Oxidized Gelcoat. Best way to repair question.

[Mygreenihc]

Hey guys,

I have read gobs of posts dealing with gelcoat oxidation and whether to sand it or buff it. Several people have stated that in most cases buffing will remove the oxidation and sanding is not needed if it is done right.

My gelcoat seems to be in good shapre on the sides of the boat, but I have not closely inspectedthe bottom yet. I will buff this thing first and i think that it will do the job, but I have some sanding questions just for my knowledge. This leads me to the following question:

From what I can gather searching this forum, when sanding I should start with 800 grit and finish up with 1500 or finer sandpaper. Also, I should use a high speed rotating sander instead of an orbital. Can someone please verify that I am correct on this?

Thinking along these lines, in my mind, this is a "wet sand only" type of job, but I didn't find in any post stating that wet sanding was used. This, coupled with using a rotary sander leads me to believe that I should sand it dry. Should it be sanded wet or dry?

Y'all straighten me out on this. I want to understand this before I start.

Thanks,
Brad

 

[elan86]

Re: Oxidized Gelcoat. Best way to repair question.

I think you need to determine how bad your oxidation is. I am restoring an 89 Sea Sprite that had oxidized from candy apple red to pink. I started with a buffer and 3m compound/wax mixture, I also have a product called PolyGlo. The PolyGlo instructions have me wet sanding with 400 or 600 grit sandpaper. The buffer was not enough on mine, I am wet sanding down all the bleached areas down to color then applying the PolyGlo. I will try to post you some pics of before and after so you can compare to yours.

 

[chriscraft254]

Re: Oxidized Gelcoat. Best way to repair question.

You can do this many different ways. i like wet sanding because you are assured that the oxidation is removed not filled over. Alot of people don't understand that oxidation is also in the pores of gelcoating. compounding works but most compounds have fillers in them to fill these pores.

If sanding by hand, you will want to use sand paper specific for wet sanding. 800 grit is usually a good place to start, then 1000, then 1200, then 1500. Some people will even tell you to go to 2000 grit. It really all depends on how oxidized the hull is and if it is a dark color you may need to go to the 2000.

Now, that being said, I use what is called film discs. They can be used on a (DA) sander which in the normal world is nothing more than a random orbital sander. Most sanders sold today are random orbital. This means it not only goes in circles but osilates so it is not sanding in the same pattern every time. The film discs can be used wet or dry. That means a random orbital electric sander can be used instead of having to buy expensive air tools.

If you use film discs, Chances are, you will not have to go past 1000 grit to get a good finish, but higher grits are available. I use Indasa Rhino film discs. You can find them at a place called Smart Shoppers online. Box of 50 is $25 dollars shipped. If you go this route, get a box of 800 and 1000. I use 6 inch discs on a 5 inch bosch random orbital so the edges don't wear out.

Smaller areas just wet sand and be careful around corners is using the orbital because the gelcoat is thinner in those areas.

Here is more food for thought. Sand paper is compound and compound is sand paper. Different compounds are different grits just like the sand paper. And should be used accordingly.

If you use a DA sander, you will use a finishing polish/compound after your last grit of sand paper to polish. then wax.

Last but not least, remember, you want the gelcoat to look new before you apply anything as far as wax or a protectant. The wax is just to protect the surface after it has been restored. Hope that helps.

 

[CaptainKickback]

Re: Oxidized Gelcoat. Best way to repair question.

Chriscraft gave you an excellent description. As for your disc sander question, I was warned on several occasions that a disc (circular) sander would cut into the gel coat and leave swirls you can't get out. Makes sense to me. I will be sticking with the DA sander and hand sanding.

 

[chriscraft254]

Re: Oxidized Gelcoat. Best way to repair question.

Chriscraft gave you an excellent description. As for your disc sander question, I was warned on several occasions that a disc (circular) sander would cut into the gel coat and leave swirls you can't get out. Makes sense to me. I will be sticking with the DA sander and hand sanding.

