Pls help filling gaps in benchwork

Model Railroader Layouts and layout building
1

Morning campers,

I am nearly done w/ the backdrop and benchwork! Two questions: how to fill the space between the masonite and syrene sheets? If use joint compound, do I just apply and sand when smooth?

Question 2: In one area, I have 1/2in gap between my masonite sheets. Should I try and cut a larger piece or just fill the gap w/ joint compound? I am using a regular saw to cut the masonite.

Cheers,

Lee

2

Are you talking about benchwork joints or backdrop joints? What you might want to do is different for each.

For joints in a masonite backdrop, handle them just like you would joints in wallboard (sheetrock). You can probably find a number of “how-to” articles (and even videos) on finishing joints in wallboard on popular handyman sites (The Family Handyman comes to mind). Here are the basics:

  1. Lay a thin coat of mud (joint compound) on the joint.
  2. Take a piece of paper joint tape and press it into the mud.
  3. Cover the tape with another thin coat of mud using a 4" knife. Try to work this smooth but don’t overwork it - you will have a “bump” and it is important that the paper tape is completely covered.
  4. Let dry - at least overnight.
  5. Sand lightly to get rid of any significant ridges. See sanding note below.
  6. Apply a second coat of mud with a wider knife (6 to 8 inches) feathering out the edges as you go.
  7. Let dry overnight.
  8. Sand again.
  9. Depending upon how flat and smooth you want this joint to be you can either stop here or put on a third coat of mud using a 12" knife. Normal house wallboard joints use three coats so that the joints appear flat and invisable.

Each coat of mud should be thin. You are just trying to even things out not pile up the mud. Keep your tools clean when applying the mud or the mud will start sticking to the tool instead of the wall. You can buy cheap plastic wallboard tools at your local home imporvement stores.

I prefer “damp” sanding to dry sanding. Dry sanding can create a lot of dust. To damp sand use a large open pore kitchen sponge instead of sandpaper. Wet the sponge and ring it out very well. “Sand” with the sponge, rinsing the sponge often.

Unlike plaster, wallboard joint compound will soften when re-wetted. You can actually push the joint c