Thread: CFP on jarrah "blistering" on second coat

Just a stab in the dark here, but you might have sanded too fine. I have had trouble with Jarrah taking finish. Admittedly on turned things. Did you wipe all the dust off? Sometimes the grain can get clogged and stop the finish from actually going IN. I have had better success oiling jarrah. Or only sand too 120# or maybe 180#.

Happened to be chatting to the paint shop guy the other day about this sort of prob, he said that the drying time in the cold weather can be another day or two over what it says on the can, the solvents remain trapped by the next coat in the previous coat, the heater was the right move but may not have been enough.

Did the sanding of the previous coat produce white powder or did it tend to gum up the paper?

Pete

Sanding produced fine white powder; didn't clog the paper at all. It would have been about 20 hours after the previous coat.

Any suggestions for salvaging this job? I'm not keen on sanding back to bare wood for a third time. I've heard of scraping off bad finishes to have a second go, but have never done it myself.

As pjt posted looks like solvent hasn't evaporated fully

Originally Posted by Edwin

Hi guys, have searched for this problem but I don't think it's been answered before. I have a jarrah kitchen benchtop which I am resurfacing. After a disaster trying to use epoxy,, I sanded the whole thing back to bare wood (again), up through the grits to 240 (good enough for a poly finish), and decided to use Cabot's CFP, as I figured this would be a hard wearing surface, and had also used it before on floors with no problem.

Well, the first coat went on like a dream. Let it dry overnight (had the wood heater going the whole time so the room was comfortable), keyed the new surface lightly with 240 as instructed on can, wiped the dust off with a lightly turps'd cloth, and started the second coat. And half way through I noticed this horrible blistering effect beginning to take hold in patches of the new coat!!! .

This photo was taken about a day later. I thought I followed all the instructions but obviously something's not quite right. Does anyone know what went wrong, and more importantly, how I can fix this?

Gooday Edwin,

since a light white powder came off from your sanding after your first coat, it means it had dried well; this is good. However, after you wiped the surface with turps to apply the second coat, the turps didn't dry off completely causing the blistering effect. I have used CFP with great results by allowing 1 full day for the turps to dry before applying further coats.
Try using Cabots hardener in your CFP; this will speed up the drying process and harden the surface further, but only do this when you are ready to apply your coat, no pre-mixing a day earlier as this brew will harden in the can.
Follow the instructions to the letter and you won't go wrong.
It is not really necessary to wipe down between coats with turps and I personally would light sand beween coats with 400 grit, just for a little white powder dust to be kicked up, then vaccuum thoroughly until no dust appears on your palm when you run your hand across the grain; 240 grit is generally for flooring.


Hope this helps.

Cheers Evan

Aha! There was turps in the cloth I used, and I only waited a few minutes between wiping and coating. So I guess I'll just sand or scrape the blistered areas, and recoat. Thanks everyone for the advice.