Good day, gentlemen & best regards from Croatia.
I need guidelines for drying 8/4 European oak in the conventional kiln. Different lengths and widths - plain sawn oak logs. Most of the material is partially air dried outside,1 year - to appr. 45-35%. Target MC is 8-10%, mainly for table tops.
First, can someone tell me the main differences between American & European oak? Or, better yet, point me to some literature where can I research this for myself? Are there any free books to download?
After analyzing all available information in Drying kiln op. manual / Drying oak lumber / Kiln drying schedules & some other books - I'm still unsure about making some schedule decisions. So here are my main concerns...
1. TEMPERATURE- all suggested schedules start around 43°C. I'm afraid that this temperature will produce "white water marks inside the material". I was taught in my former company by a mentor that the starting temperature should be around 27-31°C. I know for sure that 90% of similar companies in my area do this way. My question is why not a higher temperature if it ensures faster drying? What lead to such practice in Europe in opposition to America?
2. EMC - suggested schedules range from 18 - 12% EMC to 30% MC.
Bellow 30% it spirals down rapidly to around 6,0% and then to 3,5 %. Can this be implemented? Can someone confirm it?
3. DRYING TIME UNDER 10-11 MC% - I see that the previous operator had big difficulties with slow drying below 10%. What would be a normal drying rate at this point? Because right now as I see in the archive, it is around 0,1% per day. Is this normal or I'm missing something? I must mention that there is a limitation (by the owner) on the final temperature - it is 60°C.
Below is a picture of my current " draft version" of the schedule, please feel free to criticize, I'm open to all opinions. Of course, if you think you need any other info that isn't written I'll try to provide it.
Apologies for the longer post, best wishes...