Filling holes in aluminium deck

[Max Campbell]

We need to remove two rails that have been riveted down to our aluminium deck, which is between 4mm and 6mm thick, and we need to make the old rivet holes waterproof. We can't access the underneath of the holes. Would it be a reliable fix to work some high tech filler/bonder into the tops of the holes, or do I need to bond a layer of some other material across the top of the holes. We believe there are about 5 holes per rail.

 

[Minerva]

I'd be looking to weld them up - thats the supposed beauty of a metal boat; less need to drill holes in the first place and easy to make good as new after.

 

[PCUK]

As Minerva says, get the holes welded. If not, drill and tap the holes and screw in studding locked in with stud lock.

 

[rogerthebodger]

I'd be looking to weld them up - thats the supposed beauty of a metal boat; less need to drill holes in the first place and easy to make good as new after.

The issue with welding on metal boats is any insulation on the inside.

for small holes i would and have used on my steel boat metal filled epoxy the trick is to counter sink of hammer a dent around the holes and clean the metal very thoroughly to ensure a very clean surface

 

[Minerva]

The issue with welding on metal boats is any insulation on the inside.

for small holes i would and have used on my steel boat metal filled epoxy the trick is to counter sink of hammer a dent around the holes and clean the metal very thoroughly to ensure a very clean surface

You own and (I think) built your own metal boat so you have undoubtably more experience than I. However I am a graduate of University of Youtube so.....

Watching "The wayward life" on YouTube, they've been restoring a steel boat. They have uncovered extensive corrosion issues in part caused by the previous owner using Epoxy to fill holes rather than having them welded shut. That alone would make me wary of that approach.

 

[rogerthebodger]

You own and (I think) built your own metal boat so you have undoubtably more experience than I. However I am a graduate of University of Youtube so.....

Watching "The wayward life" on YouTube, they've been restoring a steel boat. They have uncovered extensive corrosion issues in part caused by the previous owner using Epoxy to fill holes rather than having them welded shut. That alone would make me wary of that approach.

Yes, i see your point but where I have insulation inside if you start welding its too easy to set your boat on fire. Ask me how I know.

With any steel boat it's the preparation that is the key to prevent rust getting under the epoxy filler or epoxy paint

I use acid to remove corrosion and then epoxy primer to protect the cleaned surface then epoxy filler.

If it's not prepared correctly the hole will get bigger as the rust starts again.

BTW I am a graduate of a proper UK university

 

[Max Campbell]

Thanks for suggestions so far. A reminder this is aluminium, not steel, which firstly makes finding a welder more difficult and secondly may have (?) adhesion issues for filler.

 

[vyv_cox]

I would be reluctant to weld, firstly because of what may be beneath but also because of almost inevitable distortion. A mechanical solution seems better all round but bear in mind that you do not want to introduce galvanic corrosion. A tapped hole would be good, maybe by threading some aluminium rod. Otherwise aluminium pop rivets. Use Duralac to seal and resist corrosion.

 

[Stemar]

I'd be leery of trying to make a localised dent with a hammer. My attempts at metalwork lead me to believe that there's far too high a risk of distorting the whole panel. I'd be more inclined to clean the area thoroughly, taper the hole with a countersink bit, and immediately fill with a suitable filler. Plastic Metal springs to mind, but an epoxy filler may adhere better.

 

[rogerthebodger]

I'd be leery of trying to make a localised dent with a hammer. My attempts at metalwork lead me to believe that there's far too high a risk of distorting the whole panel. I'd be more inclined to clean the area thoroughly, taper the hole with a countersink bit, and immediately fill with a suitable filler. Plastic Metal springs to mind, but an epoxy filler may adhere better.

The trick in denting the panel is to either use a small ball pean hammer or a small drift /pin punch to control the dent position

 

[KevinV]

Otherwise aluminium pop rivets

That would be my choice - simple and quick to do, reliable and reversible

 

[Tranona]

At 6mm thickness maybe tapping to M4 or 6 and a countersunk machine screw with duralac

 

[PaulRainbow]

How about https://www.ebay.co.uk/itm/39487462...3eFdzs/0T8DLCr0/EgiaWz9Rbg==|tkp:BFBMkLWruvVj

 

[Scubadoo]

Teroson chemical metal filler will give you a water tight seal, I used it on an aluminium water tank which has remained water tight since applying it a few years ago.

Plastic Padding (Teroson UP 130) Chemical Metal | Force 4 Chandlery

 

[William_H]

I would us an epoxy filler. Epoxy can adhere to ali very well if surface is clean. I am mindful of Aus Airforce using epoxy and boron fibres to repair over cracks in wings of C130 aircraft or Ali blades of giro copters (top and bottom skin) being epoxied together.
I would suggest running a thread tap into the hole to both clean the inner surface and give a shape to grip then immediately put in epoxy filler. You will need it fairly thick to avoid the filler running right through. Better still if you can put into the hole runny epoxy just on the surface of the holes then add filler to the epoxy to fill the hole. It is quite likely you will need more filler after first lot has hardened. Add more ASAP to get a chemical bond with first lot. Then finally fix up surface treatment. (paint) ol'will