Refinishing Alum. Frames for Ports

[tartan30cirrus]

I am stuck. Hoping you all can help me.

The PO of my boat had the port frames powder coated. The powder coat finish is flaking off and I want to get rid of the finish and just use a good metal wax on the frames. Problem is there is a lot of finish on one side and a ton of 4200 (why the yard used 4200 I don't know) on the other side of the frame. Removing the finish and caulk by hand will be murder...I just threw in the towel after an hour of getting nowhere. I am considering finding a place that can sand blast the frames and give them back to me so i can go ahead and polish and rebed. The question is, what would others do if this were their boat? And, what other options do I have? Darn, was hoping to rebed these pupplies this weekend. Oh well. Thanks in advance for the much needed ideas.

Cheers.

[dasein668]

If you are planning to have them blasted, find someone you trust. A careless sand or bead blast operator could chew the hell out of aluminum frames. That said, someone with some skill and care could probably do a great job.

If it were me I would probably try a drill mounted wire wheel or something similar, assuming that sandpaper wouldn't cut the stuff. What have you tried so far?

[Jason K]

The bronze portlights on my Triton were heavily oxidized and covered with carelessly applied paint that, I think, was intended for the deck by the PO. I started with sandpaper, then used a wire wheel and a dremel tool to finish things off. I still have to do the large deadlights in the main cabin.

Bad news: it took forever and I have no idea how long it'll last. Tim lacquered the portlights on Glissando to try and achieve some longevity- Tim, how have they held up?

Glissando' portlight restoration is outlined here:
http://www.triton381.com/projects/resto ... ights.html

Of course, my portlights are bronze, but it seems that the process would be about the same. While it took much longer than anticipated, if I did it again I would still go the long way. I would be hesitant to subject the soft metal to such a harsh treatment and while the job is a pain, I couldn't justify the expense of sandblast shortcut.

[Tim]

Feel free to use a real sander with real sandpaper on these frames. With aluminum in particular, obviously some care and sense is required, but you'll make far better progress against hard finishes this way. Wire wheels and brushes work, but the progress can be frustratingly slow.

You can sand metal just like any other material. Each successive grit removes the scratches from the one before. I used plenty of sandpaper and machines when removing the old paint and oxidation from my ports. Removing powder coating can be a bear, even if it's flaking in some places.

To remove the caulk, you can try some judicious application of heat to soften it. Otherwise, elbow grease and a good stiff putty knife or 5-in-1 tool are the way to go.

Bad news: it took forever and I have no idea how long it'll last. Tim lacquered the portlights on Glissando to try and achieve some longevity- Tim, how have they held up?

Jason, I can't in good conscience say that lacquer is the way to go. Like you, I couldn't bear the thought of those nice shiny, antique-bronze ports immediately weathering, so I attempted preservation with the lacquer. With no protection, the bronze will quickly weather to a darker color, and then eventually turn dark brown-green. Verdigris and weathered bronze is also a nice look, so seriously consider how much you want them to remain bright.

With significant seasonal effort, I continue to make it work year after year. The coating holds up well enough over the season (our short season), but contraction of the metal in the cold winters seems to cause the coating to fail. I still like the bright look, so I continue to refinish the ports.

Therefore, each spring, I laboriously tape off the ports, sand off the remaining coating (it comes off easily), and respray the lacquer. Sanding and respraying the lacquer is easy, but taping off the ports and covering surrounding areas against overspray takes about 2 hours.



Spraying takes 5 minutes, total, for all ports and 4-6 coats. It's a ridiculous process, but when I consider that it's 2 hours out of my year, I can continue to justify it until the time comes when I can do something better.

Here's a link to my most recent session of this, from a couple weeks ago:

Tim's Annual Folly

With the boat in warmer temperatures year-round, perhaps the lacquer would remain intact. You would still need to reapply the coating every so often, as it breaks down over time. Overall, while I continue to go this route--I just can't let the bronze ports go green now--I would not recommend lacquer, at least without clear knowledge up front as to the maintenance required and limitations of the finish. That said, it looks great.

I have no idea how other coatings would hold up. Someday, I'll remove my ports again for rebedding, and at that time I expect to re-address the port finish. Possibilities include automotive clear coat, clear Awlgrip, or clear powder coat.

