Bed Wood Finishing - Need tips!

[davepl]

I'm doing my bed wood, and I'm not a carpenter. I'm starting with the Mar-K bed wood kit. Below is what I've done so far, what I plan to do, and some things I need help with! Someone who's been through this or has carpentry skills can perhaps give me some pointers.

It came pre-sanded, I'd guess to maybe 80 grit. I did a pass of 60 & 100 on the bottom. On the top I did 60, 100, 150, 220, and 600. Yeah, I'm sore today. But the wood is almost glass-smooth on top.

Staining it is no problem. It's the top coat (varnish, whatever) that's giving me trouble. I had started with a high gloss oil-based Varathane, but the gloss was too high, so switched to "Old Master" urethane semi-gloss, and like it better.

However, try as I might, I have two issues:

1) Little specks in the clear. I don't think they are bubbles (none in the can, and I'm stirring not shaking). Yet letting it dry upside down made little difference, so I don't think its dust (or there'd at least be less). I'm sure this is common, anyone know what causes it and how to fix it?

2) Brush-marks and the START or END of the strokes. It flows out nicely except in some places where I've started or ended a brush stroke, since there is more clear there (or less, but a different amount). Since the boards are 9 feet long it's not like I can run the whole board without lifting the brush. So any tips on how to avoid this?

3) Also, I was going to do the bottom first. But I'm afraid it'll run down and around to the underside, which is the top. Do I mask the sides, or how should I prevent this?

I'm using high-quality brushes (3M stuff, $20 range). I'm applying the stain with a brush rather than rag. But it's fine, only the clear causes me grief.

Thanks for any tips! And if you've done the bed wood before and have handy tips you'd wish you'd know then, please share them!