Prepping the props: A primer on priiimer!

[Expidia]

50 degrees today, time to get busy for the first splash down. It's coming up quick (I hope).

So I put both my aluminum props on my work bench today to paint them correctly this year. I have a 13 pitch Merc OEM and the other one is a 12 Vortex which I bought last year to carry as a spare and to put on when there is going to be more than two of us on the boat.

Of course I banged each one up last season (one twice) on the occasional sandbar that came up out of nowhere when I was not paying attention to the GPS. Hudson River bottom contours are tough because once you leave the channel to fish, the bottom can change from week to week because it's muddy plus it has a 6 foot tide to deal with even though it's a fresh water river. And lotsa floating debris like branches, LOGS and TREES

So each time I got them back from the online prop repair shop I noticed the paint would chip away in spots as soon as the prop even smells sand again
I called the shop and they said they just spray them down with black Rustoleum and ships them back real quick.. They don't use any primer. For the $30 bucks or so they charge, I figured everything?s a trade off.

I hate the look of anyone's prop (especially mine) with the paint all knocked off when they pass me on the highway. Just says to me they must be as bad a navigator as I am . . . so to fool everyone into thinking I can actually navigate a boat as soon as I knock some paint off an ear or two I spray it when I get home. Stainless must be nice!

But last season after touching them up with a little grey spray primer followed by the black spray just normal use pops some paint off again in places.

So I asked on this forum last year what's the best way to paint yer prop?
Consensus was that I should first use "self etching" primer spray.
So this year I'm trying tp start out right . . . first.

I picked up a can of Dupli-Color self etching primer in Advanced Auto for about $5.98. It's green, but that makes no diff to me as it's going to be covered in black anyway.

Sanded both props down a few hours later with a Black and Decker Mouse vibrating sander. It has a nice pointed shape and it really made fast work
out of removing the chips and roughing up the whole surface of each prop.

I wiped them clean with some turpentine and put both on a length of copper tubing and set the tubing between a fence in the back yard and lightly sprayed both props with the self etching primer. Says best used in 70 degrees, so since it was only 50 I moved them back down the basement to dry.

Next step will be to lightly sand them down with 400 grit wet/dry paper as the can says and then a coat of the black. I bought two cans of the QuickSilver Mercury Phantom black last year at West for $12 each. Not cheap, but a little should go a long way once I'm only retouching chips and not the whole props.

I also bought the QuickSilver grey primer, but I called my autobody guy (guess I can't drive a car that well either if I have an autobody guy! it's OK, I have him on a retainer). He said to just lightly spray the etching stuff on, sand it a little and I should not need to use the grey primer before I spray the black coat on.

I'll report back on how well this method I used holds the paint this season. The OEM paint that came on the Mercury prop gave me about 100 hours without any paint coming off under my normal use until I hit an under the waterline stump one day. So I should be able to keep the paint on if applied correctly. I hated it last year when a big blotch chipped off a prop ear each time I painted them, I guess cause I omitted the etching primer step last year and just used the grey stuff first.

Thanks for the input last season on what I was doing wrong . . .

Starting off the new season with freshly painted props . . . now if I could just manage not to hit anything this year

 

[Expidia]

Re: Prepping the props: A primer on priiimer!

By the way, anyone know if I would have been better off buying the two cans that said Mercury QuickSilver "Prop" paint rather than the Phantom black cans I bought?

I figured the Phantom can would be better for touching up the lower unit too.

I read both cans, they appeared to be the same.

Also, before I put on the black coat after wet sanding is there any other prep work I should be doing? At $12 a can it's an expensive learning curve if the paint still flakes off because I did not buy the can that said "Prop" paint or I did not prep the props correctly this time?

Thx

 

[Expidia]

Re: Prepping the props: A primer on priiimer!

Just learned another prep tip. Nice day yesterday, about 55 degrees so I had a chance to give the props the first spray coat of black over the "etching" primer coat I did last week.

