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To wet sand or not?


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I have a 2001 Sunsetter VLX with a white hull (excluding accent stripes).  I have waxed it religiously at least 2x per year, it is store inside, but it spends many full summer weekends on the water over its 20 years.

The gelcoat is in excellent shape, but the top of the gunnels have been showing some yellowing over the past few years.  I've tried taking a buffer to them with some fiberglass compound, (3m medium cut), but have not had much luck getting the yellow out.  (In many places it is hard to get very aggressive with the buffer due to the upholstery coming right up to the inside edge, and the rails on the bow of the boat.

I'm wondering if I should consider taking some 600 or 1200 wet sandpaper to the gelcoat or should I continue working with a buffer?  What does the crew think?  I think I would be able to do a more detailed job around obstacles since all sanding would be by hand.  I think I've heard that wet sanding should be the last resort.

I'd love to hear some opinions, or even other options.




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I'm in the same boat - literally speaking (well, except I have an RLX). I've found course rubbing compound followed by fine compound seems to work, but labour intensive.  And as you say, some areas are really hard to reach.  So for now, I just attack a small bit when the mood strikes me. I've also found that even though it does not appear to be visible, Meguiar's Oxidation Remover makes a big diff to white (opal).  FWIW, I'd say 600 is really aggressive.  Don't forget that if you are sanding colours, they can be 1/3 or  or 1/4 of the white gel thickness.

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I'd be curious is FSR or toilet bowl cleaner would help with yellowing and whether buffing/sanding is the answer.  I'm not sure on this one.  

If buffing/sanding is the answer, I'd run a rotary buffer and coarse wool and coarse compound first and really lay into it.  (I use Rupes blue and Rupes pads but whatever aggressive compound you want to use).  Them move to 3M disc trizact pad with 1500 if need be.  600 seems really aggressive.  

Edited by jjackkrash
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21 minutes ago, jjackkrash said:

I'd be curious is FSR or toilet bowl cleaner would help with yellowing and whether buffing/sanding is the answer.  I'm not sure on this one.  

I tried StarBrite hulll cleaner - no worky.

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Well I've already learned (by comments and other reading, I did not start anything yet) that 600 is way to aggressive.  I should be able to use a compound, which 3m would be the right one.  

Yea, the hull cleaner does not touch the yellowing.

On 10/13/2020 at 2:02 PM, shawndoggy said:

I think the way to really to it right would be to pull the offending upholstery pieces.

lookie here: http://www.wakeworld.com/forum/showthread.php?t=796397

Wetsanding is only one of several steps.  If you sand you still have to (maybe) cut and (definitely) polish.

Now that is some awesome results, you are probably right about pulling the upholstery and rails.  I also have some snaps, unfortunately they are pop riveted

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1 minute ago, iliketoski said:

I should be able to use a compound, which 3m would be the right one. 

I use https://www.turtlewax.com/our-products/renew-restore/turtle-wax-rubbing-compound/ for the HD work.  It is fairly aggressive and needs to be followed up with a light compound.  As much as I'd love to remove upholstery and such, close work with areas taped off is fine.  BTW, try oxidation remover first - amazing how much that stuff pulls off.

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Pics would help.

i had similar on my ‘00 SSLXI and was able to buff out simply by using compound. It took 3 years of compound in the spring and 3xwax per summer but after that it shined.

i took the slow and steady approach vs sanding as that looked like a lot more work and risk.

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I had my '01 Sunsetter VLX wetsanded twice in the 16 years I had it.  The local fiberglass place did the whole boat, and then polished it up.  It looked amazing.  After the second time they said no more wetsanding since they were afraid there were places getting too thin where the colors were.  It was a few hundred dollars.  Well worth it.  Because it's a time sink.

I just restored two Seadoos that had some yellow on the white, but mostly it was hellacious oxidation on the black below the rub rail where the cover didn't protect.

I started with wet sanding.  And here's what you need.

Chemical Guys Easy Grip Hyper Flex Water Spot Sanding Block

Chemical Guys Latex Self Adhesive Sanding Sheets 2500 grit

Then I used heavy reducing compound fluid with a wool rotary buffer.  The reducing compound stuff is usually a marine compound and as it's worked it breaks down smaller and smaller eventually becoming almost a polish.  Saves several steps and works well on gel coat.  I had a bunch of this left over from ceramic coating my 2016.

Chemical Guys Marine and Boat Revive Polish

Next I used a polish with a dual action rotary buffer and a microfiber pad.  Since I was going to ceramic coat them, I used the SiO2 polish from Marine Nano Shop.  Otherwise any polish would work.

I would highly recommend a polymer SiO2 sealant or full blown ceramic coating if you're going to be leaving it in the sun like that.  Wax is gone really really fast.

Just a note.  I also got under the seadoos where all the scum had hardened up.  They sit on Hydroports so the rear of the skis are always getting damp from wave action.  Starbrite hull cleaner, Toilet Bowl Cleaner, Wood Brightener.... All failed to do much more than take a small bit off the edges of the area being worked.  I ended up with a putty knife "wet-scraping" that stuff off.  Once most was off, the rotary buffer with heavy cutting compound got the rest, took out the few scratches, and I was able to polish it up and seal it with ceramic to.  Surprisingly using that knife left very little in the way of visible marks.  Another note.  I tried those cleaners on my '01 VLX to brighten it up, and they didn't do a thing other than etch the gel a bit requiring me to polish it up again.

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3 hours ago, braindamage said:

Pics would help.


Really hard to show in a pic, The top of the gunnels just have a yellowish discoloration,

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1 minute ago, iliketoski said:

Really hard to show in a pic, The top of the gunnels just have a yellowish discoloration,

I know what you mean.  I have a bit of it, mostly near the  windshield.  I'll get at it next spring and report back.  Just getting the oxidation off was enough this fall.  Although I am now considering removing the big MALIBU side decal and getting new registration numbers which are a bit beat up from bumping into the mooring buoy.

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