How to Protect Heat Treated Pallets from developing Mold in PNW Compost Bin?

Hi all. Quick question. I have a couple free HT pallets I intend to frame out as a compost bin to keep the dogs out. What are the best options to keep mold from developing on the pallets (to prolong their use and keep air quality in and around the compost bin healthy)? I was considering Raw Linseed Oil, but it's been so cold out I doubt it would dry for weeks, and I'd prefer to use it as soon as possible, and Linseed Oil is not UV Resistant, and apparently might even promote mildew. Perhaps Tung Oil or perhaps something I'm not even aware of? Should I sand it down first? I obviously want to stick to non-toxic options. Does anyone have any good ideas how to deal with this issue?

This may not be quite what you're after, but you might want to construct the compost bin so that it's easy to replace the pallets if/when they start to rot.  I'm not sure what you could treat them with but no matter what you use, they won't last forever.

Fungus is a welcome addition to my compost piles and I wouldn’t want to discourage it.

Totally agree. Let the pallets rot and add to the biodiversity of your compost pile

Add me to the list of people that welcomes mine breaking down into the bin eventually.  Pallets are normally free.  It's much easier to replace them than to try to keep them from rotting.  

where in the PNW are you? We get 66" of rain where i am.

If you want to delay the process, do the Hobo Sugi Ban.

Shou Sugi Ban is a Japanese technique of charring the surface of wood. It's gorgeous and the layer of carbon resists decomposition. The traditional method is slow and laborious, an art form really.

If you have a propane weed burner (and if not, why not? ), flame the surface of your pallets until it chars. Even burn them a bit, till they crack superficially. Fungus may eventually prefer that surface but I've found mold is a lot slower to start on it. Another guy a mile away from me did the same thing to all his unfinished rough cut tables. We're happy with the results:labor ratio, to say nothing of aesthetics.

In my environment, which is tropical, warm year around, and fairly moist, the HT pallets that I pick up last me at least 2 years, sometimes as long as 4-5 years. Of course they are not new when I get them, so I don't know brand new ones would last.

I have 24 compost bins made from these pallets. On the inside of the bin I line the pallet side with plastic (black trash bags stapled in place), mainly to help keep the moisture in the compost. But the plastic surely helps the pallet last longer. The first spot to rot away is the bottom of the pallet that is in contact with the ground. Because of this I've taken to using brick "feet" under the pallets to keep them up off the ground by an inch or so. So far this seems to be helping.

I construct my bins so that it's easy to replace a rotted pallet.

Nice, all good tips and perspectives! I figure I'm just going to twine them tightly together, not worry too much about protecting from mold. I developed Asthma and Multiple Chemical Sensitivities from living in a house with a severely moldy basement about 10 years ago, but come to think of it, I've never had symptoms outdoors where mold was present, probably because of the larger air mass/ventilation factor, and partially because some large degree of molds toxicity comes from the toxicity of the building materials it's eating. If it's just regular Heat Treated wood, with a competing bacterial mass that comes from good compost, I think it'll be fine. I'll probably make the bottom be black polyethylene garbage bag, which won't photodegrade at the bottom, to at least loosely seperate the compost fertility from leaching out into the ground, as well as lifting the whole pile off the ground with whatever bricks and cinder blocks I've got lying around. Thanks all!