11 Tips for Priming a Fiberglass Door [No Paint Sprayer]
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The end result of priming this fiberglass front door with two coats of Kilz 2 Primer and Floetrol.
Let’s be honest. Who primes a fiberglass door? Someone who cares–like you.
I’m putting this right out there because, with my vast experience (aka my own fiberglass front door with two layers of unprimed paint), many do not prime before painting. Put lipstick on a pig and move on.
But you and I do not do that. 1 out of 3 does not make us part of the majority, but one door at a time, right? *Although it should probably should be 2 out of 4 since I’m including you–still not a majority…yet.
Let’s get started!
Tools and materials used for priming this fiberglass exterior door:
4″ (mini) high density foam roller
1.4″ angular Purdy paint brush
A brand new disposable paint tray–you’ll see why below–or skip that and just use a paint can screen
Boom! All the tools and materials needed to prime this (now finished) fiberglass front door.
Before jumping straight to the finer points priming a fiberglass exterior door, there are a few points to consider if you are working with a pre-loved door.
Are you trying to refinish an old door and the paint is in bad shape? If so, you are going to have to remove the old paint otherwise you might have a great paint job, but it’s going to look terrible and won’t last long on top of the failing paint below. Tip #2 in this post: 10 Unusual Tips on Repainting a Front Door
Also, this post will come in handy: Stripping Paint Off a Fiberglass Door
At this point, having stripped old paint off the door you may or may not have many of the original wood grain divots. Many may still be filled in, depending on the last coat(s) of paint. If wood grain matters to you, a new door may be a better option.
Tip #1. Decide on what kind of finish you want.
If you hate looking at brush strokes, use a paint sprayer. If you don’t have one, buy, borrow or rent one.
This is one of those splurges that could be worth it. If you don’t and you are left with paint brush marks, you know you are going to regret it when you see it EVERY DAY when you get home.
What you should not do if you detest paint brush marks:
- Use a paint roller (nap or sponge), sponge brush.
- No paint brushes!
If you like brush strokes (or don’t care that much), go for it!
I’m still thrilled with how amazing the finish of the Alfred DB2 plays off the white brush strokes. It’s like it was meant to be!
Suddenly, curious about that lock? Check out the full write up here: The HOTTEST Smart Lock in 2020: Alfred DB2 Review
Tip #2. Take the door off and lay it flat.
This is one step you don’t want to do in place, no matter how small of a time box you have.
The probability of a drip goes up 1000000% when a door is left vertical. So does paint buildup in the corners.
Just don’t.
Grab a friend and pop those pins out. The nice thing about a fiberglass door is it is lightweight.
Tip #3. Clean off the door one last time before priming.
Grab a container of denatured alcohol and give the door one last scrub. This will remove any last dust, dirt and fingerprints added between stripping the door and moving it to the place where you’ll be painting it.
No fingerprints allowed between the primer and the door!
Another positive property of denatured alcohol is it is…wait for it…alcohol! It dries quickly!!! You can see it in action here in the timelapse in this video at 10:45:
Tip #4: Tape off the edges of the door where the paint should stop.
A straight edge where one color stops and another begins looks professional.
Painters tape is your friend leaving a clean line with no sticky residue.
Video at:
Tip #5: MOVE FAST!
- Go to the bathroom.
- Drink an extra shot of espresso or down a Rockstar energy drink.
- Put on energy98.
Do whatever it takes to move fast, stay focused and uninterrupted.
Once primer hits the clock is ticking. Primer dries quickly. You have to move fast to keep brush strokes from going the wrong direction and catching drips.
Also, with regard to stripping off the paint–you know you’ve already spent SO MUCH TIME having removed the old paint. You don’t want all your hard work to go to waste!
Tip #6: Floetrol.
Add Floetrol to the primer.
Floetrol is so awesome it gets it’s own bullet point! Floetrol is also worthy of lots of exclamation points!!!!
Floetrol is an additive you use at both the primer and color coat steps. Flotrol changes the consistency of the paint to a smoother and oil feel. This causes the brush strokes in the paint to flow together and give you a smooth finish look.
Many contractors use water to thin the paint, but this only makes for a thinner coat that will deteriorate faster over time. While Floetrol thins the paint, it doesn’t take away from the solids in the primer and paint. It is a better bonding agent.
I had previously used the Floetrol in both the primer and white Alkyd to cover the roughsawn plywood siding we are installing to recover failing drywall under the entrance of our home. The end result was nothing short of flawless. I will admit I am disappointed it will be so far out of eyesight and reach because it is so nice to see and touch.
We wanted the same, high quality, brushless look on the fiberglass front door too. While we have paint sprayers, both handheld and the large upright kind, they are over 1,000 miles away. Literally. But we thought for sure, we could still get the finish we wanted.
Our workaround (although we’d still use it if we had the paint sprayer) is Floetrol. Floetrol, a ⅜” roller knap and sponge brush worked GREAT for the roughsawn plywood.
⅜” knap roller on the roughsawn plywood.
Using a sponge brush for detail work.
So it would work on the fiberglass door, right?
WRONG!
It.
Looked.
Terrible.
