Primer for weathered wood?
Some of the exterior windows on our 60 year old house desparately need painting - in some cases more than half of the paint is flaked off. Most of the rest looks like it will come off easily with duct tape; I tested the method yesterday. (Thanks for the tip, whoever it was who posted that here!) Apparently the previous owners never bothered to prepare surfaces before painting, when they did get around to painting at all.
I don't dare sand the weathered wood before painting, because unfortunately lead paint was used on the window trim. I'll be using Child Guard lead encapsulant paint once I have a sound enough surface.
I'm not sure what the best primer would be in this situation. The ChildGuard label suggests 100% acrylic universal primer for "unpainted wood" but I'm assuming that means new wood, not weathered. The recommendation for chalky dusty surfaces is "chalk resistant primer." I have plenty of Kilz 2 on hand but it recommends sanding the weathering off the wood first - something I absolutely cannot do.
Any suggestions? My goal is too stablize the flaking peeling paint more than to achieve a beautiful smooth finish. Water cleanup is a big, big plus too, but I'll do oil-based if that is the only appropriate product.