Aluminum Boat Bondo?

McGR

Senior Chief Petty Officer
Joined
Jun 19, 2004
Messages
664
My project boat has quite a few small dings that I would like to remove prior to painting. I've never had good sucess trying to straighten out dents and dings with a hammer. I believe, that straightening metal properly with a hammer and dolly is a process that requires a significant amount of skill and experience. I have done some metal straightening over the years, but it never really produces results to my satisfaction.

On the other hand, I can work with bondo. Give me some filler and I'll get it good and smooth. My preference would be to fill the small dings, but only if it holds up over time. It seems like Bondo is not recommended for marine applications. However, there are some fillers available for marine applications such as the compound shown. So, my questions are:

Is it OK to fill small dings on an aluminum boat? If so, what is a recommended filler compound?

 

erikgreen

Captain
Joined
Jan 8, 2007
Messages
3,105
Re: Aluminum Boat Bondo?

I think your major problem is going to be adhesion. Not much sticks to aluminum, and if it does stick it's not for very long.

If you fill the dings with that and paint over it, most likely little bits of paint covered Bondo will eventually pop out leaving craters.

If there's a filler that will work on aluminum, great, but I'd think you'd need to apply an aluminum primer first, or else fill the dings with some of that "aluminum repair" stick they sell for soldering stuff together.

Erik
 

ddrieck

Senior Chief Petty Officer
Joined
Jul 12, 2007
Messages
667
Re: Aluminum Boat Bondo?

There is the old school lead filling method but I'm not to sure if it would adhere to aluminum.
 

jspano

Senior Chief Petty Officer
Joined
Oct 30, 2009
Messages
790
Re: Aluminum Boat Bondo?

has any one thought of sanding the paint off till bare alum. hammer as much as possible and skim it with 5200 prime and paint???

joe
 

cuzzx

Seaman
Joined
Oct 14, 2007
Messages
74
Re: Aluminum Boat Bondo?

Alvins bondo is made for aluminum . hard to work with but it do do the job.
 

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
Joined
May 19, 2001
Messages
26,070
Re: Aluminum Boat Bondo?

JB weld or PC11 as long as the aluminum is prepped. These are products approved for marine and are durable to marine use.

Where are these dents and spots??

Jspano....... the 5200 is not a bad idea but it really is not sandable to the extent you might need..... it is more of an adhesive /sealant
 

reelfishin

Captain
Joined
Mar 19, 2007
Messages
3,050
Re: Aluminum Boat Bondo?

There has to be a bondo method that works with aluminum, check with your local body shop, preferrably one that's worked with aluminum body parts. Keep in mind that many car and truck hoods are aluminum, the hood on my 1989 Town Car was aluminum. Porsche made a few aluminum models, the 928 is the first one that comes to mind.

It may just be a matter of priming the metal well with a self etching zinc chromate primer then filling the dent.

Myself, I'd probably work the dent as best I could, then rough up the area and fill with a good aluminum epoxy like marine tex or Devcon aluminum putty. Then sand it smooth, prime and paint. No doubt you could also use a filler primer after the self etching zinc chromate layer, then sand it smooth and seal.
 
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