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In wood finishing hell

Cardinal

Cardinal

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I have a piece of wood that I need to polyurethane and give a strong protective shell. My equipment:

A soft, even synthetic brush, three inches wide.
The mahogany piece of wood, 18" x 12".
Varathane water-based polyurethane, gloss interior
5" DeWalt random orbit sander with 420 grit sandpaper.

Following instructions as I have understood them, I brush the polyurethane evenly and thinly in one direction, wait a couple hours, brush a new coat in the perpendicular direction, and repeat this process a couple more times.

The problem: the polyurethane never thoroughly settles, leaving me with a crosshatch pattern from the brush ridges on the surface. However lightly I use the sander to even out the surface, I take it down to the wood every single time, no matter what. The main issue here is that it is functionally necessary for the surface of the wood to be 100% flat. Any raised ridges, however slight, are a no-go.

Any advice for applying a completely even surface? I'm dying over here...
 
Cardinal said:
I have a piece of wood that I need to polyurethane and give a strong protective shell. My equipment:

A soft, even synthetic brush, three inches wide.
The mahogany piece of wood, 18" x 12".
Varathane water-based polyurethane, gloss interior
5" DeWalt random orbit sander with 420 grit sandpaper.

Following instructions as I have understood them, I brush the polyurethane evenly and thinly in one direction, wait a couple hours, brush a new coat in the perpendicular direction, and repeat this process a couple more times.

The problem: the polyurethane never thoroughly settles, leaving me with a crosshatch pattern from the brush ridges on the surface. However lightly I use the sander to even out the surface, I take it down to the wood every single time, no matter what. The main issue here is that it is functionally necessary for the surface of the wood to be 100% flat. Any raised ridges, however slight, are a no-go.

Any advice for applying a completely even surface? I'm dying over here...
Click to expand...

I feel your pain.

Other than that I got nothing.
 
Cardinal said:
I have a piece of wood that I need to polyurethane and give a strong protective shell. My equipment:

A soft, even synthetic brush, three inches wide.
The mahogany piece of wood, 18" x 12".
Varathane water-based polyurethane, gloss interior
5" DeWalt random orbit sander with 420 grit sandpaper.

Following instructions as I have understood them, I brush the polyurethane evenly and thinly in one direction, wait a couple hours, brush a new coat in the perpendicular direction, and repeat this process a couple more times.

The problem: the polyurethane never thoroughly settles, leaving me with a crosshatch pattern from the brush ridges on the surface. However lightly I use the sander to even out the surface, I take it down to the wood every single time, no matter what. The main issue here is that it is functionally necessary for the surface of the wood to be 100% flat. Any raised ridges, however slight, are a no-go.

Any advice for applying a completely even surface? I'm dying over here...
Click to expand...

A foam brush may work.

foam.jpg
 
Don't overwork the polyurethane. It starts to dry on contact. Get it on fast and leave it be.
 
Yep, I would try the foam brush. Also, how cold is the weather? The faster it dries, the less drips and strokes show.

I stained a door with Minwax recently. It was really drippy and I had to sand and redo the areas where it dripped, after they dried. Polyurethane might have been a better choice, but I wanted the more natural stuff. It was an exterior door, so I had paint on the weather side and stain on the inside.
 
I used some painters tape, and taped the outer edge of my table, and then simply pour the urithane on. The tape was raised a little, to give me a lip.
 
Cardinal said:
I have a piece of wood that I need to polyurethane and give a strong protective shell. My equipment:

A soft, even synthetic brush, three inches wide.
The mahogany piece of wood, 18" x 12".
Varathane water-based polyurethane, gloss interior
5" DeWalt random orbit sander with 420 grit sandpaper.

Following instructions as I have understood them, I brush the polyurethane evenly and thinly in one direction, wait a couple hours, brush a new coat in the perpendicular direction, and repeat this process a couple more times.

