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Author Topic:   Wet Sanding Gel Coat
wwbach posted 08-26-2005 02:02 AM ET (US)   Profile for wwbach   Send Email to wwbach  
My 1986 18 Outrage spent enough of its life uncovered in direct sunlight (console and seat were covered) that the gel coat in the bow area was very chalky. My first attempt to clean this up was 3M Super Duty Rubbing Compound with a Porter Cable #7424. It didn't even leave a dent. I needed to get more aggressive.

Last weekend I took the following course of action:

- Wet sand with 400/600/800/1000 (3M paper)
- 3M Super Duty Rubbing Compound w/ wool and Porter Cable #7424

I'm about 4 hours into it now and it is looking pretty good now. When I get a chance, I will finish up with:

- 3M Finesse IT II with a foam pad and the PC
- Collinte #885 Paste Fleetwax applied with a damp terry
towel and wiped clean with a dry terry cloth towel before dry

Probably another 2 hours or so. It is a lot of work but in the future I will just use:

- Collinite #920 Fiberglass Boat Cleaner
- Collinte #885 Paste Fleetwax

I may try the #925 liquid wax but that might be too easy :-)

Anyway, if you are faced with chalky fiberglass, wet sanding is the way to go.

-- Bud

bsmotril posted 08-26-2005 08:46 AM ET (US)     Profile for bsmotril  Send Email to bsmotril     
I agree with you 100%. I did the same to an old Sakonnet hull which had a trememdous amount of crazing. I only sanded with 600 and 1500 grit though before going to compound. I used an air powered jitterbug sander which sped up the process a lot. The crazing is still there, but almost not noticable now unless you are really looking closely at the hull. I was amazed at the amount of gloss I was able to bring out of that old hull. I used the foam pad on a Porter Cable DA buffer to do the wax application, and buffed with a terry cloth bonnet on the same tool. The DA buffer has been one of the best tool investments I have made thanks to the input from this site. BillS
Outrage18 posted 08-26-2005 09:52 AM ET (US)     Profile for Outrage18  Send Email to Outrage18     
PLease send pics when you are done!
My boat sounds like it needs this same procedure.
I cant get enough pictures of classic Outrage 18's!


Gep posted 08-26-2005 02:24 PM ET (US)     Profile for Gep  Send Email to Gep     
Two hours???
It took me days to do that to my Outrage.
I should have called you.
smirkless posted 08-26-2005 03:53 PM ET (US)     Profile for smirkless  Send Email to smirkless     
Try a little Penetrol on the textured deck. Get it at paint supply store or department. Smirk :-)
wwbach posted 08-27-2005 01:29 AM ET (US)     Profile for wwbach  Send Email to wwbach     
bsmotril, The air powered sander would be the way to go. By hand, 400, 800, 1200 would probably work well too.

Gep, I'm only talking about the bow area. I already compounded , polished and waxed the hull -- probably another 6 hours. And I still need to do the splash well (wet sand treatment)

smirkless, What does the Penetrol do on the nonskid? Clean it?

-- Bud

LHG posted 08-29-2005 11:54 AM ET (US)     Profile for LHG    
One should continue to wet sand with #1500 and #2000 before switching over to #44 Compound, then Finesse-it. I would definitely use the 925 Collinite Pure Boat Wax instead of paste Fleetwax.
The Judge posted 08-29-2005 12:27 PM ET (US)     Profile for The Judge  Send Email to The Judge     
I have owned some pretty chalked boats and 1000 wet is usually enough and then 3m super duty rubbing, a swirl remover, and 2 coats of wax is awesome. 400 is too course in my opinion.
III posted 08-29-2005 05:02 PM ET (US)     Profile for III  Send Email to III     
quick question, wet sanding can you describe this more. I just purchased 1990 montauk - trying to get hual to shine. I have used several 3M products and and Glissen Hual cleaner and then the shine... still looking for more shine. - would wetsanding be the answer?
bsmotril posted 08-29-2005 06:08 PM ET (US)     Profile for bsmotril  Send Email to bsmotril     
In and of itself, no, wet sanding won't bring back the shine. But, wet sanding, followed by compounding, then polishing, and finally waxing/buffing will get a really dull chalky crazed finish looking respectable. BillS
RJG posted 08-29-2005 09:13 PM ET (US)     Profile for RJG  Send Email to RJG     
I wet sanded my Outrage 18 and, as LHG suggested, continued with 1500 and then 2000. With the higher grits you only need light pressure as you are basicly (sp)polishing at that point. Let the paper do the work, keep it wet and change it often. I did not use a sander. I think you get a better feel for whats going on with the finish by doing it by hand.
The Judge posted 08-30-2005 01:13 PM ET (US)     Profile for The Judge  Send Email to The Judge     
Do not wet sand with a machine if just restoring shine. 1500 and then 2000 is fine but redundant. The 3m super duty is about 1500-2000 grit itself. I have done 600 then 3m and it shines like a baby's butt.....but 1000 then 3m is better unless REAL chalky.
III posted 08-30-2005 08:49 PM ET (US)     Profile for III  Send Email to III     
Thanks for insight. I will try it out and get back yo you -
any ideas on where to find whaler decals to replace those on hull?
The Judge posted 08-31-2005 11:34 AM ET (US)     Profile for The Judge  Send Email to The Judge

