Wet Sanding - effects on Fiberglass and a few test photos

[jmunro123]

We purchased our 2004 390MY in June of 2010 and as I was trying to clean it , I noticed there were places that I could just not get to shine. I tried a number of different products including compound, buff magic and while the got it cleaner the fiberglass just did not shine. I was talking to a company that sells products and he mentioned trying some light wet sanding. Before trying this I used Buff Magic, Mequirs Oxiation restores and 3M heavy compound. All work to bring back a shine BUT - there were still very small marks - kind of like an imperfection in the fiberglass. I think the marks are from oxidation and those marks made it impossible to get that new boat deep shine.

I am relatively new to boat cleaning and really resist compound so you can imagine how I feel about wet sanding. Well today after lots of reading and Googling I decided to give it a try.

l was wondering what the effects are on fiberglass of wet sanding and if it increases the speed of oxidation? Is maintanance after this procedure more time consuming?

I would be interested in other CSR members who have done this can give me some insight into what to expect for future maintanance.

Just for reference this is the procedure that I did but it not really relevent to the question.

1. wet sand with 800 with sanding block - lightly and about 5 strokes back and forth
2. repeat wet sand with 1000 with sanding block - lightly and about 8 strokes back and forth
3 repeat wet sand with 2000 with sanding block - lightly and about 10 strokes back and forth
4. compound with Buff Magic with Shurhold polisher
5. finish with Pro Polish with Shurhold polisher

The net effect of using wet sanding in this particular case is it brought back the fiberglass to what looks like new condition. The results are actually amazing BUT the effort is significant. After completing the test areas I just sat down and pondered the effort to get this deck area done. Then went to the 'library' to sit at the bar and think of my next move.

 

[beachcombersc]

You didn't mention what if any type of buffer or rotary device you used. I find it hard to believe you couldn't get what you wanted out of those products with proper application and methods. Good luck with your project, it's a true labor of love!

 

[katricol]

without seeing your boat in person, I question if you have to use 800 grit first. Would 1000/1200 first then 1500 andfinish with 2000 be sufficient? 800 just seems agressive to me unless the boat has heavy oxidation.

 

[floriduramax1]

WOW!! You are packed in there like sardines:wow: Be extremely careful if you are running a buffer, the compound thrown off the wheel can stain the fabrics on the boats around you. I wouldn't you need 800 either.

 

[jmunro123]

WOW!! You are packed in there like sardines:wow: Be extremely careful if you are running a buffer, the compound thrown off the wheel can stain the fabrics on the boats around you. I wouldn't you need 800 either.

Yes I think you are right , 1000 grit is worth a try and maybe 1200. The guy I was talking to gave me 600 grit which I never used as it seems to aggressive.

What is the effect on fiberglass after it seen sanded? Does it Oxidize faster?

 

[CoralReefer]

I bought an old Glastron that sat out for years and had severe oxidation. I decided to ditch because it had the metallic gelcoat and above the rub rail couldn't be salvaged. However, I practiced wet sanding with those exact grits and here's a few pics of the results. Same process stepping up to finer grits. I used Meguiars Ultimate Compound/Rotary. Finished off with Ibiz marine wax (family friend developed this stuff out of Pompano Beach FL...good stuff). Check out the shine under the rub rail.

This was great practice and glad figured I'd try the process out on a junker first. I was pleased. I would say it's not necessary to start at 800 grit on most boats. Only in severe cases.

Before:

After:

 

[beachcombersc]

Porter cable 7424. Best money spent! Start the unit once it's on the surface and it won't sling product. You shouldn't be using that much product anyway. Do some searching and make sure to watch the numerous videos out how to use it. Let the products break down, couldn't be easier...

 

[beachcombersc]

Just saw where you stated you used a polisher...

Try 3M heavy oxidizer with a rotary, then any polish with your polisher, then your favorite wax.

I have brought back many surfaces without needing to wet sand. In rare cases, it may speed up the final results, but they both normally get to the same shine. Your first picture doesn't seem that far gone.

 

[HIFI]

This is a good post and I think the questions whether a #800 paper is\was to aggressive depends on what you start out with. Good question, as good as the post.

The issue with not wet sanding first is what kind of work a compound and buff pad can do efficiently. If you have so much oxidation you can load up the buffer wheel fast. Even a spur cant get the wheel clean. Fresher but not clean. A wool cutting pad works best as the foam cutting pads just load up fast. So can you imagine what kind of work your buffer and compound are doing now. The product application is changing every square foot. The pad is loading up. Now you are using a pad full of removed oxidation to do your work. You still have 48 foot of boat to go. Another mistake people make is while the pad is loaded with oxidation the cutting ability decreases so they add more muscle and pressure. Heat build up occurs and a second group of issues pop up.

I Like your work and great post . . . thanks for photos.

