2:28 PM

 

 

Thanks Don.  I have a small box full of rock molds, some mine some belong to the club, but none of them have that level of detail.

Jarrell

 

Don Z

Jarrell,

I'll second the motion for Bragdon molds. The level of detail in the molds is wonderful...these photos are raw castings I made using 2 different Bragdon molds.

http://i44.photobucket.com/albums/f35/dkzimm/General%20pictures/06_20_08008_edited.jpg

http://i44.photobucket.com/albums/f35/dkzimm/General%20pictures/06_20_08009_edited.jpg

I used white art plaster to cast them, letting the mix set up to the consistency of pancake batter before pouring into the mold. The mold can be applied to the scenery while still wet if desired, allowing the mold to follow the contours of the scenery base. I let the mix set in the mold for about 2-3 minutes before applying to the terrain I was working on.

Don Z.

 HO Scale DCC Modeler of 1950, give or take 30 years.
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Posted by mikelhh on Monday, November 1, 2010 5:27 PM

I was going to suggest expanding foam in a can, carved and plastered or puttied - or clay-ed as I did mine,

 

 

but those Bragdon examples are hard to match! I'd like to get my hands on some of them.

 

Mike

Modelling the UK in 00, and New England - MEC, B&M, D&H and Guilford - in H0

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Posted by twhite on Monday, November 1, 2010 6:09 PM

Jarrell:

I don't know whether this will help or not, because you're modeling Eastern rockwork and this is Western Sierra Nevada, which means the geology might be somewhat different, but here's a shot of the sheer Sierra Buttes that I'm working on (still!) and they're made out of a combination of Cripplebush rubber rocks and Sculptamold using Bragdon castings.   I mix the Sculptamold 50/50 with water and let it set up in the casting for about 20 minutes before I apply it.  However, the resulting casting has a nice 'rough' rock texture to it and allows about 30-60 minutes to 'work' before it really sets up. 

Slow, but I like the results.

Tom Smile

 

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Posted by jacon12 on Monday, November 1, 2010 9:30 PM

 

Mike, that is a great scene!

Jarrell

 

mikelhh

I was going to suggest expanding foam in a can, carved and plastered or puttied - or clay-ed as I did mine,

 

http://i110.photobucket.com/albums/n108/mikelhh/Swanhurst/Swanhurst674.jpg

 

but those Bragdon examples are hard to match! I'd like to get my hands on some of them.

 

Mike

 HO Scale DCC Modeler of 1950, give or take 30 years.
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Posted by jacon12 on Monday, November 1, 2010 9:39 PM

 

Tom, thanks for the picture, you're pretty much doing what I had envisioned.  I think I'm going to have to do some experimenting with the molds I have on a scrap piece of foamboard and see if I like it.

Jarrell

twhite

Jarrell:

I don't know whether this will help or not, because you're modeling Eastern rockwork and this is Western Sierra Nevada, which means the geology might be somewhat different, but here's a shot of the sheer Sierra Buttes that I'm working on (still!) and they're made out of a combination of Cripplebush rubber rocks and Sculptamold using Bragdon castings.   I mix the Sculptamold 50/50 with water and let it set up in the casting for about 20 minutes before I apply it.  However, the resulting casting has a nice 'rough' rock texture to it and allows about 30-60 minutes to 'work' before it really sets up. 

Slow, but I like the results.

Tom Smilehttp://i299.photobucket.com/albums/mm310/TWhite-014/Rio%20Grande%20Yuba%20River%20Sub/DSC02357-1.jpg

 

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Posted by trainnut1250 on Tuesday, November 2, 2010 2:28 AM

Jarrell,

 

I would definitely go with molds. Let me add my voice to the chorus of approval for Bragdon (and others) rock molds.  On my last layout I hand carved rocks, not on this one...

Here is recent wall using molds.  casting plaster mixed, poured at the bench and applied when mix is beginning to set.

 

Have fun,

 

Guy

see stuff at: the Willoughby Line Site

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Posted by jacon12 on Tuesday, November 2, 2010 6:25 AM

 

Guy, what type base structure is beneath the 'rocks' and did you use the same plaster to attach them to that under structure?  How long did you have to hold the molds in place before removing them?  About how many different molds did it take?

That's a good lookin' wall!

Jarrell

 

trainnut1250

Jarrell,

 

I would definitely go with molds. Let me add my voice to the chorus of approval for Bragdon (and others) rock molds.  On my last layout I hand carved rocks, not on this one...

Here is recent wall using molds.  casting plaster mixed, poured at the bench and applied when mix is beginning to set.

http://img.photobucket.com/albums/v377/trainnut1250/20100830_0834aweb.jpg

 

Have fun,

 

Guy

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Posted by Raybo007 on Tuesday, November 2, 2010 8:59 AM

I love the way you used the painting of the bridge to add to the scene.  This idea will be used on my layout.

Thanks for sharing.

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Posted by Allegheny2-6-6-6 on Tuesday, November 2, 2010 9:21 AM

Here are a few work in progress shots of a steep almost versicle embankment leading up to a stone viaduct bridge. The face is constructed of ground goop over red rosin paper. Most of my scenery is constructed using the red rosin paper and white glue method over cardboard skeleton. just a different spin on hard-shell scenery construction. I wanted a little different look then the typical tree or brush covered hill side so i recalled asking a few members of the board who had experience working with ground goop as to weather or not it can be used on vertical surfaces.I would recommended even though the red rosin paper which holds the G/G just find one a layer of white glue starts to set up try using screen wire instead as I think it may hold the goop much better. I cut the rock strata with an artist pallet knife You can color ground goop any color you wish to suit the type of rock or ground cover your modeling simply by changing paint color. So far I am satisfied with the result.

