Cracking problem with Fuhr 9550 & 9100 Waterbased Acrylic

[MarvinWatkins]

Well, I finished this project the beginning of June for my daughter.

I just noticed yesterday morning that the two treads are starting to show small cracks along the grain on the top of each tread. I checked one of the test boards that is about the same size and it does not exhibit the same cracking.​

What could/should I have done differently. I sanded as recommended. Sprayed on one coat of primer (may have been two). Scuff sanded. Finished up with two coats of the solid acrylic.

I did not put any other finish over that. Was that my mistake? This step-stool is in our girls bathroom. They stand on it to wash hands, brush teeth, etc, so it has the potential to get a little wet. The treads are pine (including the test piece) and about 4-5" x 13".

I have another quickie project that I will be finishing with the same finish within the next week. Fortunately, I can add this into that day of finishing.

Any help will be greatly appreciated!!!

 

[DaveO]

I think that your issue is the increased humidity in the bathroom environment. Probably what you are seeing is the wood expanding across the grain and cracking the finish. Your test piece hasn't been in the same wet environment so it hasn't had the same expansion.
Now that it has been exposed to its final fate, you might be able to give it another coat of finish and hope that you won't have any more movement unless you move to the desert or the heat comes on in the winter.
That really sucks, I made something similar for my niece using Poplar, I wonder how the finish is holding up on it :eusa_thin :eusa_thin 8-O

Dave

 

[woodguy1975]

In moist environments you need to use a vinyl sealer to give the finish some flexibility for the expansion and contraction.

John

 

[MarvinWatkins]

Woodguy,

Is a vinyl sealer something you add into your finish or something you apply to the wood prior to applying the finish? Any recommendations for use with a water-based acrylic finish?

Note, I am spraying this finish on.

 

[Howard Acheson]

When you say "acrylic" are you referring to a spray lacquer or to a waterborne finish?

From you description, I would agree that the finish is not appropriate for the moist environment. In addition, two coats of either a lacquer or a waterborne is less than ideal. For a moist environment, I would use at least 5 or 6.

Finally, one caution. No matter what you use, you are creating a very slippery surface that can be like ice when it gets wet or when stood in in wet feet. I would recommend that some non-skid strips or that some non-sked granular material be added.

 

[walnutjerry]

Well, I finished this project the beginning of June for my daughter.

I just noticed yesterday morning that the two treads are starting to show small cracks along the grain on the top of each tread. I checked one of the test boards that is about the same size and it does not exhibit the same cracking.​

What could/should I have done differently. I sanded as recommended. Sprayed on one coat of primer (may have been two). Scuff sanded. Finished up with two coats of the solid acrylic.

I did not put any other finish over that. Was that my mistake? This step-stool is in our girls bathroom. They stand on it to wash hands, brush teeth, etc, so it has the potential to get a little wet. The treads are pine (including the test piece) and about 4-5" x 13".

I have another quickie project that I will be finishing with the same finish within the next week. Fortunately, I can add this into that day of finishing.

Any help will be greatly appreciated!!!

How dry was the material you used to build the project? If it was pine shelving material, it is not usually as dry as kiln dried hardwoods. Pine shelving could be as high as 12---15% whereas most hardwoods are dried to around 7%. That fact plus being in a humid enviroment could have a bearing on what is happening. Then throw in air conditioning, which most people have now, and you have an added factor in the equation. Who knows?

You are working with mother nature-----in spite of what you do, she will win.

Jerry