J-B Weld Aluminum Guide: Does JB Weld Work on Aluminum?

The list of items that JB weld doesn’t work on is a lot shorter than the items it does. Once perusing that list, you will find that this product is just short of being a miracle worker. It handles a long list of issues when you can’t afford to hire a welder.

Does JB Weld work on aluminum? Yes, JD Weld will do a great job binding aluminum pieces together. In fact, there are very few materials it does not work on and you can count those almost on one hand.

Make sure to follow the instructions to get the best bond possible as it will hold for years when applied right.

To learn more about JB weld and how well it works, just continue to read our article. It has the information you want to know about. This epoxy now adheres to lead which will be a bonus to those who have issues with lead connections.

Will J-B Weld Work On Aluminum?

This epoxy comes from a very reputable company that has been in business for just over 50 years. The company makes very strong adhesives, so strong that it does work on aluminum.

But not everything is as golden as one would like. While this epoxy works on small repairs, bigger jobs will need an experienced welder to fix. Some of those bigger repairs would be structural and would be too complicated and difficult for JB Weld. From all reports, JB Weld epoxy works like a charm on those smaller issues.

Some people have reported no problems from months to years after applying this adhesive to their different issues. By following the instructions, they have become very satisfied customers as they do not have to keep running to the store to get other products to do the job.

How Strong is J-B Weld On Aluminum


According to some scientific tests, the tensile strength of JB Weld reaches 5020 psi roughly. To reach that level of strength, you have to allow the epoxy to cure overnight. The set-up time is 4-6 hours and the curing time is between 15 and 24 hours.

Once you let it set up and cure, you should not have any problems with your repair. One boat owner said it fixed issues on his aluminum boat and he has not had a leak problem in 7 months.

That is probably because he did not use the material on any weight-bearing objects. That will be the issue with this product. No matter how strong it is, there will be some situations it is not suited for. Not because it is the wrong metal but because it is not designed to hold a lot of weight.

So make sure you apply this epoxy to the right broken issue to avoid having to repair the part more than once.

Liquid Aluminum Weld

Before using any product that falls under this category, you have to do good surface prep if you want the epoxy to adhere and form a tight bond. If you don’t do good surface prep work, you may get frustrated.

Even with JB Weld, you have to chaff the end with a nice flat file and then use a wire brush to score the end. That scoring should reach up to an inch wide from the end you are adhering.

But it will depend on the type of joint you are trying to create. Sometimes, as good as JB Weld is the product won’t hold the joint overnight and become brittle. That is because this product has a filler in it that does become brittle overnight.

This may be one of the weaknesses that JB Weld products have. There are better and stronger adhesives out there that will hold any joint when it is made from aluminum.

Best J-B Weld for Aluminum

Most likely, the best JB Weld product for aluminum would be their Marine Weld option. It is designed for boats that must handle very tough conditions that most RV users do not face.

You mix the 2 tubes at a 1 to 1 ratio and after application, you let it sit for 4 to 6 hours and then cure for up to 24. But once it has gone through that process, you can sand, tap, fill, mold, and drill the material to make sure you have the perfect hold.

This product is also steel reinforced and can handle temperatures reaching 550 degrees F. Once it is totally cured, it is waterproof and resistant to petroleum, chemicals, and acid. Being below water doesn't weaken this epoxy.

You may find comparable JB Weld products as the company works hard to make sure its products are the best quality and does the job they claim it does.

JB Weld Aluminum Cure Time


One thing the company does that makes it easier to purchase their products, is that they put the setup and cure times front and center. That allows you to see right away what time frame you need to work with this adhesive.

Generally, the setup time is 4 to 6 hours while the cure time is between 15 and 24 hours. If you are not in a hurry it is best to wait till the cure time is over before testing the repair.

You will find that there are other products on the market that do not take as long to cure or set up but their tensile strength may not be as great as JB Weld’s 5020 psi. Their packaging also gives you the color their epoxy will dry too after the curing time.

In one little box on the packaging, you get a lot of information about the product. That information helps you decide if you want to use it or not.

