GE Silicone II if it's in the tub or shower, or if it doesn't need to be
ALEX Utra 230 Premium with Microban if it has to be painted.
The general issues in selecting a caulk are:
- Silicone or urethane usually performs best overall. It lasts longest and holds up best, but is
harder to apply (can
make a real mess) and silicone isn't paintable. Silicone "Tub and Tile" caulk has a mildewcide --
use in areas that get wet, but don't use it in an area where it
will contact food or drinking water. There are other versions without
the mildewcide for these
applications. [A possible exception to
being the best caulk is urethane
caulk which may be as good and is paintable. See discussion
- Elastomeric latex
sealant (caulk) comes next in durability and is paintable.
- Latex, silicone/latex (siliconized) and acrylic is
next, but there's a lot of variation in
quality within and between brands.
- Latex is easiest to apply and cleanup.
- Butyl rubber is dead last.
Silicone is essential to seal around bathtubs, showers, lavatories, etc. There's
a special bathroom formulation for this that has a mildewcide. This poison has been known to be hazardous if used inside
dishwashers because the high heat outgasses the poison onto the dishes and is then eaten.
If silicone does not cure it makes a godawful mess. Most
manufacturers specify a shelf life of 1-year from date of manufacturer for
silicone caulk in unopened tubes. I've not seen times for partially
used tubes. Silicone will last longer than a year, but if it's old you
must test it to see if it is going to
cure. Silicone does not air dry, it has a curing agent.
If a sample placed on a non-porous surface does not cure to a resilient rubbery
consistency in 24 hours don't
THAT well known consumer product rating magazine last rated caulk a
while back. Here's what their tests
- You can't judge anything by brand. Every brand had caulks that scored throughout the range
from good to bad.
- The best silicone caulks were GE Silicone II and Ace 50 Year Silicone, with Red Devil 100%
Silicone next. GE Silicone II comes in 2 types -- one with mildewside for 'Kitchen
& Bath' and one without for 'Windows &
ALEX Utra 230 previously called DYNAFLEX 230 and before that Formula '230' is the best
latex.Note1 It's an elastomeric latex sealant. It's more expensive but, it's
better than all silicone-latex caulks and better than some pure silicones. I use this caulk where
silicone isn't appropriate . It shrinks a lot. I recommend you don't use the clear version unless
you have to. The clear has an additive to make it go on white so it's easy to see if you're
covering cracks. It turns clear as it cures. This causes it to shrink a WHOLE LOT and it can't be painted for a
week! The regular colors shrink less and can be painted in a couple of hours.
NOTE 1: I used and recommended DAP Dynaflex 230 caulk for years.
Then, I had to face the fact
that there's a serious problem with this caulk. It appeared to be one of
the worlds best nutrients for mildew. I made
this page to illustrate the
problem I've had with it. They now have a product named
ALEX UltraŽ 230 Premium
which appears to be DYNAFLEX with mildew resistance.
If so, it will be the solution, but I've never
The 2 worst other than butyl caulks were:
.....Ace 25 Year Siliconized
.. ...Seamseal Plus Silicon/Latex
Remember, you just can't judge by brand--two of the top rated and two of the worst rated caulks
are from the same brands--Ace and DAP?
The PBS program "Ask This Old House" uses a
a construction sealant by
2300. I've never used it but if they use it it's probably good.
It can be applied underwater, and to greasy surfaces. You may have to get
it at a roofing supply or lumber yard. I intend to give it a try soon.
Some people on alt.home.repair swear by a caulk named
adhesive/sealent (another elastomeric) They're particularly high on
this version for caulking tub/showers.. Unfortunately it wasn't rated, and I've
rarely seen this product
on store shelves.
Polyurethane caulk is growing in popularity.
NP 1 by
BASF/Sonneborn has won high praise from Texas A&M for durability,
and it's paintable. But, it's harder
to apply neatly than latex and, clean up requires solvents. I've been told
there's a wide range in the quality in urethane caulks and I've had not
experience nor seen ratings in these other names of urethane
caulks -- PL200 or Vulkem, GE makes one, and recently I saw an expensive ($8) tube of
urethane from 3M on the caulk shelf at Home Despot.
On Thu, 26 Sep 2002 "Bruce Brocka" <firstname.lastname@example.org>
I was reading your section on caulks. I have
used everything and the best caulk by an order of magnitude is the NP-1
series by Sonneborn. It comes in numerous colors. It is wonderful, and can be painted or left
alone. . . . NP1 was developed as a masonry caulk
Notes: 1) I've
found NP 1 difficult to gun (hard to push out of the tube). 2)
It takes a long time to cure (dry). Expect to wait two to three
days before painting. (I now see the instructions say to wait until it
is fully cured, which they say will take a week) 3) Sonneborn limits distribution of
NP1 to outlets that normally sell to the construction trade, such as roofing
supplies, real lumber yards, etc., saying it's not for use by the ordinary
consumer. I get it at a local roofing supply company.
For all this trouble I sure hope it's good -- jim
Tip1: Cold caulk can get stiff and hard to
squeeze out of the tube.
If it's cold, put the tube it in a pan of warm water for 20 minutes or so.
Tips2: Here are some ways to reseal partially used caulk tubes.
the past I used a large nail stuck into the tip. This works good for
keeping the tip clear, but the nail sometimes rusts causing you to have to pump
out a lot of caulk to get rid of the rust.
Next I used a large wirenut (used to connect electric wiring) to cap the tip
if I'd be using it again within a month. The gray wirenuts are about
the right size.
Now I mainly use a piece of
plastic (Saran Wrap or thin plastic food storage bag) over the tip, held in place with
tightly wrapped masking tape or a rubber band (Click here for
picture). Squirt a little caulk into this "sock" covering the tip --
it will harden first, helping seal the caulk in the tube. Some people use
a piece of duck tape instead of the plastic wrap but it doesn't seem to me like
it would be airtight enough.
Alonso Llano <email@example.com>
"I use a screw to seal my tubes of caulking, it's very inexpensive (actually
free) and works all the time."
NOTE: You may want to use a rust proof screw. Some folks use pliers to pull the screw out, claiming this
pulls any hardened caulk out with it. -- jim
Little Red Caps
sound like a clever way to reseal tubes of caulk, but I've never used
them. If you've used one on a tube that remained unused for as much as 3
months, please let me know whether it kept the caulk nozzle from clogging.
If you're going to store it for more than a week I'd squirt a daub of caulk
into the rubber sock.
Some people say they have good luck with
DAP Caps. I've never used one,
but they seem to be a cap for open tubes as well as a caulk troweling tool.
I use my finger for troweling and have never had good luck using a tool to
trowel caulk, but I've seen TV handymen suggest using them so others must have a
different experience with them than I have.
Recaulking a Shower or, a Tub-Tile Joint -- Getting a good seal is harder than you think.
on caulking your home for energy saving.