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Auto body repair & detailing/Rear wheel well rot and holes


First I was wondering how long a can of body filler will last in terms or yrs. I have a can quite a few yrs old that has been sealed tight, and when I opened it, it seems thick and liquid is at bottom. Would just mixing it up salvage it?

Second, I bought a 99 Buick Lesabre that is in relatively good shape for age and 115,000 miles. Problem is a rot/rust hole in the top of Right Rear inner wheel well. I noticed water entering trunk and into back floor also. It is thru well on both sides of shock tower, but the heavy main plate attached to tower although rusted, still seems pretty thick and is only rusted in well side area itself.

I have already gained access to problem thru trunk and back seat.
I have ground and sanded area, and applied Permatex rust stop.
Will the use of self adhering screen and body filler on both sides of hole be a sufficient repair to stop water entry for a few more yrs? I was also going to primer it and spray a good amount of rubberized under body coating as possible inside wheel well.

What temp should I be working in for body filler to cure properly, I have car in a garage, but it is not heated unfortunately. How long after filler is applied will I be able to prime and undercoat it.

Does this sound like it will work for this repair, as it is hidden in and out, not really cosmetic, and doesn't need a lot of sanding to be perfect. I just need to fix as cheap as possible as I'm on limited income and need the car.

I was thinking of riveting a piece of sheet metal after body filler was applied and then priming and under coating, but not sure I should.

Would the self stick rubberized sealer that the factory uses be a possible repair or use in this situation?

Your thought's and advice on this would be greatly appreciated.

Thank You,

Hi Ian!....In regards to your first question, most plastic body fillers use a polyester resin that acts as a binder between the talc filler and solvents, so over time, these components will separate. This is normal. As a guideline for myself, I generally wouldn't use a body filler over 1 year old. The reason is due to the unfortunate fact, that no matter how well the can is sealed, solvents will escape and resins will eventually become ineffective. Each component should have the proper ratio in quantity to be effective for curing and sanding purposes. That being said, (and that your application is not as critical as an exterior repair), what you can do, is to mix it up as thoroughly as possible, take 1 or 2 ounces out of the can, add the hardener, then see if it will properly cure. If it does cure, then you should have no problem using it for your intended repair. (I will give you my thoughts/recommendations as to why I would not use filler in your specific application later). As for working temperature, the best results are at room temperature (72 Degrees). A slightly cooler temperature, will just take the filler a little longer to cure, as heat is how a filler is cured by.

As for your repair so far, you are definitely on the right track. As long as the structural shock towers and components only have surface rust, the rust can safely be sanded or ground off, and then be coated or sprayed with a rust inhibiting undercoating compound.

In regards to repairing a hole in the inner wheel well, although welding in a patch is the recommended method of repair, the next best method, would be to glue in a metal patch. Glues for metal repair are available through the 3M and Norton companies, and are available at most Autobody/Parts retail outlets. That being said, in your specific application and conditions, I would recommend a repair such as this: First, grind/sand away all existing rust around where you need to install the patch on the inner wheel well, and apply a rust inhibitor to all bare metal. Next, cut a metal patch to size, then rivet it into place. After this is done, the surrounding perimeter/edges and rivet heads should be sealed with a seam sealer to prevent water from penetrating. Seams sealers are available at most Autobody/Parts retail outlets also, and are relatively inexpensive. Lastly, coat the repaired area with a rust inhibiting undercoating. In regards as to why I would not recommend using a filler in this situation, it is because a filler absorbs water/moisture. Being in a wheel well, it is prone to rocks and road debris being kicked up inside, therefore having the chance of it being exposed easily.

Hope this helps you out Ian....If there is anything that I missed, or anything else that I can help you out with, please feel free to write me back anytime...Thanks....Dave  

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Dave Norgardt


Absolutely anything autobody related... Frame repair, suspension, alignment, panel replacement, panel repair, fiberglass, plastic repair, paint, air bags, etc.....


Over 30 years in related areas. 25 years in HEAVY frame repair, suspension, and alignment procedures. As well as panel replacement and repairs, etc.....

Journeyman Autobody Technician with Red Seal/Interprovincial certification from N.A.I.T. in Edmonton, Alberta, Canada. Top Achiever award second year, also from N.A.I.T. Also have Platinum status from I-Car Canada...Also have Journeyman Partsman Certificate, Lethbridge, Alberta...

Awards and Honors
Second Year Top Achiever from N.A.I.T.Edmonton

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