We just stained our fiberglass Thermatru door and the color is TOO DARK. We have not put the topcoat on yet. Can we lighten the color a little bit? by using the lacquer thinner? OR?
The Thermatru door has been nothing but a NIGHTMARE!! they are crazy charging a fortune for it and then expecting people to stain it themselves!!
Lacquer thinner will remove the stain, just like a paint stripper. It will not lighten the stain. The only way to lighten the stain is to remove what stain is there and apply a new lighter color.
Go ahead and remove the existing stain. I recommend you do this outside and with the door on saw horses. This will make everything easier, plus lacquer thinner has a very strong solvent smell.
Use plenty of clean rags and have a 5 gallon pail filled with 2 gallons of water for the spent rags. When a rag is saturated with thinner and stain put it into the water and keep it there until your ready to put them into the trash.
It is helpful to use a nylon scrub brush while removing the stain. This will help get it out of the "wood grain" and give you a clean new surface to work on.
I recommend you use Old Masters Gel Stain for this project. They offer a neutral non-colored base that can be mixed into their gel stains to lighten or reduce the amount of color that is applied. This makes life a little easier.