fender rust

I have rust on all 3 of my cars and have tried on my oldest to sand ,use rust converter , apply (forget what it is called) like bondo , sand primer and paint.This will last me 6-8 months then rusts again.I want to fix the rust on my 2000 Durango fender wheel area as it is forming a layer of hole in the body there.What are the proper steps to do a good job short of paying a body shop.thanks

Cut out rusted area, cut a new piece of metal to fit, weld into place. Prime and paint. If the back of this is exposed to the elements prime and paint it as well, or undercoat it.

Problem is I dont weld or have access is there any way to use fibre glass or bondo.

Yeah, it's not really the right way to do it, but you could cut out the rust and fiberglass it from the back. I recommend using 2 layers of fiberglass if you use the Bondo fiberglass kit. The use a body filler to even that out with the original panels. Sand that down and fill in any small pin holes with a spot putty. Sand smooth, prime, sand, paint, and wetsand. If you do it right, should look like new; everything I mentioned here you should be able to find at an auto parts store such as Advance.

Thanks for your help.It may be tough as the rust is right at the bend of the wheel well where the plastic wheel well tucks under .So the one hole isnt all the way thru and is about 2 " by 1" and the rest is surface rust so I should cut out this hole and follow your instructions.I have a etch primer is this good.I appreciate all your help.

I'm not sure about your primer, I'm not really a refinishing expert. I've always just used the duplicolor rattle cans (never had the money for real painting equipment and never had a place for an air compressor), and if done right, they will look great. I hope everything works out for you.