Filling Knots and Cracks in Alder

Ways to deal with the surface roughness of this rustic-appearing wood. February 19, 2006

I was wondering what a good product is to use to fill the voids or cracks in the knots of knotty alder. Some of the cracks are as much as ¼ inch wide. Also, I was wondering what a good product is to use for a multi-step finish on alder. I have not used a multi-step finish yet, so I was hoping to find one that is relatively easy to learn to use and apply.

Forum Responses
(Finishing Forum)
From contributor J:
We do Rustic finish on knotty alder, knotty cherry, pine and etc. which is very popular in the states. We don't usually fill the cracks in the knots because it adds to the rustic look of the wood. We use ML Campbell stain and glaze it with water base wet glaze from Pratt and Lambert. If you really want to fill those cracks you could use tinted wood fillers after sealer, or colored wax crayon sticks from Mohawk.

From contributor D:
80% of my work is in knotty alder and clear alder. If I have a customer that likes the looks of the knots but does not want the holes in the knots to be there I use Famowood wood filler to fill them in. You can get an alder color Famowood, but for the dark knots I use the walnut color Famowood.

From contributor S:
If the knots are all the way through and you can see through them I choose epoxy putty. Epoxy putty is permanent and won't shink back or pop out later. It does need to be colored with a touch up process in between finishing steps because epoxy putty won't let wiping stains absorb during the staining process.

If the knots aren't actually holes through the boards and just small pin knots, then I use the Elmer’s stainable putty that you can find rather inexpensively at any local Home Depot. It comes in a variety of colors - natural, walnut, white, golden oak, red oak, and mahogany. Knotty substrates are pretty. They have character and a nice woody look.