JB Weld for a Hole in Aluminum

One of the best applications for this epoxy is fixing holes. If you have a stripped bolt or hole, turning to JB Weld products is a smart move to make. Threads do not always hold up under a lot of stress, use, or other tension-producing uses.

They strip out fairly easily and when they do JB Weld can come to the rescue. You can fill the hole with this product and let it set up and cure. Once that is done, you can tap the epoxy to the depth you need and put the bolt back in.

Or if you want a permanent fix, apply the epoxy to the bolt itself and put it back into its original spot. Once the epoxy dries, that bolt is never going to move again. Other holes are no problem for this product as long as they do not get too big.

With bigger holes, you may need other solutions or weld another piece of aluminum over the hole with JB Weld products.

Can You J-B Weld Aluminum ac Lines?

While some people report a little bit of success on certain AC parts, the general consensus is that this is the wrong material to fix an AC line. The JB Weld epoxy cannot handle the high pressure required for AC lines to function right.

If you have a break in the line, almost everyone recommended that you get a new line and solve your problem the correct way. JB Weld is seen as the cheap way of making an AC repair and it is not going to do the job you want.

The phrase ‘you get what you pay for’ applies to this situation and it would be best to repair any AC line correctly so it will last for a long time. This epoxy doesn't last for very long when used to correct broken issues.

Talk to a professional and they will tell you the same thing. If you want the repair to last, do it the right way the first time. In this case, JB Weld is not the right way.

JB Weld Aluminum Radiator?


Like the AC situation, there are success stories and then there are those pieces of advice that say the product doesn’t work very well in this situation. Since JB Weld epoxies are not that expensive, you can try it and see how good a hold you get.

But we will not guarantee any results as there are too many contrary pieces of information that say it is not a long-term solution. If you are out boondocking and you spot a leak in your radiator, JB Weld would be a good stop-gap fix till you got to a repair shop.

The trouble with using this epoxy even for a stop-gap measure is that it is hard to clean off once it cures. Most people recommended welding the radiator to make sure you got the right fix to the problem.

There are hot and cold temperature limits to this product so you should be careful where you apply it.

Does J-B Weld Work On Aluminum Engine Block?

One of the keys to welding this crack together is that you have to spend a good amount of time making sure the crack is free from paint, rust, and liquids. After cleaning the crack with a wire brush, you should wipe it down with rubbing alcohol.

Let the alcohol dry before applying the JB Weld epoxy. Next, use a 1 to 1 ratio of hardener and resin and mix the two until they are the same color. Then, take a scraper and put the epoxy into the crack. You may need to press hard to get the mixture to the back of the crack and really seal it.

When you are done, wait till the next day to see how the epoxy is set up and cured. Then start the motor and let it get up to the normal operating temperature and check to see if the epoxy held or not.

Because people are getting different results, we will not guarantee that your crack will be fixed and you can drive for years that way. Test it out to make sure you got a good hold. Of course, the size of the crack will play a role in your success or not.

Will J-B Weld Work On Aluminum Boat?

This material has been applied successfully to aluminum boats. If you read the section about the best JB Weld product, you would have seen how good this product is for aluminum boats.

The key to your success will be if the repair is weight-bearing or not, or too large for the epoxy to handle. While the Marine weld is top quality, it does have its limits and you should be realistic in your application of this adhesive.

Keep in mind that JB Weld products are not conductors so if you want to join two aluminum wires in your boat, this product won’t work for you. It is good for smaller repairs and once it cures it does become waterproof so it can work on those issues that are beneath the surface of the water.

Read the package to make sure the epoxy will work on your type of repair. There should be limits placed on them so you know where to apply the adhesive and where to avoid using it.

Can You J-B Weld Aluminum Oil Pan?


As long as the crack is not too large, width-wise, you should have success in using this product on your cracked oil pan. The biggest issue in using this product for that repair is the time it takes to fully cure and be ready for use.

Once it is cured, JB Weld is supposed to be resistant to petroleum products. That means you should be able to use your car without worry. The key will be waiting for the up to 24 hour time period. When you repair make sure you do not need your vehicle before then.

