Anyone tried to repair crack in winch drum

[kaki anau 5]

A crack has appeared in my Harken winch drum. The winch otherwise works very well and is regularly cleaned and re-greased, though the winch would be pushing 30 years old or so. I am thinking of taking it to an aluminum wheel repairer to see if they can weld the drum. I am wondering if anyone has tried this option and how it worked out for them.

Kind regards

Kieran 

[aardvarkash10 1,114]

Cost of new drum vs cost of repair?

[motorb 45]

Welding won't be too expensive,  so I guess it's probably worth a shot if you can't find available replacement parts. At the very least you will get a few years out of it until being forced into replacement. 

Just keep in mind that welding will remove any protective anodizing in that area.

I would wonder if a wheel place might not be as capable as a good engineering shop, but that will vary wildly between wheel shops and engineers/welders anyway.

[Psyche 826]

Worth a try, a lot depends on the type of aluminium, have you got a picture?

[kaki anau 5]

Thanks motorb, aardvarkash10. I will check out the options during this week. I have identified the cause. There is a bronze gear fixed to the bottom of the drum with stainless fixings. Galvanic corrosion around the stainless fixing has put pressure on the drum. Kicking myself for not spotting it and attending to it. Today's job is to strip the gear from the partner winch, clean and duralac etc. Learnt something new about my boat, the hard way again...

kind regards

Kieran

[kaki anau 5]

Hi Psyche. I have been googling but haven't yet identified the type of aluminum casting. Here is a picture of the damage. 

kind regards

Kieran 

[Psyche 826]

quite a crack!, step one is drilling a 3mm hole at the end stop it getting worse. Try taking it to an engineer but I am doubtful an adequate repair can be made, heating changes the temper of alloy and there are teeth inside the drum that will be softened in the process leading to failure, probably at a highly loaded moment

[kaki anau 5]

Thanks Psyche. The teeth on this model are a bronze gear that I will remove before welding. It's the fixing for this gear that I think corroded and created pressure that lead to the, as you note, quite a crack. I have loosen that fitting (bottom left hand in the photo below). I was going to ask the engineer to drill the hole rather than attempt it myself, but is time of essence and I should do that today?

Thanks for responding

Kieran

 

[Psyche 826]

Definitely one for an engineer to deal with. I am not sure of the best method but probably grind the crack to a vee shape clamp the drum to make it tight against the gear then spot weld to hold it together. Remove the gear and complete the weld. The next step may be to put it in a lathe to clean it up, then refit the gear... Allow a couple of hours. 

[aardvarkash10 1,114]

12 hours ago, Psyche said:

Allow a couple of hours.

At least.  Two separate machining operations (external and internal), plus the grinding and welding itself.

Good work catching the other one before damage.

[Cameron 97]

Have you priced up a new drum? Also check what's out there secondhand. 

[Frank 175]

After 30 years in contact with Aluminium I suspect additional shop time might be needed drill out some of the locking grub screws and careful use of heat to extract the bronze ring .

They will need to clean the crack surface to thoroughly remove any oxidised material, it can be  a surprising amount, they will also  remove the anodising around the weld margin. Post repair you will need to get the drum stripped and re-anodised.  It looks to be a relatively thin wall casting so distortion might be a risk and  as already mentioned the welded area will be weaker than the parent material. It might be worth asking lewmar for the heat treatment spec as the repair shop might need that info. 

I would see if there are any engine build shops that do weld repairs on Aluminium cylinder heads.

 

 

[Psyche 826]

I dont think this is an economical or practical repair in the long term even in the best case scenario, that said you could go down the quick and dirty route and just get it welded as is. File and sand to an acceptable finish while you find a secondhand winch. 

 

 

[aardvarkash10 1,114]

3 hours ago, Psyche said:

I dont think this is an economical or practical repair in the long term even in the best case scenario, that said you could go down the quick and dirty route and just get it welded as is. File and sand to an acceptable finish while you find a secondhand winch. 

 

 

Or grind it out, epoxy fill it, etc etc

[kaki anau 5]

8 hours ago, Frank said:

After 30 years in contact with Aluminium I suspect additional shop time might be needed drill out some of the locking grub screws and careful use of heat to extract the bronze ring .

They will need to clean the crack surface to thoroughly remove any oxidised material, it can be  a surprising amount, they will also  remove the anodising around the weld margin. Post repair you will need to get the drum stripped and re-anodised.  It looks to be a relatively thin wall casting so distortion might be a risk and  as already mentioned the welded area will be weaker than the parent material. It might be worth asking lewmar for the heat treatment spec as the repair shop might need that info. 

I would see if there are any engine build shops that do weld repairs on Aluminium cylinder heads.

 

 

Thank you Frank. I took the drum into 'Machine Part Welding' in Penrose today (they do repairs on aluminum cylinder heads, amongst other engineering). The engineer described a process almost word for word as you explain above, which gave me confidence they could do the job. 

Thank you Psyche and aardvarkash10 for helping work through the options. I am not sure yet whether Harken still supply these drums (waiting to hear back). I have found online 2 retailers in the US that have the drum; they are both seeking about $US3.6k (about NZ$5.9k) for the drum plus shipping. There is a 2nd hand winch for sale on ebay 'for parts', but the seller wants about NZ$5k including shipping from the US. 

I will try repair (by the engineer), and keep a look out for a 2nd hand unit at a more digestible price. I will report back on how the repair turns out.

Kind regards

Kieran

[aardvarkash10 1,114]

2 minutes ago, kaki anau said:

Thank you Frank. I took the drum into 'Machine Part Welding' in Penrose today (they do repairs on aluminum cylinder heads, amongst other engineering). The engineer described a process almost word for word as you explain above, which gave me confidence they could do the job. 

Thank you Psyche and aardvarkash10 for helping work through the options. I am not sure yet whether Harken still supply these drums (waiting to hear back). I have found online 2 retailers in the US that have the drum; they are both seeking about $US3.6k (about NZ$5.9k) for the drum plus shipping. There is a 2nd hand winch for sale on ebay 'for parts', but the seller wants about NZ$5k including shipping from the US. 

I will try repair (by the engineer), and keep a look out for a 2nd hand unit at a more digestible price. I will report back on how the repair turns out.

Kind regards

Kieran

Holy crap.  At those prices I'd be making all repair attempts too!!  Good luck.

[Psyche 826]

At that price, I would definitely be trying a repair! What kind of boat are they from,  they must be pretty big.

[kaki anau 5]

34 minutes ago, Psyche said:

At that price, I would definitely be trying a repair! What kind of boat are they from,  they must be pretty big.

The winch is a Harken 980.3 st. The boat is an old 1981 Swan, 51.