Stripping Paint Off a Fiberglass Door
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Welcome to my experiment on stripping paint off a fiberglass front door. This is the original fiberglass door that has been on the house from well before me owning it (but probably after it was built in 1986). A project brought on by somewhat less than 36 years of baking in the Arizona sun.
The before shot just beginning to strip the old peeling paint off this fiberglass door.
Let’s level set with my setup so you can easily identify if this same situation applies to you:
The fiberglass door originally was painted brown with a clear coat at the factory. The clear coat and most of the paint burned away in the sun. Prior to my ownership, it was eventually repainted with a single coat of dark brown oil paint with no primer. Then another homeowner added a layer of medium brown latex paint. Now the latex paint is repeating the past.
Curb appeal will also improve with a borderline professional paint job, enhancing the new (as of 10 years ago) exterior paint color scheme and stacked stone skirt.
Full disclosure, I’m a recovering software tester. Testing is what I do. Even a semi-straightforward project like stripping a door becomes an experimental testbed.
However, I also caution you that the following experiments do not always follow the rules. I want the most effective solution and I’m going to try to push some of the regular vanilla advice you’ll see out there on other tutorials.
So this is one of those posts where you *really* want to use your own judgement in your abilities before trying them out for yourself. I take full responsibility for destroying my own door.* You will have to do the same for yours if you use these methods.
Extra disclosure: I would not do some of these techniques on anyone else’s house but my own.*
Tools and materials used for this project:
Max Strip Paint and Varnish Stripper (1 quart)
Shop towels or some cloth you may never want to use again.
Plastic wrap
Lots of elbow grease and time
Let’s get started on each step and what I experimented with on each and every one.
Keep the door in place.
This is one task that requires scraping, pushing and scrubbing. Fiberglass doors are pretty lightweight. All of that pressure slides the door across saw horses / paint buckets / whatever you set it on.
Also, dripping paint stripper is not as big of a deal as dripping primer or paint.
Leaving the door in place and using the hinges and lock is a great way to keep the door still while you work on it.
Step one is to chip away the peeling paint.
Most posts on this subject state you should use plastic putty knives. These dull blades will do the least amount of harm to your door as you attempt to scrape off all the loose paint.
However, the problem is those dull blades are so thick. A razor blade scraper is so tempting…
Successfully chipping latex paint with a razor blade scraper. Warning: this is satisfying and addictive work.
Dull plastic putty knives don’t get those micro cracks you see laughing at you.
I’m the one who should be laughing as it peels off.
So on the flats, using a flat blade with a sharp angle and very little pressure will get you a lot further faster than a plastic drywall knife.
Make sure you keep the razor at a low angle!
A steeper angle will make an abrupt stop on the fiberglass faux wood divots, gouging into the fiberglass.
The curves and corners are where it gets tricky. A razor blade scraper can easily cut into a corner, damaging the fiberglass. VERY EASILY.
This is where a plastic putty is better for applying a lot of pressure to pop the paint off. You could also use a flat knife–pulling rather than pushing!
Scrape carefully!
You get zero points if you push into the corner because, guaranteed, you are gouging a line into the fiberglass. The point is to pop the flaking paint off, not scrape it off.
I will say, there should be two coats of primer and two coats of color coat. So any nicks or scratches will have a nice layer of protection from the sun.
At the same time, if the paint does not budge, leave it. That’s why there is a next step: applying paint stripper.
Tomorrow’s video will cover the use of a razor blade scraper.
Choose your paint stripper with caution.
Most paint strippers say they should not be used on fiberglass. The PH balance is too acidic and will eat on through the fiberglass.
We picked Max Strip Paint & Varnish Stripper. I’d pick it again.
Max Strip Paint & Varnish Remover and Klean Strip Denatured Alcohol
Here’s our situation and why it may or may not work for you.
It explicitly states it is not designed to remove automotive and factory finished paints. My front door once had a factory finished paint. The sun took off the factory finished clear coat. It also took off most of the next repaint job with an oil based color coat as well. Then more recent homeowners put on an additional single coat of latex paint with no primer. Then the sun baked it for over ten years to the point where it started flaking.
So it’s not like the paint stripper had a hard job.
This is probably why it only took 3-15 minutes to take off each layer, rather than the “Most Painted Surfaces: 30 min. To 1 hour”
It does not explicitly say it works on fiberglass. We had to verify it with the manufacturer website. Whichever paint stripper you end up choosing, verify if it works on fiberglass doors on the manufacturer website if it is not on the package.
Test the paint stripper on a small inconspicuous spot.
Definitely follow the directions the first time. The Max Strip Paint & Varnish Stripper recommends:
- Do not use it below 50F.
- Do not use it in direct sunlight.
- Don’t freeze it.
- Cover the area with plastic film to prevent drying.
Test an the paint stripper on a inconspicuous spot. This spot is on the bottom right where it is less obvious on a left handed door in-swing.
The first three are hard rules. Follow them.
The “cover the area” was just asking me to test it.
I still followed the rules for the first test area, as you can see in the video below (it is linked at the exact moment of setting up the test area).
If the test area works, repeat it on the rest of the door.