Make sure the oil pan crack is nice and clean and also free from any oil before you apply this adhesive. Clean off the oil thoroughly before doing any repair work. The product may be resistant to oil, but it doesn't adhere that well, if at all, if oil is present in the cracked area.

JB Weld Aluminum Bike Frame

The issue of using this product on bike frames is fairly cut and dried. The aluminum bike frame is basically weight-bearing. That means that this product is not that good at repairing the crack. It doesn't work that well on weight-bearing items.

Even regular welding is discouraged because aluminum does not return to full strength after welding. In this instance, aluminum is not like steel. Where steel returns to full strength, if not stronger, after welding, aluminum remains weaker and you could have problems with the frame if you ride it.

Most people say to get a new frame so that you are not putting yourself or family members at risk. Even if you try to weld the parts together in the traditional manner, you would still need to anneal it and then have it re-tempered in order for the frame to be safe to ride again.

Will J-B Weld Bond Aluminum to Steel?

JB weld is said it can be applied to any metal. It does not say that the two pieces of metal have to be made from the same materials. This adhesive is supposed to be great at adhering aluminum to steel. It is also great at adhering other metals to steel.

When you have a small non-load bearing weld to make, then this is the product you need to use. It has a very strong adhesive formula that makes sure your metal pieces stay together. Also, it will bond aluminum to other metals as well.

There are very few materials where JB Weld does not form a strong bond, making it an ideal product to use when you have smaller repairs. Every product has its limits so you should check the packaging to make sure what the limits are in this situation.

JB Weld Aluminum to Plastic


Plastic is one of the materials this weld does NOT work with. It is not just that there is a weak bond, it is that the product is not designed to adhere to this material. it is great when you want to weld two pieces of metal together but not plastics or metal to plastic.

Regular plastic is not the only material JB Weld does not work with. Polypropylene and polyethylene plastics are also not able to bond with this epoxy. Other materials include vinyl, leather, and canvas.

If you want to fix a tarp, then you have to use an adhesive designed to work with tarp materials. Check the package before you buy it to spare yourself any embarrassment when you have to return it and buy something that is suited for the plastic materials you want to weld together.

JB Weld Aluminum to Wood

The word is that this epoxy will work on wood. The company kept it off the list of materials their products do not work with so you can use this adhesive when you need to weld metal to wood.

That is the key. You get a great bond when welding metal to wood but not so great when trying to weld wood to wood. There are better wood-to-wood adhesives than JB Weld. Those are the ones you should use when that is your situation.

From what we have been able to find out, you can weld any metal to wood using this product. There seem to be no exclusions so you have lots of freedom when working on your repair or project.

All the warnings about the size of repair and weight-bearing will apply here as well.

How to Use JB Weld On Aluminum

The first step is to make sure the aluminum pieces are clean. This means scraping off any dirt, rust, and other contaminants. Then once those items are off, you need to use a solvent to clean off any grease or oil that remains.

You may need to score the aluminum where you are going to apply the epoxy. A good wire brush should handle this chore. A 1 to 1 ratio of the two liquids is needed and use something disposable to do the mixing on.

Then follow the instructions on the package. You will have to work quickly as once you feel any heat coming from the mixture the chemicals are reacting and begin to set up sooner than you think.

After applying the epoxy, clamp the two items together so that the adhesive can form a strong bond. Wait the required curing time before you begin to use the item. Usually, that will be one day after you have clamped the items together.

How to Sand J-B Weld


Sanding is done as you would normally sand metal. Most people are talking about the pre-sanding you have to do before you apply the glue. At that point, you need to use coarse grit sandpaper to rough the metal pieces up.

After the material has cured, you sand like normal but use a finer grit piece of sandpaper to make sure the surface is smooth and not jagged. If you want to fully remove JB Weld then you are in for a lot of work as it has to be taken off with a grinder or filing it. Extreme heat will do the job as well, over 600 degrees F.

Some Final Words

JB Weld is a great welding tool when you do not own a welder or you only need a small repair done. It bonds to the metal and holds the pieces together very tightly, even aluminum.

Its weaknesses include load-bearing repairs and cracks that are too large.

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