I’ve made several attempts to stain the new basement steps make out of standard construction lumber. It seems part of the wood refuses to take stain even after two coats, so I have bare spots of wood mixed in with properly stained parts of wood.
I have stained pine with no issue. It sounds like part of the wood was treated with something, but that’s just a guess. If no one comes along with a fix, I’ll have a chat with a few woodworkers that I know.
It’s possible, but not easy, because the earlywood is more porous than the latewood and they absorb the stain differently, resulting in blotchy or weirdly striped color. For good results you need to sand really well with a fine grit, and use a sealer before you stain. Here’s a more detailed description:
https://www.popularwoodworking.com/techniques/aw-extra-101013-staining-pine/
I spent a lot of time refinishing a pine table once, why I don’t know, but it took the stain evenly. I did sand the hell out of it though.
You need a “Pre-stain conditioner.” Home Depot has it.
Depending on how you stripped it, there may have been enough of the old finish left in the wood to act as a sealer.
I may have used a sealer, I don’t remember the exact process, but I do remember a lot of sanding.
You may have to just paint them with a good floor paint. Seal first.
I thought a little more about what I did and I’m pretty sure there was extensive sanding with fine grit to “close the grain.” Does that sound right?
One option, a last resort really is stain/varnish combos. It doesn’t actually penetrate too deeply–mostly just sits on the surface so the color is pretty uniform. I actually made my bed out of construction grade pine. Used this stuff and the be looks really good–very uniform. Its held up for about 10 years so far, but If I were to do it again, I probably would have put an additional coat of clear poly on it to protect the color. Its a Captain’s bed with drawers, so the sides are high. the area where I get in and out of bed are lightening in color a bit.