 

 

 

 

I use real dirt for ground cover with some fine black cinders thrown in here and there to simulate spill over.

Sorry to say there is no rhyme or reason to my applying ground cover. I just start adding what I think will look right for the scene and hope for the best. I think they call it shooting from the hip. My one constant though is using real dirt.

 

 

 

Just my 2 cents worth, I spent the rest on trains. If you choked a Smurf what color would he turn?
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Posted by trainnut1250 on Tuesday, November 2, 2010 12:47 PM

jacon12

 

Guy, what type base structure is beneath the 'rocks' and did you use the same plaster to attach them to that under structure?  How long did you have to hold the molds in place before removing them?  About how many different molds did it take?

That's a good lookin' wall!

Jarrell

 

 

Jarrell,

Thanks for the kind words.

The base is two coats of Hydrocal soaked paper towels over window screen.  The molds are filled at the bench and applied to the pre-wetted base when the plaster starts to thicken.  I hold the mold in place for a couple of minutes to get it to adhere to base. The mold is left in place and then removed when the plaster setting makes the outside of the mold warm (5-10 minutes - it depends) .  The plaster in the mold is enough to firmly adhere the casting to the base. 

The area in the photo is two molds one is flipped and used again.  When using molds you can flip them over, use half of the mold etc to disguise the repetition.  Try to avoid the same mold from the same angle right next to each other.

I use casting plaster for the molds ($30.00 for 100 lb bag)  I like it for this purpose because it is a little easier to trim and work with than hydrocal but is almost as strong when set up.  I am fairly careful about using fresh plaster.  I break up the 100 lb bags when I get them into tightly sealed five gallon buckets to keep the plaster from absorbing water and losing casting strength.  Fresh plaster does matter when it comes to how well the detail comes out and how cleanly the mold comes off of the casting.. 

Edit:  I forgot to mention one of the most important things when dealing with molds...Clean them immediately after use.  I keep a five gallon bucket of water nearby and as soon as the mold comes off it goes into the water for a good scrub.  You can easily ruin a mold by skipping this step.

With a little experimenting with the setting times and plaster mix, I think it is pretty easy to get great results from molds.

 

Guy

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Posted by mobilman44 on Tuesday, November 2, 2010 1:00 PM

Hi!

My previous HO layout (1993-2008) had a lot of vertical rockwork, to the point that on my new layout (now under construction) I minimalized it.  Be that as it may, it was a highlight of the previous layout, and I'd like to pass along a few thoughts on the subject gathered from my experience.

-  First of all, I recently returned from a 3600 mile auto trip, from Houston to San Diego to San Clemente to the Grand Canyon to Chama to Taos and home.  The route followed the old SP route along I-10 and old ATSF along I-40, along with a number of other RR right of ways.  We paid special attention to all the rock formations and frankly "anything goes".  We saw some that "just didn't look prototypical", which just goes to show you can't go wrong no matter your formations or colors.

-  I did all the rockwork bases with nylon screening (metal screening will bite you) over wood forms and attached with staples. 

- The media was always plaster of paris - mainly because it is relatively cheap and readily available.  I always make several smaller portions (rather than large ones), and add a teaspoon of vinegar to retard setting.  This gives you about twice the carving or shaping time and minimizes waste.

- I would put on a rough base coat - just to set up the basic form - and follow it with a second or third to get the striations or separations cut in place.  I did use a lot of rock molds, and applied some while they were setting up and others after they had hardened.  Either way worked out, although I found the second method allowed me to more easily "design" the rock surface.  I would fill in the edges of the rock molds with thick plaster, smoothed out with a 1 inch wet brush. 

-  Sometimes I mixed paint with the plaster so future chips wouldn't show bright white.  If you are putting the rock surface in heavily trafficked areas I would do this, otherwise don't.

-  I erred when I painted the rocks.  I was warned and knew better, but put on acrylics that were just too dark.  Ha, they looked good when they went on, but seemed to darken when they dried.  I urge you to go lighter than you want - for you can always go darker, but going lighter is hard to do.

-  If you don't want to use rock molds, do your cuts and striations with a 1 inch brush and a couple of artists spatulas.  You really can't go wrong, for I am convinced there is a prototype out there for any arrangement or appearance or color you can come up with.

ENJOY!

 

ENJOY  !

 

Mobilman44

 

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Posted by rrebell on Tuesday, November 2, 2010 4:27 PM

Just built mine, used thin cast rocks of plaster using rock molds and used liquid nails for projects and glued them to rough foam sheets, then filled any gaps with plaster and a little carving while wet, worked great!

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Posted by selector on Tuesday, November 2, 2010 4:35 PM

I was mixing several scores of batches of Joe Fugate's goop, and felt that it could be carved for a rock face.  I had wanted to model a small rock face on Horseshoe Curve, and it turned out not bad.  The goop was greyish tan, but I stained it with black, brown, and umber heavy washes to what you see below.

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