So the merc spray can says if you are going to put on a second coat it needs to be done within 4 hours of the first coat or the second coat will peel.
After 4 hours you need to wait a week for the second coat.

I wanted to wet sand the first coat anyway and was a little nervous about wet sanding after only a few hour drying time, so I'll just wait the week for the second coat.

I'm trying to keep each coat super thin so as not to impede the props performance.

So I bring this up in case you plan on two coats . . . depending on what your brand of paint can says don't plan on 1 coat and giving the props another coat the next day. The whole process may take a lot longer than you expected so you need to allow for this in case you plan on launching your rig soon.

I'm going to hate to wet sand them now for that second coat with the 400 grit because so far they both look amazing.

 

[Expidia]

Re: Prepping the props: A primer on priiimer!

Follow up . . . used the boat twice already and that etching primer really holds the final black coat on tightly.

Without the light base coat of etching primer I was never able to keep the paint from chipping back off once I re-sprayed the props after hitting sand etc.

Even when using the Merc gray primer first, I could never get the final coat to stay on in spots.

 

[Benny1963]

Re: Prepping the props: A primer on priiimer!

you can keep the paint on useing good primers under60 mph
and out of sand were i boat there is a lot of sand i tried everything including
a product calle tile clad used to paint bat tubs and ceramic tile nothing works for long
so i use stainless props and polish them .
let us know how it gos your lucky to have such beautifull places to boat.
in louisiana the fishing is good but the water is horrible

 

[Frank Acampora]

Re: Prepping the props: A primer on priiimer!

Wow! Painting props! Can you spell anal-retentive, compulsive-obsessive? LOL

Is Monk your hero? LOL

Yeah! stainless is nice that way and I usually take a wheel and jewelers rouge to my bronze props. Dang! They're shiny! I like the way they look while driving down the highway.

That's another thought. If you strip all paint and polish the prop, aluminum comes up almost as shiny as stainless. If you do it well, it is difficult to tell the difference.

 

[AMD Rules]

Re: Prepping the props: A primer on priiimer!

I agree, and run stainless on my 115 Mercs.

On my smaller motors, I just polish the aluminum instead. To me they look like stainless.

 

[Expidia]

Re: Prepping the props: A primer on priiimer!

Wow! Painting props! Can you spell anal-retentive, compulsive-obsessive? LOL

Is Monk your hero? LOL

Yeah! stainless is nice that way and I usually take a wheel and jewelers rouge to my bronze props. Dang! They're shiny! I like the way they look while driving down the highway.

That's another thought. If you strip all paint and polish the prop, aluminum comes up almost as shiny as stainless. If you do it well, it is difficult to tell the difference.

Oh but this part of your routine is not anal: "Yeah! stainless is nice that way and I usually take a wheel and jewelers rouge to my bronze props." hahahaha

I hate to see chipped up painted props going by me on the highway because this means the captain is as bad at navigation as me
I usually have a yellow plastic bag over my prop anyway so someone doesn't whack it from behind when I stop at a light.

Polishing the aluminum would look sharp until my luck would have a dumb thief stealing it cause he thought it was SS

 

[Starcraftguy1]

Re: Prepping the props: A primer on priiimer!

Don't use mineral oil to wipe down the prop next time,oil and paint do not mix in any way.Water is better.Adhesion problems,fish eyes.By the way,I am going to polish my aluminum prop on my Mers 40 hp.

 

[Expidia]

Re: Prepping the props: A primer on priiimer!

Don't use mineral oil to wipe down the prop next time,oil and paint do not mix in any way.Water is better.Adhesion problems,fish eyes.By the way,I am going to polish my aluminum prop on my Mers 40 hp.

Glad you caught that typo. I meant to say turpentine (mineral spirits). I corrected it above too.
Ya mean if I sprayed them down with mineral oil the paint wouldn't stick . . . hahahaha
I think people drink mineral oil as a laxative! Probably not a great bonding agent

 

[sschefer]

Re: Prepping the props: A primer on priiimer!

