ask: Any food or health-related hazards from rust inside microwave?

I have exactly the same problem with my microwave and have been wondering about any possible health risks not so much the rust itself because I cover the food when cooking but it may just be possible that the microwaves are escaping the unit and radiating us while we stand outside waiting for the food. I am going to look into this soon! I hope someone has an answer among our readers.

One worrisome thing about rust in the microwave might just be that it signals that you have uncovered metal. Some microwaves can handle this but others might spark or flare (like when you've accidentally put something with foil in there, or if you have a metal rim on a plate).

In terms of the rust itself, here's one answer from a consumer question and answer board:

"As long as the oven's metal bottom is sound underneath the rust, there isn't a problem. The cooking chamber walls are so thick and highly conducting that they reflect the microwaves extremely well even when they have a little rust on them. However, if the metal is so rusted that it loses most of its conductivity in the rust sites, you'll get local heating across the rusty patches and eventually leakage of microwaves. If you're really concerned that there may be trouble, run the microwave oven empty for about 20 seconds and then (carefully!) touch the rusty spots. If they aren't hot, then the metal underneath is doing its job just fine."

Here's another Q&A in the Minneapolis Star Tribune:

"Q I found a little rust spot inside my microwave. Is this a problem?

"A Not necessarily. Rust comes from moisture. Unless it's extensive, rust won't hinder microwave operation. But rust could lead to a penetration of the metal and arcing when the oven is operating. That could make the spot larger or cause microwave energy to leak.

"If the spot is not too large, it can be touched up. Check with your local hardware or home store or an appliance-repair shop that works with microwaves. In many cases, however, it's cheaper to buy a new microwave."

This apparently is not an uncommon problem: I found a microwave interior spray paint with a Whirlpool endorsement and a special label for "Pressurized finishes." It's possible you could get it at a local home improvement store after removing the rust yourself:

http://www.repairclinic.com/SSPartDetail.aspx?s=t-277-%3d%3di277&PartID=277

Here are some sites that tell you how to remove rust:

http://natural-cleaning-products.blogspot.com/2008/06/remove-rust-from-k...

http://www.expertvillage.com/video/165828_home-remedies-remove-rust.htm

Thank you!! I googled a question that was bothering me and your site came up first. Going to look for the Whirlpool endorsed paint!! Thanks again!

I'm glad you found this helpful! Please let us know if you decide to use the paint, as we have rust in our microwave, too, and we are trying to decide if we should purchase a new microwave, or go the DIY route and remove the rust ourselves, and apply the paint.

Very helpful coments!! Thank you

very helpful answers! I'm going to check my mom's micro tomorrow with the "run it on empty" test! In her microwave's case, the rusty area is under the glass plate that turns. I think the enamel was worn off by the little wheels under the plate...Maybe also too much cleaning! (I don't have THAT problem at home!)
Thank you again!

From:
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Repairing a rusty panel
PROBLEM: Your microwave oven has developed some rust on interior surfaces.
Rust that develops on a panel inside the cabinet of a microwave oven can eat through the panel and lead to radiation leakage. It should be repaired as soon as possible. Do the following:

Unplug the unit.
Wipe the damaged surface with a soft rag to remove loose flakes of rust.
If the rust is under a glass shelf, remove be shelf. If the shelf is held by sealer, use a razor blade or utility knife to slice through the sealer. After the shelf has been removed, clean off any strips of sealer that remain.
Buy a spray can of enamel paint for your make of microwave oven from a dealer who sells your type of oven. Also buy a tube of RTV [room temperature vulcanizing) sealer if the unit has a glass shelf.
Following directions on the can of paint, refinish the damage. Let the paint dry.
Install the glass shelf. Then, following directions on the tube of sealer, apply a bead around the edges of the shelf.
Before using the oven, let the sealer cure for the length of time specified in the instructions on the sealer tube.

(I would recommend an epoxy enamel commonly referred to as "appliance paint" sold at most home improvement centers. Also, determine how much rust there is. Strongly recommend a light sanding then the use of a "rust reformer" prior to the epoxy enamel. You don't want the rust to continue oxidizing under the paint.)

My apartment complex is trying to charge me damaging this 5 year old microwave because it has rust where the turntable goes around. They said I didn't maintain it properly. I am very unhappy about this but I see rust in the microwave is sort of common. The unit I have is an inexpensive whirlpool and I never used it for anything more than heating water for tea and popping corn. I did not cook meals in it -- I use the oven for that. It never got dirty but I wiped it out regularly.