3M Bondo Vs. JB Weld: Filling Nail Holes & Window Frames, Filling Holes, Cracks

Bondo Vs. JB Weld: what’s the difference?

3M Bondo Vs. JB Weld: Specs & Uses

Technical Info

	Bondo	JB Weld
Rating	★★★★★	★★★★
Datasheet	📥Bondo Putty	📥JB Weld
Tensile Strength	3960 psi	3960 psi
Flexural Strength	3960 psi	7320 psi
Max Continuous Temperature	500°F	500°F
Hardness	Shore D 85	Shore D 85
Shrinkage	0.0%	0.0%
Mix Ratio by Weight	1:1	1:1
Viscosity When Mixed	200,000-244,000 cps	250,000 cps
Coverage Per Pound (1/4″ thick)	65 sq in	65 sq in

What Is Bondo

✅Bondo: A Heavy-Duty Filler

When I first encountered rotted wood on my exterior door frames, I knew I needed a heavy-duty filler that could not only fill the defects but also harden and reinforce the area. Bondo didn’t disappoint. After treating the rotted areas with a water-based wood hardener, I used Bondo to rebuild the damaged sections. The putty bonded incredibly well to treated wood, making it easy to sculpt and reshape frames.

But Bondo’s versatility doesn’t stop there. I’ve used it to fill gaps between shower tiles and the plastic base, where its waterproof nature ensures a long-lasting repair. Sealing seams in crown molding? No problem! Although it requires some extra work, Bondo’s sandability and paintability make it an excellent choice for a smooth, invisible finish.

Repair Window Frames

I once had to repair window frames chewed through by a mischievous squirrel. Bondo’s strong adhesion and ability to build up in layers allowed me to reconstruct the damaged areas flawlessly. And when I needed to fill nail holes on my aluminum siding, Bondo’s compatibility with metal surfaces made it the perfect solution.

Curing and Shelf life

While Bondo may have a strong initial odor, reminiscent of its automotive counterpart, the smell dissipates once it’s fully cured. And speaking of curing, this putty has an impressive shelf life. I’ve used leftover portions from an opened can even after a couple of years in storage, and it worked like a charm.

Will Bondo Adhere to Plastic?

Can I utilize Bondo to fill the gap between the shower tiles and the plastic base in my shower? Will it be waterproof?

Yes, Bondo is waterproof and works great as one of the shower adhesives. It’s a two-part product that you mix together, with a working time of approximately 10 minutes. You might also want to read my article about Plastic Bonder vs. Plastic Weld .

It’s important to mix small batches as needed. Bondo will bond to both your shower and the shower tiles. Once it dries, it can be sanded and shaped. If the gap is small, I would recommend grouting and caulking with a good silicone caulk.

However, if the gap is large, you’ll need to use multiple small batches of Bondo to work around the shower base. Make sure to mask off the tile and base before applying. When sanding the Bondo, start with 40 to 80 grit sandpaper and finish with 100 grit. If any Bondo gets on the tile or base, quickly remove it with acetone. If it dries on these surfaces, you’ll need to sand it off. While Bondo works well, it can be challenging to work with due to its drying time, so take your time during the process.

Bondo On Plastic Bumper – Can I use this to fill a hole on a bumper?

This particular Bondo product is an all-purpose putty. While it states it can be used on metal, I have primarily used it for repairing damaged wood, so I cannot guarantee its long-term effectiveness in a bumper repair.

Additionally, bumpers are typically made of plastic or fiberglass, and there are specific Bondo products designed for automotive repairs. It’s best to use a product specifically formulated for automotive applications, such as Bondo Bumper Repair Kit or Bondo Plastic Metal. These products are designed to adhere to automotive surfaces and provide better durability and flexibility for bumper repairs. Always follow the manufacturer’s instructions and recommendations for the best results.

❌Shouldn’t Be Treated Like a Structural Adhesive

It’s important to note that Bondo shouldn’t be treated like a structural adhesive or used for applications that require screwing or nailing into it. It’s a filler, not a construction material, so treat it like you would drywall. However, its strength and durability make it suitable for various surfaces, including wood, metal, and even fiberglass (although I’d recommend using a specific fiberglass-compatible product for the best results).

One of the few drawbacks of Bondo is that it doesn’t come in smaller containers, which can be inconvenient if you only need a small amount. But trust me, once you experience its versatility, you’ll find yourself reaching for that trusty can time and time again.

FAQ of Bondo

What Is JB Weld

I’ve found that mounting under-counter items like dishwasher brackets or sinks to granite countertops is a great idea. You just need to apply a good thick bead of the epoxy around the rim, sandwiching the bracket or sink edge between the epoxy and counter. It squeezes out on both sides creating an extremely secure bond as it cures. Just be sure to clean up the excess before it fully sets.

✅How to Use JB Weld

While using JB Weld, I did notice that the recommended 1:1 or 50/50 ratio of hardener to adhesive left the results slightly sticky. However, I found that using a 40/60 ratio of more hardener still gave me plenty of time to work with and finished without any stickiness.

While JB Weld isn’t recommended for things like shower shelves or high-heat applications like ovens, they do make specialty products for extreme heat up to 2400°F. For most household repairs and projects, the standard JB Weld is more than capable.

I’ve used it to bond aluminum, cast iron, steel, and more. It can even be painted over once fully cured if you want to color match. One note – while you can mix in a powdered dye if you want a colored epoxy, I’ve found it’s easier to just do a quick spray paint or touch up once it has cured to its original gray color.

❌Cure Time Is Too Quick

The only real downside is the quick cure time – you only have around 4 minutes of working time once you mix the two putties together before it starts setting up. So make sure to work quickly. It’s not something you can store long-term once mixed.

💬 FAQ of JB Weld