So I think I can answer your question about oxidation coming back . . . from experience. Oxidation will come back just as fast and maybe faster if you don’t change the way you protect your finish. If you completely cover from any UV and dirt it will never come back. Find the best UV sauce you can and apply as often as you can. That is the only way to slow down.

Random thought . . . I think a professional using wet sand and compound will be able to preserve more original gel finish than most of the people I have seen spinning a wheel and slinging compound. That is the real goal and why I like this post.

 

[Alex F]

.....l was wondering what the effects are on fiberglass of wet sanding and if it increases the speed of oxidation? Is maintanance after this procedure more time consuming?....

Last spring I've had a similar situation where my previously use methods (compound/polish/wax) didn't work with prota cable 7424. No matter how much I tried using the orbit with compound it wasn't bringing the shine back to life. So, it was clear that I needed more powerfull tool. So, after reading more on CSR I've purchased Makita Rotary.

What a great tool and pleasure to work with. I've purchased Maguiars #91 Power Cut Compaund and this did the trick to resolve the issue.

In summary my steps were:
1. Makita Rotary with Maguiars #91 Power Cut Compound.
2. Porta Cable 7424 with Meguiars #45 Boat/RV polisher (2 coats are better).
3. Porta Cable 7424 with Meguiars Flagship Wax.

I'm not a fiberglass guru, but before using any type of sanding methods I would try looking in to better power tools with different type of compunds. Just keep in mind that there's a limited amount of gelcoat, so you have to approach it with caution or after 5-7yrs of shiniest boat you'll have no gelcoat layer left.:grin:

Just my .02c.

 

[jmunro123]

Random thought . . . I think a professional using wet sand and compound will be able to preserve more original gel finish than most of the people I have seen spinning a wheel and slinging compound. That is the real goal and why I like this post.

I totally agree, how can the least amount of abrasion be used to restore and maintain the highest level of shine. Unfortunately - in this case it also requires the most amount of effort. Next year will be much easier. I am hoping next year is a orbital with a cleaner wax and Meguiars Marine wax and I am done.

 

[beachcombersc]

Last spring I've had a similar situation where my previously use methods (compound/polish/wax) didn't work with prota cable 7424. No matter how much I tried using the orbit with compound it wasn't bringing the shine back to life. So, it was clear that I needed more powerfull tool. So, after reading more on CSR I've purchased Makita Rotary.

What a great tool and pleasure to work with. I've purchased Maguiars #91 Power Cut Compaund and this did the trick to resolve the issue.

In summary my steps were:
1. Makita Rotary with Maguiars #91 Power Cut Compound.
2. Porta Cable 7424 with Meguiars #45 Boat/RV polisher (2 coats are better).
3. Porta Cable 7424 with Meguiars Flagship Wax.

I'm not a fiberglass guru, but before using any type of sanding methods I would try looking in to better power tools with different type of compunds. Just keep in mind that there's a limited amount of gelcoat, so you have to approach it with caution or after 5-7yrs of shiniest boat you'll have no gelcoat layer left.:grin:

Just my .02c.

Agree 100%!!!

 

[Carver370]

You can get that finish back 100% without wetsanding. The main issue why the products you have used is your power tool. The shurhold polisher is a great tool for applying wax to an already buffed finish, but is not the tool for compounding.

You need a rotary buffer/polisher with a white wool pad like a Dewalt, Makita, Milwaukee, etc..

The process I would use, which I have many times on different boats would be:

-Buff with a product like 3M Super Duty and a white wool pad on a ROTARY polisher. Keep a spray bottle of water with you at all times to keep the product from drying out and keep the surface cool. This stuff is like liquid sand paper.

-When completed the above, wipe the surface down so its free of all dust. Grab a brand new wool pad with a rotary polisher and buff with buff magic. You will start seeing all the swirls removed at this point and the shine beginning to get deep like you are looking for. Use the buffer at about 1800 rpm and really work the product back and forth until you see basically no buff magic residue. You should basically be just wiping dust away, not product.

-Wax with whatever product you normally like on your shurhold polisher. I really recommend Starbright Marine Polish With Teflon, Meguiars Flagship, or Leverage Polish (Which is what I use on my boat and doesn't require a buffer for application or removal)

The above is basically if the surface is really bad, with the right rotary polisher you could probably get away with the first step and just move right on to the Buff Magic if you have already gotten a lot of the oxidation off the boat.

I use the same process as the above on my boat every year as well as about 60-80 boats a season minus step one.

Heres some 1994 Gel Coat on my boat, Buff Magic followed by Leverage Polish. I use the leverage once about mid season and the boat stays nice until the end of the season.

 

[David Paul]

I agree with Carver 370. Use a rotary polisher with wool pads and the right compounds and you will be amazed at what you can do to restore your finish.

 

[jmunro123]

Heres some 1994 Gel Coat on my boat, Buff Magic followed by Leverage Polish. I use the leverage once about mid season and the boat stays nice until the end of the season.

