by Ron Joseph
Return to search page
October, 2004
Determining Whether Substrate is Steel, Aluminum or Plastic
(Fiberglass) Q. How do I tell if my door is aluminum, steel, or fiberglass. I would like
to repaint it, but I don't know material I am dealing with. It looks like it
has been painted already, however, the frame around the outside window was left
unpainted, and it looks like some sort of plastic. Is there someway I can tell?
Can all of the above types of doors be repainted? Can you find an area on the door, perhaps near the hinges out of view, where
you can scribe a line using an "Xacto" knife or a box cutter? Carefully
make a cut through the paint and all the way to the substrate, If the substrate
is shiny and metallic then it is clearly not a plastic (fiberglass).
If the door is made of steel it will be magnetic. Therefore, if a kitchen magnet
stays put on the door, you know that the substrate is steel. Depending on how
many layers of paint have been applied you might need a stronger magnet than
the ones that are used on refrigerators.
If the doors have already been painted, you can repaint them, no matter what
substrate they comprise, steel, aluminum or fiberglass. If you need to paint
over the bare substrate, your local hardware store can supply you with the most
appropriate primer. If you are not painting over the substrate, you can use
any of your choice, and the folks at your hardware store will give you the appropriate
primer (if necessary) and topcoat.
Best wishes,
Ron Joseph
|