Zinsser Cover Stain is an oil-based stain block, sealer and adhesion primer. You can even use it to prime bare timber, meaning it’s a very versatile product and it is something that as a decorator, I always have in the van. Suitable for both internal and external use. Touch dry in 45 minutes and re-coat in 2 hours. Available from most trade paint outlets, or online at The Paintshed. This is my Zinsser Cover Stain Review
Zinsser Cover Stain the Stain Block
Oil-based stain blocks are generally a lot better than their water-based counterparts anyway. In fact, it is rare a water-based stain block will ever cope with heavy nicotine, smoke damage or water marks. Cover Stain will deal with almost anything you throw it at. If your stain is on emulsion, say a ceiling or wall and the stain is particularly bad, you can apply a full coat of cover stain, and back roll as you go. This has the effect of two coats without the added drying time. It really will stop most stains dead! No messing about!! However, it does sometimes struggle with water stains, or heavy smoke damage.
The only two products I know of that block stains as effectively as Zinsser Cover Stain are oil-based undercoat and pliolite-based masonry paint. You should never use pliolite inside!! The fumes are too much, and they can make you feel ill. Oil-based undercoat is a good option and it is cheaper than Cover Stain. The only downside of using undercoat is the 16-hour recoat time. In-fact that could be even longer if you apply a thick coat. Still, if circumstances mean the drying time won’t affect productivity, go with undercoat.
Zinsser Cover Stain has a 2-hour recoat, meaning you can easily paint over it on the same day, even with water-based paint like emulsion. You can coat a full ceiling or wall with it too. Just dilute the Cover Stain with white spirit to loosen it up and off you go. Make sure you ventilate the room as well as you can because although it is nowhere near the level of pliolite, it does stink.
Zinsser Cover Stain the Adhesion Primer
Zinsser Cover Stain works well as an adhesion primer in certain situations. Don’t get me wrong, it isn’t suitable for use on some substrates such as uPVC windows and there are better products out there for say, melamine. What I would recommend Zinsser Cover Stain for is stained or varnished timber which is to be painted. In fact, I don’t think there is a product on the market that does a better job.
I also use a very diluted coat of cover stain to prime old gloss or satinwood before applying water-based trim paints. It sticks hard and fast, then allows me to paint over it with anything I like without issue.
The alternative adhesion primers you can use on stain, varnish or old oil-based paints are Zinsser BIN, PS1 primer, or one of the water-based primers which seem to be flooding the market. Again, the water-based alternatives are generally not up to the task. They may not adhere well enough, but even if they do pass a scratch test, they will still let tannins bleed through. Zinsser BIN is a good product to use. It will knacker your brushes and it won’t level off very nicely, but it’ll do the job.
Zinsser Cover Stain will outperform both products on varnish and stained timber. It will be absolutely bullet proof in two hours and block any tannings dead! Honestly, when I say it is the very best product on the market for this task, I mean it.
Zinsser Cover Stain the Stabiliser
Yes, you can use Zinsser Cover Stain as a stabiliser, but most of the time there are better alternatives. For plaster you may be better looking at Zinsser Gardz or PVA, for masonry you may be better going for an exterior stabilising solution designed for the task. The list goes on.
There was one time I used Zinsser Cover Stain as a stabiliser to great effect. We were decorating the inside of an old church. The walls weren’t just chalky and generally unstable, but they were heavily stained with water marks and other nasties. We filled imperfections with what seemed like three tons of powder filler, then coated the whole lot in a very diluted Cover Stain. It worked brilliantly and gave us the ideal base for our eggshell emulsion.
Zinsser Cover Stain is a very widespread product which just about every professional decorator uses on a regular basis. There have been copycat products, but nothing has yet to come close. There’s a reason for this. Cover Stain is a versatile, quick drying solution for a lot of issues you can encounter when decorating. If you haven’t already, give it a go.
Zinsser Cover Stain Review – by Mike Gregory