How do I create a curved rock surface? I have a raised curve that I want to use a rock that curves. How long do I let hydrocal set before sticking the mold on the plaster sub surfeace?
Seems to me if the hydrocal is set firm and still moist that is even better than dry to get a nice Bond but you still need to put a kind of soupy layer of plaster between the plaster molds you're sticking to the hydrocal and that'll be good
I made this wall section using a flat hydrocal mold. I poured the mold and covered it with plastic wrap. After about 10-15 minutes, I moved the mold, which was still setting up but no longer soupy, to a piece of pink foam shaped to the desired curviture and let it harden there.
I've done this with a number of molds, and they've all worked pretty well. The curved subway station tile walls were bent around a section of 1x2 lumber.
A completely different option is to cast with Bragdon Foam rather than hydrocal. It can be reheated and cast around curves with a hairdryer. The foam has more of a learning curve, but the results can be quite spectacular.
It takes an iron man to play with a toy iron horse.
Cool I guess I didn't understand the question but thanks for the lesson Mr Beasley I refuse to get to the age where I'm too old to learn.
I used Sculptamold in an aluminum foil mold. The Sculpta mold has a longer working time than hydrocal or plaster, which I used for smaller rock work. First I shaped pink foam to the curvature I wanted. If you are having close tolerance for your trains, be sure to leave enough space for the form. Took a piece of foil and crumpled it, then straightened it out a little, leaving plenty of crinkles to look like rock. Mixed the Sculptamold a little thin, to fill the form. When it started to set I pressed it against the verticle foam wall. If your wall is very long you could do several forms and fill the gaps between with additional Sculptamold, then it will all take stains the same.
Good luck,
Richard
I'm not entirely clear on what is being asked, but if the OP wants to know how to apply a rock face of plaster, with its essentially flat back (top drying surface visible in the mold), onto a curved surface, it would be the same technique as 'back-buttering' a ceramic tile prior to placing it on a back-splash or on a floor. While you may place grout and trowel it prior to applying a tile over it, you still smear the back side of the tile with some grout prior to applying it in place. Same with flat-backed rock face castings, except you don't actually have to apply the 'grout' to the casting...only to the area where you intend to stick the casting. Wet any previously applied paster products FIRST, then smear some plaster that is close to setting up on the area you have wetted, then apply the previously wetted rock face molding. If you dont wet all plaster first, even if it's dry and hard for days, you'll just suck water out of the sticking 'grout' plaster you want to use as an adhesive between the two plaster faces. Wet it all first, apply the smear of 'grout' plaster product, and then slap on the rock face item. It should work well if you do it properly.
iwander How do I create a curved rock surface? I have a raised curve that I want to use a rock that curves. How long do I let hydrocal set before sticking the mold on the plaster sub surfeace?
I think I know what you are asking- how to stick the mold on the layout surface while the plaster is still wet to get the rock face to contour to a curve. I do this all the time. I don't have pics of a curve but used the same method to form the rock face here.
Its actually pretty easy if you have soft latex molds. Let the plaster set just enough so that it is like thick cream and then quickly position it on the surface. Press the mold in place so that it matches the shape of the landform until the plaster sets. Then remove the mold. Here is a section of the above rock just before pulling the mold.
And here it is with the mold removed. I use foam for my landforms but the method should work just as well for hardshell plaster.
Blending and painting are always the tricky part. But that takes practice regardless of how the rock is stuck on. I like this method because it is a lot easier to get the rock to contour to the shape of the landform (like a curve.) Getting the rock to meet the tunnel portals in this example was especially tricky.
Oh, I built above example as a module because of reach concerns. Most of the time I use the exact same method to create rock faces right on the layout. Here is a another photo of a rock face done this way.
Huntington Junction - Freelance based on the B&O and C&O in coal country before the merger... doing it my way. Now working on phase 3. - Walt
For photos and more: http://www.wkhobbies.com/model-railroad/
There was an easy way to make a rock surface shown in MR years back. It was by cutting ceiling tiles into strips, and then stacking them on top of each other. By cutting the strips into smaller pieces, the wall of ceiling til pieces can be shaped in any way you want. Finish the wall with plaster and paint.
I'm a'workin on the railroad.
Hello I made my own molds with gauze, latax so they are felxible.I used dura bond quick set it's for drywall repair. Pour it in the mold and as it start's to stiffen put it on. The back should still be a bit wet. I stuck mine to foam with a really rough surface. My mold was about 2' x4'' If I were to do it over I would make the mold 1' x 4'' would be easier to handle
Hope this helps Frank
I have done a ton of this on my layout. I put the mold on the surface of the layout as soon as the plaster is thick enough not to completely run out of the mold. It often squishes out around the edges a little, and that is good. I highly recommend dampening the surface you are putting them on slightly, especially if it is plaster or porous. If you do not, the surface will absorb moisture out of the plaster too quickly and you will not get a good bond. Hold the mold in place for at lease a minute, two or three is better. The good news is, if it doesn't adhere, it will at least dry in the contour of the place you want it to go and you can glue it on with latex caulk. Good luck.
Ron
Owner and superintendant of the N scale Texas Colorado & Western Railway, a protolanced representaion of the BNSF from Fort Worth, TX through Wichita Falls TX and into Colorado.
Check out the TC&WRy on at https://www.facebook.com/TCWRy
Check out my MRR How-To YouTube channel at https://www.youtube.com/c/RonsTrainsNThings
0-6-0. That's pretty innovative. I like how you used that idea to hide your 180 return. Coloring looks good too.
Nice work Frank
You know sometimes I'm amazed on how modelers come up with ideas to create something they need and it's almost free. I remember last winter I stumbled across, I do believe a YouTube video. This guy had his wife save the white styrofoam hamburger flats and he would cut the size strips he needed out of the bottoms. Then he used the common practice of a ballpoint pen to draw bricks or random Stone and then did color washes followed by dry brushing techniques. Then he would put them around a curve coming out of a portal or wherever he needed them. It looked fun, I had to try it. I was very pleased. They look better than the ones you can buy and it's always more rewarding to be able to say I made that.
Track fiddler 0-6-0. That's pretty innovative. I like how you used that idea to hide your 180 return. Coloring looks good too. Nice work Frank
Thanks but it was not really planed. I was just going to have a big farm but my dad gave me a shay and that's all it took. Two days later I was laying out a curved switchback. As for the color it is drak walnut stain put on with a brush and then some white craft paint dry brush on. It was a fun build but I think I would do it a little deffrent next time. Have a nice day Frank