Paint prep?

[swfl mike]

Hi, i just purchased an old gheenoe that needs to be repainted. I've spent the last several hours searching how to prep and am still confused. The boat has old paint with clear coat over it on the sides and the paint that used to be on the bottom is all scraped off.

Before I sand the paint on the sides do I need to clean them with something (lacquer thinner, acetone?)? What method do I use to sand, power sander or hand or both? and what grit do I use. Also what do I clean it with after sanding?

Sorry if these are dumb questions that have been asked before. Thanks for any responses,

Mike

 

[NateL]

Re: Paint prep?

At any automotive store (Autozone, Napa, even Wallyworld) carries cleaners for body repair prep. Should be a silicon remover in it also. Silicon products around (armorall) while painting will completely ruin your day. As far as the sanding goes it depends on how bad the surface is. Pics on here go a long long way. Are you changing the color? is the clear coat that's on it now in good shape? It could be possible that if it's just some fade that you can possibly buff the boat with a medium compound and electric buffer will shine her right up!! Pics pics pics. Hope I was of some help.

 

[swfl mike]

Re: Paint prep?

Well the on the sides the paint and the clearcoat is chipping off. On the bottom it looks like it was dragged over sand bars or something because all of the paint is gone. Also there is a couple spots on the bottom that had fiberglass repair that also need to be painted. Yes probably going with a different color.

I'll see if I can get my hands on a camera

 

[drewpster]

Re: Paint prep?

The prep work you do depends on what paint system you are going to use to re-paint.
You could use an automotive system or a marine one. Automotive paints are applied using specialty equipment. You will need a good compressor and paint guns to apply it. There are marine paints that are applied using more common tools like rollers and brushes. The advantage of the marine paints are that they are designed for the marine environment. They can be sprayed, but there are marine paints that are designed for rolling and yield spray-like shine and finish.
Choose the paint system first and it will dictate the prep work needed. Personally I prefer marine paints.

 

[swfl mike]

Re: Paint prep?

I was thinking rustoleum marine paint, and doing the roll/tip method

 

[Greg Mrozinski]

Re: Paint prep?

Mike,

Follow the paint manufacters guidance on prep. They usally spell out what grits to use and their solvents to use with their paints. Most times initial sanding can be done with paper in the 100-220 range. You can start coarser but you might need to go over with a finer paper before priming and paint. Solvent wash the hull once BEFORE you start any sanding. This will prevent grinding the old waxes and silcones deeper into the paint that is there. This could screw up the new paint when the time comes.

 

[NateL]

Re: Paint prep?

Definantly need to wipe down first as the post above. I don't know a whole lot about marine paints or how they hold up. Been a body repair man for many years and have worked with fiberglass most of that time. My opinion on refinishing is on the automotive side. Guess you should probably consider the marine side depending on your spraying skills. Clear base and clear coats can be very tricky to spray and also require the right enviroment. I'm planning to repaint my boat using the automotive side. Anyway as far as preparing the boat for refinish you should use a good sanding board (file) and hand board the patch job down to where its all uniform and flat to the rest of the boat. If I were you I'd start with as fine of grit as you can as long as it's doing the job and your not burning through paper (start small go big if needed) A little painters tip " Your paint is only as good as what's underneath" in other words bad sand and prep job = bad finish no matter how you put paint on it. If you decide to go automotive I'll be glad to help ya through to process. Good Luck hope all looks good when your done.

 

[bigbad 4cyl x2]

Re: Paint prep?

 

[bigbad 4cyl x2]

Re: Paint prep?

buy a palm dual action sander and a couple cases of 80 grit to start , i hand sanded for 3 days , then the boat yard took a air file to it and did more in a 1/2 hour , you gotta press real hard ,and go through alot of discs to get the fiberglass to a point were it will stick , i suggest an epoxy base coat ........................and i sure hope no one smeared Vaseline on the boat or you will be there for ever solvent wiping it with mek

 

[bigbad 4cyl x2]

Re: Paint prep?

on a small boat if i did it again i would just get a bottom job with vc performance epoxy at a boat yard ,and tell them to go all the way to the gunnels .then paint your topsides

 

[Yacht Dr.]

Re: Paint prep?

Hiyas Mike..

Well the paint you put on is only as good as the paint thats on there allready..

If you paint over paint thats falling off then your paint will fall off with it.

You have to remove Any and All failing surfaces before you even think about recoating.

As far as "solvent cleaning b4 you sand" .. that depends ( for your application I would say no ) However You should Wash your boat with soap and water before sanding.

Power and hand sanding is the recommended way ( I suggest hand sanding those places where you cant get a machine to FIRST .. then machine the rest )

What grit to final sand is determined Product by Product and Application method. ( 320-600 depending on the type/brand sandpaper for topcoats )

Final wipe down is Also determined by substrate ( debatable again ).
Denatured alcohol ? Acetone ? Windex ? or nothing.. Ive seen every wipe down there is and non is without its merits or downfalls.

If you ask me what the Best final wipe down Ive seen.. It would have to be the "blow off method" ( Using dry cotton wipes and a blowgun .. then Tack and spray ).

I know.. " You mean to tell me that you dont wipe down your paint job with some kind of cleaner ??? " .. erm.. no If I can help it I will not use wipe with cleaners. ( Im just very carefull not to get my oily/sweaty hands/arms all over my finely sanded 400 grit surface before I paint.

YD.