Furniture, Wood and Cabinetry Finishing - finishing weathered wood

I would like to put a heavy finish on a wooden lid that sets on a cast iron kettle. I'd like a finish heavy enough that it will seal the wood and cracks in order to not let rain through. I want to keep the weathered look. Can I put the first coat of spar urethane on without sanding first? Can I put more coats on thickly to accomplish almost a decoupage look? Or will this cause it to bubble?

If you are looking for a weathered look you don't have to do a lot of sanding, but may want to rough it up for better adherence. Just be sure you get all the dust off with a tack cloth before hand. You can lay on as many coats as you'd like just give at least 6 hours dry time after each, and do some light sanding with a 320 grit between each coat. Good luck, and try to use your local hardware store, they're in need of business these days.

Hello everyone,Here some information im putting,

You have a few options depending how important the look is to you and the time you are willing to spend on them.You could use a couple of coats of outside spar varnish,brushed on you could use a penetrating or wiping stain 1st to give them some color.Just let the stain dry a day b4 you apply the varnish.You could wipe them down with some boiled linseed oil that will soak in and protect them and look alright after.Tongue oil wiped on will protect them and look good.
Semi-transparent or solid color wood stain brushed on will add color and protect them.Thompson's water seal,or a like product will protect and rejuvenate them.The recommendations are listed from the best to easiest,top to bottom,in my opinion.Put two coats on and repeat every couple of years to maintain finish.