This week I have been preparing for next weeks router skills. During the course week make a small walnut pedestal table entirely on the router (more or less!), so I needed some good American walnut. Unfortunately good walnut seems to be as common as hens teeth at the moment. My usual supplier, Duffields near Ripon, had some very nice 2″ boards, but the 1″ for the tops was absolutely dire. I know I have already picked the best of the 1″ at my other main supplier, British Hardwoods near Keighley, so I was a bit stuck.
The main problem with American walnut is sapwood and knots. The walnut is steamed during the drying process, this is supposed to darken the lighter sapwood. What it actually does is make it appear the same as heartwood until you plane it up, then it stands out like a sore thumb. The 1″ at Duffields is skimmed (the sawn surface is sanded off), which is good as it shows up the sapwood before buying it. At many wood yards who don’t skim avoiding the sapwood is a bit of a lottery. I could take a plane with me to plane surfaces locally but if you are buying a lot of boards this is not really an option, and you can’t plane the whole board looking for sapwood.
So I was in a bit of a quandary. Then a name from the past came to me, Niche Timbers in Wakefield. I bought from them many years ago when I had a workshop in Huddersfield and knew they used to have good walnut. A phone call told me they had some 9″ plus boards of 1″. This was a good start, wider boards usually come form the centre of the log so are less likely to have sapwood. So it was down the M1 to Wakey. As expected the wide walnut was very nice, I selected six 2.4 metre boards. Unfortunately I was so relieved to find some that it was only after I had paid that I realised the eye watering price! However I do now have a nice pile of walnut planed up and ready for next weeks course.
All this begs a couple of questions. Why is walnut steamed? It seems to me that it does not improve the colour of the sapwood it just disguised it in the sawn state, so it’s harder to select out. If I was more cynical than I am I might think it was an intentional deception! The other question is why don’t our cousins across the pond send us more sap free walnut? I really don’t know what happens to the centre of their trees because all we get is the outside bits, perhaps they grow hollow.
2 Comments
Duncan Lees
18th August 2016Hello Chris,
I see that you have raised the vexed question of Walnut. To understand the reasons behind this one should take the time to look at the production process. The most problematic thickness for sap will always be the 1″ boards as these are usually the outside “jacket” boards. The Americans will not cut all 1″ from a log but open the log at 1″ untill they see a heartwood face of sufficent width and then continue through the log with a thicker size. The only time that only 1″ is cut is when they have a relativly small log to convert.
To understand the issues surrounding steaming the scale of the production has to be considered. The steaming chambers I have seen may hold 120 to 200M³ and so a batch of stock has to be accumulated and inevitably the first cut stock will have dried out a little. Walnut has to be as green as possible for steaming or else the colour from the heartwood will not migrate into the sapwood. To mitigate the problem the Americans will steam for a long time but this will not solve the issues of any fixed boards. If you want further information then please ask.
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23rd August 2016Thanks for that interesting comment Duncan. In have never been able to understand why walnut is steamed because I find so much cream coloured sapwood in the wood I buy. I have assumed that it just doesn’t work or is just done to deceive the purchaser (those devious Yanks!). As I understand it you are saying it does work but only if the conditions are right ie the wood has not had time to dry out before steaming. Can they not store it in such a way that it doesn’t dry out before steaming.