How cold is to cold to paint an outboard?

[boater1234]

Hello to all.I have posted on here about painting my outboard which is a 15hp 2stroke merc.I have attemted to paint it once and completely destroyed it by putting to much paint on it.So i started over and went all the way down to the bare metal from the cavitation plate down.I have all the info i need now to do it right but one thing.I live in tampa fl and it doesn't get to cold but it is around 65 to 70 during the day now and around 45 to 60 at night.It will be this way for the next 3 days.My question is will it be to cool to paint my outboard on days like this.It is not so much the day it's the night i'm worried about as it gets damp.I also know the paint dries fast to touch in less then 30 minutes.It cures to go in 24hrs so the can says.It's the phantom black paint.All i really need to know is will the paint be ok.

I keep getting mixed thoughts on the zinc chromate primer as i read 5 websites that say put it on thick as it will protect better and then 5 or 6 more say put it on as lite as possible.Can anyone help me on that as well as the temp please.I have the yellow marine zinc chromate by moeller.I have read and heard here to go 50/50 water/vinegar first to get the primer to etch better,wipe down with a tac rag and then prime it,then paint it.Any help would be great as i want to tackle this tomorrow or so i'm just scared it's to cool out and don't want to sand again as it took me 3 days by hand.Ohhh that hurts the fingers.

 

[RRitt]

Re: How cold is to cold to paint an outboard?

salt-water? I'm not 100% sure I would trust aerosol primers and preps in salt water. If so, then it would probably be the duplicolor self-etch aerosol first. A skinny coat that you can see through just to promote adhesion and then lay your epoxy or z/c on top of that. If you want to scale on up then go to a PPG paint store and ask for the stuff they use on aluminum airplanes.

but back to temp. pick a warm dry day and your yard job will turn out just fine. If you use higher end paints then you buy solvents to suit the temperature range. Aerosols have to be generic solvent based paint by definition and will give somewhat lower quality over a much broader temperature range. Avoid humid or rainy days. Direct sunlight will help your project harden/dry/cure. Don't wait for the insects to come back. They seem to like the smell of solvent and epoxy based paints.

If you want to di it up right, nothing beats a compressor and a gun.

it is more important to have a watertight seal with good adhesion than anything else. Do that first. Then put it on however thick makes you feel good. The major benefit of thick primers is that you can wet sand them until they are silky smooth. That will give your top coat a mirror-like finish.

 

[Yacht Dr.]

Re: How cold is to cold to paint an outboard?

Spray cans will tell you what temp range on the back lable..

Data sheets or web sites will tell you temp range for "spray" products of any given manufacurer..

YD.

 

[200SuperPro]

Re: How cold is to cold to paint an outboard?

Boater1234
RRitt gave solid advice!!
I have painted autos and aircraft for over 20 years and will give you my opinion.
Most paint Data sheets reference 75 degrees when giving drying/cure times. I personally would not paint anything below 50 degrees. Paint drys faster when warmer slower when colder. Epoxies/urethanes dry by a chemical process, most enamels latex and laquers dry thru solvent evaporation.

As far as Zinc Chromate goes, its a sacrificial coating for corrosion protection. If you have a problem you will see it thru the paint blistering later on. Most Chromate primers I have used have always been applied till coverage was achieved or barely able to see through it. I would not pour it on so to speak, these materials are thin in nature and will run quickly. Your idea of using water/vinegar is old school. An epoxy based paint is glue in a can, the scratch that you made while sanding is adequate for adehesion. There are only two ways paint adheres, mechanically or chemically. The scratch from sand paper is mechanical adhesion, the bonding properties of epoxy is chemical. Im not sure if the primer you are planning to use is epoxy based, if it is you should be fine. I would definitely wipe everything down with a 50/50 mix of alchohol and water to remove any contaminents then tackrag and spray.
If time is a concern you could apply primer one day then topcoat black the next. Just lightly sand in between primer and black,and tack off. Remember when topcoating multiple thin coats will give better results than one or two heavy coats!!

 

[sschefer]

Re: How cold is to cold to paint an outboard?

I've done a few lower units in my day and I've done them all with Moeller paints. I don't use their zinc chromate because there's no point in adding a anode under the paint. Instead, I use Alumaprep 33 as a pre wash etch then I spray and brush in Alodine 1201 (gold tint), rinse and let dry. Alodine is a chromatic converter for aluminum so you get all the benfits of the chromatic conversion with out the downside of adding Zinc.

Paint temp for the Moeller seems to be best around 65 degrees but make sure to put the next coat on when touching it will leave a print but paint doesn't come off on your finger. This will assure a good merge with the base paint. Any sooner and you'll build up too quick and it will take forever to dry and any later and it will blotch on you. After 30 minutes the temp can change all it wants, the drying process will either shorten or lengthen with the rate of evaporation. Bear in mind that I'm talking only about this Moeller paint and the way it works. It can take a month or more to achieve a hardness that's durable.

 

[fisherguy123]

Re: How cold is to cold to paint an outboard?

I too used to refinish aircraft and autos and you got good advise from the posters above. I refinished my 30 Suzuki about 6 years ago with epoxy primer and topcoat. The temps were only about 60 deg in my shed .The motor has been used every year and moored in salt water ( tipped up) for 3 months at a time and still looks good.