The manufactures web site mentions using latex paint as a primer. Other articles say use shellac as primer . Others say leave plain. I am in a Temp. controlled house. 2x6 foot layout.
What say Members with experience in use of Homosote 440 panels? Prime/No prime and if prime with what?
To The Forums.
I have been using Homasote for yrs and still do, not the 440,wasn't called that then. The 440 is already moisture resistant. Using it as roadbed, I would prime it the color of my ballast, water base or solvent, I prefer the solvent. Mine is in a temp. controlled attic in the midwest, with no problem's. Number one reason for using it is the ability to hold screws and track spikes, great for handlaying track. Some info:
http://www.homasote.com/products/440-Soundbarrier.aspx
Take Care!
Frank
BTW: I don't use it as a stand alone, not enough strength for that. It's laid over 1/2 ply on open grid.
I followed the advice in an article by Jim Hediger many years ago to seal the homasote with shellac -- real shellac, which I had not worked with (or smelled!) since my cub scout project days of the late 1950s -- because it has no water in it. I do not know if my homasote handi-panels from Mendards were pre-treated / 440 or not.
For some pieces I did use some left over latex paint with seemingly the same results. In both cases it creates a hard crust on the flat surfaces and on the open cut ends.
What I can say is this. The homasote that is sealed with shellac or latex paint is considerably less sound-absorbant than "pure" homasote. It takes more force to drive a nail into it, and it is much more difficult to push a pin into compared to pure homasote (not as difficult as plywood or pine, just more difficult than pure homasote), but on the other hand I find it easier to saw through. I am not sure why that is but perhaps the somewhat brittle exterior gives the sawblade something to react to versus the slightly mushy (hence the dust?) texture of pure homasote.
In short there are tradeoffs if you do treat your homasote and for some folks I suspect the decrease in sound absorbtion and the greater challenge in pushing in pins or track spikes might obviate the only reasons they wanted to use the stuff in the first place.
In common with my plywood, pine, and hardboard by the way, I try to have all homasote in the basement through a complete cycle of seasons before I use it.
Dave Nelson
My unscientific two cents worth is you do not need to seal it with shellac. I have read where tests show little dimensional change from having soaked Homasote in water for a few hours, then letting it dry out.
I do, however, recommend sealing it with something and latex paint is probably the easiest product to use. Why, you ask. DUST! Unsealed Homasote seems to act like a dust generator. I painted every Homasote surface I could get to resulting in minimal dust on the layout. Well worth the modest investment of time and money.
I've been told painting homasote doesn't help, but I do it anyway - at least it will have a decent base color to start with and it might help it resist moisture a little. But I use a dehumidifier too, to try to keep humidity at a good mid range. It's a good principle in the IT industry to maintain systems to keep the air in server rooms at a good mid-range to avoid both static electricity and condensation. They aren't good for computors or layouts. Dust ain't nice either soo...
Rio Grande. The Action Road - Focus 1977-1983
Latex paint doesn't help anything - latex paint doesn't seal. It may make it look nicer, so if there is a bare spot in the ballast, you don't see natural colored homasote. Stuff like shellac though, if applied to all surfaces, will seal things up and keep moisture out. When temperature and humidity are controlled, there should be no need to seal up wood or homasote.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Well, of course latex paint does "seal" material-Homasote, Homabed, wood, etc.-to a degree. I have used it over all my Homasote and Homabed and plywood; it does resist water penetration. Does it produce a completely moisture vapor-proof seal? Of course not. Only very specialized and expensive sealers can approach that. But, as stated above, the Homabed manufacturer recommends latex paint and remember, latex paints are used ubiquitously to finish exterior surfaces in building construction.
I have noticed little change in its sound absorption characteristics with the paint vs. without. There is certainly some change, but for the purposes of model railroading it is not noticeable. Finally, I spiked all my Walthers/Shinohara track into the painted Homabed and Homasote with no noticeable increase in difficulty compared to doing the same with unpainted Homasote.
And for the record, my train room is also climate controlled. Go for it!
Dante
I agree, moisture resistance is still a good thing. Yes, I don't expect my homasote to handle being submerged underwater - no, latex doesn't waterproof it. But I still think it's worth painting with latex for the resistance to moisture and a color base as well. A multifactor approach including the paint and humidity controls seems like a common sense approach, so I use it and like it enough to go back to it on subsequent layouts.
Cheers, Jim