So I've been using drywall spackle on the extruded foam for my layout to fill and level where two pieces of foam meet on the table tops. Has anyone else used this technique? Is it going to crack and peal over time as it dries and shrinks?
I have had it crack, but that is easily filed with acrylic paint of the same color. If it was wet enough to get down into the foam a bit, it seems to 'stick' pretty well.
I use spackling for roads, but when it makes the hairline crack, I just use that for a crack in the road. I feel that the artist acrylic paint would fill the crack. OTOH, such a technique for mobile or modular layouts might not work as well. I also use the spackling compound for smoothing the fascia board.
Well yes it does crack, it does shrink and it may peel. It also is very heavy. Calking will fill cracks and you can smooth it out, but it is messy. Hot glue gun to attach two pieces of foam together works for me. Other things to try, Cheeze cloth and plaster of paris tinted to ground color I ues dry earth tints you can get at craft shops. Or same set-up just subtatute plaster of paris or Hydrocal or ultra cal. This set-up is not cheap but way much lighter and you can do your rock molds with it too! Another methoid is paper-machie', dosen't crack or peel away and takes color rather well. Also makes a nice ground cover and smoothes out well for roads, river banks, and trails. Costs about $1.50 a pound and goes a long way. Hope this helps out. "Still Training After All These Years"
I use calk to fill the cracks.. you can smooth it with your finger and it will always stay flexible. Plus, it won't break away from foam as easily as Spackle will Tim
I use spackle on my last layout on beaded foam, which ran for 5 years, no problems. For large cracks I fill them with calk first, wait a few days then use spackle on in layers [drying time in-between each], till I get the look I want. I also use it after carving for smoothing out contours some. It’s rare for me to get many cracks this way and if I do, then paint and ground cover will hide them. I don’t worry bout the extra weight, no thicker layers that I use. A 3# tub will do most of 7x9 layout I’m using the same process on my new layout. inch
I'm not sure what you mean by spackle: the acrylic stuff or just plain old water-based joint compound? I use joint compound, or mud. Yes, it cracks. Mine usually cracks while drying, so I just swipe some more on. It's heavy. But consider this: I used two five-gallon tubs to finish off about 300 sq. ft. of railroad surface. I think the tubs weigh about 60 pounds each, but that's still only 120 pounds total for a large layout, or about 0.4 pounds per square foot. My layout's going nowhere, so it doesn't matter to me. Translated to an N-trak module, I'd have about 13 pounds of joint compound per module. Joint compound is dirt cheap. I went through college as a mudder, so I do know how to mix it and sling it. So your experience may vary. I'm not afraid to use it over a tape web, foam board, or foam core. But it is not water resistant, where some spackles are.
Excellent advice and insight! Thank you all! I used to do construction over the summers all through high school and college... so I'm not stranger to "mud" . For the layout, however, I've been using DAP Fast 'N Final Lightweight Spackling... since it is rather light and airy, easy and quick to work with and doesn't seem to need a lot of coaxing to get it to make smooth surfaces. The package says "no cracking"... but we all know how truthful and real the marketing on a package can be, don't we? My biggest concern was with making sure that the track going over two pieces of foam that don't quite match up exactly in height would have a smoother transition as it ever so slightly ramps up or down over the difference in height between the two pieces. For scenic effects and various terrain I think I'll stick with sculptamold, however. Spackle just doesn't seem as forgiving when dealing with delicate features.
Lloyd - I used the same Lightweight Spackling that you have and it has not cracked since it was applied two years ago. When I applied mine I added some water based brown paint to it so in the event that it chips the chip will not be as visible. I did use Joint Compound for the streets which as stated above crack but are easy to repair. Ben
I used drywall compound on my layout over top of extruded insulation foam and i have had no problems at all so far. I hope that helps.
I use the Lightweight Spackle just to fill in irregularities and to blend in around rock castings. I do not use drywall mud for anything except drywall. For general hardshell over sculpted foam, I use Vinyl Spackle cut down with water to the consistency of thick pancake batter. I then paint it on, usually two coats. It is very important that each coat thoroughly dry before re-coating and it is imperative that the last coat be completely dry before any latex paint be put on. This can be difficult in a basement where dampness is the norm. Two light coats of paint are much better than one wet heavy coat which can partially wet out the spackle, which will cause the latex paint to peel at some later point. I also ad something called Penetrol to the paint which allows it to stick better. I use fans to accelerate and ensure drying. Latex paint will not stick well to the Lightweight Spackle so it is important that the lightweight spackle be protected with a coat or two of the Vinyl Spackle before painting.
Drywall mud vs plaster On our club layout and my home layout the dense insulating foam was used for the base of the scenery. The foam was carved and packing foam used for rock forms. Hydrocal plaster the consistancy of pancake batter was applied with a paint brush. The plaster was mixed in small batches and applied until the area was covered. One has to work quickly and keep a bucket of water handy to wash out the brush before the plaster hardens in it but the process goes fast. No cracking or shrinking. After the plaster has set up it is stained with washes of earth tones blended to look natural. The scenery is light weight but strong.
