RF502M Generic Mica Sheet 300mm, Universal Microwave Waveguide Cover Material, Cut to Size

RF502M is a generic 300mm sheet of mica that you cut to shape to make a new waveguide cover for a microwave oven. It isn't tied to one brand, because you trace your old cover onto the sheet and trim it to match. Mica is a heat resistant mineral sheet that lets microwave energy pass through, which is why it is used to cover the opening where the microwaves enter the cooking cavity.

Microwave sparking inside? Check the waveguide cover

Inside most microwaves there is a small flat panel on a side wall or the roof of the cavity. Behind it is the waveguide that carries energy from the magnetron into the oven. The cover keeps food splatter and steam out of that channel. Over time fat and food soak into the mica and carbonise, and the cover starts to spark, crackle or burn through, sometimes leaving a black or charred patch. Running a microwave with a damaged cover can harm the magnetron, so stop using it and replace the cover as soon as you see sparking.

Part details

• Generic mica sheet, part number RF502M
• 300mm sheet for cutting to shape
• Used to make microwave waveguide covers
• Suits most brands when cut to match the old cover

Cutting and fitting a waveguide cover

Unplug the microwave first. This job is done inside the cooking cavity only, so never remove the outer case, as microwaves can hold a dangerous charge even when unplugged. Ease the old cover off its clips or screws, trace it onto the mica and cut it out with sharp scissors or a craft knife, including any locating holes. Clean the cavity wall behind it, then fit the new cover.

Questions about this part

Will this fit my microwave?

Mica sheet isn't made for one model. You trace your old waveguide cover onto it and cut out the same shape, so it suits most microwaves that use a mica cover. Check that your old cover is mica, as some models use a different material.