The problem: the polyurethane never thoroughly settles, leaving me with a crosshatch pattern from the brush ridges on the surface. However lightly I use the sander to even out the surface, I take it down to the wood every single time, no matter what. The main issue here is that it is functionally necessary for the surface of the wood to be 100% flat. Any raised ridges, however slight, are a no-go.

Any advice for applying a completely even surface? I'm dying over here...
Click to expand...

Poly over Mahogany is a test of will.

I take the sandpaper up to 1000 grit.

Then I raise the grain.

Then I steel wool.

Then I apply poly with with a HVLP gun. A good painters sponge would be my second choice.

Mahogany is a tough wood for poly because the grain often ends in a turn in the midsection of your boards. This makes a uniform appearance difficult. Poly has a faded look on end grain and you will get a lot of that in the middle of your boards.
 
Did you stir the poly before applying? Not uncommon for the first coat or two to disappear like that as it settles into and fills the pores. After I finish a coat, I also go back over the surface, sweeping with a "dry" brush to even things out (same brush, just without reloading in poly).
 
Cardinal said:
I have a piece of wood that I need to polyurethane and give a strong protective shell. My equipment:

A soft, even synthetic brush, three inches wide.
The mahogany piece of wood, 18" x 12".
Varathane water-based polyurethane, gloss interior
5" DeWalt random orbit sander with 420 grit sandpaper.

Following instructions as I have understood them, I brush the polyurethane evenly and thinly in one direction, wait a couple hours, brush a new coat in the perpendicular direction, and repeat this process a couple more times.

The problem: the polyurethane never thoroughly settles, leaving me with a crosshatch pattern from the brush ridges on the surface. However lightly I use the sander to even out the surface, I take it down to the wood every single time, no matter what. The main issue here is that it is functionally necessary for the surface of the wood to be 100% flat. Any raised ridges, however slight, are a no-go.

Any advice for applying a completely even surface? I'm dying over here...
Click to expand...

You should try sanding by hand or using a sanding block.That orbital sander might be too aggressive. I did some looking around and found this.

Polyurethane Finishing Help.
 
Taylor said:
Did you stir the poly before applying? Not uncommon for the first coat or two to disappear like that as it settles into and fills the pores. After I finish a coat, I also go back over the surface, sweeping with a "dry" brush to even things out (same brush, just without reloading in poly).
Click to expand...

Yes, the direction were quite clear about stirring (and not shaking). I'm at a point where the pores of the wood are no longer a factor as I've applied and sanded so many times already now. The issue now is about getting the final flat surface. I'm two steps away from KevinKohler's "just pour it on" trick.
 
Cardinal said:
Yes, the direction were quite clear about stirring (and not shaking). I'm at a point where the pores of the wood are no longer a factor as I've applied and sanded so many times already now. The issue now is about getting the final flat surface. I'm two steps away from KevinKohler's "just pour it on" trick.
Click to expand...
If it's setting up too quickly, you could try moving to a cooler/less humid location to give it more time to settle before it dries, or buy some of the stuff in spray cans to apply the final finish (never tried it, but I imagine you could get good results with a good deal of patience and many light coats).

Careful if you decide to try the foam brush, it will catch on any part of the surface that's not super-smooth, and could leave little bits of itself behind.
 
Last edited:
Cardinal said:
I have a piece of wood that I need to polyurethane and give a strong protective shell. My equipment:

A soft, even synthetic brush, three inches wide.
The mahogany piece of wood, 18" x 12".
Varathane water-based polyurethane, gloss interior
5" DeWalt random orbit sander with 420 grit sandpaper.

Following instructions as I have understood them, I brush the polyurethane evenly and thinly in one direction, wait a couple hours, brush a new coat in the perpendicular direction, and repeat this process a couple more times.

The problem: the polyurethane never thoroughly settles, leaving me with a crosshatch pattern from the brush ridges on the surface. However lightly I use the sander to even out the surface, I take it down to the wood every single time, no matter what. The main issue here is that it is functionally necessary for the surface of the wood to be 100% flat. Any raised ridges, however slight, are a no-go.

Any advice for applying a completely even surface? I'm dying over here...
Click to expand...

