Last update:
Nov 5th, 2007
My bad for the delay, just been busy!
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I will assume you have read our terms prior to reading. If not, read it now!
aluminum paint repair
Now that the legal stuff is out of the way.
The project
One 96 foot Decktor Sail Boat, Bahia Mar Marina, Fort Lauderdale Florida.
This beautiful sailboat has three blistering areas of the boat.
Aluminum paint blistering is cause by water intrusion on to the aluminum surface. Aluminum is very corrosive and pores. Just a little bit of water intrusion in an area without paint or a paint crack will cause a paint blister.
Important!!!!!
Blistering is almost always cause by water!
Either there before or new intrusion, it is caused by a breach of water resulting in the release of paint from the surface.
Paint will mildly stick to dirt far easier than water or dampness (Hint, blistering in fiberglass is the same, more on this much later).
The goal to in a high quality repair is to first:
1 Remove all of the old paint a corrosion.
2 Treat raw metal surface.
3 Perform bodywork.
4 Prime.
5 Color match paint.
6 Apply paint.
7 Buff away hallo.
The above is our 5 repair areas.
The first task is to remove all of the old paint and remove the corrosion underneath the paint repair area. You want to remove dead surface until you get to the core of the problem.
You want to get too fresh and new!
awl grip
imron
Here we use a Dremil tool to grind away the oxidized aluminum.
A good repair involves tracing the problem to the core of the issue!
For a quality repair, NEVER GIVE AN ESTIMATE without finding the core issue!
You simply do not know until you have revieled the true problem.
Watch the below picture/repair grow as a key example.
There is a very fine line between a body man professional and a professional destructionist.
The above photo ended up being water intrusion from an unknown place below the wood above.
Once you have reached the core, it is time to treat the raw surface area.
Just because it is raw, this does not mean it is ready to be fixed.
Wood needs acid
Metals need acid
Fiberglass needs lots of acetone
CONDITION EVERYTHING prior to application!
Next, we treat with Alodine aluminum conditioner.
Next we spray Zinc Chromate on all of the exposed aluminum areas. Zinc Chromate is a corrosion inhibitor.
Zinc Chromate is a simple necessity.
Just like clouds across the sky product electricity, a boat does across water.
Zinc chromate is an insulator;
(YOU ARE DEALING WITH METALS and PAINT WITH METALS, Zinc reduces the magnetic charge)
Physical science 101 here!
Aluminum has a negative charge as does lead (a heavy and necessary ingredient in marine paints)
Stick two -neg magnets together and they push away!
NOTE: Cheap Zinc chromate (the stuff in a spray can does not "stick" well.)
Spend the extra buck on quality stuff (yes, the spray can is better than nothing, just sand it viciously prior to the next step).
Sterling and Awl-Grip make some really good (stick able Zinc Chromate)
After applying the fiberglass reinforced filler to the structural repair. We grind away the excess.
What we are left with is a little rough, but our basic shape is now starting to form.
Now, for the thin layers of final faring, we use lightweight faring putty. This enables us to fine tune out shaping using sand paper instead of a grinder.
Structally, you should be sound. Use lightweight faring putty so that you do not break your arm trying to sand it smooth.
color matching
After two or three re-applications of the faring putty to fill all of the pin holes and minor modifications to the shape, you should have something like this above, with only very minor pin holes which we will fill with primer. Following the primer, apply the same light black coat of black paint, and sand again. By this time, not black or dark pin holes should be noticeably.
Primers main job is to fill all of the remaining pin holes. Once sanded (using the the black guide coat) the surface should be free of imperfections.
You are now ready to prepare for marine paint, either Imron or Awl Grip are preferred.
Now for your color match. The most important process, and the most delicate!
This lesson is about color matching. Color matching is a learned art and should be treated as such. It is a very delicate process if it is going to be done correctly.
Be ready for countless retries!
More specifically, we are going to address color matching for your whites and off whites using Awl Grip Marine paint .
Step 1
Know your whites
There are many colors of whites, as many as the rainbow. The key is to know which white you are starting from.
It is possible to get a pure white free of tints, but you us
In the above diagram, you can see that the color white is an origin of the other colors spanning from the middle to the outer layers.
Just go ahead and figure that you are never going to actually get the color white that is in the middle. On the rarest of occasions you might get a neutral white, but most chemical suppliers provide you with a yellow/white or a blue/white.
Bright white = blue/white, so if you add yellow, you get green!
Basic Crayola here.
Know the origin of your white before you proceed!
If you understand this basic concept or origin white, you should be able to compensate for mild changes in color.
Now, with this in mind, we are going to assume you are going to be working on color matching a 42’ Regal boat hull which is a know tan with red.
So, how in the world to you get that?
Read on to find out how!
