Question about varnish

[aproblemshared]

I have recently painted my kitchen wall and base units with Ronseal Paint & Grain in Limed Oak. Although not essential, I decided to protect them with a coat of varnish. I used the varnish recommended on the Paint & Grain tin. When I opened the tin of varnish & stirred it, at the bottom of the tin about an inch thick was this almost solid gunk - I'm not just talking about a little bit thick, it was, as I said, almost solid. I carried on stirring it but it was almost impossible to do it & get it mixed in. I then coated the units with the varnish & yesterday, several days after they have been done, the units look patchy and yellowy. The varnish clearly says 'non yellowing' and I am now wondering whether this varnish was possibly faulty causing the problem I now have. I phoned the Ronseal technical helpline yesterday but they are only open monday to friday so will attempt to call them tomorrow afternoon. I am now faced with having to strip the paint off & start from scratch again. I am convinced I have done everything right by preparing the wood doors correctly. Does anyone know if varnish can detioriate & cause this problem. Any answers would be very welcome. I am not a happy person because of all the hard work it took to do them

 

[Nestor_Kelebay]

Satin and semi-gloss polyurethane will have solid clear pigments in them to lessen the gloss, and they WILL settle to the bottom of the can in time. This is almost certainly what that "gunk" you stirred up from the bottom of the can was. Normally it's not a problem to get them back into suspension by stirring, but I think in your case, you either got a very old can, or perhaps one that someone else had purchased, mucked up by adding something to it, and then returned for a refund.

My guess would be that the "patchy" appearance of the finish is due to the fact that the pigments weren't fully dispersed and uniformly distributed when you applied the polyurethane. Instead, despite your stirring it as best you could to break up that solidified mass of pigments, you only broke the mass into clumps, and it's the non-uniform distribution of those clumps of pigment in the varnish film that makes the varnish look much flatter in some spots and much glossier in others, thereby giving it that "patchy" appearance you describe.

Unfortunately, if the poly has already dried for a couple of days now, your only option now is to probably remove it.

However, I have a trick up my sleeve that I think will work well for you to make that job go fairly quickly and easily and are willing to buy a heat gun with electronic temperature control. (The trick is not just using the heat gun, but what to use along with that heat gun.)

Wait until you talk to the manufacturer and see what he says. If you're in a position of having to remove that poly, post again and let me know exactly what you have on/in that wood now, and I have some confidence that I can make that job a lot easier than you are probably anticipating.