Any size any color and only one licensed by Whaler to make them.

smirkless posted 08-31-2005 12:49 PM ET (US)     Profile for smirkless  Send Email to smirkless     
wwbach The Penetrol darkens the color to a more original color and most of all eliminates the chalky whiteness. You can use it on the textured deck and flat areas as well. After it drys, you can wax over it. It's cheep, try it.
wwbach posted 08-31-2005 08:48 PM ET (US)     Profile for wwbach  Send Email to wwbach     
Well it came out pretty good the way I did it but if I were doing it again, I'd probably do 800 and 1200 then the 3m super duty. One question/issue. The 3m finesse it ii never really polished to a dry state using a foam pad on the pc. It sort of got gummy and stuck to the fibreglass. I polished it mostly off with a dry rag. I used a "swirl" on the pad and did about a 2x2 area. Is there something wrong with my technique?

I'll try to get some pictures this weekend. -- Bud

LHG posted 08-31-2005 09:13 PM ET (US)     Profile for LHG    
3M Finesse-it should be used with a wool or synthetic wool bonnet (orbital buffer), or pad (rotary buffer), and buffed until it is completely dry on the BONNET/PAD, working the same area for at least 5 minutes or more for the factory gloss. It is a time consuming process. See instructions on bottle. Very little wipe-off is required. You must buff until dry, which is where the micro-fine powders do their work. Do not use a water-wetted pad.
Sneddog posted 09-04-2005 11:32 AM ET (US)     Profile for Sneddog  Send Email to Sneddog     
With all the new glass work on our '87 22OR (pictues will be posted in the next couple of weeks when we're done). We did a fantastic job of matching the gelcoat color. Anyway in cleaning up the rest of the hull we did the following:

Interior: Wet sanded with 600 & 1000 ALWAYS USE A SANDING BLOCK!!!!!!!! Dropped to 400 in certain areas where old varnish / resin splater from our work. Finished with Meguire's One Step Marine / RV # 67 compound / polish all I can say is wow.

Hull: Mostly just the Meguire's and some 600 or 1000 wet sanding on some stains.

One other trick, when you get into corners or tight spaces where you have to sand by hand keep it vey wet and use an already used piece of sand paper you run less of a risk of doing an "oops".

I also agree with The Judge, it's more labor and your arms hurt at the end of the day but no power sanders on the gelcoat it's just too easy to dig a gash or burn through even though the factory gelcoat is very thick.

Happy sanding, it's 0830 here in So. Cal now so I'm on my way to the driveway to keep sanding and polishing.



russell grabinski posted 03-03-2010 04:50 PM ET (US)     Profile for russell grabinski  Send Email to russell grabinski     
hi i have a powerquest 26 very oxidized on the graffics. tried a few thing not so good. got collinte 920. there is another collinte cleaner with more sanding capability. just finished the two sides. first i wet sanded lite with 400 grit. later got some 500 grit. warm soapy water. lots of wateron the graffics. the sat on it with the polisher with the 920. use lots of 920. the green and the purple got clean and shiny very fast but the pink that was the probem . hand to buff that a lot looks allmost new. i did not get any sanding scatches. keep it wet and soapy. if you do use novus #2 or # 3 this will also work for your car head lights. WHAT i want to know if any one has polished the bottom of the hall and if it increases the speed. has any one tried star brite polish for the hall.
L H G posted 03-04-2010 02:58 AM ET (US)     Profile for L H G    
When you use a wet sanding process, you have to work up through the numbers: 220, 400, 600, 1000, 1500, 2000. Only then are you ready for buffing materials.

I have recently discovered a new (to me) product that buffs a boat to factory gloss. It is the best product I have ever used, simply amazing.

3M #06044 "Imperial Compound and Finishing Material".
It must be used with a power buffer, but the results are incredible. Most boat stores don't stock it, including West Marine. You can find it on the web, mail order. Follow it up with 3M Finesse-it II micro finishing. Brand new factory gloss will result if you use these products correctly. Both are pricey, but well worth every penny, about $42/qt.

