Best Epoxy Putty for Aluminum (2026): 5 Picks

A cracked aluminum bracket, a pinhole in an aluminum tank and a stripped thread in a cast housing all call for a repair that holds without welding. This guide compares the best epoxy putty for aluminum across five sticks, using lap shear figures, heat limits, set times and hardening times from the listings.

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Picks for the garage

#	Product	Shop Score	Buy
1	J-B Weld 8277 WaterWeld Epoxy Putty Stick - 2 oz.	9.6/10	Buy on Amazon
2	J-B Weld 8267 SteelStik Steel Reinforced Epoxy	9.6/10	Buy on Amazon
3	Starbond Steel Reinforced Epoxy Putty Stick (2 oz)	9.5/10	Buy on Amazon
4	Boncart High Strength AB Epoxy Putty	9.4/10	Buy on Amazon
5	Steel Reinforced Epoxy Putty,Epoxy Putty Fast	9.3/10	Buy on Amazon

1

J-B Weld 8277 WaterWeld Epoxy Putty Stick - 2 oz.

J-B Weld·9.6/10 Shop Score

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The Shop Score runs from 9.2 to 9.8 and weighs performance (35%), build (25%), value (25%), safety (10%, where it applies) and warranty (5%), using only what the manufacturer and the listing publish. How we pick ›

A hand-mixable two-part epoxy putty stick that hardens under water, with 1300 Psi lap shear strength, NSF certification and aluminum and bronze among its listed surfaces.

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Pros

• 1300 Psi lap shear strength, the highest lap shear figure here
• Hardens under water
• NSF certified and safe for contact with potable water
• Aluminum and bronze listed among its surfaces

Cons

• 25 minute set time is longer than the SteelStik 5 minutes
• Continuous temp of 300F is below the SteelStik 350F
• Warranty Description reads No Warranty
• Only a 2 oz stick is listed

2

J-B Weld 8267 SteelStik Steel Reinforced Epoxy

J-B Weld Store·9.6/10 Shop Score

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The Shop Score runs from 9.2 to 9.8 and weighs performance (35%), build (25%), value (25%), safety (10%, where it applies) and warranty (5%), using only what the manufacturer and the listing publish. How we pick ›

A steel-reinforced, non-rusting two-part epoxy putty stick with 900 Psi lap shear strength, NSF certification and a dark grey hardened color.

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Pros

• Steel reinforced and non-rusting
• 5 minute set time
• NSF certified and safe for contact with potable water
• Can be molded, shaped, sanded, drilled and tapped

Cons

• Lap shear of 900 Psi is below the WaterWeld 1300 Psi
• Warranty Description reads No Warranty
• Only a 2 oz stick is listed
• Chemical resistance applies when fully hardened

3

Starbond Steel Reinforced Epoxy Putty Stick (2 oz)

STARBOND·9.5/10 Shop Score

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The Shop Score runs from 9.2 to 9.8 and weighs performance (35%), build (25%), value (25%), safety (10%, where it applies) and warranty (5%), using only what the manufacturer and the listing publish. How we pick ›

A steel-reinforced epoxy putty stick with up to 9,325 PSI compressive strength and 900 PSI lap shear strength, for aluminum, pipe, engine and automotive repairs.

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Pros

• Up to 9,325 PSI compressive strength
• 900 PSI lap shear strength
• Withstands 500°F intermittent heat
• Can be sanded, drilled, painted or shaped after hardening

Cons

• No warranty term is stated; the 24-month figure is shelf life
• No NSF or other certification is stated
• Continuous temp of 250°F is below the J-B Weld figures
• Working time of 4-6 minutes leaves a short window

4

Boncart High Strength AB Epoxy Putty

Boncart·9.4/10 Shop Score

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The Shop Score runs from 9.2 to 9.8 and weighs performance (35%), build (25%), value (25%), safety (10%, where it applies) and warranty (5%), using only what the manufacturer and the listing publish. How we pick ›

A 200g two-part AB epoxy putty for metal, wood, tile and ceramics, with a 1:1 mix ratio, a 30 minute working window and full hardening after 24 hours.

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Pros

• 200g stick, more putty than the 2 oz sticks
• 1:1 mix ratio, cut with a spatula
• Temp range from -58°F to 266°F
• Can be sanded, drilled, tapped and painted after hardening

Cons

• 24 hours to full hardening, longer than the 1 hour listings
• No warranty term is stated
• Title states 200g while the spec table lists 0.5 Pounds
• Avoid using underwater, per the listing

5

Steel Reinforced Epoxy Putty,Epoxy Putty Fast

Generic·9.3/10 Shop Score

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The Shop Score runs from 9.2 to 9.8 and weighs performance (35%), build (25%), value (25%), safety (10%, where it applies) and warranty (5%), using only what the manufacturer and the listing publish. How we pick ›

A steel-reinforced two-part epoxy putty stick for filling cracks and holes in metal, wood, PVC, plastic, ceramic, tile, stone, glass and concrete.

