Factory sealant on riveted aluminum boats?

[FL2AK]

Do riveted aluminum boats come from the factory with sealant between the sheets of aluminum where they overlap at the rivet lines?

I'm using paint stripper to remove old paint to bare metal in the floor of my Grumman Sport Boat, and I'm using so much that I'm starting to worry that, if any chemical gets between the aluminum sheets, I'm going to have serious water leakage issues.

So far, I've used 3 quarts of StripKleen KS3 (that "super strong" gel that only comes in qts @ $9/qt.-it's really not that "super strong"). That isn't getting the job done to my satisfaction, so I'm about to buy a gallon of the "Aircraft Stripper." I'm afraid of going too far and essentially ruining the boat.

 

[Bob_VT]

Re: Factory sealant on riveted aluminum boats?

Are you going to polish the hull? There is no need to completely strip the hull and if you expose bare aluminum you will have to properly prep the surface for paint by using zinc chromate. The stripper should not be left on the seams and yes there is a factory sealant.

If you are concerned then you should apply gluvit to all the seams and rivets before you re-paint and gluvit is best applied on the inside of the hull.

Hundreds of people have re-painted aluminum hulls and just prepping the old paint by scuffing it up with 220 grit is all that is needed.

Completely stripping is only creating more work and will require more prep to properly paint. read this post. http://forums.iboats.com/boat-restoration-building-hull-repair/steps-prep-aluminuim-pics-457159.html

iboats sells the zinc chromate primer here Moeller Zinc Primers

 

[FL2AK]

Re: Factory sealant on riveted aluminum boats?

There was not going to be a way to "prep the old paint" on the inside of this boat. All but a narrow strip, about a foot wide, down the center line was flaking, peeling, or already gone-way beyond the condition of anything salvageable. Complete removal was necessary in order to be able to repaint with any degree of durability on the new paint. In addition, the previous color was a rather dark gray, and I need to repaint with a rather light tan, so hiding the previous dark paint with the new light colored paint was going to be a challenge.

The outside of the hull, however, is a very different story. The boa's original owner (or someone at some point) did a very good job of prepping and using a self-etching primer prior to painting. That paint continues to adhere very well, and I plan to only sand with a palm sander before repainting it with the same color tan as the interior. There are some very small areas that will require fresh primer, but those can be managed with sandpaper and a rattle can of self-etching, chromate primer. (NAPA sells a product for about $14 per can.)

Thank you for the suggestion of using the gluvit product-I had never heard of it before. Spendy, but if it works, it works. Once I get all the paint off, but before I repaint, I'm going to put the boat in the water, and check for leaks, and then go from there.

 

[FL2AK]

Re: Factory sealant on riveted aluminum boats?

read this post. http://forums.iboats.com/boat-restoration-building-hull-repair/steps-prep-aluminuim-pics-457159.html

Thanks for the link. Interesting enough, that discussion centers on Alumaprep 33 and Alodine, which are standard products in the aviation industry. I was an A&P (aircraft mechanic) most of my adult life, and have used those products a lot. I may have some out in the garage. However, in my experience, Alodine has not lent itself well to painting. Applying the zinc chromate over a surface prepared with the Alumaprep has given me better results in the past.