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Bondo then paint?

GeorgeRodney's picture

My newly purchased, 16 year old, stucco home is showing rusty nails through the paint in the exterior window trim. A professional painter has told me that these (not countersunk, not finishing nails) and some areas of rotty wood, can be covered in bondo. However, I was sure that I once read in FineHomebuilding that this would not be appropriate. I have always heard that 'rust never sleeps'.    How should I remove all rust and what product should I use to replace some small areas of rot? I know that there is an epoxy product on the market for wood restoration - but I was recently reading a post regarding checking in a weathered exterior window sill and the owner was advised to fill the checking only and leave no product on the surface as moisture would be trapped underneath. Help!

George (post #192106, reply #1 of 2)

I have successfully repaired wood trim using epoxy.  The post about trapping moisture with epoxy might be correct.  However, what does a good coat of paint do?

You need to take care of moisture coming from the inside that would push off epoxy and paint.  Once that is taken care of (and it was probably the cause for the rot in the first place), you can make a decent repair w/o cutting out a pc of trim and installing a dutchman.

Remove (dig/drill/cut out) all soft punky wood.  Use a Hardener to firm up what's left.  Apply epoxy, sand and paint.  If areas are deep I use a fill of PVC scraps leftover from azek trim.  Pack some epoxy, insert into that appropriately sized pcs of pvc.  Keep building up in that manner till close to the finished surface.  Final coat of epoxy.

Rusty nails are also an indication of interior moisture-the nails will often be rusted off deep in the wood.  It helps in the continuation of the rot in the wood.............that is, you'll find more punk around nails.  Chicken / Egg thing-what caused the rust-moisture/same for the rot.  Don't know if both contribute to each others demise.

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For simple rusty nails, (post #192106, reply #2 of 2)

For simple rusty nails, scrape off loose paint, sink the nails as best you can, then dab on a rust-converting primer like Extend (2 coats, per directions).  When dry, prime with alkyd primer and paint.

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