I have quite a bit of layout to scenic which is just flat homasote. I plan to use plaster-soaked paper towels over a cardboard basket-weave in places where the track is on a narrow roadbed with open space on both sides, but what is the best way to create ‘ground’/‘terrain’ on the flat homasote?
Do I lay plaster-soaked paper towels on the homasote? Slather a coat of plaster directly on the homasote? Will plaster even adhere to homasote?
'preciate the help,
jcopilot
I have used drywall joint compound directly on homesite. I would assume plaster would work just as well.
Jcopilot,
Homasote is a paper pulp product that is pressed under extreme pressure to create a very dense sheet, which is porous, so any type of plaster will stick to it…Have been using since the 50’s.
The pic’. of the little rock out-cropping, is Hydrocal casting plaster buttered to the Homasote. Been there 25yrs, all the rest around it has changed, quite a few times. LOL.
Take Care! [:D]
Frank
Is there a specific reason why you want to cover the homasote? And have you sealed it with paint or something else? Plaster will stick much better to the raw homasote, maybe not so well to the paint. The areas where you’re just putting on a thin layer need to be on something that will not flex or the plaster will crack eventually.
If you just need to cover the homasote, painting it is a good first step, which is one reason I asked earlier. You can then apply any of the various ground covers and bond them down with matte medium or whatever you prefer. Of course, everything will be pretty flat like that, which is maybe why you’re thinking plaster.
Another product you may want to consider is Sculptamold. You can mix it was wet or dry as you want, which helps facilitate forming and spreading it. It holds up much better in thin layers, because the fibers in it help bind it together. You can rewet it later and texture the surface or add more. . Moderate flexing will likely not break it, but this depends on what you use for subterrain. It is more expensive than plaster, but gives good coverage. If you have a big project order a 50 lb bag. Most art supply places stock it and the cost per pound is much lower. Dick Blick usually has a good price on it in the various larger sizes and can send it right to your door.
In any case, Sculptamold is much easier to shape with a putty kinife than plaster for those gently undulating terrain forms around most RRs.
We all have our pet peeves. Mine is excessive flatness. Even spots that look flat in nature are rarely perfectly flat unless some person has made them that way. In model railroads the problem is emphasized by the fact that we all know there is a sheet of plywood under that scenery. To overcome this, I like to see an exaggerated variance in elevation. Something like sculptamold or Joe Fugate’s ground goop put down with a variance of plus or minus a quarter of an inch or so makes a big improvement in the appearance IMO.
Jim, Frank, Mike and Carl,
Thank you for your answers.
Frank - I like that rock. Adds a little natural interest to the scene.
Mike - No, I haven’t painted the homasote, don’t plan to. I don’t think it’s necessary to seal the homasote and as for scenery, I really want to avoid the pool table look. I hadn’t considered Sculptamold on the flat areas since I have already decided to use plaster over the cardboard lattice.
Carl - I agree with you about excessive flatness and that’s what I’m trying to avoid. Even little humps and bumps look much more natural than table-top flat and smooth.
Jcopilot
You’d be surprised to see what can stick to homasote – Especially if you need to remove it and then see how some of its’ paper-plys peel off. Experiment on a scrap piece of homosote for its’ long-term stickiness to homasote.
P.S.: March 2015 Model Railroader (and here) has a Lou Sassi update with his Make “ground goop” for ground cover. Ground goop can provide a ground surface that has a higher level of strength (especially for thinner cover), and can give that gently-rolling landscape on a flatter terrain. Also for roads, consider Durham’s Water Putty found at any LHS (local hardware store).
A quick way to make some moderatly sized hills on a flat surface is to crumple up some newspaper, then put your plaster soaked cloth, paper towels or newspaper over it. Saves a thick coat of Sculptamold. You could then spread in a thin layer over the new hill if desired.
Good luck,
Richard
Jcopilot,
The reason I asked about whether the homasote was sealed is that if it already was getting plaster to stick might be iffy. You would’ve wanted to rough it up again to get a decent bond.
I agree with Carl and you that you don’t want that pool table look – when things are finished. In my own case, modeling mountain RRs, I’ve overdone the “don’t make things flat” approach a few times and it’s been a PITA to go back and relevel stuff. Thank goodness for Scupltamold, which makes that relatively more easy. I generally leave plenty of level to begin with, then as I make final placements of buildings, lay out roads, etc I go back over things as needed to contour things in 3D, which is just a lot easier for me.
I mentioned Sculptamold because it is much easier to control than plaster is. Not that plaster wouldn’t work, as it will even in thin layers if it has solid support underneath. It’s just that Sculptamold is very easy to shape and taper. You can easily use it to form roads and terrain features and get them to convincingly transition into your various building sites and industries. It also will stick to most things, including plaster. It does absorb stains differently than plaster will, but there are ways to work around that. I thought it worthwhile to mention Sculptamold because it is just darn handy stuff for doing what you want to do and much more if you haven’t given it a try before.
I use Plaster of Paris, Hydrocal and Paper Mache on top of everything without any problems. You have to be careful using Paper Mache because it shrinks and has tremendous warping power as it dries. All can be sculptured to form rocks and ground variations. Plaster of Paris makes beautiful mountainous rocks and takes stains very good. Paper Mache needs scenery flocking, it doesn’t detail like plaster, it accepts stains as a base color.
