Wet Sanding - How Do You Know You've Gone Too Far???

[ShellBack89]

Hello All,

I'm new to boating and iboats. I just bought a 1988 Sea Ray Seville and I'll be working on several restoration/repair projects.

The boat is incredibly oxidized and I've read a number of threads regarding wet sanding vs. rubbing compound. Now, I'm a Paramedic so I believe we do the least invasive treatment first and see what the results are however, in this case the rubbing compound didn't cut through the oxidation. Yesterday I started wet sanding using 1000 grit paper and I could tell the oxidation was coming off. It looked like night and day.

My question is how do you know when you've gone too far and have removed all the gel coat? What will this look like and if done how do I fix it? I'm just preparing incase I go too far.

Thanks in advance for your help.


Shellback89

 

[Yacht Dr.]

Re: Wet Sanding - How Do You Know You've Gone Too Far???

My question is how do you know when you've gone too far and have removed all the gel coat? What will this look like and if done how do I fix it? I'm just preparing incase I go too far.

Hello ShellBack and welcome to Iboats ..

Well..with white gelcoat it will start to look like a shadow coming through the gel. Just slightly darker then the white..more you sand in that spot the darker it will get ( your starting to see the fiberglass ).

With dark colored gel its hard to see when sanding. You almost will not know you sanded too far until you buff it out.

Your sanding with 1000 grit so I dont think your going to go too far.

Are you sure you cant just buff it out ?

What materials and tools are you using ? What buffer and compound are you using ?

Sometimes it takes 3 passes with compound to get it back to shine.

I personally have Never had to sand a boat prior to buffing it out. I have rubbed out some pretty Hammerd boats before.

YD.

PS. Do NOT sand on the radi .. ( external radius' ).

 

[oops!]

Re: Wet Sanding - How Do You Know You've Gone Too Far???

lol.....at 1000 grit......you are going to be sand for a long long time before you burn thru....

but as yd said.....just watch out for the outside corners.

one trick is to look at the sand paper....is it the dull grey of the oxizadtion?...or the color of the gell?

 

[tpenfield]

Re: Wet Sanding - How Do You Know You've Gone Too Far???

That's what I hate about wet sanding gelcoat . . . sometimes you go too far. It is often tough to judge how thick the gelcoat is to begin with . . . and it is not all that thick.

I usually start with rubbing compound an see how that does. I only sand if absolutely necessay and then it is with 600 or finer.

 

[ShellBack89]

Re: Wet Sanding - How Do You Know You've Gone Too Far???

Thanks everyone for the help. Today I was doing a mix of both. I would wet sand the real bad stuff and then switch to the 3m 1 step heavy oxidation/wax. This seemed to get most of it. I've posted a couple of pictures to see what you all think. I'm using a porter cable variable speed random orbit sander/polisher. I have the speed set between 4000 - 4500 rpm. Anything below that and nothing was coming off and above that and my arms were coming off.

Thanks again and I'll make sure I don't do the outside edges with the wet sanding.

http://i1170.photobucket.com/albums/r538/shellback89/IMG_0248.jpg
http://i1170.photobucket.com/albums/r538/shellback89/IMG_0245.jpg

 

[Yacht Dr.]

Re: Wet Sanding - How Do You Know You've Gone Too Far???

I would wet sand the real bad stuff and then switch to the 3m 1 step heavy oxidation/wax. This seemed to get most of it. I've posted a couple of pictures to see what you all think. I'm using a porter cable variable speed random orbit sander/polisher. I have the speed set between 4000 - 4500 rpm. Anything below that and nothing was coming off and above that and my arms were coming off.

Well there are your two main problems right there.

First..you need be using something more aggressive in your compound. Like 3m super duty, Aquabuff 1000,Meguires heavy cut or something of that nature. After that compound you can use a polishing compound.

Secondly .. You should be using a Rotary Buffer. That dual action wont cut the mustard. Google 'rotary buffer' and you should come up with something in your price range. Yes..Harbor Freight does carry a cheap model.

Use a Wool pad for your cuttin compound .. WOOL ..

Good luck.

YD.

 

[ShellBack89]

Re: Wet Sanding - How Do You Know You've Gone Too Far???

Again, thank you for your help and I'll definitely get a rotary buffer however, I have bigger troubles to tackle. I'll be starting a new post since I found soft spots in the rear section of the deck. Once I started poking around the deck was just mush (not sure if that's a nautical term or not). I drilled in forward areas and found dry, firm wood but that doesn't mean anything until I start demo-n the area. I getting the gas out now (at least I'll have an extra 20 gallons to throw in my truck and since I'm paying $4.25 in CA, that's good news). I'm sure you fine gentlemen will have some great advice on how to proceed so like I said I'll start a new thread and post pics. I know there is a gentlemen that posted an extensive thread on this very subject so I'll be watching and reading that. Thanks in advance.

Shellback!!! (not a WOG)

 

[JDA1975]

Re: Wet Sanding - How Do You Know You've Gone Too Far???

"at least I'll have an extra 20 gallons to throw in my truck"

Not sure what engine you have but make sure that isn't mixed fuel before ya throw it into your truck!

 

[ShellBack89]

Re: Wet Sanding - How Do You Know You've Gone Too Far???

It's a mercruiser 4.3L 6 cycle so no chance of it being mixed but thanks for thinking of that.