Maybe screw some sheet metal to the wood sides of the door to prevent taking the paint off your wood too.
How to remove paint from galvanised garage door.
First you need to give the metal doors a really good scrub with soapy water and a clean cloth.
It removes paint from all surfaces plus its non toxic no fumes or skin burns and is just as effective as your normal run of the mill toxic products.
Then degrease the door with sugar soap and allow to dry.
Thoroughly soak the sponge and wring out the excess water to make the sponge damp.
I ve never stripped the paint off a garage door before but i d think that would be a good application for a pressure washer.
Dampen a rag with isopropyl alcohol rubbing alcohol if latex paint or acetone if an oil paint.
Wipe down the steel garage doors to remove the dust and debris.
Fill a bucket with the hot water and several drops of the dish detergent.
Clean the garage door s surface with a water based cleaner and a sponge.
Rub it into the galvanised surface until the paint begins to thin.
Rinse the excess paint with a wet cleaning cloth or sponge.
You want the water to be soapy.
Use lacquer thinner for especially thick layers of stubborn paint.
Sand the areas with medium grade sandpaper where the paint has been removed to lightly roughen the surface of the steel garage door.
After scrubbing the entire surface wipe with a clean cloth to remove any residue that may remain from cleaning.
Using a heat gun outdoors is like trying to staple jello to a tree.
Here s the link to the projects page on home strip and there is a link to purchase in the tool store.
Remove all stains from the doors as they may alter the color of the finished paint.