To clarify this, a (DA sander) is the same thing as a (Random Orbital) A rotary sander which can look exactly like a random orbital sander can leave nasty marks in gelcoat and should not be used.

I went years not knowing what the marine world meant when talking about a "da" sander and then I asked. felt stupid but then I knew.

The good thing is, being in the construction industry I already had multiple da/random orbital sanders.

A rotory sander is a sander that just goes in one circle formation. It has no osilation or randomness to it. just goes round and round.

 

[Mygreenihc]

Re: Oxidized Gelcoat. Best way to repair question.

Thank you guys for the input.

The main reason for the questions were that I just couldn't wrap my head around why a circular sander would work and not an orbital. It didn't make sense to me. I am glad that you guys clarified it.

Special thanks to Chriscraft, That was a lot of good information and if you type like most men, you put some time into that.

I have an electric and a pneumatic DA sander, so I should be good to go. I have this fetish that requires me to have one of every tool made. Then, once I get one and figure out how to use it, I realize that I should have bought the other one and go get it too. Buying a new tool is half the fun. My wife has started making me finish the job before I can buy another tool lately though. Oh well...:facepalm:

Thanks again guys. This is just the information that I was hoping for.

Brad

 

[CaptainKickback]

Re: Oxidized Gelcoat. Best way to repair question.

You have 2 DAs. Good. One for each hand. Lol

 

[chriscraft254]

Re: Oxidized Gelcoat. Best way to repair question.

Thank you guys for the input.

The main reason for the questions were that I just couldn't wrap my head around why a circular sander would work and not an orbital. It didn't make sense to me. I am glad that you guys clarified it.

Special thanks to Chriscraft, That was a lot of good information and if you type like most men, you put some time into that.

I have an electric and a pneumatic DA sander, so I should be good to go. I have this fetish that requires me to have one of every tool made. Then, once I get one and figure out how to use it, I realize that I should have bought the other one and go get it too. Buying a new tool is half the fun. My wife has started making me finish the job before I can buy another tool lately though. Oh well...:facepalm:

Thanks again guys. This is just the information that I was hoping for.

Brad

Brad, seems you either miss typed or your still confused, the bold printed section is backwrads, a random orbital will work and a circular will not.

Sounds like you already have a couple da sanders, that is what you need. And your welcome and welcome to iboats.

 

[Woodonglass]

Re: Oxidized Gelcoat. Best way to repair question.

The first thing you want to do before attempting to de-oxidize your boat is to give it a thorough cleaning/washing with a good degreaser. Tri-Sodium Phosphate is excellent for this. You can get it at Lowe's and follow the directions on the box. This will enusre you don't drive contaminates deeper into the pores of the Gelcoat. JMHO.

 

[Yacht Dr.]

Re: Oxidized Gelcoat. Best way to repair question.

What kinda boat do you have there Green ?

There are too many variables to restoring an "oxidized" boat.

You might be trying to remove oxidation..or you might be trying to remove some crap wax that is hammered.

There really is no One Specific Magic Bullet remedy for faded out Gelcoat.

Basically if you can not 'buff it out' then you need to remove whatever is on there that is preventing the compound to work properly. Some polishes work good to solidify whatever is on there..then you go back to the course compound..then back to the polish.

You can try the sand/buff method as a Last resort. Be aware that your gel might not be thick enough to complete the procedure without sanding/buffing through the Gel ( depends boat to boat ).

If you plan on using a DA (dual action) or a Random Orbital ( there is a difference between the two BTW ) then you have to be Very careful. .. you can put some Moon cuts in your Gel if you do not know how to work your tool.

If you choose to use the power sander then you should be using an "interface pad". Basically its a foam pad that velcro's onto your disk..then you put the disk paper on the foam pad.

Sanding gelcoat is only done for Extreme cases..and not typical.

Personally I would rather "wheel out" a boat 3 times before I took a power sander to it.

