Advise please.

With much help from the forum I have brought the mechanical side of the boat to a good place - until the next thing goes wrong lol.

Now I'd like to improve the cosmetics, and have three areas I would like to start on.

1. As you can see the paint has flaked off the grab bar on the radar arch. I'm assuming the bar is aluminum? If so, is the process to chip off all the paint, sand and repaint? Should I use any particular type of paint?

2. A friend, who is now abroad and out of touch, rebed the stanchion bases, and in the process left those ugly black marks which I assume is sealant of some kind. What should I use to clean that up without damaging the gelcoat?

3. In the third set of pics you can see the black scuff marks, the edges of which are just noticeable to the touch. There are quite a lot of these, the ones in the pic being the worst. What is the best solution to this problem?

Thanks in advance for suggestions, much appreciated

I could be wrong but that looks like the gelcoat is cracking and falling off. I am hope I am wrong.

Per the black, start with acetone and cloth. Perhaps someone else has a better solution. Dont rub too fast or you might break through the gelcoat.
You might try some fine rubbing compound.
Dont use scouring power.

Per the hand rail.... remove it if possible, strip to bare metal, primer it and repaint it.

I'll be very interested in the answers to #1 because I have the same issue. My radar arch is all welded aluminum pipe and the white paint is flaking off in a few spots just like that. I was going to sand then steel-wool the edges of the chipped areas and re-paint with a good enamel, but maybe there's a better, more durable way. I'd really like to remove the whole thing and have it sandblasted and powder coated but that's just not practical and nobody sees it up there anyway -- except I know those chipped areas are up there and it bugs me.

Aluminum poses a special problem in getting the paint to adhere to bare metal.
My last boat had an aluminum house and I had it painted with 2-part LP paint.
We always prepped it with Alodyne which chemically converts the metal surface.
I never had a problem with the paint peeling or failing to adhere.

kthoennes said:

I'll be very interested in the answers to #1 because I have the same issue. My radar arch is all welded aluminum pipe and the white paint is flaking off in a few spots just like that. I was going to sand then steel-wool the edges of the chipped areas and re-paint with a good enamel, but maybe there's a better, more durable way. I'd really like to remove the whole thing and have it sandblasted and powder coated but that's just not practical and nobody sees it up there anyway -- except I know those chipped areas are up there and it bugs me.

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Don’t use steel wool. It will leave minute particles of steel in the metal and then rust.

KnotYet said:

Aluminum poses a special problem in getting the paint to adhere to bare metal.
My last boat had an aluminum house and I had it painted with 2-part LP paint.
We always prepped it with Alodyne which chemically converts the metal surface.
I never had a problem with the paint peeling or failing to adhere.

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This.


I'm in the ongoing process of repainting my aluminum doors and window frames as needed. It is important to treat the metal before you prime and paint.


Acid wash, Alodyne (or similar), then two part epoxy primer and paint (I'm using awl grip) is the method I have been using. It's a lot of work but looks nice and hopefully will hold up.


Doug

I hate repainting aluminum. It’s a process that is to lengthy for me to go into here.

As for the black marks. I would buy 3 products. A cleaner wax, a polishing wax and a restoration compound formally known as rubbing compound. Start with the clearer, it is the least aggressive, if it doesn’t do the job try the polishing wax, if necessary progress to the restoration compound.

Painting ally properly is a huge multi coating process if doing it right and even then, if the surface is compromised it leads to bubbling and flaking.
Powder coating is the same.

Now, i'm a firm believer in unpainted aluminium or at most, acid wash and clear tectyl.
Used to use it when building masts.

A bit late for you now.
Good luck with it.

Thanks everyone for the speedy replies. I have a place to start with the aluminum handle and the stanchion base marks.

Any thoughts on the scuffs? Does it look like it has gone deeper than the gelcoat. By the way, how deep is an average gelcoat?

TorronaPwr said:

Thanks everyone for the speedy replies. I have a place to start with the aluminum handle and the stanchion base marks.

Any thoughts on the scuffs? Does it look like it has gone deeper than the gelcoat. By the way, how deep is an average gelcoat?

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20 mils usually.

For black marks Id try acetone as mentioned or Colinite cleaner. I've had good luck with the cleaner as a gel coat prep for wax or polymer and it has removed some stubborn stains... worth a try as it improves the gloss in the process.

If the other scuffs are surface I'd try the same and add a mild compound if necessary for both. if they are digs then you will need to fill w/ gel coat.

IF you elect to use 'wool', use bronze wool and not steel wool. Little flex will remain on deck and rust over night.

TorronaPwr said:

Thanks everyone for the speedy replies. I have a place to start with the aluminum handle and the stanchion base marks.

Any thoughts on the scuffs? Does it look like it has gone deeper than the gelcoat. By the way, how deep is an average gelcoat?

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1st step on any scuff marks should be magic eraser pad (just a fine abrasive really). Second step, if needed could be an Oxalic acid based stain remover (Bar keepers friend, Y10, gel, FSR (Fiberglass stain remover) gel, 3rd step acetone, after that, if deeply embedded, you may be regelcoating.

Usually with gel coat refurb I have read about the most aggressive step used is very fine wet - dry used wet followed by decreasing aggressive compounds.
I would tend to stay with accepted & proven abrasives processes if the solvent approach doesn't "cut it"

As a first step on the scuff marks, try Barkeeper's Friend in the household cleaner's aisle at grocery store. Very mild abrassive and oxalyx acid. Hopefully available in Canada. The stuff is pretty magical on many things boat-related.

