Unwanted dip in the plaster shell - ideas?

[tbdanny]

Hi all,

While putting the plaster shell in place for my On30 Bradford Valley Lumber Company layout, I noticed that one part of the scenery had developed a bit of a sag:

I have tried filling it with layers of plaster, which is what's caused the dark brown outline around it.  However, I'm still going to have to do quite a few more layers of plaster before I can bring it up level.  It is supposed to be flat, more or less, as this is where part of a logging camp is going to go.

I'm wondering if I should keep going with the layered plaster approach.  I'm a bit concerned that it would concentrate a bit of weight there and possibly lead to failure further down the line.  The underlying scenery is chux cloth infused with plaster.

Should I rip this section out and start again, or just continue going with the layered plaster approach?  Any thoughts would be appreciated.

[mlehman]

If the worry is about weight, then take a thin piece  of foam and embed it in plaster. The flatness will also help level things up.

[gmpullman]

Do you have any scraps of flat material such as thin plywood (old paneling or lauan) then cut it into the shape you envision for the logging camp, oval or kidney shape, then using scraps of any kind of rigid foam, balsa or scrap wood shims use caulk to tack these in place. Probably only three would be needed to make the "camp ground" level.

Once this is dry, take damp wadded news paper, grocery bags or toweling and stuff it in the gap between the plywood and the present contour. Once this has the shape you like, brush on a coat or two of thin plaster, allow that to cure then place a little thicker coat of heavier plaster until you have it strong enough to support scenery.

Hope that gets you out of the bind,

Ed

["JaBear"]

Rip it out and get some more  light weight structure in there especially if it’s to support logging camp structures.

The Bear.

[riogrande5761]

Just fill it in with more plaster or if you have it over there, sculptamold.  A layer of paint for base scenery color should cover any lines around the edges.

[BigDaddy]

What Lies Beneath to support the chux?  I found that using a cardboard lattice didn't lend itself to getting a flat layer of plaster.  A flat piece of box cardboard worked fine. 

If you don't have much support underneath, adding lots more plaster may affect the surrounding area.  If you cover your track with blue painters tape, you will have less of a mess to clean up on the track.

[wjstix]

In nature, the ground is rarely flat. I'd just scenic over it. If it's really noticeably low, it might be a good area for a small pond or swamp/wetland area. Low places tend to gather water afterall. Sometimes with building a layout you just have to 'go with the flow' and improvise, rather than trying to do it all to a rigid plan.

[riogrande5761]

BigDaddy

What Lies Beneath to support the chux?  I found that using a cardboard lattice didn't lend itself to getting a flat layer of plaster.  A flat piece of box cardboard worked fine. 

If you don't have much support underneath, adding lots more plaster may affect the surrounding area.  If you cover your track with blue painters tape, you will have less of a mess to clean up on the track.

Yes, of course support is part of what is needed.  On some fairly large area's on my layout it was obvious that cardboard lattice was not going to support the area without sagging.  In those cases I predicted the future and added support in the middle to attach the cardboard to.  Nothing major but just enough to keep it up.

[ACY Tom]

Adding more plaster just adds weight & mass. It can create structural prtoblems. I see two possible solutions:

1. Cut out the old offending section and start over with better support underneath.

2. Add a level layer with foam, thin plywood, or something similar. Even cardboard or balsa sheet might work, if properly sealed, painted, and covered with appropriate ground cover. You can secure it with something like hot glue.

Tom

[Medina1128]

A couple of things I learned (yes, the hard way):

• If using the lattice method to create the landform, stuff wadded up newspaper underneath to support it.
• Cut a piece of plaster cloth large enough to cover the offending dip. Glue one side down with white glue. If you want, add some 1/4" plywood underneath to help support it.
• After the glue sets, stretch and glue the other sides/ends. You may have to pin the plaster cloth in place until the glue sets. Then brush with a wet paint brush to "activate" the plaster cloth. Once it sets up, paint and add scenery.