Sealing Door Bottoms
Painters on site typically don't take care of door bottoms, so door makers recommend priming with shellac or epoxy. October 19, 2013
Question
I am looking for a better way to seal the bottoms and tops of doors after they have been machined for the last time. I don't want to rely on the painter, since they seem to miss this and for huge doors, they have limited access issues. Hopefully something that dries fast, doesn't require mixing, and is waterproof.
Forum Responses
(Architectural Woodworking Forum)
From contributor M:
Shellac?
From contributor D:
If we fit and hang an exterior door, the top and bottom get a coat of West System epoxy. You are right, the painters never do it right, so we take care of it. The epoxy is neither fast or cheap, but it soaks in about 3/16" on end grain and really adds to the life of the door. The 5 minute epoxy is thicker and does not penetrate as well, but is better than nothing.
From contributor V:
Problem with pre-finishing on some woods is that it leaches up into the faces and subsequently won't accept finish on top of that. Paint obviously not a problem. Epoxy is real bad because of the slow set time. We leave it in the hand of the finishers with removable warning stickers on the edge of every single door shipped. Have to remove them to finish the doors so we know they saw them.
From contributor A:
It's hard to beat 2 quick coats of shellac. It will soak into the end grain by the time you walk from one end of the door to the other. The other good thing is everything sticks to it.
From contributor W:
I don't know of one single painter that will pull that $5000 door off its hinges and put a proper seal on it. At the most they will swipe the bottom with a rag with something on it. If I don't do it right nobody will later. I've used epoxy a lot but I am inclined to coat the bottom with whatever glue I am using to build the door with. On my doors I still cut a notch in the bottom for a brass hook strip so they absolutely, positively must be sealed at that point.
From contributor D:
Contributor W, you have it right. Most hangers will not use the brass interlock or even put a drip groove in the door bottom. Much less coat it with anything. "Ain't my job - that is the painter" is what you hear.
For 20 years here, we had an irascible old guy that "weatherstripped" doors. He would cut off the bottom of the door, spray on some Ace Qwik Varnish, and silicone on a .49 cent sweep. Since the sealer was wet, and the silicone was gooey, he nailed it on. Three months later, the rail and stile joint would start to open and he'd blame the maker. Every time.
I now have doors out there for 25 years with epoxy seals that show a little telegraphing of the rail, but the joints are as tight as when they left the shop.
From contributor M:
Two coats brush on so fast it will not affect the production line at all. If it bleeds to the face it will not affect any finish I have ever used. It never gets old and brittle; I have seen museum pieces with 100 year old shellac that looked perfect. It is relatively expensive but the simplicity of application and the cleanup makes it the most economical as well.
My second choice would be a good vinyl sealer. They are usually used under conversion varnishes and other industrial finishes.
Oil goes in nice but after 5 years will offer little protection. I doubt even after 2 years in a harsh environment. Other sophisticated finishes (like epoxy) are expensive and not suitable for a production environment. Too much clean up, mixing and you waste a lot of material.