[tartan30cirrus]

TX for ideas...forget the sandblaster...will use the Dremel on this one with wire wheel and sandpaper bits and try my sander too to see which is best. Any recs on grits....the finer I go to the nicer the final product right? Do you think starting @120 grit will cut the powder coat? MIGHT get this done this weekend afterall.

Cheers.

[Tim]

Start with 120 and see what it does. It's always best to start with something finer; it's easy to go coarser if need be.

[dasein668]

I still like the bright look, so I continue to refinish the ports.

Each year I have visions of Tim thumping around on his peg-leg shaking a spyglass in the air shouting "Dicky Moe! Dicky Moe!"

Let's see who gets that fractured reference....

I have no idea how other coatings would hold up. Someday, I'll remove my ports again for rebedding, and at that time I expect to re-address the port finish. Possibilities include automotive clear coat, clear Awlgrip, or clear powder coat.

I suspect that powder coating is not a good option for you, Clint. When I brought my aluminum frames in to see about coating, the guy said "Nope, I wouldn't touch em" because of the oxidation. He said that once aluminum oxidizes like that, you can never get them prepped well enough. He said that the baking process will bring up additional oxidation from the pores of the metal and cause premature failure of the coating system. Sounds like that's what happened with yours.

I refinished with the Awlgrip one-day process using the etch and primer, then sprayed silver Awlgrip topcoat. Looks good, but we'll see how she holds up....

[tartan30cirrus]

He said that once aluminum oxidizes like that, you can never get them prepped well enough. He said that the baking process will bring up additional oxidation from the pores of the metal and cause premature failure of the coating system. Sounds like that's what happened with yours.

That is VERY interesting...a lot of the powder coat failure occured around the bolts where the finish started lifting. Huh. Well it was a good idea of the PO but unfortunately I have to be the one to undo that work! Here I go.

Cheers.

[Tim]

Each year I have visions of Tim thumping around on his peg-leg shaking a spyglass in the air shouting "Dicky Moe! Dicky Moe!"

The ports may be my white whale, but unlike Captain Ahab, I slay the whale each spring.

[tartan30cirrus]

Well...the port frames look great....RO sander with 100, 120, 220 then 320, 400, 600, and 800 grit by hand and they shine. Then some polish/wax and wala...tx for ideas. Shinier and better looking that the powder coated versions for sure.

Cheers.

[Tim]

...and wala...

That would be voil?... :<)

Glad you had success with the job!

[radicalcy]

Just a thought. What would the powder coating company use to remove the coating if they made a goof? Keep in mind, powder coating is essentially just electrostatically applied paint. There must be a solvent that will dissolve it without damaging the aluminum.

[David]

Clint,
<<a lot of the powder coat failure occured around the bolts where the finish started lifting>>

Unless you are using aluminum screws in your frames the failure of the powder coating at the screw holes is probably a reaction between the aluminum and the stainless steel screws.

You might consider getting them hard coat anodized, or chrome plated, or nickel plated (which makes a very attractive gun metal gray). In the end I think aluminum is a bad choice for port frames--I have certainly suffered with mine in my Bristol and have decided to replace the darn things.

David

[tartan30cirrus]

SO David, what material are you new port frames...stainless I presume?

I just picked up Woody Wax from West...has anyone heard of this stuff. I plan to try it on my port frames...it is a wax and a "sealer".

Cheers.

[Jason K]

Haven't tried it, but let me know how it turns out... still looking for a good way to preserve the hard work.

David - tell us those portlights aren't plastic. I think "plastic classic" went to the head of the PO and he replaced two of the portlights with chintzy plastic ones. AARRGGHH.

[David]

Nope..no plastic, just 316 stainless opening ports from www.Marinershardware.com

David

[Tim]

I just stumbled upon a website yesterday that offers a detailed description of metal polishing and self-anodizing. Perhaps this will be of interest.

http://www.myholeinthewater.com/Anodizing_Polish.htm

[Jason K]

Quote from myholeinthewater.com:

"One of the greatest websites I found on complete boat restoration with many tips available is: www.triton381.com The author of this website has wonderfully written and illustrated his two year project on the restoration of a Triton sailboat."


Shameless, Tim, shameless. :)