Lower unit painting

[ZmOz]

I just removed my lower unit to get the powerhead off, while it's off I think I'm giong to paint it. First of all, how should I prepare the surface? Strip it? (with what?) Then what do I need to do to the bare metal? And finally, what paint should I be using?

 

[ZmOz]

Re: Lower unit painting

Don't all jump in at once now...

 

[VistaMan]

Re: Lower unit painting

Hey Z you got the lower off, did you get the power head off too? I repainted the gear case on my Nissan. I sanded down to get out all the chips, etc. Then cleaned and degresed well. I used zinc oxide primer (yellow stuff that I got at an auto parts shop). Sanded this and the gave it another coat. When all was dry I shot several coats of your normal auto spray paint in a bomb. I then let it harrden for about two weeks (was done in winter so I was going nowhere). I ran this for 3 seasons with no problem, except where I scraped it on sand and stuff but nothing peeled off.

 

[ZmOz]

Re: Lower unit painting

Powerhead's almost off...it's finally free, now I just have to figure out how I'm going to remove it from the contraption I made to get it out. <br /><br />I'm thinking about getting a cheap sandblaster to do the lower unit, I wouldn't have to do any sanding if I sandblasted it would I?

 

[VistaMan]

Re: Lower unit painting

I guess snadblasting would be the best, it would get into all the little crooks and crannies. Just make sure you de-greas it well before putting on the primer. Do you intend to dissasemblt the gear case or just paint as is? If you don't disassemble mask off the various bearings and seal well before sand blasting.

 

[DJ]

Re: Lower unit painting

I would NOT sandblast it. You want to leave any paint on there that is still there. The factory did a better job of prep than you will be able to duplicate.<br /><br />With that said, I agree with the others about using zinc chromate primer-a must. You only need it on the bare aluminum parts. Before spraying the ZC wash the entire unit with a 50/50 solution of vinegar and water. That will further "etch" the bare aluminum and give the ZC something to bite into.

 

[VistaMan]

Re: Lower unit painting

In reflection I agree with not sand blasting. unless, of course, there is more bare aluminum than paint in which case the original finish will be minimal. Just make sure that everything to be painted with primer is CLEAN. even touching it with your fingers will leave grease that will cause the ZC to not hold.<br /><br />Good luck.

 

[shuff]

Re: Lower unit painting

Even if you sanblast the lower unit, you still need to sand out all of the embedded residue from the sandblaster. I agree it is best to feather out the chips and scratches, wash with mild acid solution and prime imedietly with zc. Aluminum does not rust but it will oxidize very quickly.

 

[ZmOz]

Re: Lower unit painting

So should I paint over the original paint with the aluminum primer?

 

[VistaMan]

Re: Lower unit painting

I did, seemd no problem.

 

[BrianTindall]

Re: Lower unit painting

If you do use a media type removal system, DO NOT USE SAND. Sand is an abrasive and will remove metal which is what you don't want! Use a fine grade of glass bead material. This will remove paint and oxidation but not metal.