Is Drywall Plaster Mud Good For Modeling Hills???
I would give it a C+. If you can layer it over something that will support it and not allow it to crack or be eroded by contact, including the unwanted kind, it can be used. I used it most recently as a filler for a wooden door frame shim ramp on either end of the turning wye.
My terrain is plaster of paris mixed with a smaller bit of portland cement and fine vermiculite, as suggested by Joe Fugate in years past on this forum. I back that mixture with aluminum window screen, and when I layer the mix over the screen, I support behind the screen with newspaper-stuffed shopping bags. Once it hardens, it takes a hard knock to get it to cave.
Bottom line, sure, use it, hopefully stained or painted, but don’t expect it to stand up on a slope unsupported unless you make it very thick.
-Crandell
Drywall mud should be used the way it’s supposed to be used on drywall - as filler between two solid, and solidly anchored, objects. The objects could be plywood and a block of foam, blocks of stacked foam, the subgrade and foam or cork roadbed (to form more accurate ballast slopes)…
I have used it to level out the humps and hollows of the subgrade before laying roadbed. In some places it took two layers because the stuff shrinks.
Mud is one of those, “If you have it, use it. If you don’t have it already, buy something more appropriate” - like the Fugate mix or Hydrocal for base work, or ordinary plaster for molds and surface features.
Chuck (Modeling Central Japan in September, 1964)
Thanks a bunch guys!
There are far better products to use over the DW “mud”. many just love the stuff, it will shrink, crack and take considerable coats to build up, besides taking a long time to dry. in a case as this, use Durabond 90, base plaster would be better choice to use Hydrocal, Plaster of Paris, Veneering plasters ( Unical or Diamond), Durabond or Scuptamold. Many variations and other mixes can also be done as described. If using Joint Compound, remember to seal/ paint it completely as it will soften w/ water as you continue w/ the scenery. I keep that “mud” for finishing drywall, and still will use Durabond for my first coat (tapered seams and corner beads).
Drywall mud doesn’t have much strength unless it’s backed by something solid, will crack if applied too thickly, and is soft and easily damaged. I used it to smooth the surface of a couple of roads, but I’m forever touching-up the colour where the tip of the vacuum cleaner hose touches it during the annual (well, maybe not that often) [:-^] layout cleaning.
For landforms, I use Durabond 90 patching plaster, applied over aluminum window screen. It can be mixed as thin or thick as desired and it will still harden in approximately the 90 minutes stated in the product name (it comes in various setting times, as indicated by the number following the name). It can also be applied as thickly or thinly as you wish, and it won’t crack. Once fully-hardened it is extremely strong, and it you wish to make changes to it, a hammer or sawz-all is required. I colour mine with flat interior latex house paint, thinned one-to-one with water. This is easier to apply than unthinned paint, dries quickly, and covers well enough that you can apply ground cover over it with no further preparation. It also won’t re-soften like drywall mud when you’re adding water-based scenery.
Here’s a partially-finished area, with the bare-but-coloured Durabond visible, along with some sceniced portions. The area to the right is in a corner, and I supported myself on the hill at left (minus the trees) while reaching in to apply ground cover and trees.
This river is also Durabond, applied over a 3/8" plywood riverbed, with a depth of no more than 1/8". After colouring with full-strength latex paint, I gave it three coats of high gloss water-based urethane, and it’s extremely durable, requiring only an occasional dusting. Many times, cameras are placed directly atop the “water” for photo taking, with no signs
I fill cracks and use it as a skim coat. One advantage is you can clean it in the sink without clogging the drain. If you have not heard, DO NOT clean any plaster type product in a drain with a trap. I use a 5 gallon bucket that I through out when filled. The difference is that plaster “cures” and once hard, stays that way. Dry wall mud drys and can be wet again and it will dissolve.
Plaster of paris works great and 50 lb bag goes a long way.
I have used drywall mud to cover screens that make the underframes for sloped embankments. Applied thickly and allow it to crack, giving naturally occuring ravines and erosion areas. I sealed the drywall mud, and then used dried lichens and other plant material to recreate the brushy-ness of unmaintained slopes. Done properly, it will keep for years.
Don H.
Glutrain,
I agree with you, Plus who wants to go,all the way to Paris,for a 50lb,of plaster? [(-D] [(-D]
Just couldn’t help it.[:o)]
Cheers, [D]
Frank
Hi,
The short answer is “it depends”… On my current layout I did a fair amount of experimenting and used a couple of tubs of premix drywall mud. It was easy to apply, but anything thicker than 1/8 inch or so cracked when it dried. IMO, you can work it in conjunction with your regular plaster of paris or hydrocal with the mud as the “icing on the cake”.
Hey, try it out. You will soon find out if it works for you or not.
That would be my concern as well. I have always used Hydrocal and have been very happy with the results.
Rich
Drywall compound works great for things like smoothing a river bed or laying a road because you don’t have to make forms to keep it in place. It can also be worked with water and a sponge even after completely dry to form a crown. But for most scenery like hills patching plaster works better.
Bill
Had another thought with the plaster of paris, I’ve very often also used it like it was paint on a brush to fill in bases or add texture , just need to mix it up thinner than normal so it takes longer to set. Been a while but I think if you add vinegar to the batter it will prolong the setting.