Sounds like you have them all done now, so for next time, use the same method for preping the props, clean them thoroughtly and dewax them with mineral spirits, (aka paint thinner). No, not mineral oil, mineral spirits, LOL..
When you have them all cleaned up shoot them with a wash coat (thin) of the zinc chromate etching primer and let it dry for about an hour. Do not sand it. Next shoot your first tack or half coat of color followed immediately by a full coat and let that dry until touching it leaves a fingerprint but none of the paint comes off. Shoot your second full coat and call it good.

If you shoot the second coat at the right time, paint will merge and the two coats will dry as one. The result will be a super high gloss finish that will be fully bonded to the aluminum.

As a side note -Most prop paints do not achieve maximum protective hardness for about 7 days so don't paint and run.

I'm doing mine this weekend, I'll post some pics in my thread.

 

[Expidia]

Re: Prepping the props: A primer on priiimer!

Sounds like you have them all done now, so for next time, use the same method for preping the props, clean them thoroughtly and dewax them with mineral spirits, (aka paint thinner). No, not mineral oil, mineral spirits, LOL..
When you have them all cleaned up shoot them with a wash coat (thin) of the zinc chromate etching primer and let it dry for about an hour. Do not sand it. Next shoot your first tack or half coat of color followed immediately by a full coat and let that dry until touching it leaves a fingerprint but none of the paint comes off. Shoot your second full coat and call it good.

If you shoot the second coat at the right time, paint will merge and the two coats will dry as one. The result will be a super high gloss finish that will be fully bonded to the aluminum.

As a side note -Most prop paints do not achieve maximum protective hardness for about 7 days so don't paint and run.

I'm doing mine this weekend, I'll post some pics in my thread.

Thx sschefer, I printed this thread out for next time . . . Oh and I'm sure there will be a next time
I've read the zinc chromate thing on another thread before I did it. I found the Duplicolor etching primer in an auto store. I was on my way to the auto paint store, but they were closed for lunch. So I said the hell with it.

The primer I used just said etching primer (no ZC on the label) it seemed to be a toss up on the consensus from the other thread regarding primers, etching vs chromate.

My Merc spray can said if you don't hit it with the 2nd coat within 30 minutes you have to wait 7 days for another coat which is what I did. I wanted to sand some over spray smooth anyway.

I'll try what you suggest. They do look great though. Better than when they came from the factory.

I'm getting good at this spray painting stuff . . . I've now graduated up to radiator covers after the props I picked up this cover at a factory store (it was $200) a bit of a rip on the price for unpainted and unassembled yet, but I've been wanting to cover this ugly radiator for 3 years now.

So I asked them since it's unpainted what's the best primer to use and she said "oh' no need to prime it, it's already ZINC coated" (get it, here's that zinc again). Used a semi gloss spray can of Rustoleum for the job. Finish came out excellent!

The flash in this pic highlighted the radiator through the grid, but you really can't see it at all anymore!

 

[sschefer]

Re: Prepping the props: A primer on priiimer!

Zinc Chromate is an etching primer and it's a common name for etching primer. It's illegal in California now and they stopped calling it Zinc Chromate but we still have etching primer. It is really only necessary if you can't apply paint to aluminum within 10 minutes of sanding. That's about how long it takes for clean, bare aluminum to begin to oxidize.

The important thing to remember about primer is that it is designed to act as a bonding agent and filler. If it hardens it will still stick to the base material but the paint will not adhere as well to it because it can't merge with it as it should. The fact that the radiator was pre-primed with ZC probably won't be a problem since it's not in a harsh environment but it will make a difference in a situation such as a prop where cavitation can strip paint like a Porter Cable paint eater.

 

[Expidia]

Re: Prepping the props: A primer on priiimer!

Ya, that's what was happening to me. I was putting the repaired props back on too fast without waiting at least 7 days from when they painted them each time. The props rotation would tear bloches of paint right off.