Clear water-based acrylic floor varnish staining pine floor yellow

When we moved into our 1980s house five years ago we removed the carpets and varnished the pine floorboards with Ronseal diamond hard clear matt floor varnish. The floor boards were in excellent condition, and required very little prep other than a wipe down.

In one of the rooms, there has been some water damage to the varnish, that we have decided to remove and re-varnish. The old varnish was removed using a solvent for acrylic varnish (containing acetone) and some vigorous sanding of increasing grit to get a varnish-free, smooth, perfect finish to re-varnish. The boards were a nice pale pine colour, not too dissimilar to the unvarnished area....before we applied some new varnish.

We have used exactly the same varnish as the rest of the floor; however, the varnish has turned the area of floor a tan/tea-stained/yellow sort of colour which is quite a lot 'darker' and does not match the rest of the floor in that room or rest of the house.

This happened after just one coat, that we sanded off (thinking that would help), before trying again. The same thing happened again.

Does anyone know what is going on please? This is a water-based varnish, i.e., there is no oil in it, so that is not the problem.

Many thanks in advance.

 

I wonder if they changed the formula ??
I rarely use water based or waterborne polys. Oil base poly will both deepen the color in the wood and amber over time. Waterborne polys are similar to oil base but clean up with soap and water.

 

Thanks marksr

We have tried the varnish applied on another area of the floor, over the original varnish, and it is fine. We have also tried it on a piece of wood, and that is also fine.

We are now beginning to wonder if our sanding the floor area we want to re-varnish has caused the problem. We originally varnished the floor boards after they had had nothing more than a wipe down. The piece of wood we have tried it on is also unsanded.

Would sanding the wood have perhaps 'opened' the surface, allowing the varnish to penetrate and react with some natural oils in the wood?

 

Sanding first is always a good practice. Coarser sanding will allow the coating applied over it to suck in and adhere better, fine sanding can close up the pores/grain of the wood making it harder for a coating to penetrate into the wood. Sorry I don't have a better answer for you

 

Sanding seems to be the variable which changed - what was the final grit of sandpaper used? Have you tried sanding another piece of wood the same way to see if that mimics the results you're getting on the floor?

 

Was the sanding dust removed prior to applying the poly?

 

Thanks both - yes, we also think it might be something to do with sanding.

We used 80 grit to get the old varnish off, the 120 grit, then finished with 240 grit.

Yes, the dust was completely removed.

 

I realize this link is a bit old, but... I have amerikan black walnut flooring that I put down myself back in the 80's. Regular tongue and groove 3/4" flooring that I had milled locally. I put this new 'magic' water based 'Swedish' finish on it. I'm sure it was just a 2 part water based finish. It went on and hardly changed the color of the walnut. Over 30 years now the wood has turned to a yellowish brown color. In places where I've sanded the wood for repairs (dog pee stains that were not cleaned up fast enough) the wood returns to it's un-patina state and no matter what kind of finish I put on it, it always turns darker than what is currently on the rest. I just live with it, although actually now I tend just to sand the stains off and leave it plain. I'm really not sure what a finish does for the floor. I sort of wish I had put a polyurethane finish on it from the start, although it would have turned the walnut dark, but it still would have lightened up through the years. I can see under some of the orientals where it's been out of the light, it's much darker. In general, dark wood turns light and light wood turns darker. Just the way it is, and when you sand it, you're back to when it was new.

That walnut was beautiful when it was put down in it's unfinished state, there were all sorts of colors in it from brown to blue. It's all turned to a kinda yellow brown now. But I love the grain in it and the orientals look great on it, it was ungraded walnut, not clear panel grade, but I cut all the knots out of it for the most part. It was 3 width, 3, 4 and 5" widths. I got it back then for a buck a covering foot, milled T&G. Cheaper than any commercial grade flooring. And I was cheap at the time.