Monday, November 26, 2007

POR-15 Rear Window Area

Yesterday I set out to treat the area around the rear window opening with POR-15. The bottom and sides. I'll do the top when I do the rest of the interior roof. This is in preparation for welding in the new section between the bottom of the window and the forward edge of the trunk.

The flange that the window sits on consists of two or three layers of sheetmetal spot welded together. Along the right vertical joint (the C-pillar) the gap is filled with lead, but along the bottom and left side there are many gaps.

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The first task was to remove the old paint and what little loose rust was present. For this I used a die grinder and at first a synthetic wire wheel followed by a real wire wheel. After blowing all the dust away I washed the area with Marine-Clean, and when that was dry I brushed on a coat of Metal-Ready. The instructions said to keep the area wet for fifteen minutes so I kept going around and around.

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Up to this point everything worked fine, but here is where I ran into the problem I was concerned about. I gave the Metal-Ready coat an hour to dry, and after an hour it was still tacky. I had to call it a day without applying any POR-15.

The shop is closed Mondays and Tuesdays, so it will be Wednesday before I can even attempt to apply a coat of POR-15. This area deserves two coats, which means going again on Thursday.

Painting projects are difficult for this reason, especially when you only have one day a week to work on them. Surface prep takes a long time, and waiting for something to dry chews up big chunks of valuable time. maybe a hair dryer would help.

Update: Pics to show how POR-15 turned out. First two show zinc (white splotches) where Metal-Ready converted rust, before applying POR-15. The rest show treated area. POR-15 brushed on easily.

This job used no more than half of the very small can of POR-15 that came in the starter kit. I poured it out into a clean soup can. After I was done I did not bother to clean up, just tossed the tin can and brush.

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1 comment:

Anonymous said...

Hi Gary,

I live up in New England where the winter definitely shortens the time you can work on your coupe (especially painting). I've use Por-15 extensively for rust repairs and what I've found to be helpful is the use of a heatgun to dry out the metal before I paint it.

Where ever possible, I use the heat gun to "cook" the metal, not red hot, but at least hot enough to dry up any remaining moisture from from the metal prep process.

I've read that leaving behind any traces of moisture on bare metal and then painting over it is a perfect way for more rust to form, even in small amounts.

I'm no chemist, but it seems to make sense. It's worked for me, so I'm just throwing it out there.