Using Mahogany for trim

In another thread, I am working out how to have a 0.5" by 2" by 6' piece of trim in a bathroom stay put.

that particular piece of wood is, over its entire length, over a mirror, so will be held in place by silicone or other similar adhesive.

My question for this forum...(please forgive me cause some will say to post all this together :)) is about the finish:

I have the thought of using some mahogany (lots of scrap on hand), because of it's stability in humid environments, etc, and relatively straight grain.

But, what about painting it white?

I saw on YouTube a lady said use Sherwin Williams Shellac based primer, and there will be no bleed through of the pink pigment. (It has been well established in this forum that shellac is a superb sealer.)

And, how about wanting to have a really smooth surface, the trim will be right in front of her face.....just sand well, and maybe use two coats of said primer?

As always, Thanks!

Mahogany = open grain = needs grain filler.

I recently painted some red oak, because that is what I had on hand for the job, and I filled the grain with "setting type" joint compound. This is the stuff that comes in a bag as powder and you add water and then it sets in a certain amount of time. I mixed it up like cake batter, rubbed it on with a rag, then struck the surface clean with an old credit card. Then I sanded it after it was cured hard. The painted surface is quite smooth.

But I would question the use of painted mahogany. The moisture is going to destroy the paint long before it destroys any reasonable substrate.

Personally, I would use maple if you want a smooth surface for paint. Why make your life difficult. I'm not sure why people think bathrooms are like steam rooms. Mine sure isn't. Doesn't everyone have an exhaust fan these days?

John

Here, here. I've used pine and MDF trim in the bathroom and it's been fine. As long as it's painted well, it will be fine.

I'm with JT. Filling the mahogany will be more work than just going with a smoother, easier substrate like pine, mdf, or maple.

You guys are the best!
I thought it not a good idea
I will go w maple in full confidence
Thanks!