Is it okay to caulk over day-old caulk tomorrow?

The type of caulk you are using is the deciding factor here. If you are using an acrylic or latex-based product, you can usally get away with overlapping the new bead onto the old stuff after 24 hours without a problem. But if you are using **100% silicone**, which is what you shoud be using for a shower surround, it will not bond to itself once it has cured or even started to skin over significantly. Silicone is chemically designed to be non-stick, and that applies to fresh silicone trying to grab onto a dry layer too. Since you mentioned you're already halfway trough and it's your first time, I'd honestly recommend scraping off what you've already done while it is still relatively fresh. It is much easier to remove caulk that hasn't fully cured for a week. If you try to just bridge the gap tomorrow, you'll likely create a weak point or a thin seam where the two beads meet. That tiny gap is exactly where water will eventually seep in, leading to mold growth behind the surround that you won't see until it's a massive headache.

Grab a plastic caulk tool or a dull putty knife so you don't scratch the tub or the surround, and pull up that first half. Clean the area thoroughly with **denatured alcohol** to get rid of any oily residue before the new tubes arrive. It feels like a waste of time now, but doing the whole thing in one continuous pass is the only way to ensure a truly waterproof seal.

When the new GE silicone arrives, try the finger-and-soapy-water trick to keep the mess down. Keep a roll of paper towels handy because silicone gets everywhere the second you stop paying attention. It’s better to spend an extra hour redoing it now than to spend a weekend next year tearing out moldy drywall because the seam didn't hold.

Listen, if you're using GE Silicone II, don't even think about layering. That stuff skins over in 30 minutes. If you want a pro result, use a sharp 5-in-1 tool to get it off now while it's still gummy. When your new tubes arrive, cut the tip at a clean 45-degree angle for a consistent 3/16 inch bead. I always keep a bottle of mineral spirits around for the cleanup—soapy water is okay, but mineral spirits on a lint-free rag is how you get those crisp lines. Make sure that joint is bone dry. Even a drop of moisture trapped under there will cause a blowout in six months.

Back when I started, we didn't have these fancy 100% silicones for every little thing. I remember trying to 'patch' a bead in a rental back in '88 and the seam looked like a mountain range within a month. If you're pulling it up, hit the tile with a bit of white vinegar after you scrape. It cuts the film better than most of the weak stuff they sell at the big box stores now. If you leave even a tiny ridge where those two beads meet, you’re just giving soap scum a place to live. Do it right the first time or you'll be doing it again by Christmas.

Man, I've been there. Since you're waitin' anyway, grab some blue painter’s tape. Since you said it's messy, tape off both sides of the joint before you start tomorrow. It’s the only way I get clean lines without it gettin' everywhere. Just don't let the tape sit too long after you’ve smoothed it or it’ll pull the edge of the bead up when you peel it. It’s a total pain but you'll be glad you didn't just wing it.

I learned the hard way that 24 hours is way too long. I tried to bridge a gap in my own shower after a parts run took longer than expected, and within six months, that seam turned black with mold because the bond failed. Now, I always wipe the joint down with a microfiber cloth after scraping to catch those tiny leftover silicone crumbs you can't see. Also, since you're new to this, don't over-cut the nozzle. Start small. It’s way easier to go back and make a bead bigger than it is to clean up a massive glob that's oozing everywhere.