Door frame rust

[james gevay]

Here's a couple of photos of what I found under the door channel. I knew Pipers had problems with this sort of thing and I wanted to check to see what was under my frame. I used a Dremel tool with a cutoff wheel to carefully cut the tack welds. This is just surface rust with no pitting but any rust is not good. I assume there was never any rust protection from the factory. I now have epoxy primer on everything, but will need to have the channel welded back on. I'll have to grind or sand the paint off the weld area and I think TIG welding would be best. I think this would be an area to check if your doing a restoration on your plane.

[MikeB]

I've ran into that too. The big trick is how to weld the channel back on without burning all the new paint off. I guess some type (TIG, as you described) of low heat welding would be best, but it is a problem and still burns some of the protection.

Anyone have another idea?

Mike

[Carl Prather]

The is something called weld-through primer but I have never heard of anyone using this stuff on airplanes. Depending how and where the channel is welded, one might mask off just the area actaully is welded leaving this heat resistant paint surrounding the weld area and primer the rest of the frame as needed using more "conventional" paint.

Just a thought.

Carl Prather

[DELCOM]

When I was at this point in my restoration, I removed the welded in channel, cleaned and epoxy primed the area, and then gas welded the channel back into place using the same process that was originally used. This did indeed cause burning of the newly primed area. After the welding I reprimed the area again both on the outer surface and underside as best i could and called it good. I found that I was able to re-shoot the primer under the channel pretty well and was satisfied with the results. Not perfect but at least this area now has epoxy priner under it. My rust appeared to be very simular to yours.

[Bill Bussel]

Mike, and All,
I am passing this along, from another restoration thread concerning a Piper Colt. The fellow welded the door channel back on after painting and after the welding, he then made a "cone shaped nozzle for a grease gun. He then put the narrow nose of the grease gun at the top and forced silicone chalking the length of the channel. I have never tried this but it sounds as though it would stop all further corrosion.
Bill