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Sterilizing reclaimed wood for kitchen.7/3
This is outside our normal process so I need advice from fellow manufacturers.
We just completed a fairly large house (~80 cabinets) and the clients are now asking us to provide some floating shelves using reclaimed pallets--- quite literally, the pallets we have sitting out back getting baked in the sun.
We know how to build these and suspend them from the wall-- we do this quite frequently, but since they are wanting reclaimed stuff straight from "the back yard", we want to make sure these are thoroughly de-bugged.
How do we sanitize these reasonably well? It would be roughly 75 boardfeet of reclaimed wood, varying thickness from 1/2" to 3/4", like what you'd see on pallets from Conestoga or Northern Contours.
The standard sterilizing technique for wood is to heat the wood to 133F through and through. To get this temperature in most instances requires air temperatures of 150 F or hotter. When the lumber leaves the sterilizer, it can become reinfected, so it must be handled carefully to avoid contact with non-sterilized wood, etc.
Does anyone venture a guess at how long to hold the temperature at 150 degrees for 1 inch boards stickered with 1 inch spacers. I have 3 kerosene heaters going in a green house with a squirrel cage off of an old furnace. to circulate the air. the stack is 6x6x16 feet. I started yesterday, but only got to 130 then the temperature fell significantly through the night. I purchased another kerosene heater this morning and am trying again. This is an aggravating process. Clouds are giving me trouble today as well. Maybe I should just put them in a room with a dehumidifier ( my next planned step)
You will likely never maintain temp in an uninsulated space and your fuel costs will be astronomical. The issue of dry wood reinfeststion has gone round and round many times as has the concept of finish providing any protection.
I'm of the belief that once the wood is dry your in much better shape but not completely safe. Boracare can help but heat is your best bet. If your pile is of value to you I would build a simple insulated enclosure and get your material to 150 for many hours.
It is indeed best to sanitize "according to the book, and document in writing what you did. Every so often, due to poor storage of lumber or wood products after drying, especially in a facility that has other lumber or bamboo that is infected, a client will have insect issues in well dried wood. They will blame the kiln drier, and not storage, unless the kiln people can document what they did to sanitize and how long and under what conditions the KD lumber was stored. We look for 150 F, a week or less of storage, and a "clean" storage facility.
Good advise, thanks guys. We do have a rather sizeable kerosene "torpedo" we can use, as well as a metal storage container with some old machinery in it. I think we can move the old stuff out that might be sensitive to it and heat it.
If you use "torpedo" type heaters that draw in outside air and attempt to heat it to 150F, you may be asking for the impossible unless it is really hot. I've never seen one of these heaters designed for that much rise.
Kerosene heaters are not great heat sources. They can actually increase the humidity as a by product of combustion. A highly insulated box can be brought up to temp with electric heaters. One member here uses an oven heating element and a thick piece of aluminum as his heat source. For my little woodturning kiln, I use a hotplate with a huge aluminum heat sink sitting on top of it.
Would a good solution be boiling the wood? I've heard that it will kill most of whatever is in and on the wood well enough for you to be able to work with it! Anything past that like chemical treatment is really beyond me but perhaps you could find someone locally who might be able to get the right kind of chemicals to you. Perhaps even your local hardware store might be able to provide some sort of good advice for you to keep the wood in storage well!