1976 jet boat restoration

[Jpostal]

Last week I stopped by a new customers house to take a look at his boat...it was built in 1976 and appeared to be in reasonable condition with "minor" oxidization on the top side of the boat. I don't have a lot of experience with boats but I have polished about 5 in the last few months. With every other boat I have done a wool pad with M105 or similar is enough to take care of the oxidization, but with this boat my most aggressive pad/polish combo on my Makita didn't even put a dent in the gelcoat. I was about to throw in the towel but just for fun I decided to wet sand the back end of the boat. Fortunately wet sanding made the finish shine like new but my concern now is will it last? The owner of the boat wants me to come back and sand out the rest of the boat but I'm not sure I want to spend a day sanding it out if the gel coat will oxidize again within a few months.



Does anybody with gel coat wet sanding experience know what to expect with this? Should the results last? What would be the best product to seal it off? I have Flagship marine wax, the Klasse twins, and a few other automotive waxes.

 

[Greg Nichols]

If you do this job, charge by the hour 30$+ it is a ton of work. Get a PC with a flex backing plate and use a squirt bottle to lube the gel coat and then sand. Unless you really remove the oxidate it will return. Test your sanded area with a strong dawn wash and see what happens? Its hard to tell, but maybe the "oxidation" is hidden by water scale, also try a 1:3 muratic acid rinse and water, if the surface bubbles likely lots of hard water scale, that may hinder the polishing, strong vinegar might also tell. Tell the client you cant guarantee the oxidation will not return, but a dried out gel coat can be helped by Megs #81/#3 IME, allow for lots of dwell time and apply several times, then coat with megs flagship.



Cheers,

GREG

 

[Jpostal]

Thanks for the feedback Greg. Would an IPA wipe be a suitable replacement for washing with Dawn?



My quote is $40 an hour plus materials and my best guess would be 8 hours above the rub rail to sand/compound/polish/wax. I have a PC and will be trying to source hook and loop sanding discs tomorrow. If I cant find hook and loop discs would the 3M stickit discs work? I was going through some of my boxes of supplies that I bought from a detail shop that was going out of business and I found a bunch of 3M P1200 "Production Resin Bond Pre-Cut Film" sanding discs that appear to stick on to a backing plate. If these will not work, would 1000 grit be a good place to start?

 

[Greg Nichols]

any thing that will remove the oils so you can see exactly how the polishing is coming along, once you find the point you like then add back in the oils with megs 3/81.



Don't limit yourself to hours, these jobs are best if the clock just ticks. Remember 105 and wool will remove 1200/1500 sanding marks, so you might have to two step sand the finer you can finish sand the better on gels, 105 will then finish out the process mostlikely.



Cheers,

GREG

 

[Jpostal]

Thanks again for the help Greg.



My local auto body supply store only carries Norton brand sanding discs so I picked up a pack of 1500 grit 6" pads (1500 was the coarsest grit they stocked in the 6" discs). On the heavily oxidized areas I guess I could use 1000 grit paper by hand and finish out with the 1500 grit via DA. I'll try take some pictures of the job when I do it on Saturday.

 

[Jpostal]

I did the job today. 70% of the boat came out really nice, but the front end was another story. I spent half my time working on the front end and it still had the appearance of oxidization in some areas. There are a lot of body lines and ridges on this boat so getting the sander and polisher in tight was a challenge.



My process was as follows...



Wet sand by hand with 1000 grit

Wet sand via DA with 1500 grit

Cut polish with M105 or Autoglym 02B on wool pad with Makita

Polish with M205 on orange pad with PC

Megs #3 via white LC pad with Makita

Megs Flagship wax hand applied



Just wondering if I should have started with a lower grit paper...I'm not real sure how aggressive you can get on gel coat. I've never had a problem with hand sanding using 1000 grit. Maybe 800 would be a better choice???