Bottom Paint question

[Reely Hall'n]

Hello all, going to be painting the bottom this spring. Original paint was blue and someone painted black over it which is peeling and flaking. I was told to sand it with 80 grit first and then repaint. What paint would you recomend for cold fresh water? Thanks for any help

[Buckknekkid]

blast it. we spent 2 weeks sanding before we did the BOTTOM KOTE

[capt ralph]

hi guys,i too am going to repaint the bottom this spring.my mechanic suggested to blast it.he said you wont be able to sand off all those yrs of paint,and it will look much better.im going to take his advice

[Reely Hall'n]

What type of blasting are you sugjesting, portable sand blaster?

[Reely Hall'n]

Won't sand blasting cause damage to the bottom?

[jimbo36]

Interlux fibreglass bottom kote. I have used it for years. A two coat job lasts me 2 years. (lake Ontario)

[capt ralph]

i am not sure about that yet,he just works on the engines.it sounds good but i am going to have anything done until i find out for sure

[capt ralph]

he did say he will use a potable

[jimbo36]

Just a caution regarding sand blasting. This will blow through gelcoat fast (particulaly, in the hands of a novice) creating a whole new problem. Soda blasting is a better choice or even co2, which uses dry ice and leaves no residue behind other than the old paint. None of the choices are cheap. So, if you can get away with sanding it is the way to go. After all, by nature, antifoul dissappears while the boat is in use so excessive build up should not be an issue.

[Wes]

I had the bottom sand blasted 14 months ago by a professional that was recommended by the maina service techs. He did a great job and made life much easier. We're in salt water so I put 4 barrier coats on, a tracer coat and finished with 2 ablative coats. The whole process, with me doing the painting was around 2800.00. It was a lot of work but I saved a bunch of money.

Wes

[chauzer]

i think soda blasting is the way to go. if you want i can call a guy i know and he would do it. with soda blasting you won't mess up the gel coat. he also does media blasting and that is done with crushed walnut shells.

[cookscomp]

Well I'm wondering about the chemical removers like soystrip and such. I'm a complete novice when it comes to bottom paint and want to do mine sometime. Does anyone recommend this method? Doesn't sound like it's even an option with you guys. Thanks for advice. Tim

[Wes]

I was told if you just want to take 1 coat off soda blasting was fine. If you want to go to the gel coat you have to sand blast and use a guy that really knows what he's doing. The depth you go depends on the pressure to use. I also did a lot of research on chemical removal and with the EPA regulations here in CT and being in my 60's I decided that the easy way was to have it sand blasted.
Wes

[prowlersfish]

They have been using soda blasting around here to remove muilti coats .
I guess it depends on whos blasting .

[gjrylands]

Hello all, going to be painting the bottom this spring. Original paint was blue and someone painted black over it which is peeling and flaking. I was told to sand it with 80 grit first and then repaint. What paint would you recomend for cold fresh water? Thanks for any help

Don,
For those of us living in the north and boat in fresh water, bottom paint is not quite as important as for those living in the warmer climates and keeping their boat in the water year round. Our boats are only in the water about 7 months a year. They get pulled and power washed each fall. Each spring we start the season with a clean hull. I paint the entire bottom every three years. I paint the bow, sides, stern, and touch up any chips there are on the bottom every year. I use Interlux Fiberglass Bottomkote.

You stated that the black paint is pealing and flaking from the blue. This could indicate that the paints weren't compatible. If the problem is with incompatible paints there will be large sections of paint coming off in a sheet. Take a putty knife and try chipping off more black paint. If it comes off easily you have a problem with the bond between the black and blue layers. Nothing short of stripping will stop the paint from pealing. Blasting it off is the best way to remove it. This is an expensive process and should be left to the professionals.

If, on the other hand, the chipping and pealing are minor and it’s difficult to chip off any more black paint, you should be able to paint the bottom. Sand the bottom with 80 grit paper. Sand the paint around the chips to blend in the chipped areas; give all the chips a coat of paint and let dry; then paint the entire bottom.

Next year when the boat is pulled and pressure washed, check how the paint held up. If the paint is OK you will have saved a lot of money by not blasting. If large sections have pealed you will know that there is a problem with the compatibility and can then conceder blasting the paint off then.