Check price on Amazon

Pros

• Multi-surface: metal, wood, PVC, plastic, ceramic, tile, stone, glass, concrete
• Waterproof and heat-resistant when hardened
• Can be sanded, drilled, tapped, filed, machined and painted
• 1 hour hardening time

Cons

• No strength figure is stated, though tensile strength is named
• No size or weight is stated
• No warranty term is stated
• No working time is stated

Best epoxy putty for aluminum compared

We copy each listing’s rated specs exactly as the manufacturer gives them; as of 30 October 2026.

How the points were given

The Shop Score weighs five factors: performance (strength figures and heat limits), build quality (reinforcement and finish options), value (size and kit contents), safety (certifications the listing states) and warranty (term and coverage). A factor the listing does not state scores zero.

The displayed number is the weighted point total scaled linearly between 9.2 and 9.8. Earning more points is the only way up.

What the listings tell you

Five listings, two from J-B Weld with NSF certification, one Starbond with compressive and lap shear figures, one Boncart with a 200g size and one generic stick with no strength figure. Lap shear is stated on three listings, heat figures appear on four listings, and a warranty term on none. Read the set time and the hardening time as two different figures: one is when the putty stops moving, the other is when it reaches full hardness.

Buying guide: epoxy putty for aluminum

Lap shear vs compressive strength

Lap shear and compressive strength measure different things, so do not compare them against each other. Lap shear figures here are 1300 Psi for WaterWeld and 900 Psi for SteelStik and Starbond. The Starbond 9,325 PSI figure is compressive strength, a different metric from the same listing, and it does not make the other sticks weaker on lap shear.

Set time and hardening time

Set time is short on the J-B Weld sticks: 5 minutes for SteelStik and 25 minutes for WaterWeld, with both reaching full hardness in 1 hour. Starbond gives a 4-6 minute working time instead of a set time, Boncart gives a 30 minute window before hardening and 24 hours to full hardness, and the generic stick hardens in 1 hour. Plan the job around the window in the listing you pick.

Heat limits

Continuous and intermittent limits are different ratings. SteelStik states 350F continuous and 450F intermittent, WaterWeld states 300F continuous and 350F intermittent, and Starbond states 250°F continuous and 500°F intermittent. Boncart states a range from -58°F to 266°F rather than a continuous rating. Compare continuous figures with continuous figures, and intermittent with intermittent.

Aluminum and other surfaces

Four of the five listings name aluminum directly: both J-B Weld sticks list Aluminum and Bronze among their surfaces, Starbond names aluminum in its title, and the generic stick names aluminum among its metals. Boncart names metal in general without naming aluminum. If the job is aluminum, pick from the four that name it.

Finish after hardening

Four listings describe finishing after hardening: SteelStik can be molded, shaped, sanded, drilled and tapped, Starbond can be sanded, drilled, painted or shaped, Boncart can be sanded, drilled, tapped and painted, and the generic stick can be sanded, drilled, tapped, filed, machined and painted. WaterWeld does not state finishing, so do not assume it from the other sticks.

Garage Fit Check

• Size on the shelf: four listings state a 2 oz stick and one states a 200g stick.
• Power: all five mix by hand with no power needed, by kneading or by cutting and kneading.
• Check before the first job: times run from a 5 minute set time to a 24 hour hardening time, so read the listing you pick.
• Check the surface list: four listings name aluminum directly, while Boncart names metal in general.
• Check heat limits against the job: continuous figures run from 250°F to 350F across the listings that state them.

FAQ: garage tools

What is an epoxy putty stick?

A two-part stick that you cut, knead by hand until uniform and apply to a cleaned surface, where it hardens into a shaped repair. The listings here describe sticks for filling cracks, holes and gaps and for rebuilding damaged sections.

How strong is epoxy putty?

It depends on the metric. Lap shear figures here are 1300 Psi for WaterWeld and 900 Psi for SteelStik and Starbond, while Starbond also states up to 9,325 PSI compressive strength. The generic stick names tensile strength without giving a figure.

Is epoxy putty heat resistant?

Within the limits each listing states. SteelStik states 350F continuous and 450F intermittent, WaterWeld states 300F continuous and 350F intermittent, Starbond states 250°F continuous and 500°F intermittent, and Boncart states -58°F to 266°F. The generic stick states heat resistance without giving a temperature figure.

Can epoxy putty be used under water?

WaterWeld hardens under water, per its listing. Boncart says to avoid using its putty underwater. The other listings do not state underwater use, so do not assume it from WaterWeld.

Can you sand and drill epoxy putty after it hardens?

Four listings say so: SteelStik, Starbond, Boncart and the generic stick all describe sanding and drilling after hardening, with tapping and painting on most of them. WaterWeld does not state finishing.

Related: the best automotive epoxy primer, our engine and shop equipment hub and the best squeegee for epoxy garage floor.