It looked like I was painting on carpet!
Said carpet.
I was horrified. As I stated above, all I could think about was the four afternoons I spent on stripping the old paint, just to replace it with a terrible paint job.
Disappointment was setting in as I knew the primer was already drying the moment I put it on. Thankfully, my husband grabbed a few brushes and jumped in to help.
The other issue is one of our “helpers” had picked at the paint tray. Little flecks of old paint were making their presence known. There is a reason for using a NEW disposable paint tray every time…
Stressed, and upset are two other words you can add to describe this point in the process.
This was an awful time, but I couldn’t see myself stopping in the middle. So I continued on and consoled myself by thinking at least the door was a nice, bright white.
Obvious at minute 7:09 in the video bloopers:
I applied two coats.
After it dried, I was THRILLED. All the brush marks were minimal.
I also noted the door did not have the chalky primer feel. I can’t wait to see what the thicker color coat is going to look like with the Flotrol.
If you’ve never heard of Floetrol, you can check it out for pricing/reviews here.
Tip #7: Use a high density foam roller to apply the primer.
In retrospect, I should have used a high density foam roller instead of a knap roller. Both apply the paint evenly. Much more evenly than a paint brush which is prone to thick and thin patches.
A high density foam roller looks like berber carpet compared to a knap roller’s 70’s shag.
**Spoiler alert**
The color coat went on soooooo nice!
Tip #8: Attention to detail!
You may have sanding and two more layers of color coat to go, but those next steps won’t cover brush marks going the wrong direction.
It is much harder to hide drips and buildup when the paint has dried.
Like when you repaint all your interior doors over a bad paint job (from past owners). Hey, at least it is now bright and white (and admittedly, our paint spraying skills have much improved since then too)!
Proof, it was not me–the red Milwaukee paint sprayer is in the foreground. Memories from 9 years ago…
Looking a second time before stepping away is a good idea too.
Tip #9: Use a razor blade when needed.
I can’t stand looking at brush strokes going the wrong direction (aka, when I don’t perfectly match the direction of the wood grain). Because of this there were a few brush strokes I refused to leave behind.
Keeping my paint transitions straight with a razor blade.
My patch job.
When the paint is already dried in place and you are still working on the area–attempting to get it going in the correct direction–a little heavy handed intervention can be a good thing.
While a razor blade is on the extreme end, that’s what I had on hand so I used it.
Definitely don’t wield it with a lot of muscle. The whole point of this is to preserve the door, not make more lines. I mostly dragged the blade backwards so I would not dig into the fiberglass. Mostly.
Here is the end result of that spot after two layers of primer.
Using a razor blade is only an option for the first coat. After that you’ll need to catch errors when the paint is wet. This is where wearing gloves (Tip #10) comes in handy. A gloved fingernail is also a nice “tool” that allows you to remove the errant paint while not digging into the layer below.
Tip #10: Pull your hair out of the way.
I always forget this step and have some bit of primer at the very ends.
A quick ponytail or bun will keep your long locks out of the difficult-to-remove primer.
If you watched the video already, did you notice how my hair went from a ponytail to a bun?
Tip #11: Prevent clean up.
Similar to tip #10, prevention is easier than cleaning.
Drop cloths / builder paper / plastic lining are a good idea if you are concerned about the look of the floor space after your paint job is complete.
Wear gloves to prevent days of primer on dry hands.
Winter and I don’t agree–my hands are almost as white as the primer from being sooooo dry!
FAQ for Priming a Exterior Door:
Q: Do you need to prime your door before the color coat?
A: Yes! Two coats of primer is necessary to create a continuous layer without any holidays (spots that inevitably appear on each layer caused by bubbles, an uneven spot, etc. Two layers guarantee a solid bonding coat.
Q: What if the exterior door is already pre-primed?
A: Still yes! At least one layer is necessary to adhere the color coat properly.
Q: Do I really need to prime? “I’m asking for a friend…”
A: See previous answers…YES! Primer is the bonding element between the door and paint. Primer will also protect the door beneath and help the color coat last longer. Please send them this post or, in the least, advise them to spend a little extra time on their project to prime.
While it was satisfying to strip the old layers of paint (none of which had a single layer of primer), it still took multiple afternoons. I don’t want to do this again anytime soon. Primer will help ensure my paint job lasts longer than the two layers I discovered–combined!*
*In fairness (or perhaps, not in fairness, but it was just done wrong), I’d almost bet there was only one layer of latex paint and the oil based paint below might have only been one layer too, with no primer. I’m feeling pretty confident my paint job will last longer than maybe even the two layers AND the factory finish. I’ve lived in the house for 11 years. I’ll give an update in 11 years. Or less if it turns out otherwise.
Thanks for stopping by and thanks for caring about your door. And caring about how the finished product will look and last! I sincerely hope your project goes smooth and lasts a VERY long time.
Related posts:
Stripping Paint Off a Fiberglass Door
10 Unusual Tips on Repainting a Front Door
Why Every Smart Lock Needs a Gasket!!! <– Spoiler alert: because you don’t want it digging into your newly primed (and painted) door!
Related videos:
And of course, it is obvious I made a primer video:
