We recently got some new exterior fiberglass doors installed. I was told by the door company they are not primed, but just raw fiberglass...questions:

1) prime them before painting? <== I was always told the answer to this is yes
2) is there a certain primer I should use for fiberglass?
3) The paint I plan on using is water-based...not sure if this changes any of the discussion or not?
4) I plan on brushing...what is my best bet to reduce brush marks and get a smooth coat out of it?


TIA

CapCity12thMan said:

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We recently got some new exterior fiberglass doors installed. I was told by the door company they are not primed, but just raw fiberglass...questions:

1) prime them before painting? <== I was always told the answer to this is yes
2) is there a certain primer I should use for fiberglass?
3) The paint I plan on using is water-based...not sure if this changes any of the discussion or not?
4) I plan on brushing...what is my best bet to reduce brush marks and get a smooth coat out of it?


TIA

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1/2) prime - use some kind of primer for slicker surfaces, do not use a generic, all purpose primer like Kilz2.

3)use a water-based paint for doors and trim that is interior/exterior. It will be more durable, regular exterior house paints are pretty soft. I would only use a true exterior paint if the door gets a lot of full sun.

4) use a good quality nylon brush, they are softer than polyester blend brushes. You can use a product like floetrol or XIM latex extender to help the paint flow out better. Most of your good paints don't need additives though, just get them on even and let it flow itself. Over brushing it will cause more friction and make brush marks worse.

The paint for my house is Sherman Williams and two reps there told me to use a bonding primer. Both paints I am using are water based, and both doors will be out of sunlight. The doors are white on the outside and off white inside, hence two paint colors. The white paint is an exterior paint though, so it will match trim and porch ceiling. I got a new Purdy Nylon (Soft 100% dyed Nylon) brush to use: https://www.amazon.com/dp/B00ANG1T6A/ref=sspa_dk_hqp_detail_aax_0?psc=1