This is a beater car and I'm not worried about fixing it "properly" really. Trying to spend minimal dollars on this. My main concern is keeping rats or bugs out of the car.

Basically the car completely rusted through where the spare tire holder is. What can I use to plug or patch this hole with so bugs / rodents don't get in?

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  • Welcome to Motor Vehicle Maintenance & Repair! Dec 21, 2017 at 20:17
  • 2
    While you're doing your repair, consider why it rusted out - probably pooled rain water from a leak in the boot/trunk seal. Chasing leaks can be a long and fruitless task, but if you spend a bit of time, you might find and fix (or mitigate) the leak.. Otherwise drain it occasionally and dry the wheel well periodically. Storing the car in a garage, in a carport, or even just under a car cover will help. Yes, I understand its a beater.
    – Criggie
    Dec 22, 2017 at 8:05
  • If it's a beater why fix it? Chances are the next stop for it is the junkyard, and a hole in that area isn't likely to be a way vermin to get in.
    – GdD
    Dec 22, 2017 at 9:14
  • At first I read "Large Rust Cohle in...".
    – shekeine
    Dec 22, 2017 at 11:18
  • Several good answers here, but whatever path you choose please make sure it entails grinding all the rust, then fill/fix, then prime and paint. Otherwise, it will continue rusting after the fix. Jan 12, 2018 at 17:35

4 Answers 4


The following repair is cheap, easy and should last for 3 to 5 or more years depending on your climate, but it's not the "correct way" either.

  • Remove the rust, paint and body protection around the hole with a wire brush wheel. Extend the area until you have clean, non-rusted metal all around the hole.
  • Cut some glass fiber pads that cover the hole and all of the rusted area. Test-fit them and make additional cuts such that they bend nicely around the metal.
  • Put on gloves and mix some polyester resin.
  • Apply it first to all the exposed metal in- and outside, then soak the fiber pads.
  • Put them onto the hole form the inside and outside.
  • Use a hot air gun to make the resin gel quickly while you hold the pads in place. The resin gets quite runny when heated, but gels in about 5 minutes when it cools down, then the glass fibers should stay in place.
  • Let it cure for a day.
  • Apply some body protection.
  • Drill a small hole, such that the water that collects at this point can run off. Or get some new rubber door seals to prevent it from entering the trunk.
  • I'd say your approach is perfectly reasonable given the "beater" status of the car in question.
    – Bob Cross
    Dec 21, 2017 at 23:03
  • Thanks @BobCross! I've only ever owned "beater" cars :)
    – alain
    Dec 21, 2017 at 23:14
  • 2
    Just a quick remark: you should wear gloves also while handling the glass fiber pads :-). First, because body fat is an adhesive and second, because glass fiber irritates the skin.
    – user35915
    Dec 22, 2017 at 8:42
  • Yes, this. Or ditto ditto ditto epoxy resin, i.e. Random $3 packs of epoxy at the hardware store. Choose a cure time that is workable , e.g. At least an hour. Dec 23, 2017 at 1:04
  • I've used this approach before, but instead of using epoxy resin gel, use POR15. This does two things, first it encapsulates any left over rust so it won't continue to deteriorate the metal. Secondly, it bonds with the fiberglass and with the metal, making it incredibly strong and resilient. Better than resin would do with the fiberglass. I mean, it ends up like rock. Using two sheets of fiberglass, one on either side of the metal surface and you'll have absolutely no issues. Dec 23, 2017 at 16:24

I have no idea if this is legal where you live, or what tools or supplies you have, but this is what I would do to repair a junker/beater. I have used this for quick farm fixes without welding. You will need;

  • a piece of sheet metal a few inches larger than the rusted area
  • drill and bits
  • pop rivet gun and rivets
  • some kind of sealant

Now the fix;

  1. Clean the area inside so there isn't loose dirt and rust.
  2. Flatten the metal to somewhat form to the area so it will lay in place.
  3. Put sealant around the whole away from the edge, but beneath the metal.
  4. Lay the metal in place and set something heavy on it leaving a couple corners exposed (this can be removed after you get a couple rivets in place).
  5. Drill holes thru the metal and car.
  6. Insert pop rivet.
  7. Do this is multiple spots.

Disclaimer: this is a cheap temporary fix that is not intended to be the "correct way" of repairing this type of body damage.

  • Nice answer. I would recommend spray on wax as some sort of sealant/rust protection
    – Martin
    Dec 21, 2017 at 21:49

You can fix that by removing the remaining rusted metal, and welding some new steel there. There's really no other way if you live in an area with mandatory yearly car inspections. Try to patch the hole using a simpler way, and you soon find yourself with a failed mandatory inspection.

Welding isn't expensive. If you don't have the required skills, you can find some cheap garage somewhere to do the welding. Of course, a proper welding job would include very careful rust protection, but since you're having a beater car, you can skip on the rust protection. Of course then you can find yourself with the same problem a year or two later.

  • 5
    In some countries, if the metal is not within 30cm of a load bearing or suspension point it won't necessarily cause a fail. So could be repaired by removing the rusted stuff and sealing with fibre glass and resin.
    – Solar Mike
    Dec 21, 2017 at 21:13

If you are not worried about appearances (or failing a vehicle inspection) and the main goal is just to prevent further rusting and closing the hole:

  • Remove the rust as much as possible (wire brush, maybe cut of the worst bits with a angle grinder or hacksaw).
  • Dab some rust-stopper/sealant over it to stop further corrosion. (Some leftover Hammerite from another job will do as well.)
  • Tape over the hole with duct-tape or gaffer tape. The aluminum tape used for heating pipes and the like (if you have some) would be even better. 2 layers of tape, at angles to each other should do the trick. If the underside of the car is easily accessible apply a tape patch on the outside too.
  • If you are worried about animals gnawing through the tape put a piece of chicken wire or other fine metal mesh under the tape.
  • Last but not least: You've got moisture collecting at the lowest point of the booth and that is what causing the rust: If you can't find/seal the leak at least punch a couple of small holes in the tape-patch so any new moisture has a way of draining out.

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