Why prime bare wood?

[^woody^]

On the basis that gloss paint seems to stick well to many things, why is a wood primer necessary before glossing?

And if water based emulsion is often used instead of a primer and works as a primer, then why can't a water based gloss be used to prime bare wood?

Asking for a friend.

 

[Doggit]

Emulsion is often used by quick and dirty painters, but doesn't work so well long term. But if you don't prime the wood first, then the gloss paint doesn't go on evenly, and keeps soaking into the wood. The primer raises the grain on the wood, and seals the top layer, but you still need the undercoat (or emulsion) to support and give a grip for the gloss.

 

[Gerrydelasel]

Yeah I made the mistake of trying to gloss straight onto wood once, and the wood kept drinking it in! Took days and days to dry too, for some reason.

 

[chappers]

Asking for a friend.

Tell your mate to stop asking silly questions and go to bed

 

[^woody^]

Tell your mate to stop asking silly questions and go to bed

He could be in Austrailia

 

[^woody^]

So its not a problem with adhesion then, just of potential finish?

So if that is it, and it can be smoothed down between coats, then is there any other reason that primer is a necessity?

So if say, someone rubbed down an external door, and there were large areas of bare wood, and it had to be recoated before it rained later in the evening, but then that someone found that the primer he thought he had was actually water based gloss, so he used that anyway, then would the gloss still stick and be OK as a base for the oil based gloss later?

 

[chappers]

I think your Australian mate would probably be OK I would tell him to let the w/b gloss fully cure (48hours) give it a light sand then go over it with the oil based

 

[^woody^]

Bonza

 

[Doggit]

Actually it is a case of adhesion as well Woody. You can put oil gloss on top of water based undercoat, but not the other way round. There was a very interesting interchange recently, where a damn good painter was explaining how to handle water based gloss to get the best out of it, as it needs far more consideration than oil based gloss does. In the case of your Aussie friend, I think he'll find he has to eventually bite the bullet, rub the door down again, and then prime it properly toseal the grain.

 

[chappers]

not if he's got a flat coat on, I doubt.

 

[^woody^]

Surely the gloss should stick well to the bare wood? I can't see why it should not.

 

[chappers]

yep can't get it off of my brush handles