You putting enough on the brush?
Is it only going on one side?
There are pour-on polyurethanes if you can dam the edges to form a kind of pool.
 
Cardinal said:
I have a piece of wood that I need to polyurethane and give a strong protective shell. My equipment:

A soft, even synthetic brush, three inches wide.
The mahogany piece of wood, 18" x 12".
Varathane water-based polyurethane, gloss interior
5" DeWalt random orbit sander with 420 grit sandpaper.

Following instructions as I have understood them, I brush the polyurethane evenly and thinly in one direction, wait a couple hours, brush a new coat in the perpendicular direction, and repeat this process a couple more times.

The problem: the polyurethane never thoroughly settles, leaving me with a crosshatch pattern from the brush ridges on the surface. However lightly I use the sander to even out the surface, I take it down to the wood every single time, no matter what. The main issue here is that it is functionally necessary for the surface of the wood to be 100% flat. Any raised ridges, however slight, are a no-go.

Any advice for applying a completely even surface? I'm dying over here...
Click to expand...

I'd focus on getting something softer than 420 grit to finish and lengthening the drying time between coats and before finishing.

Warm, dry conditions are ideal for drying. They generally assume that you are applying an appropriately thin coat under ideal conditions. Some finishes prefer days or even weeks of drying. The manufacturer prints an idealized drying time for marketing purposes (because we are impatient), but real world conditions are often worse.
 
RetiredUSN said:
Poly over Mahogany is a test of will.

I take the sandpaper up to 1000 grit.

Then I raise the grain.

Then I steel wool.

Then I apply poly with with a HVLP gun. A good painters sponge would be my second choice.

Mahogany is a tough wood for poly because the grain often ends in a turn in the midsection of your boards. This makes a uniform appearance difficult. Poly has a faded look on end grain and you will get a lot of that in the middle of your boards.
Click to expand...
Would a cloth, lint free type for spreading the poly work?
 
Absentglare said:
I'd focus on getting something softer than 420 grit to finish and lengthening the drying time between coats and before finishing.

Warm, dry conditions are ideal for drying. They generally assume that you are applying an appropriately thin coat under ideal conditions. Some finishes prefer days or even weeks of drying. The manufacturer prints an idealized drying time for marketing purposes (because we are impatient), but real world conditions are often worse.
Click to expand...

To address several questions, I'm in the Southwest, so the climate is warm and relatively dry. The can says to wait two hours, but I can certainly try upping that to a full day as well as to get the next smoother grit sandpaper.
 
Cardinal said:
To address several questions, I'm in the Southwest, so the climate is warm and relatively dry. The can says to wait two hours, but I can certainly try upping that to a full day as well as to get the next smoother grit sandpaper.
Click to expand...

Good luck !

You can also try something really soft like quality 0000 steel wool with some kind of lubricating wax.

I know the temptation is to put on thick coats, and to finish the surface quickly, but patience can counter-intuitively speed things up by taking away the need to repeat the process.
 
JANFU said:
Would a cloth, lint free type for spreading the poly work?
Click to expand...

Poly doesn't work as nice with rags as a oil based product. Poly loves to be sprayed, or sponged. But, you have to be careful with sponge brushes, as they will leave those pesky microbubbles some times.
 
RetiredUSN said:
Poly doesn't work as nice with rags as a oil based product. Poly loves to be sprayed, or sponged. But, you have to be careful with sponge brushes, as they will leave those pesky microbubbles some times.
Click to expand...

That would cause an ego boost.
 
You could try this: take the poly and mix it with 1/3 turpentine and 1/3 tung oil. Apply with a soaked rag. Once the mixture begins to slightly tack on the wood surface, wipe off the excess with a clean, flatly folded cotton rag until smooth. On every third application or so of this method, you can use a piece of very fine steel wool over a sanding block to wipe the finish off to assure the surface remains flat. This requires many applications, but the results will be flat and smooth if you're careful. Alternatively, you could just buy a wipe on poly finish.
 
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