How strong is J-B Weld, What You Can Use It For, Your FAQ’s Answered

Last Updated on Nov 19, 2022

If you’ve ever had problems while trying to fix something, for instance, a piece of carpentry or part of your plumbing, that’s because you haven’t tested the JB Weld strength. JB Weld is a company that creates easy solutions for repair professionals and mechanics. This company launched its first product in 1969, and since then, they have included many variations of the main formula.

Sam and Mary Bonham, owners of the business, came up with the idea after Sam needed a cold weld alternative for his truck service garage. Together with an A&M chemist from Texas, the original formula of the J-B Weld was created. Their motto is “Don’t scrap it, J-B Weld it.” Furthermore, it is advertised as a permanent bond. Is that really the case? 

This article will discuss how strong JB weld is and how the different products available can help you fix items you thought were lost forever.

 J-B Weld uses and products available

J-B Weld can be used on plenty of surfaces, including wood, metal, plastic, and even automotive pieces. Glass is also included. Basically, if it’s broken, J-B Weld can fix it within a few minutes.

While many products are available and can work on diverse surfaces, you can also find formulas for a specific surface type. Most products have pretty much the same effect but in different presentations. You can find some of the following versions:

  • Twin tubes
  • Instant adhesives and their extreme version
  • Light-activated instant glue
  • Clear Weld Syringes
  • And many others.

J-B Weld has been expanding its product catalog throughout the decades, allowing people to fix problems on different surfaces. 

With J-B Weld, we may have the impression that it only fixes hard surfaces. However, you can also find products meant to restore rotted wood or a piece of cloth or fabric. Thus, if you have a certain appliance at home that you would like to bring back to life, the Premium Epoxy Putty or the Liquid Hardener from the Wood Restore line can help you. As for fabric or cloth, you can use instant adhesive or instant glue, among a few other options.

Sort your choice by color

If you want to preserve your piece’s original finish, you can also opt for using the different color versions available. This way, you won’t have to worry about running your piece’s original look, maintaining it as well as new.

How it works

Unlike many people believe, the cure time of the J-B Weld products varies based on what you’ve picked. For instance, the standard formulation has a set time of 6 hours, and the cure time is between 15-24 hours based on what you’re trying to fix.

You can find some products that allow you to fix your items as quickly as possible, such as the J-B Weld KwikWeld. This product is as strong as the original formula but works way faster and provides a nice dark grey color. Furthermore, it can endure temperatures of up to 300ºF. This product is safe to use on tons of surfaces, including household repairs.

The J-B Weld KwikWeld will be set in six minutes and has a cure time of 4 hours. However, in temperatures lowers than 40ºF, it will take more time to set.

With that being said, let’s see how we can use the J-B Weld products properly.

Getting started

First, prepare the surface where you’ll use the product. Make sure to clean it thoroughly until you’ve removed all the grease, debris and other possible residuals that may disturb the process. J-B Weld recommends using degreasers or detergents, then “roughen” it up with a file or a similar option. This way, you can be sure that the product you’ve chosen will work as it should.

Next up, you’ll need to squeeze each tube and mix equal parts of its contents. Make sure both substances are thoroughly combined. When you do, it’ll be time to apply it to the surface you’re trying to fix. You can do it as needed.

Once you’ve applied the product to the surface, you’ll have to wait for a few minutes until it sets. This period varies from one product to another. For instance, the standard formula may last a few hours, while the KiwiWeld version sets only five minutes. A similar principle applies to cure time. As we’ve explained, you may have to wait between 15-24 hours if you’ve used the regular formulation, while the KwikWeld version cures in only four hours.

How strong is J-B Weld?

J-B Weld’s effectiveness has been proved since the brand first appeared in the market. If you try to look for examples around the web, you’ll likely find very interesting videos using the product on different objects. Here you have a few examples:

  • Using J-B Weld to repair a broken connecting rod
  • Repairing a cracked aluminum block with Marine J-B Weld

Like these ones, you can find many other examples that prove that J-B Weld is strong enough to repair considerably hard stuff, including marine equipment and even hard metal pieces. 

If something has broken in your house, you can be sure that J-B Weld will be able to fix it and keep it working for a few more years. This company has been around for more than 50 years. Thousands of satisfied customers worldwide can confirm its effectiveness.

You can use it to repair small items or put together bigger projects and expect similar results. The key is to choose the right product based on the surface you’ll work in. This way, you can assure the best results.

J-B Weld heat

As for J-B Weld’s heat resistance, we’ve mentioned that the Kwik Weld can endure up to 300ºF. However, that it’s not the case for all the products. The heat resistance for all the products found within the catalog of J-B Weld is between 300ºF and 600ºF. The original formula can endure up to 550ºF when fully cured.

As for low temperatures, multiple tests have been made, and it can work in temperatures of -67ºF, for instance. This resistance makes it perfect for indoor and outdoor use, regardless of the season.


Finding the right J-B Weld product for you

J-B Weld is available pretty much everywhere, but we highly recommend navigating through the main website ( before buying anything. The website is highly optimized and allows you to perform specific searches based on the project you currently have in hand.

For instance, suppose that you want to repair a piece of glass. In that case, you can choose between options like ClearWeld or the SuperWeld Instant Adhesive. Either option is equally effective, but those aren’t the only ones available in this case.

You can also choose to sort your products by project instead of the surface. Either way, you’ll be able to find the perfect product for you very quickly.

What J-B Weld CANNOT do for you

Here are some situations where the J-B Weld strength can be compromised.

Not an electrical conductor

J-B Weld does not conduct electricity, even if it’s partly made of steel. This product is an electrical insulator. 

Think thoroughly about where you’ll use it

On the other hand, it is important to choose wisely the J-B Weld version you’ll use, as the original formula turns dark grey when it dries and cures completely. Thus, on surfaces like copper, for example, it will be very visible.

Not the best for exhaustive repairs

As for the automotive use of J-B Weld, it can serve as a solution for certain repairs based on its nature. However, it may not be the best option if you need certain exhaust repairs, like the catalytic converter. Since this part gets insanely hot in certain engines, it may end up weakening the repair you’ve made with J-B Weld.

Works great in hard plastics, but not so many inflexible ones

It won’t provide satisfactory results if you’re trying to bond materials like polypropylene or polyethylene. Furthermore, it won’t provide good results on any flexible materials.

How to remove J-B Weld

J-B Weld is advertised as a permanent bond, and the company truly delivers these results. Thus, once the product has fully cured, it will not be as easy as you think to remove it. Get some of your best tools, and start thinking of it as a metal you need to crack. It’s the only way available to remove it.


J-B Weld is an excellent solution for multiple problems we deal with on a daily basis. Whether you’re trying to repair a broken pipe or maybe get started with a DIY wood project, you can be sure that J-B Weld in all of its presentations will help you. 

Once the resin has fully cured, it will remain that way for a long, long time. Thus, you can be sure that your items will be as strong as new after completing the repair.

Before you use J-B Weld, we recommend you to go through the MSDS Safety Data Sheet.