How Do I flatten a Dent In the Bottom of My Aluminum Hull?

[Doolin]

Hi All,

I was looking at the bottom of my boat for the source of a leak. I noticed a fairly sizeable 'dent' in the hull. It's basically circular shaped, a little over a foot in diameter and maybe better than an inch deep. It's pushed up, from the outside, into the boat.

The boat is an '84 Valco runabout. Sort of like a john boat but there is a shallow V to the hull. The floor boards are marine plywood held in place with stainless steel screws. The seats are also marine plywood but rivited to the aluminum bases that are welded to the hull.

I will be removing all of the seats and floor boards to seal the seams with Gluvit. While I've got everything out... I'd like to flatten the hull.

The question is... can I just pound that back flat? Do I need to use a 'softer than aluminum' hammer or use a hammer on a piece of hardwood to return it to shape?

Any suggestions would be appreciated.


Thanks!

 

[buddybarnhill]

Re: How Do I flatten a Dent In the Bottom of My Aluminum Hull?

i would use a peace of hardwood and a hammer but be gentle dont go breaking brick apart if you know what i mean in nothing else consult a body shop for some of their ideas

 

[5150abf]

Re: How Do I flatten a Dent In the Bottom of My Aluminum Hull?

I personally wouldn't mess with it, older aluminum gets kinda hard and brittle and it is really hard to work with, chances are you will beat the snot out of it and just make your one big dent 50 little ones.

I have heard of guys heating the aluminum then pounding it out or putting dry ice on it, the sudden cooling makes the metal contract and get straighter.

I work with new aluminum boats and have done alot of repairs and it is really hard to work a dent out, like I said I would probably leave it alone so all the pounding doesn't loosen more rivets or anything.

 

[SKEETR]

Re: How Do I flatten a Dent In the Bottom of My Aluminum Hull?

It is amazing how much force is needed to pop a dent back in a hull. When I did one on my boat it took two of us. Unfortunately for my boat the dent was directly under an aluminum stringer. I took a 2x4 and held it up to a good side of the hull and transferred the radius then cut it out. Then placed it against the hull at the dent location. With some additional bracing and a jack I was able to get it to sit tight to the hull while my buddy (in the boat) proceded to hit the dent from above with a mini sledge. After several swings it became obvious that we were underpowered. So we broke out the the big sledge and with several full swings and some repositioning of the brace we got the hull back to shape. That 1/8 stuff is stronger than it looks.

 

[Doolin]

Re: How Do I flatten a Dent In the Bottom of My Aluminum Hull?

Wow. I'd really like to have the bottom of my boat flat... I guess I have an idea now of what it'll probably take and an an idea of how to get there.


Thanks!

 

[5150abf]

Re: How Do I flatten a Dent In the Bottom of My Aluminum Hull?

I still wouldn't mess with it, all that banging is bound to do more damage than you fix with making rivets leak.

 

[Doolin]

Re: How Do I flatten a Dent In the Bottom of My Aluminum Hull?

I would definetly be more concerned about leaks than dents... but this hull is all welded.

Are welds likely to crack from pounding that isn't directly on the weld? The dent is about midway from the center of the boat to the side.