Touching Up Knot Bleed-Through

Tips on sealing and re-tinting spots where knots have bled through a pigmented conversion varnish. February 12, 2010

We did a distressed finish on a project a year ago and the knots on the knotty pine we used on our door panels are bleeding through the finish. The client doesn't mind the knots being visible, but they have taken on a greenish-yellow hue. This is fine on the green cabinetry in the kitchen, but looks terrible on the off-white portion in another room. We anticipated that the knots might bleed through the finish, but not that they would come up green. We used a pigmented catalyzed conversion varnish color, glaze (for distressed effect), and top coated with a clear conversion varnish - all from Sherman Williams. Is there a quick fix that can be done in the field to help mitigate the green of the knots that is bleeding through? I've tried to touch them up with the glaze, but this doesn't seem to be the right fix, as the knots simply look like I dabbed glaze over them.

Forum Responses
(Finishing Forum)
From contributor A:
You need to put a coat of shellac over the knot. Glaze over the shellac if you have to get it to look okay. Shellac sticks to everything and everything sticks to shellac. It is by far the best product for stopping knot bleed through. Sealcoat or BIN pigmented are good choices.

From contributor G:
Do you have any touchup markers? Even black magic marker would look better than green.

From contributor C:
Buy super blonde shellac, thin it out to 1 1/2 lb cut, add TiO2 to color it and whatever pigments you used in the glaze or touchup powders. Mix thoroughly and strain, apply with air brush after diluting to 15 seconds zahn #2. Air pressure should only be 10-15 lbs to minimize overspray. Do sample areas till you get the right color. Wipe off with alcohol on a rag till you hit it correctly color wise. Use one door/drawer for sample work. Wait overnight and re-spray with a thin topcoat.

Make sure you sand the entire piece before you do the touchup and it will probably take 2-3 coats to get the opaqueness you'll need. Lightly sand the touchup before you topcoat for smoothness and best adhesion of topcoat without cutting through the repair.