Flex Glue in 2026: sizes, price and where it is cheapest

What Flex Glue is and what it bonds

Flex Glue is a thick, rubberized, waterproof adhesive from Flex Seal, the company behind Flex Tape and Flex Seal Liquid. The official Flex Glue page says it can go on dry or wet surfaces and even underwater, and that it does not run or drip, so it can be used overhead.

The label lists these properties:

• Solvent-free, paintable and sandable.
• Resistant to UV light, chemicals and mildew, for indoor and outdoor use.
• Instant grab, with firm pressure for 10 to 30 seconds after you press the parts together.

Flex Seal lists a long set of surfaces it works on, including metal, stainless steel, fiberglass, glass, wood, concrete, brick, ceramic, stone, drywall, PVC and some plastics. Suggested jobs include roof and siding repair, bath and shower fixes, shoe and furniture repair, and auto, boat and RV repair. The phrase "some plastics" matters: the maker does not claim it bonds every plastic, so a small test spot on an unknown plastic is a sensible first step.

Flex Glue sizes and official prices

The product now comes in more sizes than the single 10 oz cartridge that older reviews describe. Prices on flexsealproducts.com on Oct 18, 2026:

Per-ounce figures are PickedBox math from the listed price and size. The MAX cartridge was marked sold out at the time of checking, so the 10 oz white cartridge was the lowest price per ounce that could be ordered. Flex Seal says all cartridges need a standard caulking gun.

Flex Glue price at Home Depot, Walmart and Amazon

Store prices move often, and some listings come from outside sellers. This is what could be confirmed in October 2026:

The Home Depot figures come from its own product pages. Walmart and Amazon pages did not load directly when checked, so those figures come from search results and a deal forum and may not match the live price. On these numbers, the cartridge costs about the same at Home Depot, Walmart and the Flex Seal store. The tube is where prices split most: $9.99 direct versus $14.87 in the Walmart snapshot, which may be a marketplace seller.

Before buying at a big-box store, check the size on the label. A 6 oz tube and a 10 oz cartridge can sit at a similar price, and the cartridge holds two thirds more glue.

Tube, cartridge or mini: which size to buy

The right size depends on the job and on having a caulking gun at hand.

• Mini (0.6 to 0.75 oz): a shoe sole, a loose tile or a single small crack. It is the most expensive glue per ounce, but it costs the least to buy once.
• Squeeze tube (4 or 6 oz): household repairs without a gun. Flex Seal says the tube now uses an Easy Squeeze formula for smoother dispensing.
• Trigger Flow (4 oz): a built-in adjustable nozzle and trigger, for people who find a tube hard to squeeze. It costs about twice as much per ounce as the cartridge.
• Cartridge (9 or 10 oz): larger jobs like siding, gutters, boat or RV repairs. The Pro Formula has more instant grab, according to the maker, and needs a caulking gun.

On the official prices, two 6 oz white tubes cost $19.98 for 12 oz, while one 10 oz white cartridge costs $14.99. For a job that needs more than one tube, the cartridge is usually the better buy, as long as the cost of a caulking gun is counted for anyone who does not own one.

How to pay less for Flex Glue

• Buy the white 10 oz cartridge when the job allows a caulking gun. It had the lowest price per ounce that was in stock.
• Watch for the 28 oz MAX cartridge to come back in stock if you do large repairs. It works out to about $1.25 an ounce at $34.99.
• Use the bulk offer on the Flex Seal store. The product page says buyers can save up to 20% when buying in bulk. Shipping is free on orders of $30 or more, so two cartridges plus one more item clears that bar.
• Compare per ounce, not per tube. Retail listings mix 0.6 oz minis, 4 oz and 6 oz tubes and 9 oz and 10 oz cartridges under the same name.
• Check the store coupon pages. PickedBox keeps current offers on the Home Depot coupon page, the Walmart coupon page and the Amazon coupon page.

Home Depot sells the 10 oz cartridge as a 6-pack online, and the 6-pack price works out to the same $14.99 a unit as a single cartridge on the Flex Seal store. A 6-pack only saves money if you need that much glue.

Cure time, safety label and when to pick something else

Flex Seal states that Flex Glue fully cures in 12 to 24 hours and reaches full strength in 7 days. With the cartridge, the object can be repositioned within 10 minutes, and some jobs may need bracing while it sets. To store an opened cartridge, the directions say to squeeze out a small bead to form a plug and cut it off next time.

The safety label warns that the glue may cause an allergic skin reaction. It says to avoid contact with eyes and skin, wear gloves and safety glasses, and keep it away from children. The product also carries a California Proposition 65 notice.

Flex Glue is a general repair adhesive. For structural work, such as anything that holds weight overhead or carries a load, follow the building product the job calls for or ask a contractor. Flex Seal also sells a separate construction adhesive and a thin Flex Super Glue for small, tight-fitting parts.

How we checked this

In October 2026 PickedBox checked the Flex Glue product page, the Flex Minis page and the Trigger Flow page for sizes, prices, directions and warnings, and the Home Depot product pages for the 6-pack prices. Walmart and Amazon pages blocked direct access, so those prices come from search result snapshots and a Slickdeals post dated March 2026, and are marked as such. Per-ounce figures are calculated from listed prices. No product testing was done for this article.

• Flex Glue product page, Flex Seal
• Flex Minis product page, Flex Seal
• Flex Glue Trigger Flow product page, Flex Seal
• Home Depot, Flex Glue White 10 oz 6-pack
• Home Depot, Flex Glue Clear 9 oz 6-pack
• Walmart search, Flex Glue
• Amazon search, Flex Glue
• Slickdeals, Flex Glue Mini at Amazon (March 2026)

How we test codes and what the labels mean: How we verify coupons.