Step 2
Know the rules
Rule 1 : Always scrape the sides of your mixing container vigorously. Notoriously you will be close to the color and then scrape the sides and find yourself 3 shades backwards.
Rule 2 : Always color match in dull white light. I.e. early morning 7am – 8am, late afternoon 5pm – 6pm, or under cloud cover. Can’t tell you how to do it indoors, I never get the chance. Why you ask? Because bright light will fool you into thinking the gloss from a fresh gel coat drop is a darker color!
Rule 3 : The way it looks wet, is the way it will look dried and buffed! The simple answer is no, it will not change color. Other than some tricks that bright light will play on you, the color will remain exactly the same!
Rule 4 : Always make a color trail. Every drop you put on a surface makes where you have been and can easily be wiped with acetone to remove it at any time as long as you have not catalyzed the paint with hardener. Your trail of color attempts is your reference.
Rule 5 : Always wet sand with 1000 grit and buff with compound the surface area you are trying to match. Matching the color of dirt is a pain and will leave you with bad results. Take the time to prepare correctly!
Finally the area that we intend on doing our color trail, apply a light coat of wax.
Next, prepare your work area and use small amounts of the paint.
Ok, so we are under the understanding that you know the rules and you have prepared your surface correctly for your color match. So lets get the materials you are going to need.
1. 1 qt of white paint.
2. 2 mixing cups
3. 4 wood stir sticks
4. the following tints yellow, brown, black, blue and red. (we may not need all of these, but it is good to have on hand when color matching. i.e. I was color matching a 2006 Regal which looked like a typical light brown, got close the color and saw a definitive red, added one drop and bah-da-bing, nailed it!
Let's begin!
First, break one of your wood stir sticks into shards by twisting it. You only need pieces to dip into the pigments.
Then, poor about 8 oz of gel coat into a mixing cup (No matter how much gel coat you are going to need, you always start of with 8 oz to find your basic color configuration)
Put one drop of plain white gel coat onto the surface you are trying to match. You will 99.99% of the time see right off that the drop is way too white, but this begins your color trail.
Now, as we begin to add pigment, understand that there are 2 parts to color matching.
1. Color shade i.e. black and brown.
2. Color tone i.e. yellow, red, blue
First we address the tone which is to darken the color slightly so that we can accurately see what color tone you will need. You will see new colors needed as we shade the white down.
Add about 4 to 5 drops of brown or yellow (keep in mind, most brown paint tints are red and require black and yellow to bring to a brown) to you white Awl grip and mix. Be sure to scrape the sides of the container. The put one additional drop of your mixed color right next to the first drop of your color trail. You should already notice the drastic change, but more than likely, you still have far to go. Normally you will need at least 15 to 40 drops of brown tint before your shape is even close, but do this slowly and in increments of 5 drops so that you do not go to far. Every 5 drops add another drop to your color trail so that you can compare the results to your previous mix.
As you get close to the shade, put your eye right up next to your drop on the color trail, like 6 in or less and stare at the drop/surface with a dull stare. You will begin to notice color richness of brown in your drop, and hopefully begin to notice color richness in the surface, meaning, you will actually notice the millions of occupancies of brown in the drop on your color trail drops and also be able to compare the millions of occurrences of different colors in the surface you are trying to match. It is very mild, but as you shade down, and stare dully, you will now see definitive differences!
BE CAREFUL NOT TO SHADE TO MUCH WITH BROWN (too rich in brown)!
You are just trying to add enough brown to begin to see the other colors in your surface!
Once you have shaded the color about 10% lighter than your surface, begin to look for the other colors that are needed.
You might see red? add one drop of red and see if that moves you closer. If not, you have only added one drop and you should be able to off set it without having to dump your color out and start all over again. Generally, most white boats have a combination of brown, yellow and black.
The more times you add one or two drops of a pigment and stare at it with a dull stare (or use a magnifying glass) you will notice richness of a particular color. Simply add one drop and see if it moves you closer. If so, try adding 2 to 4 drops of that color and see how that responds.
SLOW INCRAMENTS FOLLOWED BY A DULL STARE IS THE KEY!
If you go too far on a color, simply add white (4 to 8 oz) to back it off and then tone it down or color it to suit your needs.
Don't be afraid to say you messed up and start all over again. I have been doing color matching for 8 years and I still have to do this from time to time.
Eventually, you will notice that your colors will become a match. To verify, touch the drop with your figure to flatten down the drop.
WHEN YOU HIT THE COLOR YOU WILL SEE ZERO DIFFERENCE BETWEEN THE DROP AND YOUR SURFACE!
TRICK!
Once you have "hit the color" and you know that there is zero difference. I mean that every angle, close or far, everything indicates that that is the exact color without a doubt. Add 5% or slightly less white. Usually the gloss will trick you slightly! 8 years and many redo's have taught me this trick!
more to come!
