On the bottom of my microwave, the coating started "chipping" off and now there is a fairly large area that appears to be rusting and makes where the turntable wheels rest look really dirty. Is there anything I can put on the bottom to keep the coating from chipping away more than it already has?

You can only use appliance paint which can be bought from the local home improvement store.

The exact instructions will vary from brand to brand and type of paint application used but you can follow these general steps:

1. Clean the appliance thoroughly with soap and water and leave to dry.
2. Apply a treatment on rust spots to prevent the rust from spreading or showing up through the new paint.
3. Unplug and move the appliance to a well-ventilated area or create good air circulation in the painting area.
4. Remove or protect areas (such as handles and other decorative details) on the appliance that should not be painted.
5. Paint the appliance according to the product instructions.
6. Let dry thoroughly before moving.
7. Apply a second coat if necessary.

Check to see if there is any rust or cracks in the coating that came from the factory. Some microwaves use metal underneath an epoxy type coating and if it is exposed, it can cause an arc from the microwave generator. If there are any defects in the surface, it can be sanded down and you can purchase a can of interior microwave paint and put a coat of paint over the defective area. Also look for any exposed metal in the area of the sparks, there should no metal exsposed anywhere, if it is, cover it with the paint. hope this helps.

Very difficult to explain briefly as microwaves are truly complex.
You will almost certainly have 2 problems. 1)You need to carefully sandpaper the area where the paint is peeling off and "only paint with appliance paint as this does not have lead in it and 2)The sparks are due to a variety of things, but the most obvious, replace your main capacitor and HV diode. This combination is the normal culprit for arching. If it continues after that, the Magnatron needs replacement as well (Unfortunately, for first time diagnosis, electrical testing equiptment is needed.)

Hi,

Scratches, flaking and bare spots are fairly common, but should be addressed as soon as they arise so the corrosion will not spread and arcing does not occur.

Unplug the power cord first.

Take some mild sanding cloth or scotchbright and clean the bare and rusted areas in the microwave. Use appliance touch up paint to re-coat the surface. You can find the touch up at most anywhere that sells appliances, it comes in a plastic bottle similar in appearance to fingernail polish, yes it does have a brush inside.

Let it dry per the instructions on the bottle or 24 hours if not specified.

Hi,

Scratches and bare spots are fairly common, but should be addressed as soon as they arise so the corrosion will not spread and arcing does not occur.

Unplug the power cord and remove the turntable and the support that is under the turntable. Clean the surface of the support wheels or any other part that rubs on the oven cavity.

Take some mild sanding cloth or scotchbright and clean the bare and rusted areas in the microwave. Use appliance touch up paint to re-coat the surface. You can find the touch up at most anywhere that sells appliances, it comes in a plastic bottle similar in appearance to fingernail polish, yes it does have a brush inside.

Let it dry per the instructions on the bottle or 24 hours if not specified.

Yes you can, it is a painted surface correct? If so buy some rust inhibitor spay or primer and spary the bottom and then paint. Make sure you tape off any vents on the bottom before you do anything

Hi,

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.

Thanks.

just use sand paper to clean the rust then use some high temperature paint (sold in tins) eg spray paint but it must be labeled high temperature and spray 2 to 3 coats . your microwave should be safe again

Yes, if the cavity metal of the oven is chipped or charred, it will have to be sanded smooth and clean and dried thoroughly.

Then you can apply some high-temperature appliance paint, available from places like Wal-Mart, Lowe's or Builder's Square.

Otherwise, you can have rust and arcing.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

The areas can be sanded and painted, but first make sure there are no holes rusted through. If it's all surface rust, then sand and clean as best as you can. If you have any areas rusted through - get rid of the microwave.
Use the paint sparingly - don't try to cover in one or two coats. Best results are obtained with very, very light coats drying 10 minutes or so (depending on the humidity) in between. 10- 15 coats usually works well.
It's best to do this outside, as you'll have lots of overspray.

As far as the paint - the best I've used for the last 20 years or so comes from A.M.I. Parts. You can find them @ www.amiparts.com or toll free 1-800-522-1264.