Ah - that’s the one - we had some Zinsser 123 left after using for priming oil based yellowed skirting. I just used it on the walls - covering yellow and blue paint which we then painted white. Expensive and maybe not the right product but only took 2 maybe 3 coats of white emulsion for a good finish. I just made it up as I went along so listen to Airhead not me!!
There's a new version 123 plus, roughly £40 for 2.5lts but a real improvement in opacity on woodwork, covers more stains as well. Yet to try it on bare aged redwood, most waterbased primers fail to stop redwood (pine) bleed.
Ah - that’s the one - we had some Zinsser 123 left after using for priming oil based yellowed skirting. I just used it on the walls - covering yellow and blue paint which we then painted white. Expensive and maybe not the right product but only took 2 maybe 3 coats of white emulsion for a good finish. I just made it up as I went along so listen to Airhead not me!!