Caulks and Caulking Techniques
Two Basic Types of Caulk
There are two basic types of caulks in use today: water based and non-water based. Each type has distinct advantages and disadvantages. Within each grouping, as you might imagine, there are various sub-groupings.
One thing the two basic types do have in common, however, is the fact that chemically speaking, they are closely related to adhesives. This makes sense when you think about it, as the caulks usually are quite sticky when you apply them. Also, when you select the right caulk and apply it properly, it has a tendency to stick to the item you apply it to for quite some time. In fact, some caulks are formulated to be more of an adhesive than a caulk. My guess is that you have seen tubes of "adhesive caulk".
Water Based Caulks
The latex caulks that many of us are familiar with use water as a basic ingredient. The presence of water in the caulk is an advantage if you are interested in clean-up and workability. It is a disadvantage if you are looking for extremely long life.
Often, these caulks have primary ingredients, which add to their flexibility. Commonly, latex (basically synthetic rubber) and acrylics (highly flexible plastics) are found in these caulks. Once again, my guess is that acrylic, latex caulk rings a bell with you. Caulks need flexibility, as they are intended to bridge gaps between things that commonly move.
Silicone can be added to a water based caulk in small amounts. By doing this, the flexibility of the caulk is increased. These are the caulks you frequently see advertised as siliconized acrylic latex caulks .
Caulking technology has created specific water based caulks for specific jobs. This is a distinct advantage. The caulks have been formulated to give you maximum performance depending upon the job you are going to undertake. Almost every manufacturer clearly prints on the caulk tube label just what that caulk will caulk best. I highly recommend that you read the labels first before buying them and using them. This will ensure maximum performance and satisfaction on your part. Try to break the habit of reading the label after a problem has developed!
Non-Water Based Caulks
There are several widely used non-water based caulks. However, most homeowners are only familiar with one of these, that being silicone. The other two widely used caulks in this group are urethane and elastomeric caulks.
Silicone caulk has won widespread acceptance by many homeowners. However, it can be difficult to apply. Some silicones can cure quite rapidly, making for messy application jobs. Also, because they stick sowell to many non-porous objects, removing excess silicone can be difficult. Virtually everyone knows that paint will not adhere to pure silicone caulks. Well guess what? In many cases, silicone caulk will not adhere to previously applied silicone! This means that your first application must be your last. You have to get it right the first time!
Urethane caulks have been used by commercial builders for years. These caulks offer unbelievable flexibility. Some of these caulks can withstand up to 50 percent movement in the caulked joint! These caulks are difficult to work with, however the work is well worth it in many cases. Often you need to use solvents, such as mineral spirits or lacquer thinner to tool the joints. I have used caulks like this to caulk expansion joints in masonry with tremendous success.
Elastomeric caulks are non-water based caulks which have both interior and exterior applications. They tend to exhibit more adhesive type qualities. For the most part, they are not nearly as flexible as the urethane caulks. Tooling and cleanup require the use of solvents, just the same as the silicones and urethanes.
Advantages
Because the non-water based caulks are tougher to work with, they must offer something in return. These caulks offer superior durability, flexibility and adhesive strength unobtainable from the water based caulks. Many of the non-water based caulks cure quite rapidly. This allows them to come into contact with water soon after they are applied. This water rarely, if ever, harms the caulk.
It shouldn't surprise you that the non-water based caulks are more expensive. The ingredients which give them their positive qualities simply cost more. Water, on the other hand, is very inexpensive.
When faced with that next caulk job remember to take your time. Think about how much time you are about to spend. The little extra money for a high quality caulk and the extra time spent applying it may pay huge dividends! Don't always opt for the easy way out. Good luck on your next project!