Plaster of Paris is my choice for large rocks, 70% $$ less at Big Box Stores than the cost of Hydrocal. I prefer Paper Mache for a ground cover base, again the price factor and because of it’s tremendous strength, applied ¼’ thick it almost has the strength of plywood. Paper Mache is a great material for making mountains but again beware of shrinking as it dries. I use Activa Celluclay from Beverly Fabrics, it comes premixed and ready to go by adding water. It is very slow drying and is easily contoured during the drying process. Fully cured it drills and sands like wood and cuts easy with a small saw. Unlike plaster Paper Mache is not messy, that’s a big plus for me.
A ¼” thick layer of Paper Mache 18” square will shrink ½” as it dries. I use a layer of Saran Wrap over the base material to prevent damage from the shrinkage. When the Paper Mache is fully dry the Saran Wrap pulls off easily and the Paper Mache can be glued in place with Elmer’s white glue. Paper Mache is strong enough to be used without a support structure.
Mel,
I recently used some pre-made paper mache I’d had for years (Celluclay or something similarly named gray stuff). Neater to use than plaster and similar to but not quite as manageable than Sculptamold. I only used it finally because I was out of Sculptamold and the shop didn’t have any on the shelf. I can see where it would work.
Sculptamold doesn’t really shrink that I’ve noticed. In any case, if it does, it’s so minimal you’ll not notice it, so I suppose that’s another advantage. You mentioned the lack of mess with paper mache vs plaster. I forgot to mention that as it’s one of the big reasons why I prefer Sculptamold for scenery. Even if you mix it wet, it’s still far easier to control and shape than plaster is. You contour something the way you wnat it and it stays, dries, and comes out just as you shaped it when applied.
Mike
I liked what you said about Sculptamold so I ordered a 3 pound package this morning. After some really bad shrinkage with Paper Mache several years ago Sculptamold sounds like the way to go.
I originally used Paper Mache without any problems back in the early 90s applying it ¼” thick over carved 2” x 12” x 16” foam packing blocks. I know now that the Paper Mache shrunk but I couldn’t see any damage because I was in the starting process with my mountains and had no reference points. All went well until I decided to go with some removable modules, that was a disaster. Check my blog post for pictures
Mel,
Nice work there, so I can understand how frustrating the craking was for you.
I think you’ll be really pleased with the Sculptamold. It’s very stable dimensionally. You mentioned applying the plaster-cast rocks with the paper mache to your scenery base, in this case also paper mache. I use basically the same technique with Sculptamold and it works well. never had an rocks come loose anyway. The only trick is to either push the plaster rocks closely together or space them far enough apart so that the dried Sculptamold represents dirt and texture it apart from the rocks if you plan on staining the rocks. Plaster and Sculptamold take up stains differently, so you really can’t stain everything together and have it work.
There’s a couple of other workarounds to this. You could prestain the rocks, but that still leaves the problem of what to do to get the Sculptamold in between looking as you want. Depending on the terrain it may solves itself as you add textures, but in very rocky terrain it’s harder.
The other solution is to seal everything with latex paint, then paint over that. But this doesn’t work with stain.
In any case, I have very good results with Sculptamold. As I’ve become more skilled with hacking Styrofoam, I’ve needed to use less Sculptamold. Shape the Styrofoam, don’t stairstep it, basically, then coat with Sculptamold.
Here’s on of my really big liftouts from my Cascade Branch thread, where you can see lots more of how I work with it.
http://cs.trains.com/mrr/f/88/t/219241.aspx?page=1
Looks like there’s lots of plaster rocks up there, but it’s mostly Sculptamold, because a 6’ long liftout full of plaster rocks would be heavy. The only paster rocks are those right above the peak of the roof on the mill. The rest is Sculptamold painted with acrylics.
WOW Mike!
I thought I was going too big with my 24” x 48” removable/lift out section. Most of mine are smaller than 24” x 24”. USPS tracking says my order of Sculptamold will be here Tuesday. I have several patch jobs I’ve been putting off that I’m going to experiment on.
Mel
Mike
I received my order of Sculptamold Saturday and I did a repair to a tunnel portal. You are correct about it working better than Paper Mache! It mixed perfectly, went on perfectly, set up and dried quickly with no shrinking or cracking . . . it’s great stuff. I’m sold, I’ve bought my last Paper Mache. To bad I didn’t run in to this a long time ago, my model railroading scenery life would have been a lot better.
Thanks Mike
Mel,
Glad to assist. Sculptamold is like a universal solvent for scenery. It’ll fix just about any problem in a jiffy with minimal mess and fuss.
A couple more tips. You can mix it as wet or dry as you need and still have it work well. More moisture means a longer drying time, but that’s about it. Also, keeping it thin as it goes on also speed drying time.
If you see a need for large quantities, don’t be afraid of ordering large quantities. It’s considerably cheaper and keeps well. I used 3 of the 50 pound boxes if it in the main scenery construction phase. The last 10 pounds or so I nursed along for little project for probably 4 years, just twisting the bag shut each time, and it was just as good at the end as at the beginning.
It’s just an incredibly versatile and forgiving product.
Mike
Too bad I didn’t find out about Sculptamold 30 years ago when I started building my layout. Over the years I’ve used about 100 pounds of Plaster of Paris and 30 pounds of Paper Mache. As a layout is never finished I’ll continue on using Sculptamold down the road. I’m down to about the last 10% of scenery to do. My original plan was to use several removable sections so I could change the look and area of my layout so when I start the different look sections it will be much easier using Sculptamold.
I’ve got rock formations down pat using Plaster of Paris so I’ll stick with that for making rocks.
Mel