Hope this helps.

YD.

 

[Yacht Dr.]

Re: Oxidized Gelcoat. Best way to repair question.

The first thing you want to do before attempting to de-oxidize your boat is to give it a thorough cleaning/washing with a good degreaser. Tri-Sodium Phosphate is excellent for this. You can get it at Lowe's and follow the directions on the box. This will enusre you don't drive contaminates deeper into the pores of the Gelcoat. JMHO.

Good point..you dont want a chunk of dirt getting in your pad while wheeling out..this can leave Serious scratches.

And you dont want build up on your pad..

Good catch Woody .

YD.

 

[CaptainKickback]

Re: Oxidized Gelcoat. Best way to repair question.

Yacht Dr, can you elaborate on the differences between DAs and random orbit sanders, as wellas expexted outcomes? Thanks.

 

[ondarvr]

Re: Oxidized Gelcoat. Best way to repair question.

One thing you need to remember is that each boat (actually the gel coat on it) will be slightly different in how it responds to sanding and buffing, this is why you will find different methods and results reported by people giving opinions. Some gel coats are softer than others, so you may be able to sand with 600 and easily remove the scratches, others will need 1500 and it still may be tough to make it look good. Color has a huge influence also, dark colors will show more defects so you need to use finer grits and compounds, colors like red will fade more and need more sanding to remove the bleached out pigment. White may only need to be buffed to regain its color and gloss.

Plus when sanding with a DA you will be able to use a slightly coarser grit than when hand sanding and still be able to remove the scratches.

The best thing to do is start on a small section and try several different methods. Use just a buffer first, if that doesn’t do it use a fine grit paper 800 or 1000, then buff it again. The goal is to use the least number of steps with the finest grit products as possible. Once you’ve found out what works on the small section you can go after the rest of the boat.

The deck will have the worst weathering and the hull sides will be better, this is assuming they are both the same color. But even this can vary if the boat has a cover.

 

[ondarvr]

Re: Oxidized Gelcoat. Best way to repair question.

It looks like everyone was typing at the same time, my post covers some of the same things as the others.

 

[Mygreenihc]

Re: Oxidized Gelcoat. Best way to repair question.

Thanks for all the information gentlemen,

Chriscraft, I got it. I need to use the DA sander. I read a post earlier stating that a DA sander would not work and it didn't make sense to me. That is why I wanted to get it clarified.

Sounds like I have to get some supplies and get busy this weekend.

Brad

 

[Yacht Dr.]

Re: Oxidized Gelcoat. Best way to repair question.

What kinda boat do you have there Green ?

YD.

Thanks for all the information gentlemen,

Chriscraft, I got it. I need to use the DA sander. I read a post earlier stating that a DA sander would not work and it didn't make sense to me. That is why I wanted to get it clarified.

Sounds like I have to get some supplies and get busy this weekend.

Brad

Basic question.. what boat are we dealing with mate ?

YD.

 

[Mygreenihc]

Re: Oxidized Gelcoat. Best way to repair question.

Yacht Dr.,

We are dealing with a 1986 Venture Stallion. It is a 16' 2" bass boat.

I live in GA now, but I grew up on the gulf coast and I an very familiar with gulf boats as well as fresh water fishing boats. The oxidation on my boat is not like the powder oxidation that I have seen on many gulf boats. It is also not really very bad, but I have not been able to polish it out by hand with rubbing compound.

The cap on the boat is blue metal flake and it has been buffed out and looks good except for a small place where the gel is separating. The sides of the boat are gray with a blue metalflake stripe down the side. The stripe has some minor oxidation or fading, but the gray hull is what I really want to clean up. It looks faded and "dirty".

Thanks for all your help.
Brad

 

[Mygreenihc]

Re: Oxidized Gelcoat. Best way to repair question.

