Solvent Cements For Plastic Pipe-No. 1

Solvent Cements For Plastic Pipe
No. 1


There are many things to discuss on solvent cements and primers for plastic pipe. You can discuss directions on how to make a good connection, special directions for making a good connection in hot or cold weather, set times, cure times, warnings for working with solvent cements, shipping information, and much more. In this particular blog, we will discuss none of the above. Today we will answer the most popular questions that Black Swan is asked every week. Hopefully this information will be helpful.


1. Why are there different thicknesses of solvent cements?

Generally there are three different thicknesses of solvent cements-regular bodied, medium bodied and heavy bodied. Solvent cements work by attacking the plastic, connecting the pipe and fitting, and then the solvents evaporate. These solvents evaporate very quickly. On small diameter pipe (up to two inches), you can apply the cement very quickly because you do not have a big area to apply the cement and primer. Thus, you can use a thin (regular bodied) product and you can make a good connection. On larger diameter pipe, you will need more time to apply the cement. A slightly thicker cement will dry slower and allow you time to make a good connection. On pipe up to six inches in diameter you can use a medium bodied cement. On pipe sizes larger than six inches, you should use a heavy bodied cement. This cement will dry the slowest (because it is the thickest) and you will have enough time to apply the cement and primer properly to make a good connection.

The other feature of cements is that the cement does fill the voids betweent the pipe and fittings. On smaller size pipe, the voids are small. A regular bodied cement works fine to fill these voids. As the pipe size gets larger, the voids are larger and a thicker cement fills these voids better. Medium bodied cements works great on the pipe sizes between two and six inches and the heavy bodied cement works great on pipe sizes from six inches and twelve inches.


2. Questions are asked if a certain cement can be used with a certain ingredient running through the piping system.

Solvent cements are basically solvents with a resin. PVC Cement contains PVC resin which is the same resin as the PVC pipe and fittings. CPVC Cement contains CPVC resin which is the same resin as the CPVC pipe and fittings. The same concept for ABS Cement. After the cement is applied and the connection is made, the solvents evaporate. The only thing left of the cement is the resin.

So, the question should not be will the cement be able to be used with a particular ingredient running through the system. The cement is gone and only the resin is left. The question should be will the pipe and/or fittings be acceptable for a particular ingredient. That is the question.

3. Does primer need to be used to make a good connection?

There is no question that a good connection can be made without using a primer. Many professionals use this technique with great success. We know this because Black Swan sells a lot more cement than primer. However, you will have a much better chance of making a good connection if you use a primer. A good primer will clean the pipe and fitting and will soften the pipe and fitting prior to applying the cement. With a clean pipe and fitting and a softened pipe and fitting, the chances of making a good connection have improved dramatically.

Black Swan's advice-use the primer and avoid problems later. Also, remember it is usually important to use a primer if you want to follow the local plumbing codes.

4. What can I do if I spill purple primer on the floor, bathtub, etc?

This is a very difficult question. The purple dye is very difficult to get out. Some suggestions are to use clear primer and apply it to the purple stain. This does work in many situations. Sometimes using water and baking soda works. Sometimes a good household cleaning agent will work. It really depends on the surface that the purple primer has been dropped on.

The best advice is to be very careful in advance of using the purple primer. Cover up the area where you will be using the primer. Also, if you can use Clear Primer and not have to worry about the local code, definitely use the Clear Primer.


5. Can PVC Cement be used on CPVC pipe and fittings?

The answer is negative. The strongest (or hardest plastic) is CPVC plastic. The next step down is PVC plastic. The weakest plastic is ABS plastic. So, the strongest cement is the CPVC Cement. This product has the most THF (the main ingredient that attacks the plastic). The next strongest cement is the PVC Cement. This product has less THF. The weakest cement is ABS Cement. This cement has no THF in it.

So, the CPVC Cement could be used on CPVC plastic and PVC plastic and even the ABS plastic. The reason is because it is a very strong cement. The PVC Cement can be used on PVC plastic and the ABS plastic. But, this cement can not be used on the CPVC plastic because it is just not strong enough to attack the CPVC resin.


These are the most popular questions regarding solvent cements that Black Swan answers. If you have any other questions, please feel free to contact us and we will get the answers.

Good luck in making your next plastic pipe connection.