I took a basic timber framing course last summer and am finally ready to start cutting some mortises, tenions and scarf joints for the sole plates of my small garden shed. In class, they used an emulsified wax coating to put on the fresh cut tenons and mortises to keep them from drying out and cracking. My notes say this was "Anchorcote" but I cannot find this with any internet search. Can someone help me? What is the stuff? Where can I find it? Is it absolutely necessary? Thanks for your help.

Anchorseal, likely they still will send you a free sample bucket with enough for a small project.

It is absolutely not necessary. Some use it, some don't. I compare it to sharpening with a jig, it is a crutch. Ever used Blistex for cracked lips, it seems like you become addicted to it. Same with Anchorseal.

I find medicine useful in many situations, including on chapped lips and hands. I'd opt for a beeswax based lip balm, blistex is full of chemicals though.

I think it is useful when working with green timber. I've used it in production settings and when I was hand cutting. Get a free tub, and try it out yourself.

i use raw linseed oil. That works well enough for me.

I haven't found it necessary for softwood, but it can help if your hardwood will be sitting around for a while.

Historically I have heard of applying white lead to joints as a preservative in shipbuilding, but I have never seen evidence of any type of coating in building joints.

I agree that their may be some woods that end-sealing helps minimize cracking such as the tropical hardwood cambara mahogany, but generally is not needed.

Perhaps applying anchorseal to the joints of an outdoor frame such as a pergola would increase durability?

Good luck with your project;
Jim

I wonder if sealing on an outdoor frame would be a good idea? Let's use the post to sill tenon as an example, if you coated the mortice and the tenon, could the coating on the tenon act as a bucket and hold water in causing premature deterioration of the tenon? I suspect it would be much slower to dry out after a good winters soaking. I think it would be interesting to look at frames 150 years from now to see how thing went, with all the newfangled devices thrown at them, from metal connector, curved members, glues used, air tight houses and such.

Hello,

Drainage out the bottom,or at least a free flow through there is a good point. In Holland we have a particular approach to window frame construction in which this specific matter is considered and even though now it has been generally abandoned and glued joints are normal, this was not always so and personally I never glue or in any other way treat these joints. As for framing joints of a structure, in principle it is the same and I think this coating idea would do more harm than good. What about the principle causes like how the wood has been processed including the presence of the pith? Is the heart boxed in or has it been sawn out and a lot of other things?

Greetings,

Don Wagstaff

I don't like using sills in completely open frames for this reason. We did a frame that was infilled and it had sills -- we drilled drainage holes through the bottom at every mortise. I'm sure they were filled up by dirt daubers or spiders or something else within a year or two, but hopefully they are doing some good.

I agree with the others that say sealing joinery can be helpful in some circumstances. You wouldn't want to cut an oak frame in Georgia during summer without sealing the end grain.