Research, Research, Research!
     There is always something new to learn about painting and old houses

There are three rules for making wood last:
     Number one is keep the water off
     Number two is make sure you keep the water off
     Number three is be absolutely sure you keep the water off

The rules for long lasting paint are similar:
     Number one is keep the moisture out
     Number two is make sure you keep the moisture out
     Number three is be absolutely sure you keep the moisture out

The key is preparation:
     Here are the requirements we used on our old house:
     Remove all old paint:
          No open flames
          No pressure washing
          Collect all lead paint
     Sand all bare wood to remove old paint seal
     Repair defects and metal prime all exposed nails and metal

House with 100 year old siding and 7 coats of paint prior to paint removal:

House after paint removal before painting:

Paint application:

Priming and/or painting is only allowed when the moisture content of the entire area to be painted that day is 12% or less.

Paint is to be hand brush applied. (At the minimum, if you are allowing spray painting, the paint should be brushed in to ensure penetration into the wood).

Each coat on area segments to be painted in one session to avoid unblended paint lines.

Each paint color will be blended and stirred thoroughly before application.

Apply a water proof sealer containing a mildewcide and fungicide additive (Do not use a sealer containing linseed oil in a wet climate as it will tend to cause mildew and mold.)

Apply an exterior oil based primer with mildewcide and fungicide additives.

Caulk where needed, (avoid horizontal seams except around doors and windows, etc)

Apply two top coats of Latex paint.

We found that the best removal tools were a
heated air blower and different width putty knives.

The width of the putty knife depended on the wrist strength of the user. The key is to not overheat (less than 700 degrees) the paint and to keep the blade of the putty knife heated as it is moved along the board surface. This allowed a continuous movement which reduced significantly the amount of damage to the siding. Move the putty knife with the grain of the wood if at all possible. This process also lessens the amount of lead paint vapors released. The operator should still wear a breathing mask at all times. Paint removed in this manner can be easily captured in cans hanging from the ladder by wiping the knife on the rim.

We also tried mechanical paint removers.

They worked fairly well on boards that had one or two coats of paint. They did not work well on seven or eight coats of paint. The operator was spending more time cleaning the discs than it took to scrape the boards by hand. We modified this one to accept a dust collecting vacuum normally used for drywall sanding.

The bare wood was sanded with a variable orbit 5" sander with a dust capture
attachment.

A section of small shop vacuum hose was attached to the bag outlet and allowed to hang below the sander. This carried the sander dust away from the operator and reduced the amount of time spent emptying the dust bag. This unit can also be attached to a drywa vacuum to capture the lead paint dust.

During nail replacement and/or repair be careful to use only quality galvanized nails. We found that some galvanized nails rusted through the metal primer and the paint within three years.