I am about to have the bottom blasted to bare metal for the first time in the boat's 20 year life. There are at least 20+ coats of stuff on there now. The surface is ragged and ugly looking. Who knows if that translates into speed or fuel use, so the re-paint seems logical. After all, we aren't motoring very far this year at today's fuel prices.

Here is the paint mfr's recommended process.

- Wipe the hull w/202 solvent to get rid of grease et al that could be driven to the surface by blasting. Make sure your Capac probe and thru-hull transducers and any other places you don't want blasted are adequately masked. I plan to tape a pie plate section over my Capac and transducers. Perhaps, the water intakes as well should be taped off.

- Sand blast w/80 grit or lower to get a "better profile". (I will probably go with soda blasting because that appears to be what is locally available - the factory prefers sand as noted but the marina thinks soda will work OK. Incidentally, the marina will sub out the work to an experienced "blaster" with whom I have spoken and who has done half a dozen M's and IU have confidence in the marina painter's judgment)

- Brush, air blast, or vacuum off the residue. Don't, the factory cautions, wipe down with rags because fibers will be pulled out of the rags and will show thru the finish and be "ugly!"

- Quickly, go to Vinyl Lux Prime Wash, 1 coat thinned 25% with 355 solvent. Critical: this step must be done within no more than a few hours of sandblasting so the aluminum does not oxidize. Aluminum oxidizes rapidly, adding a thin protective coat to keep itself from rusting which is the beauty of aluminum and the curse of painting. This should take about 1 gal of the Prime Wash. The Prime Wash should be allowed to dry for one hour minimum, but no more than 24 hours before going to the next step.

- Apply 4 coats of Interprotect 2000E. Four coats will take about 6 gals. Minimum 40-degrees ambient air temp. Allow a minimum of 5 hrs drying time or use the "thumb print test". That is, press your thumb onto the painted surface and if you leave a print but get no paint on your thumb, the paint is ready for another application. After the first coat of Interprotect you can relax because the aluminum has been sealed. Whew! You can wait up to 6 months, says Interlux, between coats. But when you are ready to apply the final bottom paint coats, see the next step.

- Between the last coat of Interprotect and the first coat of Trilux (if you are using another brand such as ePaint or Kolor, check those paint mfrs for recommendations) you have a tight window. Again a minimum wait of 5 hours or the thumb test noted above...and a maximum wait of 9 hours before the Trilux goes on. This means that the last coat of Interprotect and the first coat of Trilux should be done on the same day. The mfr rep explained that the Interprotect must still be curing to grab the Trilux, that's why the max 9 hour window is specified. Obviously, if the weather is really warm, you may not want to wait the full 9 hours.

- Home stretch. Three coats of Trilux which, for a 32 foot boat should take 2.5 gals. Follow paint can recommendations for time between coats. With luck, next year you should be able to apply a single coat after a light sanding. I plan to make the final coat a different color so wear will be obvious.

When this is done I will post some before and after pix.

Excellent procedure. I did one thing different: Knowing I couldn't get the vinyl wash primer on in time, I used a pure etchant first, then hosed it off. Nasty stuff, but you'll know it's working.

Jeff

When spraying pure etchant on bare metal, always read the directions which say to dillute it with water. Otherwise, the odors coming off the hull are overpowering?

Right, John S?

Hah!

Jeff

Elsewhere in the forum I have posted some pics of my hull in the various stages.

I don't know why, either, since Primacon is used on running gear I would think that it would be fine for the hull. Doesn't matter now, water under the keel and all, and I hope it's a few years before I revisit that problem.

IAW is "In Accordance With" and is a common abbreviation in NASAland - I don't do text messaging. I guess it's not in such common use, I'll try to avoid BTW and FIGMO as well. Not to mention FUBAR.

Yeah, I was at Patrick Air Force Base in '67 supporting an instrument package on a U-2, as part of the Arthur D. Little Meteorological Research group. Most of the weather of interest to us was over an island just south of the Florida Peninsula. I was with a group of beer-drinkers on the end of the jetty at Jetty Park in Cape Canaveral and watched the Apollo 6 launch. My first thought was, with this going on here, what the **** am I doing living in Cambridge, Massachusetts?

It took me until '75 to get back to Cocoa Beach full time, but I lived there and worked at the Rocket Ranch for over 30 years. My boat is still at a marina on Merritt Island, just off the road that leads south from the space center.

I worked on Polaris, Poseidon, Trident (Navy programs) and in Payload Processing for the shuttle, many payloads, then on the expendable Delta, launching the first tier of GPS satellites. I moved to Spaceport Florida, a state agency, and ran some small launches, including one out of Santiago Ixquintla, Mexico, during the total solar eclipse in '91. I was project manager for the construction of a facility in North Florida which is (was) used to store the solid rocket boosters for Titan. I did software consulting for quite a while, but after reading all the postings by MarinetteJoe I realize that that industry has passed me by -- my CS degree was back in '80.

Would I waste my life on rockets again? Damn straight.

Bottom overhaul update:

Someone is looking down over us -- the soda (not really) blaster cleaned Charlie B's belly today. It was about an 8 hour job for two guys that included tenting the boat, blasting, and cleanup. Cost will be about $1,300. Bill to come.

The really good news: there is no corrosion anywhere on the bottom...clean as baby's rear. That's pretty good for a 20 year old boat. The cleanup squad departed around 5pm. I pitched in to do some taping and then the marina sprayed on the first Interlux barrier coat, Vinylux Primewash, finishing around 6:30pm. Tomorrow, the first of four barrier coats of Interprotect 2000E goes on. There may be multiple applications if the weather stays on the warm side.

I thought baking soda was to be used but it turns out that the abrasive was ground recycled glass. It left a relatively but not too smooth surface, one with some texture for the paint to cling to.

RR:
You posted just as I was trying to figure out how to insert some photos to illustrate the sandblast project.
- The paint amounts for my '32 were calculated by the Interlux tech. Their web site has the info but you really have to read thru a lot to scope it out. The 5 minute phone conversation was extremely useful. It took him seconds to calculate the paint required.
- I just painted the bottom, waterline down.
- Sorry, no info on topsides. But do what I did and call the mfr. You'll probably want to go with Imron or Awlgrip - perhaps a different product. You might send them a photo of your boat or a similar model to help them calculate better since every watercraft model may take differing paint amounts, more or less.

My take on these projects is to listen carefully to the mfr for best results. Good luck on the repaint. I had topside done 9 yrs ago, negotiated a flat price so never inquired about paint amts/

Cool photos Thanks,

Gives me an idea: Maybe the first Marinette Hovercraft!?!?

great pics...

what did the $1300 include??? ..i'm thinking of doing this next year and want to get an idea!

thanks!

ok...well shoot me a pm when you get the full bill so i know what i'm looking at...i'm probably going to be doing the entire hull, so i'm thinking it will probably be double what ever yours comes out at.