Substitute for Homasote?

One way to help provide stability in moisture sensitive materials is to apply one or more coats of a water resistant wood primer. I believe a lot of these primers are latex-based, so should not cause any product compatibility issues.
--Joseph

SNIPS
Do you mean something like KILZ? That has great stain hiding ability and is very good over wood with lots of knots as a undersurface before a finish paint coat.
Or do you have something else (specific brand name) in mind as a "..water resistant wood primer.."?
Being here in the Pacific Northwest Rain Forest we do get humidity issues a lot, and I have found a local dealer for Micore, so I am going to try some, depending upon its cost. Wonder if I can get a sample from the manufacturer? I'll check on that on Monday
-- Jim McLaughlin
Please don't just hit the reply key. Remove the obvious from the address to reply.
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I would think ballasting using a wetted glue would make the humidity... oh perhaps 100%! ;-)

Kilz is a good one, along with whatever is cheapest in proximity to it on the shelves. In a pinch, a couple of coats of latex paint is better than nothing, too...
--Joseph

I would think latex paint would be the easiest, cheapest, and most useful, since it will form a barrier on the surface of the homasote that will stop moisture penetration. I don't think it's necessary to actually soak the material in a penetrating sealer to make it useful.

I didn't seal mine and have not had swelling/shrinkage problems. Of course I am in a basement with fairly constant (high) humidity so I wouldn't really experience trouble from humidity driven size changes 'cause my humidity doesn't change much even in heating season. I have seen 2 by 6's shrink much as 3/8 inch across the width of the plank and a 16 * 24 inch hardwood table top shrink nearly 1/2 inch over the years. I find homasote dimensionally stable compared to that. I have a 4 * 8 layout, (one sheet of homasote) laid on a frame of nominal 1 inch wood with joists on 24" centers. I did experience a bit of sagging, perhaps 3/8 inch in-between the joists. I believe had I backed the homasote with 1/4" plywood, that would have been enough to keep it flat. Naturally the "more is better" principle holds, and 1/2" plywood is clearly stiffer than 1/4". Then of course there are those, like the head gandy dancer down at the club, a man whose opinions command respect, who don't recommend homasote for anything. They prefer clear white pine or basswood for roadbed. David J. Starr

About Homasote etc. and continued. Many years ago I had the priviledge to visit a layout in a trailer. It was about 35'x10' or abouts and built by a career Army officer. I can not remember his name, but I remember the layout quite well.......and it's one fault. The pike was beautiful...complete with scenery based on a mythical South Jersey shortline. Due to frequent travel it was constructed on very strong benchwork with 3/4" plywood sub-road bed and code 100 True Scale track/wood road bed, the ultimate ready track for the time.........and here in lies the fault!!! The operation was completely smooth.....no wabbling, swaying, dipping or whatever...........just smooth as silk. It took me a long time (decades) to realize this imperfection in this really great model railroad. I along with just about every model railroader strive to achieve this smoothness in our trackwork. When I was constructing section 2 of my Piermont Division layout, some of the Homasote had been warped (probably stored improperly). This went into the yard at Old Bridge. I new about the slight warpage, but let it go. After initial track was laid and cars were tested...........wow!!! The swaying and dipping of the train was extremely realistic, so I continued this type of construction pretty much throughout the whole layout and now in section 3. It is necessary to seal Homasote when curfing it as the segments will swell if not. If you are going "cookie cutter", you probably could not seal and it will be fine and the slight swelling would give that "real world" look. I use curfs and do seal with semi gloss laytex mainly to protect the surface from ballast "wetting". The curfs give the irregular look I've been striving for........but if allowed to warp more, it could be disasterous.
Howard Zane 5236 Thunderhill Road Columbia, MD 21045 410-730-1036

On Sun, 4 Jan 2004 04:55:13 UTC, "Jim McLaughlin" wrote: 2000
These types of sealers are basically shellac with a pigment added. One of the best sealers you can use is plain old shellac. Yes, I know it water marks easily but it also is extremely resistant to the penetration of water vapor. Note, I said resistant. Nothing (other than complete encapsulation in a thick layer of plastic or similar material) will stop penetration. It delays it.

I think the Army officer referred to was Jim Findlay.