Roof coatings revisited

[belfert]

I think I'm going to hold off for now at least on doing any roof coating.  I might do it later this summer.  I took a look at the roof today and I was able to identify the main sources of water intrusion.  There is a crack in the rear fiberglass cap that I had caulked a few years back, but the caulk is totally gone now.  There was a huge pool of water inside in the rear and I'm certain one of the rear marker lights is leaking.

I've read about folks doing bed liner on the roof, but I imagine it isn't cheap.  A bed liner for a truck is close to $500.

[Gordie Allen]

I'm close to doing my roof ('56 4104).  I'm palm sanding all the paint down to the green primer or bare metal.  If you use stripper, you must get down to bare metal or you'll have weakened primer remaining.  The original green primer on aluminum is ultra-durable.  I'll green prime it, then use one part automotive seam sealer along all panel seams, finger wiping smooth to about 1/4" wide.  This seam sealer is sand-able and paint-able, but remains slightly flexible.  I'm then painting the entire roof with bright white commercial aircraft paint which is designed for the rigors of expanding and contracting riveted aluminum panels and sitting on the tarmac 24/7/365.  Friend who is helping me painted planes 8 years for Duncan Aviation - a high-end aircraft conversion / restoration company.  Roof will cost about $450 in materials.  I figure applying more layers of non-compatible coating on degraded existing surface is just not a good idea.  The best sealer in the world won't work if applied over degraded, pealing or otherwise leaking substrate.

[belfert]

I decided I do need to put on a roof coating after all.  I had a heck of time finding any good roof coatings actually in stock at any local stores here in Minneapolis so I ordered two buckets from Lowe's that should be at the store in a week.  I guess we don't have that many flat roofs here so nobody carries the good roof coatings in stock.

I didn't realize the coatings don't want to be applied two hours before sunset so I need to wait until a weekend to do it.  It will be raining this weekend so it doesn't matter if I can't get the product right away.  I'm hoping it will be nice the next weekend so I can at least get one coat on.