Let’s clarify what “works” means:
- It removes at least one layer of paint, AND
- It does not eat into the fiberglass.
Both are required before declaring it works. Obviously, it has to remove paint. But don’t expect it to do more than one layer at a time. It certainly MAY take more than one, but paint stripper may have to be re-applied to each layer of paint.
Test results of Max Strip Paint & Varnish Stripper. Nice and bubbly after 15 minutes.
That was certainly true on this door where the factory paint was still present under the repaint jobs.
For example, here we are with the protected paint beneath the door knocker:
Latex paint on top of the factory finish. Of note, there was no trace of brown oil based paint. That was a nice surprise. You just never know what is going to be under that next layer…
The first layer easily stripped the old, but clearly covered by the door knocker, latex paint.
Factory finish paint is difficult to remove.
Then I had to reapply the Max Strip two times covering it for 15 minutes each time before scraping the factory paint completely.
I applied the Max Strip one more time after this photo was taken, in an attempt to get at all the factory finish in the faux wood grain.
Despite still seeing some shine in the wood grain, the primer and paint layers are seamless so that you can’t even tell a door knocker was ever there.
Observations on this step:
You don’t have to cover the area with a plastic film. A liberal coating, as recommended on the container, is quite effective.
Just a reminder, this is in Arizona, where it is dry. VERY DRY.
After 3-5 minutes (I wasn’t really timing it scientifically), the paint looked bubbly enough to attempt scraping. And scrape off, it did!
YMMV. Just to be clear, the shorter time was on the barely there latex paint. The barely there oil based paint needed a longer cure time.
There is only so much space you can do at once.
A small amount of success leads to attempts at larger and larger spaces. If the area is uncovered you only want to place a liberal coat of Max Strip on an area you can clean off before it dries. While you can put on another coat to rehydrate and restart the process, keep it to a minimum by not getting to enthusiastic with the paint brush.
I certainly failed at this by the third area (as seen in the video where it just doesn’t scrape off along the bottom of the door). It is easy to get too excited with progress and underestimating the time it takes to clean the curves.
Curves and corners take a long time to clean out.
No surprises here.
When you get to the curves and corners, your progress will slow down. Corners are the most likely area for paint to pool if previous paint jobs were not the highest quality (and if the door was painted in place–vertically).
Excess paint in corners. Almost all corners required a second layer of Max Strip paint stripper.
We all want to paint both the primer and paint as good as possible to have a clean look. However, digging out extra paint in corners is good motivation to keep your primer and paint layers clean!
See the picture above…the third area has way too many curves and corners.
When the MAX Strip dries out, you just have to reapply another coat.
It is nice to know when you overestimate your abilities it is not the end of the project. The area gets gummy and will eventually harden, closer to its original state.
Just put on another layer and try again.
Keep the Max Strip away from all other paints and plastics.
Despite the fact that this paint stripper is lightweight–enough to use on fiberglass–it WILL eat other plastics.
Like when the Wyze Cam was accidentally set in the bag of discarded paint…
Likewise, you don’t want it to come into contact with any other paint you DO want to keep. A door jamb and any paint on the step below are prime examples. I don’t know what it does to a metal threshold or TREX porches.
Keep the discard bag handy, but not handy enough to set things down in it. 😉
Discarded paint bag and scraper tool.
Use denatured alcohol to neutralize the chemical reaction of the paint stripper.
While the Max Strip Paint & Varnish Stripper says that it can get washed off with water, denatured alcohol stops the reaction and cleans off any of the gummy paint left behind.
In fact, it can be used to remove latex paint entirely…with a lot of elbow grease. It isn’t fast, but it is possible.
Case in point: I used denatured alcohol solely for the edges on the door when I didn’t want to keep the door open. This area had a better paint layer because it was protected by the door jamb. It was a nice enough day, but I did not want to wait for the Max Strip to take 15 minutes to soften the paint.
The denatured alcohol took it off in a few minutes with a lot of scrubbing.
Just remember to change spots frequently. Otherwise, you are just rubbing paint on the towel against paint on the door.
Denatured alcohol is also a quick-dry cleaning agent. It gets off any last fingerprints and grease. Let’s say you are trying to strip the paint and get it primed in one day. Instead of cleaning off the door one last time with water and waiting for the water to evaporate, the alcohol evaporates in moments.
Denatured alcohol also cleans off excess paint and Max Strip Paint & Varnish Stripper from a Wyze Cam. Unfortunately, it does not fix the disfigured plastic.
So there you have it. Our lessons learned and observations from stripping paint off a fiberglass door. It actually looks better than it started–and I’m not the rustic look type!
Alas, I did not take a good photo of the fiberglass door after stripping it. This is the best I have. Spoiler alert: this is a screenshot from the intro for the video on how to prime a fiberglass door.
Planning on stripping paint off your own fiberglass door? Stop on back and share your experience!
*Also, the fiberglass door is at the point where the amount of effort to doing this project is questionable…the amount of time and effort it takes to strip and paint the door is significantly more than getting a new preprimed door, priming and painting it. However, I am curious and would prefer to keep a useful door out of the landfill, especially if I can make it more beautiful than it ever was before. So…this article was born.
Related articles:
10 Unusual Tips on Repainting a Front Door
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