Thanks for the tip WoodonGlass. I actually picked some up Friday at lunch. I had no idea what it was, but this forum ( actually you in another post) said that it was what I needed and Lowes had it. I had a Lowes gift card and one right down the street from work. Now I just gotta figure out how to use it.

Thanks again,
Brad

 

[chriscraft254]

Re: Oxidized Gelcoat. Best way to repair question.

Thanks for the tip WoodonGlass. I actually picked some up Friday at lunch. I had no idea what it was, but this forum ( actually you in another post) said that it was what I needed and Lowes had it. I had a Lowes gift card and one right down the street from work. Now I just gotta figure out how to use it.

Thanks again,
Brad

Acetone wipe will do the same thing and you should always start with a clean slate before wet sanding, compounding or polishing. Cleaning the hull and stripping off the residual wax etc gives the products used a chance to work to the best of there ability.

All boaters should have acetone on hand for alot of different things. Its a great cleaner/stripper

Your boatt is a prime example of a boat that will be a test and go type thing. Alot of bass boats had very thin gel coating and blue is one of the harder colors to keep looking good. The grey as well. Darker colors in general are harder and take a longer process to make them look great.

Just my opinion, but after seeing many bass boats with metalic flake in the gel, I think the flake helps destroy the gelcoat by reflecting heat all the time. I have seen gelcoat on bass boats that could not be restored even by wet sanding.

I disagree that wet sanding is a last resort, I think it gives you the best finish and removes oxidation instead of covering it up with a compound that has fillers in them.

 

[Yacht Dr.]

Re: Oxidized Gelcoat. Best way to repair question.

If you plan on using a DA (dual action) or a Random Orbital ( there is a difference between the two BTW ) then you have to be Very careful. .. you can put some Moon cuts in your Gel if you do not know how to work your tool.

If you choose to use the power sander then you should be using an "interface pad". Basically its a foam pad that velcro's onto your disk..then you put the disk paper on the foam pad.

Sanding gelcoat is only done for Extreme cases..and not typical.
YD.

Yacht Dr, can you elaborate on the differences between DAs and random orbit sanders, as wellas expexted outcomes? Thanks.

Well if Lock down your D/A for sanding .. you might get some 'Moons' in your finish if your not carefull.. like I said..

Yacht Dr.,

We are dealing with a 1986 Venture Stallion. It is a 16' 2" bass boat.

I live in GA now, but I grew up on the gulf coast and I an very familiar with gulf boats as well as fresh water fishing boats. The oxidation on my boat is not like the powder oxidation that I have seen on many gulf boats. It is also not really very bad, but I have not been able to polish it out by hand with rubbing compound.

The cap on the boat is blue metal flake and it has been buffed out and looks good except for a small place where the gel is separating. The sides of the boat are gray with a blue metalflake stripe down the side. The stripe has some minor oxidation or fading, but the gray hull is what I really want to clean up. It looks faded and "dirty".

Thanks for all your help.
Brad

That is why I asked what your boat is..

Clearcoat over gel is a different nature. You have only 2 (3) options..

Buff it out if you can.. Try some TV ad crap ..or paint it.

Acetone wipe will do the same thing and you should always start with a clean slate before wet sanding, compounding or polishing. Cleaning the hull and stripping off the residual wax etc gives the products used a chance to work to the best of there ability.

All boaters should have acetone on hand for alot of different things. Its a great cleaner/stripper

Your boatt is a prime example of a boat that will be a test and go type thing. Alot of bass boats had very thin gel coating and blue is one of the harder colors to keep looking good. The grey as well. Darker colors in general are harder and take a longer process to make them look great.

Just my opinion, but after seeing many bass boats with metalic flake in the gel, I think the flake helps destroy the gelcoat by reflecting heat all the time. I have seen gelcoat on bass boats that could not be restored even by wet sanding.

I disagree that wet sanding is a last resort, I think it gives you the best finish and removes oxidation instead of covering it up with a compound that has fillers in them.

I dont see anyone saying wetsanding as a last resort ..

Pics please ..

YD.