Pink wood primer in the olden days...

[A.Steve]

I wonder if anyone here can offer me advice. I apologise in advance that this is a bit half-baked.

In the 1990s, I did some (amateur) renovation of wooden window frames. I didn't really know what I was doing - but I copied things that I noticed appeared to work for tradesmen. My approach was to use primer; undercoat then gloss paint - for a white finish... fit for harsh outdoor weather.

The primer I used was commonly available - and distinctively light pink. Using this primer really improved the durability of my results over just undercoat/gloss. Thereafter... I used smelly undercoat and smelly gloss. I'm sure I shortened my life with the fumes (today, I'd ventilate better) but the results were good.

In the last 5 years, I bought undercoat and gloss again... and was blind-sided when I discovered, after purchase, that my undercoat was water soluble. I hadn't expected this. The gloss I used was almost as I remember from the 1990s - but I felt it was more transparent... perhaps that was just my imagination. I hadn't tried buying primer again, in recent years, as all my painting was just interior finishes.

I now need to renovate some exterior wood. My first thought was "that pink primer that worked so well in the 1990s." - but I can't find it for sale in the UK. I might have found it for sale in South Africa and India - I'm not sure - and don't want to visit to check it out.

Hot on the heels of this surprise was another. The interior decorating I did with water-based undercoat and oil-based gloss - on a windowsill - has failed in a very funny way. I painted it about 18 months ago... and, a couple of weeks later, left some DIY products on the windowsill - including boxes of screws and similar (clean) things to which I didn't give a second thought. I then closed the door - and didn't look again for over a year... until last week. The paint had failed.... in a curious way. Under the boxes (which happened to be yellow - but I think that's a fluke) the white paint has tuned a fairly bright yellow. (I think it's a fluke as there are yellow marks under things that were not yellow boxes too.) I had imagined the painting I'd done would be good for a decade... as there'd be no wear and tear... but I was wrong.

Questions:

What's the deal with that light-pink wood primer that was inexpensive and worked so well in the 1990s... but now I can't find. Am I looking for the wrong product (I don't remember what it was called) Has it been banned? Was it white undercoat with a drop of "red-lead" in it? Is it still available (at a sane price) in the UK? Has it been superseded by a better alternative paint... about which I'm unaware?

Are the curious bright-yellow patches on my windowsill related to the paints I used? Could it be the water based undercoat... or was it the gloss?

My intuition tells me to use oil based paints for the best (most durable) finish. Am I misguided? Am I making a mistake, other than paint-selection, for my recent failure?

What paints would you recommend for the most durable white gloss finish? Is the answer the same interior vs exterior?

 

[JohnD]

For external wood, I've found Aluminium Wood Primer to be most durable.

White Oil Based gloss goes yellow, if it is not exposed to sunlight which bleaches it.

Skin oil also leaves yellow marks on white cotton shirts, mostly round the collar, and cooking oil on tablecloths, as ordinary laundering does not get it all out, if you put them away in a dark cupboard.

 

[sparkwright]

You are right that wood primer was often pink 30+ years ago.

There are white or light grey wood primers out there.

JohnD is spot on about the aluminium wood primer being the most durable, for external wood.

Oil-based white paint can indeed go yellow, but typically indoors. Putting things in front of white oil-based painted surfaces will nearly always cause yellowing.

Water-based undercoats can 'bleed' through oil-based topcoats, I have experienced. Best not to mix them if you can.

(Any yellowing from water-based paint COULD be caused by a water stain on the surface.)

One modern alternative for exterior wood is Sadolin Superdec. It is water-based, quick drying, easy to apply, but resists cracking and blistering, It can be used to prime, undercoat, then topcoat - so you can often complete the job in one day with just one tin of paint.

You do need to sand all previously painted wood first though, as always.

 

[A.Steve]

Many thanks for your replies. I think the answer about sun 'bleaching' makes sense for my yellowed paint... The effect is *far* more dramatic than any I'd anticipated. The yellow marks were all under things placed on a windowsill a fortnight after painting - then left there for a year or so. I assume that exposing the yellow bits to sunlight (after more than a year) is unlikely to turn them the same colour as the rest.

Aluminium wood primer sounds like what I want... for my external wood... and light grey is a fine colour choice. I had been flummoxed when I discovered "the pink wood primer" didn't seem to be a thing in the UK any more. I don't care about it being pink - though I did like that it was not the same white as the undercoat.

I'm going to hunt around for oil-based undercoats... I think I can still get those... These water based acrylic undercoats do make brush care easier... but I don't think I get comparably durable results from water soluble paints. (Is this a sign I'm getting old. )

 

[JohnD]

. I assume that exposing the yellow bits to sunlight (after more than a year) is unlikely to turn them the same colour as the rest.

It can.

Start today.

Leave a coin on one of the yellows and watch the difference develop.

 

[opps]

White Oil Based gloss goes yellow, if it is not exposed to sunlight which bleaches it.

The light doesn't bleach the white paint per se, it is the lack of UV light that yellows it.

As you say, if exposed to sunlight, the paint will become white again.

On an exterior job last year, I only needed about 0.5L to finish the job. I found an old tin of oil based Dulux Trade gloss in my garage. The paint in the tin was yellow but I knew that after 2 or 3 days it would turn white (which it did).

 

[opps]

Water-based undercoats can 'bleed' through oil-based topcoats, I have experienced. Best not to mix them if you can.

If a client has new woodwork, I routinely use water based primer. I tend to use the cheap Leyland Trade acrylic primer. The primary reason being that it is a dream to sand back. I use it as a "search coat", by that I mean that I sand it back so much that most of it is gone before I apply the oil based coats.



With respect, I disagree with your initial statement. I do however think that you might be referring to knots bleeding through. Knots can be problematic. Traditionally, one would have used knotting solution, but that won't work if the knots are particularly resinous.

 

[A.Steve]

Start today.

I started a fortnight ago... haven't been back in the room yet. If daylight fixes it, I'll be amazed (but more narked about the bit I chipped... that sunlight definitely won't fix.)

I still think my technique needs improvement. I blindly used acrylic undercoat how I'd have used oil based undercoat in the past. I had bought it without even thinking undercoat could be acrylic. I think I need to use oil based undercoat to get the finish and durability I want on windowsills etc. I still have desperately little time to tackle my DIY jobs - but both aluminium primer and oil based undercoat are on my must-buy shopping list. Thanks.