Best Epoxies for Aluminum 2020 – Reviews and Buyer’s Guide

Best Epoxies for Aluminum 2020 – Reviews and Buyer’s Guide

When it comes to gluing metals, you have to be careful. There are a large number of commercially available glues that simply won’t bond with metals such as aluminum and steel. Labeling will often tell you which glues will bond to aluminum, but this is not universally true.

This is why I thought that some research was necessary. Since epoxies are usually the strongest class of glue, I have put together a list of the top 5 epoxies that can be used on aluminum. Extensive research has been done to ensure that all of these products are safe and effective for use on aluminum surfaces.

Best Epoxies for Aluminum in November, 2020

1. 3M Marine Adhesive Sealant 5200 – Top Epoxy for Aluminum

This epoxy is the only sealant on our list that is intended for marine use. This means that it is meant to withstand water without breaking down or coming loose, even when underwater.

This kind of adhesive is commonly used for boats, kayaks, jet-skis, and other marine vehicles. This product has a proven history of effectiveness, though it is not without its downsides. It takes a long time to dry, and even longer to cure.

Pros
  • Extremely resistant to water
  • Flexible when dry
  • Safe for fresh or salt water
  • Not very expensive
  • Well-proven
Cons
  • Takes two days to dry, and another week to fully cure
  • Somewhat thin- can make the adhesive difficult to apply
  • Smells very strong

2. Loctite Liquid Professional Super Glue  – Strong Transparent Option

It would be very surprising if you had never used super glue before. Nearly everyone has used it, and Loctite makes what is arguably the strongest glue of this type on the market.

This particular version is meant to bond very quickly, fixing the object in place within seconds. Loc-tite is so strong that you have to be very careful with it, which represents its first significant drawback.

It bonds well with virtually everything including aluminum. That being said, Loctite’s Professional Super Glue is a bit on the expensive side.

Pros
  • Very fast-acting
  • Very strong and long-lived
  • Completely transparent
  • Easy to use due to classic design
Cons
  • Pretty expensive
  • Very hard to remove from your hands
  • Highly toxic
  • Tip will always get clogged after each use

3. PC-7 Heavy Duty Epoxy Paste – Both Epoxy and Filler

This is a great example of a two-component epoxy. PC-7 is the strongest epoxy made by this company, and has several distinct advantages.

For one, it can be applied as either a filler aluminum patch or a coating with equal efficiency. For another, it can bond to virtually any surface except for certain plastics. It should bond very easily with aluminum.

The product comes in a tube that contains two different substances that are mixed together to create a long-lasting and paintable filler. It requires only one day to cure and gives the user 30 minutes to an hour of work time before the mixture begins to harden.

The only real disadvantage to this product is the fact that it has to be used within 30 minutes of mixing to avoid waste. This product does create an ugly surface, but the fact that it can be painted makes this less of a problem.

Pros
  • Very strong
  • Long work time
  • Short dry time
  • Very versatile
Cons
  • Must be used once it is mixed = harder to avoid waste
  • Creates an ugly surface (paintable)

4. J-B Weld KwikWeld Quick Setting Steel Reinforced Epoxy – Great for High Temperatures

If you know anything about epoxies, you probably know what J-B weld is. It contains powdered steel, making it an exceptionally strong glue. It also allows the glue to bond more easily with a metal surface, including aluminum.

J-B weld is perfect for applications that require a high-temperature epoxy, as it can withstand temperatures of up to 300 degrees Fahrenheit.

There are those who claim that J-B Weld is not as strong as advertised. However, when we look at their stories we can see a pattern. It seems that some people expect J-B Weld to be as strong as solid steel.

The KwikWeld variety is meant to be a faster-drying version of the classic formula. One small problem is that JB Weld doesn’t adhere to a surface quite as well as some of other choices on the list.

Pros
  • Good strength
  • Excellent temperature resistance
  • Longevity
  • Trusted Name
  • Very inexpensive
  • Fast-drying formula
Cons
  • Must be used once mixed= harder to avoid waste
  • Slightly inferior adhesion
  • Not as strong as solid steel

5. Hy-Poxy Alumbond – Specifically for Aluminum

This is the only product on the list that is specifically intended to bond with aluminum. At first glace, this alone might make it seem like the best choice. When you look at reviews for the product, most of them are positive.

Some users did report a failure to bond with certain aluminum surfaces, particularly when doing automotive repairs. This could be due to the dirty nature of automobile parts in general.

A dirty surface would impair the adhesion, to be fair. The only provable negative that I can find with this product is its somewhat ridiculous price.

Pros
  • Specifically intended for use with aluminum
  • Doesn’t take very long to cure
  • Can be sanded, threaded, and drilled after curing
  • Easy to use
Cons
  • Way too expensive
  • Requires a very clean surface

Buyer’s Guide

When selecting an epoxy for your next project, you should be aware that there is no one answer for everything. An epoxy that works great for one purpose may not necessarily work so well for another purpose. There is no one-shot cure-all for everything.

