Aluminum Launch

boatchic

Recruit
Joined
Nov 23, 2008
Messages
2
Hello, I'd like to introduce myself and ask a few questions. I work for a yacht club and do all the structural and cosmetic repairs on fiberglass/gelcoat boats for them. We have 2 custom made 28 foot aluminum launches that are approximately 30 years old and need alot of love. They're structurally sound, couple minor welding areas that I've completed (learning to weld aluminum was a chore) but cosmetically....... I'm at a complete loss as to what to do now. I've prepped and painted the boats the past few years with no problems. Primewashed any bare areas, undercoat, prime, 2 coats paint. Looks nice and shiney beautiful...except a few areas. They would like the boats to be "flat" with no dings and wavering. I have heated and rolled the bad areas so they're relatively flat, and am satisfied with the way that part looks. However. Where the handrails are, from years of use, has slowly bent in. It's not really possible to get under the gunnel to push this back up. It's too tight of an area. Is there anything on top that I can do to flatten this before putting the handrail back on. Someone a few years ago before I got there has used bondo, but of course, it won't bond and just cracks out. If this was a fiberglass boat, no problem. The areas are too large to JB Weld it, each is approximately 4"x4". Any ideas?
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,525
Re: Aluminum Launch

The areas are too large to JB Weld it, each is approximately 4"x4". Any ideas?

Ayuh,...

The Only thing that comes to mind is,...

Mixing your Own fairing compounds,..
I'd think that some Epoxy, Cabosil,+ Microbubbles might work....

It's kinda like a Super bondo fairing mix....:D
 

boatchic

Recruit
Joined
Nov 23, 2008
Messages
2
Re: Aluminum Launch

Hmmm, I'll try that. Unfortunately, won't know if it will crack out until April'ish since we don't run launch service in the winter. I'm worried that in the summer heat, the aluminum will give and flex some, but the epoxy/cabosil mix won't and again crack out. Will this mix actually bond to the aluminum? Primewash and undercoat first? should I bond the epoxy to the undercoat like I would primer?

Thank you for your help
 

NoKlu

Senior Chief Petty Officer
Joined
Feb 23, 2008
Messages
786
Re: Aluminum Launch

You could mix a test batch and apply it to some scrap aluminum. Leave it outside over night and bring it in during the day or something else to simulate the temperature swings and abuse it will go through. By the time the season rolls around you might have an Idea of how it would hold up.
 

sschefer

Rear Admiral
Joined
Nov 13, 2008
Messages
4,530
Re: Aluminum Launch

That's a tough one. Sounds to me like there is continous movement and without some sort of re-enforcment beneath it, plastic fillers will just continue to present problems.

One time I managed this by coating a block of wood with epoxy and then pushing it up within a couple of inches and pulling it the rest of the way up with 6" coarse thread deck screws from the top. Once it was up against the deck surface and the epoxy had time to set a little, I removed the deck screws and filled it with bondo. It looked pretty ugly until it was finsihed but it never caused a problem again.

Maybe that could work for you too.
 
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