I have had problems with rust staining around the stanchions and the end fittings of the canvas cover frames on every boat I have owned. The tube and stanchion sockets hold water and being stainless the ends of the tube and the socket are deprived of oxygen which can accelerate the crevice corrosion.
The use of acid specifically designed to remove the rust and tea staining from stainless does work well. However the down side to the use of acid is that I needed to spend a great deal of time spraying rinse water into the fittings to flush any remaining acid from the fitting. This in its self wasn’t easy and usually meant I got wet and used a great deal of water in the process. If I didn’t spend the time and use a lot of rinse water the end result was that an acid and rust mixture would slowly weep down the side of the socket and crystallize. I did find that even after flushing the sockets as best I could with fresh water the rust would reappear in a short time.
I think there are a couple of options to remedy the problem. The first would be to weld the end caps on to the poles; this could be a costly exercise paying a welder by the hour to complete the job. The other question is how to get the parts to the welding shop. A further draw back I see is if the poles and fitting have been in use for some time the micro pores of rust present where the welds are to go may cause problems getting a decent clean weld. I finally settled on drilling a small 2.5 mm drain hole in the base of the end caps that can retain water. Removing the grub screw that retains the end cap on the awning bows can be near on impossible as these become locked.
I don’t have any reason to separate the parts to drill the drain holes. With care I have been able to drill the small drain holes with most of the awnings and covers still in place by just dismantling one part at a time. I found a high cobalt drill bit makes the job easier as it retains a sharp cutting edge for longer when drilling stainless steel.
|After, cleaned and hole drilled.|