I used to recommend the Meguiars products. This 3M stuff is FAR superior, and faster.

littleblue posted 03-04-2010 03:35 AM ET (US)     Profile for littleblue  Send Email to littleblue     
LHG, are you using the 3M Imperial Compound after wet sanding or just by itself?
Wasatch Whaler posted 03-04-2010 10:31 AM ET (US)     Profile for Wasatch Whaler  Send Email to Wasatch Whaler     

Have you tried any of 3M's "Perfect-It" finishing system products?

It's a complete system with 1500 and 3000 grit sanding discs (used wet with a D/A sander) as well as compounding, machine polishing and swirl elimination liquid compounds. The stuff isn't cheap, and I've found it much cheaper on the Internet, even sometimes on ebay.

I don't know if they still have the promotion, but they had a complete kit with discs, interface pads, and one quart each of the compounds for about $90.00. MUCH cheaper than buying the individual items.

L H G posted 03-04-2010 10:49 AM ET (US)     Profile for L H G    
I never wet sand unless I am doing a gelcoat repair. For just oxidized hulls, the #3M Imperial is all you need.

I have never used the Perfect-it system. The Imperial product seems to do all of this. It is an interesting product, since it has agressive cutting and super fine swirl removing material all at the same time. When you first hit it, you can feel the material cutting the oxidation or dullness, then keep working the same area for a few more minutes, and it begins to finish in a high gloss. Like Finesse-it, you work it on the same area until the pad surface is completely dry. This is where the high gloss comes from. Using it by hand is difficult and tiring, but it can be done for little places where the buffer can't reach. Use a wool or synthetic wool pad, not terrycloth.

jtanner posted 03-05-2010 04:04 PM ET (US)     Profile for jtanner  Send Email to jtanner     
Here is a great place to find those products at the best price:

3M Imperial:

3m Finesse It: 3M-Marine-Finesse-It-II-Glaze-09048-1-pt-M09048.htm

L H G posted 03-05-2010 04:14 PM ET (US)     Profile for L H G    
Thanks for that tip. Good pricing.
grander posted 03-05-2010 09:57 PM ET (US)     Profile for grander  Send Email to grander     
I have just finished wet sanding my 17 montauk. I used 400,600,1200,2000 grit and finished it with rubbing compound using a power buffer with wool pad. I waxed after the rubbing compound and I am very happy with the results. The entire project took me 12 hrs. I did all the sanding by hand and I agree that you should do it by hand for the "feel". The boat looks brand new again.

It was worth the pain and suffering!!
aleve works for the finger and hand pain.

contender posted 03-06-2010 06:08 PM ET (US)     Profile for contender  Send Email to contender     
As you all know I'm currently reduing my 16'7'' whaler. I have taken the entire boat apart and built a new console (even most of the engine, lower unit, lower cowling, and carbs) I was just reading about the 3m product in the above thread (3M Imperial Compound) So needing some type of polish compound I thought I would give it a try. Well I went down to the fiberglass shop (yes we have a large dealer/store that just sells fiberglass, resins, paints ect. for the marine industry in Ft. Lauderdale called Fiberglass Coatings, they even sell blanks for surfboards). The salesman at the store told me that the big fiberglass/boat/marine repair shops are getting away from that product(3M)and are now using this: Farecla Profile 500 Light Cut Compound. He said the 3m prouduct is good but not as good as this new product. The cost for the 3M was about $34.00 a Quart and the Farecla was about $31.00 a Quart. I do not think the guy was trying to screw me for two reasons, 1. I'm a customer that uses his store a lot, and 2. He could of made more money on the 3M product. I have just thought I would give everyone a heads up....good luck
grander posted 03-06-2010 10:50 PM ET (US)     Profile for grander  Send Email to grander     
I have always steered away from the fast "cure" methods. we need to get rid of the layers of old gel coat. That takes place only when you remove layers of oxidation. Wet sanding does this very well, and it is a time proven proceedure, that you can rely on, if you want to put in the time and muscle to accomplish the task at hand. When you are finished,there are no surprises, just a good looking boat.
Wasatch Whaler posted 03-07-2010 11:11 AM ET (US)     Profile for Wasatch Whaler  Send Email to Wasatch Whaler     
Whenever I wet sand by hand I ALWAYS use a pad or sanding block underneath the sandpaper. The choice depends on what is being sanded.

The danger in both wet sanding and power buffing is going through the gel coat (or paint). In my experience this usually happens on an edge, for example a chine. To reduce the probability of this happening I take narrow masking tape (usually 1/4") and cover the edges when wet sanding.

I will remove the tape after I have finished wet sanding and prior to buffing, but I am very cognizant when I'm getting close to an edge with the power buffer.

1974revenge posted 03-08-2010 06:56 AM ET (US)     Profile for 1974revenge    
Has anyone tried this product:
I am looking at it as a substitute to the wet sanding/waxing.


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