Cut kerf slot for weathersealing

I want to put weatherstripping in on my exterior doors and the house currently had none. I really want ton use the kerf slot stuff, but I either don't know how or don't have the right tool to cut the kerf slots in existing jambs.

What would be the most idiot - proof way to do this?

This is kind of a tough one to give advice on as each door assembly can be different. "Kerfing In" is one method but not really the best, as it is a specialty method and has a tendency to rip out easily.

Actually, if the door design can take it, good old fashion "felt welting" on the jamb and door will create a much better draft proof lock to the elements....

Jay C. White Cloud wrote: good old fashion "felt welting" on the jamb and door will create a much better draft proof lock to the elements....

What would this entail? I'll try to post a picture of the door later, and how poorly it's hung/ how big a gap there is. I have no idea how an 80-something year old man survived in this house.

Hi Will,
I typically weatherize doors by cutting a kerf in the corner between the jamb and the stop, then use a silicon rubber tube with a special fin that fits exactly into the slot. This is a great system, but definitely for pros only as the router can get out of hand if you're not careful, just ask my apprentices. I have better results with this system than I do with felt, but if you don't have all the tools and materials accessible, then I would second Jay's recommendation of felt nailed on with little copper coated nails. If you have old windows, that is another place where Wx can make a big difference.
I don't have any door Wx photos, but I just took a a photo of a window rebuild. The silicon rubber tube is at the top and spring bronze is on the sides.