Marine Grade Alloy

Hightower · 04 July 2007, 21:36

Is there a specific Alloy for the Marine enviroment?

If so, what is the spec?

Can I anodise it and does this stop corrosion long term?

Any Idea on a cheap source for some plate?

I have a plan!

codprawn · 04 July 2007, 21:50

There are loads of alloys for the marine environment. Stainless is an alloy - as is corten steel and bronze - be more specific!!!

Hightower · 04 July 2007, 21:53

Oh OK Codders

An Aluminium based Alloy....Thought the Anodising bit gave it away

codprawn · 04 July 2007, 22:03

Quote:

Originally Posted by Hightower

Oh OK Codders

An Aluminium based Alloy....Thought the Anodising bit gave it away

Nope - other metals can be anodised as well...........

Should have guessed aluminium though - just being pedantic for a change!!!

A lot depends on the application - some alloys are very corrosion resistant but a bitch to work with - is it going to be welded for example?

6063 is a common one but even that has many different grades depending on use. A lot of it will depend on supply and cost - find a local aluminium stockist and see what they have going spare - most of them are pretty helpful.

Some aluminium doesn't need to be anodised but the one I mentioned does. You can also get lots of nice pretty colours.....

Hightower · 04 July 2007, 22:09

Yeh, it is going to be welded, but only in a couple of places. If I go ahead with the project, it will be quite a large structure, it'll have cut out "lightening" holes on the major supports. I'll have to find out how much this thing weighs, but I think that cost will be a deciding factor in whether I go ahead.

codprawn · 04 July 2007, 22:12

The cost of all metals is crazy these days. If you can use scarp and offcuts etc you will save loads. Depending on what you are after - thickness etc try other sources - many horseboxes and lorry trailers have ali sides for example.

The local gyppos have found out that Motorway road signs are usually ali as well.........

Hightower · 04 July 2007, 22:18

Well I want 10mm stuff, but I'm concerned about the weight. I've got some calculations to make.

Are there any shipyards that make Aluminium Alloy boats locally (Portsmouth, Southampton) that I could pop in to?

codprawn · 04 July 2007, 22:20

Quote:

Originally Posted by Hightower

Well I want 10mm stuff, but I'm concerned about the weight. I've got some calculations to make.

Are there any shipyards that make Aluminium Alloy boats locally (Portsmouth, Southampton) that I could pop in to?

They won't let you near their boats with a plasma cutter mind........

Hightower · 04 July 2007, 22:26

Quote:

Originally Posted by codprawn

They won't let you near their boats with a plasma cutter mind........

Could end up with a 8x4 porthole

.....I'll choose a big ship then

IBWET · 04 July 2007, 22:56

Quote:

Originally Posted by Hightower

Could end up with a 8x4 porthole

.....I'll choose a big ship then

Sooo..are you inviting guess's then..

Hightower · 04 July 2007, 23:18

Quote:

Originally Posted by IBWET

Sooo..are you inviting guess's then..

If you like!

Don't think this is a difficult one though.

Jimmy_Beam · 04 July 2007, 23:56

The specific grade of aluminum for marine apps is 5086. I used 6063 T6 extrusions in the building of my cabin on my boat, and stick welded it using 4043 rod. The welds are strong, and I haven't had one fail or crack yet, but If I could have I would have used a mig welder.

Chris · 05 July 2007, 06:54

Aux motor mount?

Chris

Nasher · 05 July 2007, 07:35

Andy

Take a trip down to Pepe marine on Hayling Island, they fabricate the range of Aluminium fishing boats in the shed alongside. Its an amazing process to see, Ali hulls being welded up from sheets over a former then lifted off.

When I was rebuilding transom on my boat they supplied and cut to shape a sheet of Aluminium 15mm thick and about 120 x 75cm for a very reasonable price. It was an off-cut from one of their transoms.

They have lots of off-cuts, are very helpful, and take a genuine interest what you are doing.

Oh, you are probably making your swoopy not an 'A' Frame piece of sculpture for the project.

Nasher.

Hightower · 05 July 2007, 07:46

On the money as usual Nasher. Yes an "A" frame, design won't be finalised untill I've got the RIB back home and I've made a cardboard mock up.

I'm off the portsmouth later this morning to rumage though some scrap bins at Elliotts Signs (find some Polycarbonate) might just take a trip down to Pepe after.

Is that the place you told me about Nasher?

Andy

Rogue Wave · 05 July 2007, 08:19

Have you considered asling this question on Boatmad for some other input. Theres a lot of knowledge on boatbuilding over there and a few of the members CYCO springs to mind have business's producing marine fabrication. Also Ribnet's nemesis Johhnny Fuller is very knowledgeable about this stuff

Hightower · 05 July 2007, 08:29

Quote:

Originally Posted by Rogue Wave

Have you considered asling this question on Boatmad for some other input. Theres a lot of knowledge on boatbuilding over there and a few of the members CYCO springs to mind have business's producing marine fabrication. Also Ribnet's nemesis Johhnny Fuller is very knowledgeable about this stuff

I'll have a go in a mo Stuart. Thanks.

IBWET · 05 July 2007, 08:56

Quote:

Originally Posted by Hightower

If you like!

Don't think this is a difficult one though.

10mm,

Got me.

Hightower · 05 July 2007, 22:06

Went down to Pepe's boatyard and had a chat, they suggest that instead of using two large pieces of plate I should have a welded box section that would be much lighter and be more ridgid. I think that the price will be beond me however.

I will still persue this enquiry however and look forward to hearing from Pepe's with regard the price and design.