Bottom Paint Situation

[bayonnebandit]

Hello all,
This is my first post. I can't believe there is a StarCraft group! I actually renovated my fathers 1978 21' Mariner a few years back and I never knew that there was such a following for these boats. I will post pictures of my renovation soon!
That being said, I do have a problem that I hope you guys can help me solve. When I painted the bottom of my boat I used regular bottom paint that my brother had left over from his boat. I had no idea that this would react with the aluminum...... so now I have a problem. The paint has started to deteriorate off badly and its quite rough on the bottom of the boat. So, my question is if I can sand the paint smooth and then paint over with aluminum safe bottom paint, or do I have to completely strip the old paint off and start new. I know option two would be better, but I do not have much free time these days, and I would rather not have to strip everything. What do you guys think. Thanks in advance

 

[CheapboatKev]

Re: Bottom Paint Situation

Hate to say it..But I really think you will need to go bare metal to make sure any of that old bottom paint is all gone.

 

[ezmobee]

Re: Bottom Paint Situation

I agree. A number of guys on here have had great luck stripping these hulls with chemical stripper.

 

[bayonnebandit]

Re: Bottom Paint Situation

Thats what I was afraid of. I actually used chemical stripper to strip the topside of the boat when I repainted it. Worked out well, but it was quite a lot of work. Do you guys suggest a primer to used when painting it after it gets stripped. I used the interlux self etching primer the last time I did it and it was really hard to work with given the fact that there was a "window" of time that you needed to paint over the top of it. Thanks a lot.

Also if I am going to strip the entire bottom I think I want to use that coating stuff that is supposed to seal leaks. I am not sure of the name or how to use it. Can anyone help me out?

 

[ezmobee]

Re: Bottom Paint Situation

Gluvit. It works better applied from the inside though. You definitely need etching primer. I found Duplicolor's at Pep Boys for about $5 a spray can. You only need a light dusting of the stuff.

 

[barato]

Re: Bottom Paint Situation

i feel your pain on the stripping. but yeah, you definitely need to get the old stuff all off....has to do with galvanic corrosion, contact between the copper in bottom paint and alum hull causes alum hull to become a "sacrificial anode" and corrode. esp if you go near salt water. check this out: http://en.wikipedia.org/wiki/Sacrificial_anode

what about walnut shell blasting? as in, pay someone else to do it. or even pay someone else to chem strip it? then just scotchbrite it and/or clean with Dupont acid wash prep right before you hit it with the self etching primer. i'm a DIYer all the way, but would not feel my life was colorless and devoid of adventure if i never worked with chem stripper again......

 

[coolbikeguy]

Re: Bottom Paint Situation

if you want to strip it .... i got some stuff from lowes. it JASCO paint stripper. its in a bronzeish colored can. this stuff works great and FAST ( atleast it did for me ). brush it on, let it sit, then i used putty knives and wire brush to remove. this stuff is crazy, sometimes you can actually hear it fizzing as it bubbles up ..lol i have used zip strip in the past for other projects and tried it on the boat but the results are not even close to the JASCO stripper. heres a pic of a section i did in about 10 min ......

 

[bayonnebandit]

Re: Bottom Paint Situation

Thank you all for the help. I know its recommended that the gluvit be put on the inside of the boat but I have already refinished the floor and I would rather not go through ripping that up. If I do put it on the outside, at what point in the process do I put it on ............ before primer, after primer, before paint, after paint? Also where is the best place to get it. Thanks in advance.

 

[ezmobee]

Re: Bottom Paint Situation

Gluvit is self etching so it can go on first.

 

[fshngho]

Re: Bottom Paint Situation

there are several places online to get Gluvit, but we try to support IBoats and you can get it from them. There is also a thread that shows someone coating the complete bottom hull on the exterior with Gluvit, then painting.
Good Luck

 

[bayonnebandit]

Re: Bottom Paint Situation

Ohh ok. Just to make sure..... If the Gluvit is self etching and can be painted there is no need for a primer step right. Or is it still recommended to prime. Thanks guys. And I will try to get you the pics of my restore soon. As I see there is bragging rights for restoration of the year. I'm keeping my fingers crossed.

 

[ezmobee]

Re: Bottom Paint Situation

Strictly speaking of your Gluvit application....no primer needed.

 

[fshngho]

Re: Bottom Paint Situation

Ok Bayon here you go: Gluvit is what everyone has explained. When you strip the hull you will apply Gluvit to the seams and rivots. Gluvit 'flows' into the cracks and crevices to seal anywhere it may leak. Some guys even tilt the boat and re apply to make sure it flows where needed. You will not paint the hull with Gluvit because its expensive and...why? You don't need it where there is no danger of leakage. So my friend you will want to lightly paint hull after Gluvit with an aluminum self etching primer. That will hopefully keep the paint you apply sticking to the hull. Check out the resto's and you will understand the concept. Good Luck, Dale

 

[qjaybo]

Re: Bottom Paint Situation

I like ZINC CHROMATE as a primer for bare aluminum. Just a light coat is all you need. My Starcraft is getting the zinc primer followed by Interlux primer and Interlux Brightside finish paint. Not sure how well it will hold up, as i am doing it now. But this seems to be the way to go, at least from everyone i have spoken to about it.
Good luck.