Walnut Steaming Difficulties
Steam that is too hot and "dry" will not have the desired effect. Here is some technical advice on operating the steamer successfully. December 12, 2008
Question
Our walnut comes in and we put it in the steamer within three weeks of receiving it. Then we stick it within two weeks and it air dries for a couple of weeks or so. We are finding that our walnut is not as dark as it should be and are finding a lot of pieces with a lot of sapwood not changed colour. Is there a time frame that the walnut has to get into the steamer and then put into the kiln?
Forum Responses
(Sawing and Drying Forum)
From Professor Gene Wengert, forum technical advisor:
You are not treating the wood as one would normally suggest, but even so, the color should not be so bad. I suspect that you have steamer problems. Do you know the WB and DB temperatures (actual conditions and not the set points)? How long do you steam? The handling after steaming is not an issue for color. Any pieces that dry a bit in your three weeks of storage before steaming can be an issue.
From the original questioner:
We wait for the core of the wood to hit 180 and then we steam for 60 hours. And yes, the computer is set for 208 and on the computer the wb and db are 208. Now the problem is I don't actually know what it is in there physically. Is there something that can read this and can be on a cord outside the steamer?
From Professor Gene Wengert, forum technical advisor:
Is your steam boiled through water after it enters the steamer?
From the original questioner:
We have the floor filled with water and these 3" evaporator tubes half in the water which is injecting live steam into them. The only thing is, our computer reads dry bulb and wet bulb setpoints and actual, but how do I know what the actual really is? We have no way of telling if the computer is right.
From Professor Gene Wengert, forum technical advisor:
The tubes should be fully submerged in water at all times. You can determine the temperature of your steam about 20' before it enters the steamer. This should be no hotter than 215 F. If you have a higher pressure, but use a pressure reducing valve, the heat will still be there. That is why the steam must boil through water once it is in the steamer. I feel that you do not have wet steam and that is your problem.
