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View Full Version : Painting 'pre-primed' doors - Do I undercoat?



mebilloz
13th Jun 2010, 10:54 PM
Hi All

I have a number of Corintian 'impression' doors. These have a moulded pattern in what appears to be a white primed MDF facing. I am getting close to painting them - air spray with Aquaenamel most likely - I did read the threads about its downsides.

Question 1. Do I need to (or should I) prime them before coating? The DULUX shop says 'of course you should prime them with our primer ....'. Is this a ploy to sell more paint? or has somebody had a bad experience from not priming.

Question 2. Not doors, but architrave painting. I was wanting to pre paint my mouldings before fitting. Given I will have brad nail holes after fixing I am thinking about spraying the base coat on and doing the final coat sometime later. Is there a problem (or proceedure) if the second coat is not for 1,2, 12 months?

Thanks

Bill

Honorary Bloke
13th Jun 2010, 11:16 PM
1. The whole point of pre-primed is to not have to prime. Just spray them. :)

2. No problems. If a glossy enamel, just rough up around the filled in holes a bit and touch up with a brush. If a flat finish, no rough up needed.

Craigoss
14th Jun 2010, 02:01 AM
I have asked these same questions to professional painters I had at my house several months ago.

1) Yes they require undercoating. The doors are primed, but require a coat of under coat and at least one coat of top coat i.e. enamel etc. Usually the edge of the doors are not primed, so it will need priming anyway.

2) No.

Strom
14th Jun 2010, 10:59 PM
You hit the nail square on the head craig..
The doors faces (MDF) are factory "Primed"..
The door edges are not..
A decent enamel Undercoat will do the job fine. I also tint the undercoat (If its practical) to the same colour as the finishing coat to give better coverage.
Also enamel undercoat will give a much better sanded finish than acrylic.
And don't neglect undercoating the top and bottom of the door..

Goodluck.. :2tsup:

OL' PAINTING
15th Jun 2010, 09:41 AM
You must undercoat all bare timber areas (like door edges). If the finish is a very different colour from the pre-priming Ė you can paint doors first with tinted undercoat, just to ensure better coverage (Aquanamel covers very poorly, itís like water), or be prepare to do 4-5 coats of paint.


It depends on finish. If itís gloss - you will have to light sand and undercoat it before painting, or the paint will not stick and will be stripping off. Satin finish can just be light sanded before painting (if there are any cheeped or bare areas they have to be touched up with an undercoat first).

Pulse
15th Jun 2010, 10:12 PM
An old painter friend of mine insists on undercoating these before the finish coat. I had to stop him from doing two undercoats he likes it that much. He says the top coats cover heaps better. As a minimum undercoat the unprimed edges.

Cheers
Pulse

JohnnyD
17th Jun 2010, 11:15 AM
And don't neglect undercoating the top and bottom of the door..

Goodluck.. :2tsup:


I thought it was best to avoid painting the top to allow any moisture out.
I used to think it was lazy painters until I did the top on my bathroom door, which then started to 'swell' and I couldn't close the door. Maybe this just applies to wet/humid areas.

John

Pulse
18th Jun 2010, 07:31 PM
The door should be pretty dry when it comes out of the factory, most sticking doors seem to be the jambs/reactive foundation rather than the door itself changing shape.

Cheers
Pulse

Strom
18th Jun 2010, 08:20 PM
I thought it was best to avoid painting the top to allow any moisture out.
I used to think it was lazy painters until I did the top on my bathroom door, which then started to 'swell' and I couldn't close the door. Maybe this just applies to wet/humid areas.

John

First I have ever heard of it !!!
Normal practice is for doors to be painted all edges / faces to "seal" the door completely !!!
That way no moisture is able to penetrate into the door and cause it to swell !!

rantenNraven
24th Jun 2010, 04:34 PM
Im a painter by trade, and i say undercoat every time. then when it is dry, sand the edges and coat them again. (the faces only need one). if your painting with aquanamel made by dulux it is water based so use a water based undercoat. (i use haymes tri-coat) there is no primer like it. but you can just use dulux paint.

2) if you are going to put 1st coat of undercoat on now and do top coats later the only thing to that is make sure there is no grease or dust before you do it, and there should be no dramas.