I am building a N scale layout and wanted to try hand laying my rails on a bed of Homtosote. I cut out sections about 16" to lay the track on. What i was planning to do was build the sections than install them on the layout but when I painted the top of the homtosote to seal it i noticed that while setting my ties in place that there is a slight warping! I think I will try again but fasten the section down until it drys. Anyone have another suggestions? Thanks Les
Suggestions? Yes, don't use it. Use extruded foam. It won't warp, is easily layered and is carveable. cork and track can be glued directly to it with a foam safe adheasive.
Suggestion...remove the plastic film from the foam surface before gluing roadbed, track, or scenery. This allows the glue to penetrate the tiny pores in the foam for better adhesion. Otherwise the glue can release from the plastic sheet after a while.
What plastic film? The pink (Owens Corning) or blue (Dow) extruded foam I get doesn't have any plastic film that has to be removed. I just glue the cork to the foam and then the track gets glued to the cork. Or the track can be glued directly to the foam without the cork.
Homsote was once the go to product for home layouts. Its advantages were its ability to deaden sound and accept and hold nails. However, these advantages came at a price in the form of disadvantages. Homasote is a pressed paper product and needs to be supported every inch of the way to prevent sagging. It is also heavy which is a no-no in this age of modular layouts. It can delaminate when exposed to water. There are other products today that are more advantageous than Homasote. The blue or pink foam insulation has been mentioned. I use this for scenery profiles but I lay my track on cork roadbed glued to underlayment plywood for my modules. The plywood is supported every inch of the way by 1/8 thick masonite splines that are 1 inch wide. The roadbed thus becomes a beam bridge. This results in a light weight yet strong module.
The foam board that I buy from Home Depot and Lowe's, both Dow and Owens-Corning, have a very thin plastic film on both sides. The film is attached very securely and can not be seen with a casual glance. I only noticed it after I had cut a piece a foam board, then rasped it slightly for a tight fit. It was then that I saw a small edge of film curling up. I didn't think anything about it until I bumped a piece of glued cork roadbed with a fair amount of unintended pressure and the Liquid Nails released from the board, actually from the plastic film. Now whenever I use a new piece of foam board, I take a knife and peel back a corner of the plastic film, then peel the entire film sheet off the board.
I have seen this foam at some Home Depot locations, but the foam we use is extruded blue or pink and there is not a plastic film on this stuff.
The pink "Owens-Corning" foam DOES indeed have a thin film protective sheet. I believe it serves dual purpose........protection from dings, and as a "vapor barrier" for contractors. Just peel it off & throw away. If you use the correct glue, you can glue foam, track, scenery materials, etc. to it that won't !! come loose. :tb-cool:
I have examined the foam sheets I have on hand as well as the foam I have on my layout. None of it has a plastic sheet on it. It's in thickness's from 3/4", 1", 1-1/2" and 2". This is foam I purchased from lumber yards. Not Home Depot or Lowes. I do have some 1/4" foam sheets that do have a plastic coating and it is labled as underlayment that was left over when a contractor did some work on my home. I don't have any Idea what the plastic coating is for with the exception of being a sealer for nail holes or staples.
All but my first layout have been on Homasote and I have never experienced any ill effects. I, however have never used it as the actual road bed material, but my past and current track is laid directly on Homasote supported every 16" with no sagging or separating. On modules though we did experience swelling at the joining edges. We are also in an arid climate and my train rooms have always been climate controlled. I can find Homasote easier than the proper foams here where I live. IMHO Mike
Homosote is quite sensitive to moisture and if you used a latex (ie water based) paint then just painting one side might have caused the warping. Sealing it against moisture is highly recommended and if you do so, doing all sides/edges is best. You don't say what method you are planning on using to hand lay your track. If using spikes then you probably want to stick with the Homosote as just cork and foam don't have a good holding property. If you're using pc board ties and soldering or wood ties and gluing the rail down then switching to a foam subroadbed might work out better - avoiding the usual Homosote problems of expansion and contraction as the weather changes and moisture absorption. John H. Reinhardt
I am building a layout with homasote as the roadbed with Peco flex track. The roadbed is supported every 5-16" and I have noticed some slight sagging between supports; less than 1/16". I think the sags add to the appearance. Since I have not started laying track I am only guesstimating how the final alignment will appear. I sealed the homasote's back side before affixing to the supports and will seal the top side before gluing the flex track.
In the construction of all of my modules for the last ten years I have used thin masonite as the base, with the rough side up for better adhesion of the foam. As far as foam goes I have used the thicker blue or pink foams, used for house insulation, for the terrain, which is all glued together with Elmers carpenters glue. While the masonite can warp slightly it is better for structural strength, and once screwed to the layout base with brass scews the sometimes slight warpage is resolved. There have been no issues of separation of any of the layers over the years. Often my final top layers have been using the thinner white foam available through hobby supply outlets. I also use a hot wire knife to do all the basic contors and cutting which reduces all the foam particles. Cork road bed is glued onto a foam bed, again using the carpenters glue and pegged in place until dry. As far as the thin film on the foam I have not observed it, or at least with what I am using.
I've been using blue and pink extruded foam for model airplanes and model railroading for about 10 years. In my experience, if there is any printing on the sheets of foam, then the foam has the thin plastic film on it. Removing the film removes the printing because the printing is always on the film only, never on the foam itself. This is my experience with all foam sheets I have purchased in New England and Ohio. - Jeff
Thanks for all the replies! I picked up some 1 " foam and will do a practice section of track. I am hand laying all 40' of track and am trying to use the small spikes from proto87 they are very small and just slightly go threw the ties so not much holding there.
The guys I know that handlay N and Z don't use spikes at all. They use PC board ties every couple inches and solder the rails to the those ties. The remaining ties are glued to the rails. In such a small scale, a scale spike is really useless anyhow. They don't have enough holding power being that small. Check out here: http://www.handlaidtrack.com/ and here: http://www.bronx-terminal.com/ Chris333's Nn3 hand laid micro layout... http://youtu.be/-pQ9nC7hsKk
I use both pink and blue foam for my layout, bought from Home Depot and Lowes, and neither has a coating of any kind. Both the blue and pink have the brand printed on one side. I have cut the foam, shaped it with a Sureform tool, and glued pieces together. There is no coating of any kind. There might be a different product sold in different parts of the country. I live in the northeast. The foam available in warmer climates might be different.
Some foams sold at Home Depot are based on arsenic, highly suspect as a cause of diabetes in very low doses. Arsenic is a contact poison, which means touching it is very bad. Never ever use a heat wand on materials where you don't have the MDS from the store where you purchased it (ask, they will give it to you, might take a while though...) Outdoor wood is also treated with arsenic in low doses. Many public water systems have huge problems with arsenic, usually coming from old mines improperly sealed. The boffins are working on it as fast as they can, and as quiet as they can to avoid public panic. http://www.ncbi.nlm.nih.gov/pubmed?term=arsenic diabetes http://www.alamosanews.com/V2_news_articles.php?heading=0&story_id=4354&page=72
