How to Choose a Joint Sealant: A Step-by-Step Guide
If you are planning to use a sealant in your next project, you want to pick the best one for the job. With so many options, it can be hard to know where to start. This guide will help you to make the right choice.
Step 1–Consider the Requirements of Your Job
Before you start thinking about which sealant to use, you first need to have a very clear understanding of what you need from your sealant. So, answer the following questions in order to give you a list of comprehensive requirements for your sealant.
- Will the sealant be used on the interior or the exterior?
- Will the joint be subject to any movement or vibration? If so, how much?
- Does the sealant have any special resistances for the environment it will be in, e.g., moisture, UV, chemicals?
- Will you be able to apply it quickly or will you need a longer open time?
- Are you attempting to bond any difficult materials?
- Will you need to paint over the sealant?
Step 2–Review the Types of Sealants to Narrow Your Choices
With your list of requirements in mind, consider the different types of sealants available and narrow your choice.
There are six main types of sealants available, and they all have different properties.
- Latex–Water-based and easy to apply, these sealants are an excellent choice for interior jobs. They have the bonus of being very easy to paint over, especially with latex paints. Their uses are limited but they are inexpensive and easy to apply.
- Acrylic–These sealants are solvent-based. They are not suited to joints that will experience a large number of movements, and they can be hard to apply. Their strength lies in the fact they perform well on submerged joints. They have reasonable UV resistance but don't do well on exterior projects. They are easy to paint.
Butyls–These are synthetic rubber materials that have excellent adhesion with the majority of substrates. If your joint is going to be experiencing a large number of movements, then it is best to steer clear of these sealants. They work well for interior projects but are hard to paint and should be kept away from any source of UV light.
- Polysulfides–These are considered to be high-performance sealants and are often used for industrial applications. They are especially favored in situations where chemical resistance is required. They also perform well for submerged applications. If your joint is going to be experiencing cyclic motions, then it would be best to avoid this sealant. They work equally well for interior and exterior projects.
Silicones–These sealants are highly versatile and can be used in a wide range of applications. They are particularly durable and remain flexible over time. This makes them an excellent choice for joints that are likely to undergo large amounts of motion.
The downsides to silicone sealants are that they are unsuitable for submerged applications and they are not paintable. Silicones perform well as interior sealants and even better for exterior projects as they have a high UV resistance. They are poor choices for brickwork but otherwise will bond well with most other materials. A good choice for these will be RTV sealants.
- Polyurethanes (PU)–These sealants are the most versatile. The only applications for which they are unsuitable are ones involving glass. They are very resistant to wear and perform well on joints that have high levels of movement; they are also paintable. They can, however, be a little difficult to apply and, unsurprisingly, they are the most expensive option.
Narrow your choice to one or two sealants, and then decide based on your budget.
Here’s an Example
You need a stainless-steel pipe thread sealant for a joint that will be inside a pneumatic drill.
The sealant needs to work in exterior settings, it will be subject to large amounts of movement, it must be resistant to UV and the seal must be durable and flexible.
Consider the Types of Thread Sealants
From the requirements, it seems clear you will need high-performing thread sealants and, because of the movement, the choices are limited to either a Silicone or PU sealant. It would be worth looking for a brand that is marketed as being especially resistant to vibration.
We’re the Sealant Experts
If having completed these steps you still find yourself unsure, then ask for some help. Our customer service representatives are sealant experts. We will work overtime to find the perfect solution to meet your needs and budget. Give us a call at (855) 437-7700 or start a Live Chat today!