Coat-it on the DB - acid treat or not?

[PacificCoastSteel]

doing the DB's first new coat of coat-it and the can says to use phosphoric acid to treat the aluminum before applying the coat-it...

i got a bottle of OSPHO which contains phosphoric and dichromate... i did a test patch of the OSPHO yesterday and applied a test patch of coat-it over it this morning... will be able to tell tomorrow or later today if its taking ok...


my question is this - those of you who have used coat-it (not gluvit) on your boat:
1. did you use a phosphoric acid?
2. did you use OSPHO?
3. if you went straight on top of sanded aluminum with no acid, how has the coat-it lasted for you?

thanks

PCS

[deepsix]

I used it straight on top of sanded aluminum. It lasted OK but is now coming off in sheets. I crab in the bays and really don't think I will be putting it back on. Once cracked the salt water gets under it and is trapped next to the aluminum. It will eventually develop a pitted hole unless the salt water is removed. I'm not so sure bottom coatings are worth the cost and effort on any boat that sees salt water.