Painting aluminum

[Woodonglass]

Re: Painting aluminum

I'm thinking a quart. Typically most alodines I'm aware of, a Gallon covers approx 800 sq ft. I'm guessing your 22 footer should have approx no more than around 160 sq. ft. of tin.

 

[Yacht Dr.]

Re: Painting aluminum

Aye.. 1 qt Should do it .. Should depending how much you put on the floor ( apply with a rag or sponge ) .

YD.

 

[relocyo]

Re: Painting aluminum

Truely some fantastic info here, you pros sure know your stuff... I was curious about the comment YD made about the outdrive needing to be done all at once, im sure logistically it makes sense as an outdrive is usualy a small paint project, but, say someone sanded,prepped, and zinc chromated an out drive, then went boating for a season would that person have to restart the process of sand, prep, ZC? Obviously hypothetical but was wondering after YDs comment... Thank!

 

[Yacht Dr.]

Re: Painting aluminum

I was curious about the comment YD made about the outdrive needing to be done all at once, im sure logistically it makes sense as an outdrive is usualy a small paint project, but, say someone sanded,prepped, and zinc chromated an out drive, then went boating for a season would that person have to restart the process of sand, prep, ZC? Obviously hypothetical but was wondering after YDs comment... Thank!

Yes..that Hypothetical person would need to Degrease .. and reprep for a mechanical bond ( I would suggest another coat or 2 of primer after this situation ). As this hypothetical person would know how much of a PITA it is to prep a drive .. reprep would be something he would not want to do again .

YD.

 

[relocyo]

Re: Painting aluminum

Yes..that Hypothetical person would need to Degrease .. and reprep for a mechanical bond ( I would suggest another coat or 2 of primer after this situation ). As this hypothetical person would know how much of a PITA it is to prep a drive .. reprep would be something he would not want to do again .

YD.

Roger that... (hypothetically speaking )
Thank goodness if this ever happened it would only be the lower unit on an outboard, but I would suspect its still no fun... Lol... Thanks for the info....

 

[boatnut74]

Re: Painting aluminum

I was thinking I had over 200sq ft. but I could be wrong. I'm thinking about doing the inside to, as I also plan on painting that. The alodine is only like $35 a gallon and I'm sure I'll end up with some on the floor.

 

[djpeters]

Re: Painting aluminum

Will you be completely stripping off all the old paint? If so how?

 

[boatnut74]

Re: Painting aluminum

All the old paint will be stripped.....I'm actually over halfway through. I'm using Kleanstrip aircraft stripper, it works great. You can see my thread for the results, page 2 I think.

 

[sschefer]

Re: Painting aluminum

Things to think about -

Aluma Prep is not a cleaner, it is a preping process that etches the surface. The surface must be really clean before you use it or it does no good at all. Any oily or dirty areas will not get etched. It's most effective on virgin aluminum than it is on old tired stuff like you find during a restoration. Its best to either glass bead or soda ash blast the surface before using it.

Alodine 1201 is a chromatic conversion process where the aluminum surface is converted to a highly corrosion resistant chromatic surface with excellent bonding charateristics. A primer is not needed if you are using alodine.

Application - it will be nearly impossible to get a proper conversion using the spray and brush method on a surface as large as a boat hull. The correct method would be to build a tank and dip it.

Given the fact that your application of the Alodine will probably be severly flawed you are better to off to thoroughly wash the hull with Dawn dishwashing liquid followed by several wipe downs with Acetone. Wipe it until the rags no longer show any dirt or discoloration. Use an etching primer designed for the coating product your going to be using. If you're using Interlux perfection then use their two part etching primer. If you're using a different product use only etching primers that are compatable with the product. Zinc chromate is not the best product to use and hard to find now. There are any number of other products on the market that do a much better job. Talk to your local automotive paint supplier, many of todays cars have aluminum body panels, hatches, etc. The old days of only boats being made from aluminum are long past and the automotive stores have a good handle on the products that work best.

 

[boatnut74]

Re: Painting aluminum

Wow, so much great information. My head is spinning now . I've been doing some research on awlgrips website, which gives information on prepping aluminum. On anodized parts they recomend using their wash primer. I always thought every surface needed a primer (but I learn new things all the time). I don't really want to blast the hull and risk alot of warpage. I'm stripping all the old paint off and was going to give it a thorough cleaning before alumaprep and alodine.

 

[boatnut74]

Re: Painting aluminum

Aluma Prep is not a cleaner, it is a preping process that etches the surface. The surface must be really clean before you use it or it does no good at all.

Not trying to say your wrong here, but this is how Aumaprep is described on aircraftspruce.com
"Use to clean, brighten and transform badly corroded aluminum to its natural appearance."

it will be nearly impossible to get a proper conversion using the spray and brush method on a surface as large as a boat hull. Given the fact that your application of the Alodine will probably be severly flawed

Why would the application of Alodine be flawed? They anodize aircraft the same way, and there's no way they can put those in a dip tank.

 

[Yacht Dr.]

Re: Painting aluminum

Wow, so much great information. My head is spinning now . I've been doing some research on awlgrips website, which gives information on prepping aluminum. On anodized parts they recomend using their wash primer. I always thought every surface needed a primer (but I learn new things all the time). I don't really want to blast the hull and risk alot of warpage. I'm stripping all the old paint off and was going to give it a thorough cleaning before alumaprep and alodine.

