I have some bare aluminum spots on my lower hull. I am painting with schilling shedding paint. Where do I get the items to prep the bare spots?

Hello---I'm new to the forum. Have a 32' express that I'm currently (and endlessly) working on. Stripping the bottom paint. Jeff mentioned a "pure etchant" before the prime wash. Is there a brand name? Is it the same as phosphoric acid?

I have used alodine successfully above the waterline, and I have used Petit Metal Primer Pack 6455 below the water line, both with good results. After prep, I have used both Interlux Primocon and Interlux Interprotect 2000, with good results. I think that I prefer the 2000, and will likely use that next time I have the hull stripped and painted.

Thanks ---the biggest problem is that the sanding and stripping has taken a LONG time, so the oxidation has been present for a while on the areas I started first. When it is fully stripped I'll post a picture.

Joel is spot on. You MUST acid etch before applying the epoxy or it will fall off. That aluminum oxide film is a lubricant.

Jeff

Bill...first the easy part: You are right, it's the center disc that is sensitive. But I covered the whole thing because I didn't wanted the embossed letters "Do Not Paint" blasted smooth. A pie plate overcoated with masking tape did the trick. Used the same kind of protection for a depth finder surface and something else that I can't remember. I also taped the bootystripe myself to make sure it was done right.

I think Interprotect is the stuff to use. It's supposed to go onto a clean surface. They airblasted (just plain air under pressure) mine after the bottom was stripped. And, I would wipe it down with a recommended solvent to get all the dust off. check my how-to post from about 4 years ago. If you have the least uncertainty about which etchant/first coat to use, call the mfr..don't rely on us geniuses. It's too important for a costly job like you have undertaken. Pls let us know how much speed gain you enjoy from your new smooth bottom and good luck with the project.

Well, the sand blasting was completed on Saturday and the first coat of Interprotect was (feverishly, but thoroughly ) applied. It was rolled on and it took a bit longer to apply because of the pitting that I knew was there (had been painted over by someone in the past [and some pits are pretty deep]). Next process will to be to apply PC-11 marine epoxy to fill in the pitting. This, I believe will make the application of the subsequent coats a lot easier and go faster.

The one thing that had me initially perplexed was that the Interprotect 2000 shows a 3 to 1 ratio of paint to activator. Having not used the product before and the paint showing as a "1 gallon" I wondered... "Well, if there are 4 quarts to a gallon and there's a 1 qt activator with the kit, that means I'll have a quart left over?!? [3 qts paint to 1 qt activator]". Opening the paint can answered that question: The VOLUME of the can is 1 gallon, but the AMOUNT of paint is 3 qts. This would allow the purchaser to mix (carefully) the full quart activator in to the semi-full 1 gallon paint can.
NOTE - You will want to use a 5 qt pail for the 1st coat mixing. This is to allow for 19.2 oz of thinning agent to be added to a full gallon of paint (15%).

Disclaimer....
The following section is made without benefit of any libation or brewski. Comments made should be taken with the application of a minute amount of sodium chloride....

Joel...
I'm not sure how much speed I'll pick up. With gas prices as they are, or may go up to... I'm thinking of using a new type of bottom paint: ... HeliumH2 ... It's intent/use is to lighten the boat which will help it move through the water with minimal effort.


Bill