Caulking Questions


I need to re-seal my bathtub. I removed all the old caulk because the guy at Ace Hardware said that new material won't always make a seal when added to old. Is this correct?
There are some gaps up to about 1/4" that need to be filled. Should I first fill these gaps and let the caulk dry, then come back and make a nice neat seam?
Finally, is there a type of caulk that has some chemical that will prevent mildew? My wife says that if this stuff doesn't exist, someone should be able to get rich from her idea.
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Bob Simon wrote:

Yes, you should always remove the old stuff.

The 1/4" gap should be OK to fill with caulk on the first shot. I would suggest using masking tape on both sides of the area so you will make a nice even seal with no mess.

GE makes a caulk that is mold and mildew resistant. I've used it, works pretty good:
http://www.geadvancedmaterials.com/geam/gesa/Residential/en/Products/ProductDetail/gesiliconeiikitchenandbath.html
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wrote:

Good information, I was told when in doubt use caulk backer rod. This can save time, and caulk.
Just sharing what I was told.

later,
tom @ www.WorkAtHomePlans.com
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Agreed.
Agreed. Taping both sides makes the work so much easier and lets you worry less about screwing up.
The other tip that finally got me making really nice caulk beads is: o do only about 24" at a time o keep a cup of water with dish soap in it. Moisten your clean finger to tool the bead after laying it down with the caulk gun. Clean caulk from finger with a paper towel o Once tooled, don't f with the caulk again.
By the time you're done with an entire bath/shower, you'll feel confident enough to do some things without tape and it'll actually look good. The soapy finger trick though was huge for making it look professional. My tile refinishing guy I have to credit for giving that tip to me.

http://www.geadvancedmaterials.com/geam/gesa/Residential/en/Products/ProductDetail/gesiliconeiikitchenandbath.html
After trying other brands, I too have a strong preference for that caulk.
Best Regards, -- Todd H. http://www.toddh.net /
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Bob Simon wrote:

Logic tells me that once caulk is fully cured, no additive will prevent mildew because it has become inert. Mildew needs only moisture and food, the spores are everywhere, so the key is not feeding it.
Gotta get the seam as clean as possible, including wipe with full-strenghth bleach just prior to caulking. Make sure all moisture, grease and soap scum are gone and area is dry. Gaps can be filled with backer rod - firm foam "rope" sold in the caulk department. Comes in different sizes. Painters' tape helps get a nice smoothe edge, but needs to be removed right away.
If there is a little slant to the tub or floor to be caulked, such that it collects standing water, it will probably grow mildew. Soap scum is yummy food for mildew.
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That's an excellent tip and important. Gotta get that tape out of there pretty quickly before the caulk sets up too much or you'll ruin stuff.
-- Todd H. http://www.toddh.net /
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Bob Simon wrote:

The 1/4" is kinda' on the edge -- they make "backer bead" for filling the bulk of a sizable crack. Serves two purposes -- first, it's likely there's really nothing much behind that opening so you start squirting in caulk and it just goes into space and you use much more than needed for no real purpose. Secondly, larger gaps don't seal as well and tend to pull away at the edges more easily. All in all, I'd probably recommend some backer first.
Mildewcides do exist -- think of the famous Kilz primer. I believe all major manufacturers now have products which contain such. Undoubtedly they won't be 100% effective, but I suspect the manufacturers will have test data that supports improved resistance.
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dpb wrote:

I'm getting ready to do my tub, and there are these 1/4 circle ceramic pieces over the seam. After I get everything taken apart and the old caulk cleaned up, how do I put it all back together? My base plan is to caulk the seam, wait a day, then put the ceramic parts back and caulk the resulting two seams of those. Is that the right approach?
I just wonder if I should be treating them like bricks and caulking the edges of the cercamic before I stick them on. :-)
And has anyone used this Caulk Be Gone Stuff? Does it work and do I have to worry about the residue affecting the new caulk?
Thanks!
-P
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On 29 Dec 2006 12:12:54 -0800, snipped-for-privacy@yahoo.com wrote:

I've used this product (Caulk Be Gone Stuff?) with great results and absolutely no damage. In another thread I could not think of the name of it. It works slower on silicon caulk and faster on a latex.. Just let it work awhile and don't rush or you might to do a second round.
I like it for jobs that are in tight spaces or a pinch, but especially that you can leave it on and got to lunch... no harmful affects. Clean well before new caulk.
-- Oren
"Well, it doesn't happen all the time, but when it happens, it happens constantly."
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Thanks to Mikepier, Norminn, and dpb for your comments. I'm going to HD in a few minutes to get some blue masking tape, backer rod or bead, and some GE Silicone II for Kitchen and Bath (or equivalent).
How often does this job have to be repeated? Like once every two or three years or what?
I'm sure I'll only use like maybe 1/4 of a tube at most. How long will it keep and what's the best way to keep the remainder fresh?
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Fill the tub so that it's weight pulls down and the gap widens, then caulk. No luck on saving unused caulk beyond a month or two here. Use it where you can, remember it doesn't hold paint.
Bob Simon wrote:

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On 29 Dec 2006 13:29:46 -0800, snipped-for-privacy@localnet.com wrote:

Thanks!
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snipped-for-privacy@localnet.com says...

...and leave the water in the tub until the caulk cures (24 hours).

I've had luck using it for quite some time. I put a large nail in the business end.

Depending on the caulk. <snip>
--
Keith

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krw wrote:

I have kept opened tubes of caulk for quite a while, just putting a couple of pieces of painter's tape over the tip. Nails are nice, but they rust.
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clipped

Oh, and make sure you get silicone, not latex. Get an extra tube and practice on a cardboard box until you get the hang of it. Caulking doesn't generally have to be repeated if done right - absolutely clean and dry to start. Caulk is more inclined to get mildewey if not applied smoothely. Also, if there are spots that collect water, such as a tub rim that isn''t level, it helps just to wipe it dry after use. Of course, a good exhaust fan.
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Hi Bob,

Yes, remove as much of the old caulking as you can. Clean everything as best as you can to remove soap scum or mildew that might affect adhesion. Also you may want to wipe everything down with rubbing alcohol to remove any oils that might be present from the previous cleaners.

You should be able fill a gap that small with the caulk in a single application. But if you have larger gaps, you should probably pick up some "foam backer rod" and fill the majority of the gap with the backer. It comes in various sizes and is usually located in the painting section of hardware stores (though some stores put it in the insulation department).

The most reliable way I have found to produce picture perfect seams is to use a caulk labeled for "water cleanup". You apply the caulk as usual, then run your finger along the seam to smooth it out. Especially with larger gaps, you may have to add more caulk and redo the finger thing.
Then, you need a bucket of water and a sponge. Get the sponge wet, and wring out the majority of the water. Then use the wet sponge to wipe the caulk joint down. Rinse the sponge in the bucket, wring out the excess water, and repeat for the rest of the seam. Repeat the wipe and rinse procedure as often as needed to complete your project.
The beauty of this approach is you can clean up places where you applied too much caulk, or apply more caulk to areas you take too much out of and redo it.
The end result is a very clean looking joint.

There are many caulks available that are mold and mildew resistant. They're usually specified as "bath" or "shower" caulks, but read the label to be sure.
Anthony
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Yes, "kitchen/bath" caulking already contains mildewicide..READ the label(s)
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