Your on the right path ..

Bare Alum = Alumiprep + Alodine + Primer all in the same day .. True this ..

Dont head spin this IS the the Old book way .. Tried and True .. anyone can say You dont need to prime .. but .. Well I have not Tried that so good luck to you if you want to "skip a step" .

YD.

 

[sschefer]

Re: Painting aluminum

Not trying to say your wrong here, but this is how Aumaprep is described on aircraftspruce.com
"Use to clean, brighten and transform badly corroded aluminum to its natural appearance."

Why would the application of Alodine be flawed? They anodize aircraft the same way, and there's no way they can put those in a dip tank.

AlumaPrep is the etch process. Yes it will help to clean up old aluminum but it can only clean what it can touch. If the oil and greases are deeply imbeded it will not touch the metal. I've used a ton of it for cleaning mill slag off virgin aluminum before welding and it does that well. On old aluminum you really need to glass or soda ash blast it first then etch it with AlumaPrep.

Most aircraft parts are dipped after etching, cleaning with a non petroleum based cleaner then brushing with de-ionized water until the water sheets off in a solid sheet with no breaks. Once you have it that clean you can apply the Alodine 1201 using any method you wish and you will successfully convert the entire surface and not just selected areas. A streaky looking finished Alodine conversion is worthless. The size of the area you are trying to work with will be very difficult and since you're not required to meet MIL Spec standards so there's no point in going through all that work for virtually no gain.

This is why I say you should just follow the manufacturers recommendations for surface preparation for the product you intend to use.

 

[boatnut74]

Re: Painting aluminum

Thanks for the info Steve. The reason I'm thinking about alodine is for the corrosion protection. I don't plan on going in any salt water but you never know. I was also told alodine helps give a better bond. Would it be good enough to sand with 320 to rough it up, vinager/water clean then use a self etching primer? I don't want to have to do this again.

 

[boatnut74]

Re: Painting aluminum

Talk to your local automotive paint supplier, many of todays cars have aluminum body panels, hatches, etc. The old days of only boats being made from aluminum are long past and the automotive stores have a good handle on the products that work best.

I actually stopped in and talked to one the other day. They carry Sherwin Williams, he carries a 2 part primer which is $200 a gallon plus another $50 for the additive. Seems kind of pricey but he was confident this would work for me and I have heard good things about Sherwin Williams, or I could always go with Rustoleum. Any thoughts on that?

 

[sschefer]

Re: Painting aluminum

I used Interlux product on my boat. On the bottom I sanded with 80g then, cleaned it with Dawn dishwashing detergent, rinsed with fresh water then wiped it down with acetone. I then applied a single coat of their 2 part etching primer followed by 2 coats of their barrier coating and the 5 coats of their VC-Performance epoxy. On the remaining hull I sanded with 220g, cleaned, then applied a single coat of etching primer and 2 coats of Perfection 2 part epoxy. This is what the folks at Yacht Paints advised and I was totally satisfied the results.

I've heard that PPG products are very good but I haven't heard anything about Sherman Williams products. I'm not a fan of Rustoleum products as a marine finish but a lot of guys on here seem to like it.

 

[boatnut74]

Re: Painting aluminum

Do you have any pictures of your paint job? Or is there a thread somewhere where I can look. Seeing finished products helps me get a better idea of the finish. Thanks.

 

[boatnut74]

Re: Painting aluminum

Nevermind, I found it . That turned out excellent!! If mine turns out half that nice I will be satisfied. Would this be a good etching primer? Looks like it's zinc chromate, or is there another you would recommend.
http://shop.torresen.com/ships_store/index.php?p=details&mfc=Interlux&sku=353/54G&frm=g

 

[boatnut74]

Re: Painting aluminum

Alright, I spoke with Interlux and this is what they recommend. Any feedback would be great.

Above the waterline:

1. Degrease the surface with Fiberglass Solvent Wash 202

2. Sand/Grind/Blast the aluminum to a bright white metal

3. Remove all residue with a broom/vacuum/clean air line

4. Immediately (within 2 hours) apply 1 coat of InterProtect 2000E which has been thinned 15% by volume using 2316N

5. Apply 2 coats of Pre-Kote

a. Thin each coat up to 10% by volume using 333 when brushing/rolling or 10-15% by volume using 216 when spraying

b. Sand between coats with 220 grit paper

c. Remove all sanding residue with 333 or 216

6. Apply 2-3 coats of Brightside

a. Thin each coat up to 10% by volume using 333 when brushing/rolling or 10-15% by volume using 216 when spraying

b. Sand between coats with 320 grit paper

c. Remove all sanding residue with 333 or 216

Below the waterline:

1. Degrease the surface with Fiberglass Solvent Wash 202

2. Sand/Grind/Blast the aluminum to a bright white metal

3. Remove all residue with a broom/vacuum/clean air line

4. Immediately (within 2 hours) apply 1 coat of InterProtect 2000E which has been thinned 15% by volume using 2316N

5. Apply 3-4 coats of VC Performance Epoxy

a. Thin each coat up to 10% by volume using 2333N when brushing/rolling or 10-15% by volume using 2316N when spraying

 

[ezmobee]

Re: Painting aluminum

Analysis paralysis