Peter

Greetings,
Mr. TP. As suggested, try a "benign" solvent first in the marks around the stanchions/fittings. My go to, in order of attempts, is usually: Rubbing alcohol, acetone, xylene/xylol, lacquer thinner. Since any of these solvents can be the wrong thing to use on some materials I try a very small test spot first. I think they're all OK with gelcoat.

I suspect the marks are residual material your AWOL friend used to bed the stanchions. Hopefully he did NOT use silicone. On magnification of the stanchion photo it appears it may be the dreaded Devils goop (silicone). For your sake, I hope it is not.
IF it IS silicone, strike that person OFF your Christmas list and never talk to them again! Send them to Coventry.



Regarding the scuff marks: I would try my solvent group although IF the gelcoat IS damaged (scratched) you will have to go with the abrasives. Again, using the least aggressive first.


Can't help you with the Al bits.

Please br advised that sanding aluminum will create more problems down the road by encouraging lots of corrosive oxide deposits and pitting. Aluminum creates a protective oxide surface layer that left alone prevents most corrosive activity except galvanic. This is the reason many workboats built from 5000 series aluminum are left bare without problems other that aesthetics. Sanding removes this protective coating. In fact the same principals are utilized in anodizing which in fact is a process that generates a thicker oxide layer most often tinted or colored. The stuff is very hard and is in fact a ceramic in type II & III class processes.

If you can take it down and find an anodizing shop or perhaps powder coating you’ll be way better off. Otherwise locate strontium chromate primer and follow the prep etch directions and paint. Zinc chromate will also work as a good base and primer however many of the companies have, or are, dropping it due to EPA pressure. Do not sand and good luck

BTW I doubt your mast is gelcoated as polyester has a terrible time bonding to aluminum and I’ve never heard of it being done. Take a chip and burn it if it smokes black it could be polyester.
Rick

This is such a valuable forum, especially when tackling new job arenas! Thanks to everyone who contributed, I've copied out all the suggestions and will use them to plan my work

Oh boy. If you total up all the chipped areas on the entire radar arch pipes it probably totals one square foot, but it's mostly spots as big as a thumb-print. Looks a lot like the OP's initial photo. And the chipping is probably where they used a cherry picker (and steel cable slings instead of nylon straps? ) to lift off the radar arch and put it back on. Or pressure points where the radar dome and GPS and antenna brackets are cinched around the pipe. And it's purely cosmetic. Maybe I just have to live with chipped paint up there. I'm beginning to think my to-do list is too long.

If it is dreaded Silicone as RTF mentions I have had good results using very fine wet-dry wet to remove it.

Good news guys, I was at the boat today, and tried a gentle rub of acetone first which did remove some of the scuffs around the stanchion bases, turning it into tiny rubbery balls. What was left, like a cloudy dark shadow, came off with the white magic eraser pad I stole from my wife's pantry. On the weekend I'll complete the port side and next week turn the boat to do the starboard side. After that I'll let you know how the etch/paint of the aluminum grab bar goes. Thanks again for the ideas

You might keep the fact that you are now an experienced Magic Eraser user to yourself. I can imagine all kinds of requests that could be added to the "Honey Do" lists.

lol Baccus - wait until she sees the black stub that is all that is left of her formerly pristine bar. Not much magic left in it now

I have the same issue with my flybridge, which is aluminum. There are large chips coming off. I'm pretty sure all the paint would come off if I started chipping away at the edges. Does anyone know a technique that is proven? I know prepping is key for aluminum, but I'm not sure how to start. Do I feather the edges with sandpaper, or use an electric drill with wire brush? I was also thinking about filling with a two part epoxy primer (after etching) to even out the chip with the surrounding paint before painting. Any help would be appreciated.

I use this stuff to cover and seal tiny surface cracks in my gelcoat -- works very well and bonds like iron and it's self-leveling when I use a toothpick to apply it. The only problem is that over 2-3 years UV exposure turns it from bright white to ivory colored. But I have been thinking of mixing up a blob of this instead and coating a chipped spot on the radar arch instead of using any kind of paint, to see if it adheres to the aluminum.

Kthoennes can you post result if you try the product out as a substitute for paint?

Mac2 said:

I have the same issue with my flybridge, which is aluminum. There are large chips coming off. I'm pretty sure all the paint would come off if I started chipping away at the edges. Does anyone know a technique that is proven? I know prepping is key for aluminum, but I'm not sure how to start. Do I feather the edges with sandpaper, or use an electric drill with wire brush? I was also thinking about filling with a two part epoxy primer (after etching) to even out the chip with the surrounding paint before painting. Any help would be appreciated.

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The longer lasting solution is also the bigger project, i.e. stripping all of the
painted metal. If that isn't feasible then scrape or sand off all the loose stuff and
test the epoxy you plan to use on a small area of the paint to see what happens.
Epoxy can attack some types of paint. I had good results with Alodyne pretreat.

KnotYet said:

The longer lasting solution is also the bigger project, i.e. stripping all of the
painted metal. If that isn't feasible then scrape or sand off all the loose stuff and
test the epoxy you plan to use on a small area of the paint to see what happens.
Epoxy can attack some types of paint. I had good results with Alodyne pretreat.

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Thanks. Looks like a good product. I'm going to attempt to match the small areas the paint is peeling. Hopefully I won't have to strip the flybridge.

Beekeepers Friend liquid for the black marks. Good on gelcoat or paint. It also is great on stainless and for cleaning/brightening unfinished wood.