Bottom Paint Job

[DiverDennis]

We (wife and I) did a complete bottom job in 2006 on our 'new' 1975 28' Marinette Express (aluminum) trailer boat, Surface Interval. It really needed it and I wanted to know if any corrosion was hiding under the many coats of paint. Thought you might enjoy reading about how we did it.
Bought 4 new Brownell boat stands (WM) and two 6 ton hydraulic bottle jacks. The boat sits on a level concrete floor in our pole barn. The first thing was to get the trailer out from under the boat using, what I would call, a 'block and inch' method. We lowered the trailer tongue jack so it was down to the floor, placed boat stands under the stern and chained them together, cranked it back up as high as it would go and positioned a bottle jack under the forward keel. Then we raised the stands and jack so the boat was off the trailer a couple of inches. For safety the aft keel was blocked. (see photo gallery) http://s277.photobucket.com/user/DiverD ... JOB%202006

Pulled the trailer up until a cross member was against the bottle jack, put another bottle jack on the other side and raised the boat to get the first jack out. We continued to alternately swap them to allow clearance of the cross members until the whole trailer was clear. Then the other two stands were set amidships and more blocks were put under the keel. Most of the weight was on the blocks and the stands were for stability.
Removed all the zincs. Started with a orbital sander hooked up to the ShopVac but it was WAY to slow. Used a air chistle with the corners rounded to help prevent gouging. Too hard on the arms and slow. Went to Lowe's and got 3 gallons of Jasco Paint Stripper. It's $30/gal but this stuff works! You just brush it on and scrape it off. It was a REAL messy job but we got it done in five weeks.

Nice things about the paste stripper:
1.semi-paste: apply with brush
2.works in cold weather >35*
3.fast acting - scrape off after 5-10 minutes or
4.wipe or spray off with hose
5.Non-Flammable

After all the paint was off, the entire surface was sanded to shiny, cleaned with metal prep, (http://www.sherwin-automotive.com/media ... h/5103.pdf) and coated with etch immediately. Then, primed with 3 coats Interlux Interprotect 2000E, finished with 2 coats of Trilux 33. All done with Shur-Line Woven Microfiber Plus Roller Covers.

We let the paint dry for 2 weeks before bringing the trailer back in.
Won't have to do another FULL bottom paint job ever again. Whew.

[newendeavor]

Anybody have any experience using Belzonia as a Bottom paint rather then TriLux. I've heard it requires little prep and is its own Barrier coat. I tried a Rustoleum epoxy 2 years ago and it held up well and did a good job as a Barrier coat. But my boat was covered with Zebra mussels ( Ohio River) and reduces my drag. My top end was down 5-7 mph.

[jralbert]

Not sure what you mean by barrier coat. The first coat between hull and the outer bottom coat? What was the final coat that didn't stop the zebra mussels (they are tough to control, I've have heard)? If you used only a primer, then you weren't protected. But I suspect you used something on top of the Rustoleum and just forgot to name it. I know Trilux is an expensive brand but on the Chesapeake Bay in brackish water it does well against barnacles. If your top end of 15-20 mph is down by the amount you report, that's a huge waste of gas - about 33%. A paint that gets you a smooth bottom will easily pay for itself in fuel savings.

Here's an idea: Coat a surface with different kinds of paint, keep it under water for a while and see which one works best for you. Report the results here. A paint mfr might send you a sample or other forum users might help here with a small bottle of their favorite brand.

I did this ten years ago to see whether the Z-O No Foul to which I had switched was still performing better than Trilux. The results were dramatic: Trilux outperformed against algae/slime/barnacles by far. Some of the oldtimers on this forum will remember the posts. Results could be different in your Ohio River fresh water setting with zebra mussels as the main threat. All the advertising claims in the world, as some might say, don't mean sxxx.

[Maestro]

Dennis,

What was your method for sanding the chines and weld seams? Seems like this would be tricky with an orbital sander.

What grit did you use for sanding the aluminum to shiny?

[TinLizzy]

When etching the hull, is this a spray on etching primer? Or a is it something you wipe on with a rag. I have to do some touch ups this year and have the interprotect and bottom paint, but not sure what the etching process is.

[Maestro]

For touch-ups, I used an etching kit made by West System:

http://www.jamestowndistributors.com/us ... ?pid=12214

It's a two part deal. You brush part 1 on the bare metal, rinse it off with water, and then do part 2. With this little kit, you don't have to mix or dilute anything. Just follow the instructions on the bottle. I brushed both parts on with a cheap foam brush.

I used this last year to touch up several little bare spots and it worked great. The new primer and paint held very well.

[DiverDennis]

Dennis,

What was your method for sanding the chines and weld seams? Seems like this would be tricky with an orbital sander.

What grit did you use for sanding the aluminum to shiny?

Jasco paint stripper and 80 grit by hand.

[DiverDennis]

I have to do some touch ups this year and have the interprotect and bottom paint, but not sure what the etching process is.

Sandblast or grind to bright metal finish. Remove all blasting/grinding/sanding residues with a clean air line and sweep with a clean brush or broom. (Vacuum clean for best results.) Immediately apply Viny-Lux Primewash 353/354 thinned 25 percent with Viny-Lux Solvent 355.
http://www.wholesalemarine.com/blog/201 ... al-primer/