How necessary is primer on bare wood outside?

[Driver23]

Hi,

As far as I know bare wood should be primed, then undercoat, then gloss (or primed then one coat). Our builder has turned up with just a tin of undercoat and I'm nervous - don't really want yet another fight over how to do things properly (!) unless it's really necessary.

This is exterior pine soffits.

Any experienced painters (eg who've gone back to jobs after a few years) out there who could advise?

Many thanks.

 

[joe-90]

It's essential - absolutely essential.

 

[Driver23]

Er, right. That seems pretty clear then!

Thanks joe-90.

 

[Robbie uk]

A lot of people will use undercoat as a primer before giving it another coat of undeercoat.
Thing is undercoat and primer are two different things and that is why a proper prime should be used. This will soak in to the timber surface and raise the grain of the wood so it can be rubbed down properly. Then one or two coats of undercoat can be applied, sanding between, then the topcoat of gloss.

 

[Driver23]

I'll ask for primer, but if I ask for the primer to be sanded before the undercoat I'll probably be chucked off the scaffolding! Might do it myself if it comes to it, an hour's work is probably easier than three hours of moaning/arguing

 

[0000]

If you are paying for primer, then he should put primer. I'd be pretty mad if someone pulled that on me.

Only thing that should be used is primer is stuff that is formulated as primer. It is possible that you might have a combined primer and undercoat. But Outside I would definitely go for separate primer. Primer doesn't even look like paint when it dries. Like Robbie says it impregnates the wood/material. it is a preparation for pain rather than paint itself. "Size" is basically a primer for paper, so ink doesn't run, and graphite sticks.

 

[Driver23]

Done it, only took 90 minutes. Thanks for the advice guys.

 

[Nige F]

Hi,

As far as I know bare wood should be primed, then undercoat, then gloss (or primed then one coat). Our builder has turned up with just a tin of undercoat and I'm nervous - don't really want yet another fight over how to do things properly (!) unless it's really necessary.

This is exterior pine soffits.

Any experienced painters (eg who've gone back to jobs after a few years) out there who could advise?

Many thanks.

Builders who think anyone can paint He needs an enema of shellac knotting bet he didn`t use that on the knots Because he bought wood from a tree with no branches . You gotta love Joe 90 - an all rounder who does know what he`s at

 

[opps]

Cats amoungst the pidegeons time...

The lack of mention of any primer by the builder would worry me- or at least the lack of justification for not using one.

I would not paint any kind of oil based UC straight over wood BUT Dulux Trade weathershield, for eg., uses a liquid preservative as a primer (not a paint). one might be able to argue that any solvent based wood preservative might suffice, rather than the proprietary one.

Additionally the sadolin "oils" do not use primers or undercoats.

i agree that most "builders" assume that painting is very basic but I don't want to slag someone off without knowing the back story.

 

[WhiteVanJack]

On the subject of Dulux Trade Weathershield Gloss paint, if I wished to have this as the final coat on my outside window frames, what would be my process starting with bare wood/sanded residual paint after sanding off the previous flaked and loose paint. In some cases it is right down to bare wood in other places the paint is intact

Ideally, what would be the choice of primers and undercoats before applying the final Dulux Gloss coat and is it a light sanding in between all coats. From reading the above post it seems as though Dulux Weathershield Gloss requires a special primer rather than a standard primer?


Rgds
Jack

 

[opps]

Hi jack

I recommend Weathershield system but Trade not retail.

Apply the blue liquid to all bare wood- wipe off any excess on previously painted work with kitchen paper.

You need to either paint over with the undercoat in under two hours or wait until the next day. i prefer to wait other wise the paint can turn slightly blue. If you are going to overfill with resin filler then allow the primer to dry fully before applying the filler.

Apply two coats of U/C, the resin filler wont need an extra primer.

I then apply two coats of gloss- I like the extra depth.

The paint can be a bit of a pig to work with on hot or cold days so I add a little owatrol to help it flow. Since 2010 VOC paints take longer to cure so i add a tiny amount of terebene. The latter will make it easier to sand between coats with 320 grit silicone carbide if necessary (by making the paint dry faster). You do not need to sand between coats unless you want to reduce tramlines or contaminates.

 

[WhiteVanJack]

opps,

Thank you for the detailed reply, it is very useful, not only to me but to any others who wish to follow this method.


Regards
Jack

 

[sparkwright]

What about knotting solution on the knots?