Sealing wood for basking spot.

murrindindi · 10-27-15, 05:35 PM

Quote:

Originally Posted by chairman

Sorry, no citations available. Also, I believe the risks associated with using either bare plywood or polyurethane-coated plywood under a basking lamp to be negligible. I was simply suggesting that a person that is concerned about what toxins may leach from plywood would also be concerned about polyurethane under the same conditions.

In terms of pure conjecture, we know that many hydrocarbons are volatile under low temperatures. We know that hydrocarbons can break down under long term exposure to low heat. All polyurethane is made from hydrocarbons, even the water based varieties. All polyurethanes degrade over time and with exposure to things like the heat created by direct sunlight (example, the polyurethane coatings on hardwood floors wear much faster under windows). I doubt that sun-heated floors get much hotter than 100F (and the affect even occurs with glass that blocks UV). Water based polyurethane is more fragile than solvent based polyurethane as evidenced by the manufacturer-provided use guidelines. So, in theory, there is the potential for harm.

I suggested that the potential for harm is greater for polyurethane than for plywood because I'm only aware of plywood containing formaldehyde whereas polyurethane contains more complex hydrocarbons capable of breaking down in to a wider variety of chemicals. Once again, conjecture, and it isn't like formaldehyde isn't nasty enough on its own.

All the safety data I've seen (mostly in the form of MSDS) suggests that only a very small portion of the population with high sensitivity to low level exposure will have any adverse effects to either product. And the effects I've seen listed looked minor for the most part. Add in anecdotal evidence that using the products yields no averse impacts... I don't see any problem using plywood or cured water based polyurethane.

But natural slate tiles are a good alternative for anyone that reaches a different conclusion.

Thanks for the detailed explanation. I do agree that tiles/stone, etc are better alternatives as far as basking objects (retaining heat is concerned).