It might be time for a new mower

It’s possible but not pretty to patch rust hole in the deck

Q I have a beloved lawn mower — starts every time on one pull. But it has a rust hole on the body. Is there any way to repair this?

A If you ask a company that repairs lawn equipment, you’ll probably be told that you’d be better off buying a new mower.

The rust you’re seeing was undoubtedly caused by buildup of wet grass clippings against the back of the mower deck, the part that supports the motor and shields the spinning blades.

Tip the mower and inspect the underside of the deck. If the rust is widespread, it might not be worth trying to patch the area where the rust has eaten through.

Mower-repair companies can order a replacement deck, but by the time you pay for labour, the cost could be 75 per cent or more of what a new mower would cost.

These concerns aside, because the mower has been working fine, there are ways to patch the holes. Simplest and cheapest, though not the most elegant, is to cover the damaged area with duct tape. Clean and dry the surface first, and use a heavy-duty type, such as Gorilla Heavy-Duty Duct Tape ($4.97 for an 11-metre roll at Home Depot).

Niki Popken, a consumer affairs specialist for Gorilla Glue, suggested wire-brushing the damaged area first to get down to shiny metal where the paint is gone. Otherwise, she said, the tape will bond to the rust, which is prone to flaking. Apply a couple of layers of tape, with each new layer extending out a little farther than the one underneath.

You also can patch the holes with metal flashing, cut big enough to extend past the rusted area. You can glue on small patches with a two-part epoxy, such as J-B Weld Twin Tube Cold Weld ($5.67 at Home Depot for a package with two 28 g tubes). For a larger patch, you could secure it with pop rivets. You will need a rivet gun, a hand-operated contraption that looks a bit like a wrench, and a few rivets; the Tekton Rivet Gun with 40 rivets is $13.51 at Home Depot. You will also need a drill with a bit matched to the shank diameter of the rivets.

Or, for the tidiest patch, apply multiple layers of fibreglass cloth with epoxy resin. Wearing rubber gloves, hold an oversized patch of cloth in place and brush on the resin. Press with the brush to form the mesh to the curve of the mower deck. Build up the patch with multiple layers. A 2.5-metre package of Bondo Fiberglass Cloth costs $6.97, and 946 mL of Bondo Fiberglass Resin is $14.97 at Home Depot. Once dry, the patch can be painted.