Help caulking a bathtub. (1 Viewer)

[Greg_S_H]

The very bottom line of caulking was looking bad around my bathtub, so I scraped out the old stuff and ran a new bead in there. The instructions called for 36 hours of time before you used the bathtub again, which was impossible, so I covered the new caulking with duct tape--being careful to kind of bow it so it would keep out the water without actually touching the caulking. Just to be safe, I left the tape in place for a week or so. I peeled it off, and the bathtub looked nice. For a couple of weeks. Then, the new caulking started to crack, warp, and turn black. It looks even nastier than it did before. It's screamingly awful.

At this point, I must mention that God alone knows how old the bottle of caulking was. I had to clear out some dried gunk, but then it flowed nicely and was pure white. But, could this be the problem? Maybe old caulking doesn't hold up well? Or, am I missing some curing process that would make it work?

It really sucks that I can't get this to work. The bathtub looks really nice at first. Then, it turns into an embarrassing nightmare. Any tips would be appreciated.

 

[BrianW]

By taping it, you kept moisture in, which didn't allow it to dry (acrylic) or cure (silicone) properly. Plus, if any moisture did seep in underneath the tape, chances are, it stayed there. It needs exposure to air in order to harden. After it was taped, it may as well have never left the caulking tube.

Silicone-based caulk should definitely be used by the expiration date. Old stuff will never harden. I do think silicone caulk is superior to acrylic, but it needs to be new, and it is more difficult to work with.

Scrape it out, clean the gap, start over, provide plenty of dry ventilation for it to harden, and in a day-and-a-half, you'll be able to enjoy a nice, clean shower.

 

[Jeff Ulmer]

You should also be using a caulk that is designed for the bath with a mildew inhibitor. Make sure all surfaces are clean or you are wasting your time.

 

[Greg_S_H]

I thought about trapping moisture with the tape, but I have since redone most of it without using tape and had the same problem. So, it probalby is the age of the stuff. You're right--it never hardens. When I pull out an old piece of caulking, it's almost like a rubber band--flexible, stretchy. This stuff stays pretty tacky even after days/weeks. So, I just need to buy some new stuff and start again. I definitely am careful to clean everything first, but I'll look for either silicone or one with a mildew inhibitor, or both if they make one that is both.

Thanks for the replies.

 

[Eric_L]

I seem to recall a radio program which called a Home Depot to ask them questions about caulk in the shower. Is white caulk better than dark caulk? How much caulk is just right? Where is the best place to put your caulk? Etc. QUite funny - but I couldn't find it online in my brief search.

 

[DougR]

http://www.factsfacts.com/MyHomeRepair/caulk.htm

 

[Brian Perry]

You should also fill the tub with water before caulking so that the weight maximizes/stretches the seam between the tub and the wall. If you don't do this prior to caulking, filling the tub could pull the bead of caulk apart.

 

[Greg_S_H]

That's something I would never have thought of. Thanks. I'll use hints from this thread and from that link and maybe do it this weekend. Eventually, I need a pro to redo the whole thing anyway. There was a loose tile and the sheetrock is all messed up. I had to wedge a board back there to hold the lower row of tiles in place. Besides, it looks really old anyway. Yuck.

 

[Randy Tennison]

Also, something I learned is to use rubbing alcohol on your finger if you are going to smooth the caulk. I used it instead of water, and got a fantastic looking caulk job around the bathroom sink. Worked so much smoother than water.