However, the above doesn’t really help you very much when it comes to specific options, so let’s take a look at the factors you need to consider.

Drying Time

Usually, this won’t be a big factor. When a problem needs to be fixed, it doesn’t really matter if it takes a little longer. That being said, professionals who are working on a timeframe might find this factor to be a lot more important. As a professional, you want to get the job done quickly so that you can get paid and move on to the next job. For the home user or the hobbyist, it simply boils down to convenience.

Tensile Strength

Most types of glue will tell you their exact tensile strength in pounds per square inch somewhere on the package. You may have to look for it, but it is most likely there. This gives you a set of numbers that you can compare when deciding which glue will be sufficient for your needs.

Temperature Resistance

Ask yourself what kind of temperatures your surface will be exposed to. Think about the hottest temperature that it will ever see. In most cases, you don’t need to give a whole lot of thought to this, but when fixing anything that comes into contact with high temperatures, it will be a critical factor.

Looks and Paintability

Not all epoxies can be painted. While this may not matter for strictly utilitarian jobs, cosmetic issues may be relevant for the average home user fixing a piece of furniture. It doesn’t do much good to fix your things if they turn into an ugly mess in the process. Make sure you always check the packaging to see if your epoxy can be painted.

Frequently Asked Questions

Will epoxy glue stick to aluminum?

Yes, epoxy glues will stick to nearly anything. That being said, there is an extra step that must be taken if you want your aluminum-epoxy bond to hold strong. Aluminum doesn’t exist in nature (at least not in an unmixed form) and comes instead from an ore called Bauxite.

When made pure, aluminum tends to react with the atmosphere readily. This results in a dull gray layer of aluminum oxide developing on the surface. Unlike iron oxide, aluminum oxide isn’t corrosive, so you don’t need to worry much about that. However, that oxide layer can prevent the epoxy from bonding to aluminum surfaces properly. All you need to do is clean the bonding surfaces with something abrasive, and you should have no problems.

How do you bond aluminum without welding?

Because aluminum melts rather easily, you don’t really need a welder to achieve proper bonding. You can always use mechanical methods like screws and rivets, but that doesn’t really create a “bond.” You can also use epoxy as described in the last question, but the oxide layer can make that problematic.

A lot of people will use soldering as an alternative to welding. In fact, it is a much better alternative for soft metals. An acetylene torch (which is needed to melt steel) is so hot that it would destroy aluminum quickly. It takes at least 2500 degrees Fahrenheit to melt steel, while aluminum requires only about 1200 degrees.

Soldering involves the use of rods that are made of similar metals. An inexpensive propane torch is used to melt the rod, allowing the metal to flow into the desired cavity. This does take a little bit of skill, but it’s a pretty basic process.

Conclusion

It probably surprises you that a tube of glue can be this complicated. However, most of the products that we use on a daily basis have complex science behind them. It may not seem relevant for the average person, but understanding the things you buy gives you a better idea of which products are worth using and which ones are best avoided. I hope that this guide has been helpful, and that your repairs go off without a hitch.

6 thoughts on “Best Epoxies for Aluminum 2020 – Reviews and Buyer’s Guide”

  1. Thanks very helpful,I have slight spider cracks in my crank case of compressor so now I will fix with Hi-Epoxy Alumbond after completely cleaning it thanks you saved my compressor problem I thought was impossble,I was so discouraged cause I just invested a lot of time and money in it and then discovered a minor oil leak in small cracks thanks so much

  2. Hello
    I have a stainless steel heat exchanger with a small pin hole erosion from chlorinated spa water and high calcium. Many years ago a repair man put some type of white past over a different area and it is still is holding very well.
    Do you know of a product that can do this?
    Thanks,
    Doug

    • Hi Doug,

      Your repairman was most likely using some sort of metal filling compound. This is very similar to wood putty, but it is meant to bond with metal surfaces. As such, it is a great way to fill pinholes on metal objects. The most well-known example of a metal filling compound would probably be Bondo, which is sometimes known to be stronger than the materials that it replaces. You might want to go with that one, just because their reputation is well-established. Of course, a layer of clear coating wouldn’t hurt either, just to make sure that the compound doesn’t break loose.

  3. Hi,
    I have a weeping radiator tail, tried everything, plumbers mate, tape, la co pipe thread compound, ls-x, and it still continues to weep. Any advice on which glue is the best to stop the water weeping.

    • Some people will try to tell you differently, but you shouldn’t be putting epoxy in or on your radiator. At best, it will be a temporary fix and probably won’t last all that long. If your radiator leaks, it is best to get a new one. Even if you are not mechanically inclined, it should be well within your ability to change a radiator.

      In most cases, you just have to undo a couple of bolts and hoses, pull the old one out, and replace it with the new one. The only thing to remember here is the position to which each hose must attach. As long as you put it back the same way it came off, you will be fine. Epoxy is great for a lot of things, but this isn’t one of them.

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