Sounds like a good approach. I was wondering - What do you do to maintain the finish so you don't have to do all that work. Gelcoat is only so thick so I would think using Buff Magic every year might be a bad idea. I was hoping that next year I could just use a cleaner wax. Does fiberglass oxidize faster after all the work?

 

[Carver370]

Sounds like a good approach. I was wondering - What do you do to maintain the finish so you don't have to do all that work. Gelcoat is only so thick so I would think using Buff Magic every year might be a bad idea. I was hoping that next year I could just use a cleaner wax. Does fiberglass oxidize faster after all the work?

Buff Magic really is not very abrasive. You wont own the boat long enough to buff through the gel coat if you're using Buff Magic. I put a maintenance coat on on wax or polish about mid season and then all it needs is a light application of buff magic in the spring to make it pop again. Also I try to only use a very light boat soap like brite wash or simply water to wash the boat.

Mine has been buffed in some way shape or form every single year since new at least once a season, sometimes twice when I was using different waxes that didn't hold up at all.

Now wetsanding it often, thats another story. You greatly diminish the thickness after a couple of times. Think about it, you are sanding grooves into the gelcoat, reducing the thickness and then buffing the finish which is reducing it even more to remove the scratches left from sanding.

 

[CoralReefer]

I think Buff Magic has a "progressive cut" meaning the product breaks down and the cut diminishes as you apply. That's why is was attractive to me. I haven't used but the information out there says it works well. Can't wait to try it with my new Shurhold DA polisher. I have a Dewalt rotary as backup.

 

[jmunro123]

Buff Magic really is not very abrasive. You wont own the boat long enough to buff through the gel coat if you're using Buff Magic. I put a maintenance coat on on wax or polish about mid season and then all it needs is a light application of buff magic in the spring to make it pop again. Also I try to only use a very light boat soap like brite wash or simply water to wash the boat.

Mine has been buffed in some way shape or form every single year since new at least once a season, sometimes twice when I was using different waxes that didn't hold up at all.

Now wetsanding it often, thats another story. You greatly diminish the thickness after a couple of times. Think about it, you are sanding grooves into the gelcoat, reducing the thickness and then buffing the finish which is reducing it even more to remove the scratches left from sanding.

Yes - that makes total sense. I think once the Oxi is gone this will be a much less abrasive process. I was planning on waxing the deck mid summer. Anything I can do to reduce my work load long term I am totally in favour of.

 

[HIFI]

The concept of wet sanding a heavily oxidized boat was only what I am referring to.

My thought was this. The oxidation residue has to be removed. If you use the proper tool and very best Diminishing Value Compounds with a Wool or Foam cutting pad the residue collects in the pad. It is collecting every square foot and now you mix that material you came to remove as a cutting agent. While not as drastic this is the equivalent of polishing with a dirty rag.

Wet Sanding is a hand job. You need to have the mind set of washing away the oxidation and not sanding away gel coat. Lots of soapy water, lots of squares of wet sand, NOT a lot of pressure. That is the real technique. Less room for errors if you start with the right grit and keep the pressure low. Start out at 1200 grit and see how quick the paper loads up and stops cutting. If it loads up quick, and therefore needs replaced quick, you may try 1000 grit. The oxidation washes away. Keep in mind there is no heating of the finish in this entire process. This step goes by quick when you add to the time savings of muscling a Dewalt or Makita speed governed buffer. Now that you have washed away the surface contamination and oxidation the compounding step is a clean buffing. Less muscle, less heat, a more pure and clean buff job, less room for error.

This technique yields the highest optical finish and leaves behind the most original gel finish. . . ASSUMING YOU STARTED WITH A HEAVILY OXIDIZED SURFACE.


To the original OP . . .I doubt that fresh gel in a year of Florida sun with some basic protection and maintenance would need wet sanding. Time will tell. That time, whatever that time is, will depend on the level of protection and maintenance one provides for their boat.

 

[Skuza]

My take.
Compound first-If not happy try the highest grit sandpaper-1000-1500 then compound again.
I've actually compounded out 400 grit scratches with a rotary buffer and my regular compound. I wouldn't do that on a flat surface though. This was small repair areas.
We have some areas that had heavy oxidation that actually gave the gelcoat a pitted appearance-base of the side windows. The first couple of years I basically shined up the pitted area but the texture remained. This area seemed to fade faster then the unharmed areas. Over the years and more compounding has eventually smoothed out the damaged ares and they hold up much better now. I do think severely chalked gelcoat will fade quicker UNLESS it is wet sanded or compounded out. Then it should revert back to normal durability if maintained. My thinking is to stay ahead of any chalking because once it starts it seems to snowball.

Carver: Your boat looks great! I give ya bridge guys credit as thats ALOT of gelcoat to take care of!