Bronze Casting

[pauls_SPT]

Hello,

although I'm nowhere near the stage of actually having to worry about this yet, I've been wondering about the rudders missing from my boat.

Originally, she would have had two bronze rudders - I assume for the weight/durability/that's just what rudders used to be made of... They've long since been pawned by a previous owner and are probably a hundred mantlepiece ornanments by now, which leaves me in a quandry as to what to replace them with.

I've considered investigating bronze casting, but it strikes me that this will be inordinately expensive and quite beyond my abilities, anyway. I've also looked around to see how many commercial bronze-casters there are in my local area and, unsurprisingly, the Yellow Pages isn't fit to bursting with them...

So, is there an (better) alternative? I would imagine the rudders will have to have a bit of weight to them, as the boat is a 40ft planing hull powerboat, in theory capable of nearly 30kts. Mind you, there's the engines to find/fit before then...and the decks...and the floors...and the superstructure...and etc etc etc


Thanks

Paul

 

[Tisme]

You could try and talk to some of the many artists that ply their trade in your neck of the woods. Find a good sculptor (i.e. not craft shop type, but a real artist) and they will be able to point you in the direction of a bronze caster.

I imagine that it would be a different alloy, but it may be worth following up.

Sounds expensive though. I never knew that rudders were made of bronze.


edited comment. Just a thought ...or try "Bell Founders"

 

[pauls_SPT]

Thanks for that.

It's all part of the fun of having an ex-RAF boat - cost was absolutely no issue when they put her together with her double-diagonal mahogany hull, all-teak decks, all-mahogany superstructure and all-bronze fittings...

Paul

 

[cliff]

Bronze castings are not that expensive - the bulk of the cost is in the patterns so if you can make them yourself you can save quite a bit.

I had some castings made a couple of years ago and was surprised at how cheap they were but I made the patterns so all the foundry had to do was make the moulds and cast the pieces. I did the fettling, machining and final polishing.

Have a look for foundry, metal casting, investment casting etc and I am sure you will find someone not too far from you.
--------------------

"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>

 

[ccscott49]

You need the midlands! or north west/east, you'll find foundries there. But just as has been said by cliff, make the patterns yourself and the casting is not expensive, alternatively, you could fabricate them from bronze sheet material, probably cheaper, but you need somebody who can bronze (sip) weld or braze very well.

 

[burgundyben]

Not quite....

If fabricated they'll not be profiled like a aeroplane wing, on a high speed boat this will result in a dead patch in the steering.

Paul - Hope you are getting on well, now you could try Wessex Castings in Southampton, they have done lots of marine work, cant find their website but google will get you the details, my rudders are Nickel Aluminium Bronze with Stainless steel posts, lots of the cost is in the mould as other said.

You might need to cast P brackets and stern tubes too, would most likely pay to get the whole lot cast at once.

 

[srp]

My first stop would be Moray MacPhail at Classic Marine. No connection other than as a customer.

 

[cliffordpope]

I was talking only on Saturday to a man at Milford Haven dock, whose boat had a very impressive cast bronze stemhead fitting. He said he made the pattern himself, out of plywood, body filler, etc, and then got it cast. he said the cost was no more than having it fabricated in galvanised steel.
It's important to fillet all the corners and angles, so that there are no stress points when cast.
He said finishing off however was a labour of love - he wore out half a dozen cheap B&Q drills and flap wheels. That was in Aluminium bronze, which apparently is very hard.

 

[ruairidh]

Hi from a lurker. I actually trained as a sculptor, just after the last Ice Age, so maybe I can cast some light. (Ho ho.) Bronze casting should not be very expensive. I would be very surprised if a commercial foundry would do a tiny job like this alone anyway so they'll probably do it alongside another one -- just make sure it's a job for a boat and they regularly do marine work. Not all bronzes are the same! Most founders are pretty clued-up, make sure you tell them exactly what you need.

As somebody said, the pattern-making is the expensive bit. I've not seen your rudders but assuming they are sort of flattened foil shape (ie quite complex) you would actually be better to make just one pattern and have it cast twice...This way you can be sure the two rudders are actually identical.

Make the pattern out of a sheet of thin ply with balsa wood glued to it. Get the shape and finish as fine as you possibly can with fine sandpaper to finish and then varnish it (you should use shellac, really, but you don't have to.) I was always amazed at the smooth surface on a good sand-cast straight out of the box. The finer the surface of the pattern the less work you'll have later.