On Thu, 08 Apr 2010 16:48:13 -0400, J Burns
wrote:

Four years ago I replaced the rotten threshold of my back door. I took
a plank from a pallet, sawed and planed it to fit, caulked, applied two
coats of Thompson's sealer, and painted.

Before long, the wood was getting wet. It soon rotted.

What's a better way to make a threshold?

As Keith notes- best plan is to make it stay dry. chances are you
are rotting out the nearby sill 7 god-knows-what-else. And you're
throwing money away with Thompson's.

Then I'd make it out of Mahogany, Ipe, or even PT Yellow pine.
[I made one 25 yrs ago from whatever red mahogany-like wood was found
in an old castro-convertible sofabed- It still looks like new.

Most [domestic] pallets are made from twisted elm. Hard stuff to
break, but not known for its decay-resistance. Come to think of
it, a friend worked in a BeechNut factory in the 60s. All the gum
came from south America and was on Mahogany pallets or in mahogany
boxes-- lots of the boards were 5/4x12- but never more than 3-4' long.
Me made a lot of bowls and trinkets with it, though. I doubt you'll
find mahogany pallets these days.

If you like the wet-wood look that you get with Thompsons- mix Boiled
Linseed oil & Turpentine 50/50 & apply until it will take no more.

Jim