Designing Kitchens and Bathrooms - polyurethane cracked

I've painted my kitchen cabinet's black with latex paint. Then put a water based polyurethane on top. I did my doors first and they turned out good. But on my drawers when I applied the first coat of polyurethane it cracked. WHY? So I've started to sand it off but on a lot of places it still shows faint crack lines. Do I sand down to take the paint off? How do I not repeat the problem? And should I not use polyurethane I've heard Tung Oil is better? Any advice would be great.

Welcome to the forums

I seldom use any waterbased poly but it sounds like a contamination problem, especially since the same procedure worked well on the doors.

Did the drawers have as much time for the black to dry as the doors did?

The drawers will need to be sanded down enough for the cracks to dissapear, it might require another coat of the black to get it ready for the poly top coat.

I seldom use any tung oil but it is my impression that it is only used over raw wood, not sure it would work over paint. Oil base poly might be a better choice but it might cause a slight difference in the black color appearence.

THANKS! And thanks for the info.

Yeah the black had the same time to dry. :thinker: I've also sanded the edges so the wood shows through then rubbed some Old English for dark wood to darken the edges. It was a day and a half when I put the poly on my doors but only a few hours when I put it on my drawers. That's why! So I need to sand until I can't see ANY lines. What grade of sand paper do you suggest?

By using the water based poly is that why it lightened up my black a little, and the oil based won't?

The 'old english' is probably the contamiment that caused the cracking! It would be better to use a dark stain or some thinned down black to get the same effect.

I'd start with 120 grit sandpaper and finish up with 180 or 220.

Waterbase polys don't change the color much but adding sheen will affect how the finish reflects light. Oil base poly often darkens or deepens the color and will amber some with age. Oil base poly dries to a harder finish than waterbase.

Well i've been sanding till my fingers are raw and there are still some crack lines but it's smooth. If I paint over it will the paint stick, or just add to my problem.

Thanks for helping, feeling better about moving on!

As long as the surface is clean the paint should stick ok. If the lines still show after painting you can resand and repaint them.

:wall: Okay I don't Know what I did now. I ended up stripping the paint off my drawer fronts and left them to wait. So I moved on to my wall and floor cabinets. I cleaned them and did all the exact things I did with the first doors. I didn't even sand the edges. I put on 2 coats of primer, waited a day to dry. Then I put on 2 coats of paint (waited a day in between coats).After it was dry to the touch (over night) I loosely covered the bottom with plastic. It waited 3 days before I started with the polyurethane. Did all the right things, even bought a new can of the exact same poly. Just in case the other was contaminated. Stirred all through out painting. So what is going on that I have faint crackling lines?Why did it do it now and not to the first doors?

If cracking is confined to the drawer fronts where you applied the oily Old English, the surfaces were contaminated by the oil.

No it's not the drawer fronts, those I stripped of paint and are down to the bare wood again. This is the wall and floor units, the wood frames. I haven't even had the Old English near it. I even wiped them down with a clean cloth to make sure there wasn't any dust on them. And I haven't cooked in my kitchen since I began. So what do you think it is? Have you seen this before, or heard of it? I just want to find out what I did so I don't do it again.

Thanks for any info!

Did you clean the cabinets with TSP or degreaser before beginning to make sure all surfaces were grease free?

Are you sure you removed and neutralized all the stripper before you started painting/priming?

I'm working on the WALL and the FLOOR cabinets. NOT the drawer fronts with the stripper. I just told you that so you would know were I was at. But thanks for the heads up about neutralizing the stripper before I begin again on them.

But YES I did use a good cleaner, and then went over again using clean rags, with TSP. The same things I did when I began with my first set of doors that turned out great!

The only thing I can think of that I should have done, is sand lightly in between coats of primer, paint, and before the first coat of poly. I didn't read about that till after I was done. But I DIDN'T do that on my first set either. So why did they work and not these?

I don't know :o :(

Did you rinse off all the cleaners well?