welding galvanised steel

[mainbrace]

The galvanised pulpit on my boat has gradually acquired a small rust hole about 1cm square. Whilst not yet unsafe, this has to be fixed one way or another. Would it be possible to cut a section out and weld in some new? Removing the thing is to be avoided as the through deck bolts are totally unreachable without dismantling the forwardmost bulkhead (unless I can find a 19th century chimney sweep...)

Thanks

 

[David2452]

It can be done, but, the galvanising will need to be removed from around the area to be welded first, and as you can't remove it for re galvanising that really is a non starter.

How about a mechanical method. cut out the affected area and place a smaller Dia tube inside to support the joint and either screw it or use suitable metal adhesive.

David

 

[pjs100]

It would depend on what your skills are as a welder and whether you are too bothered about the finish on the end result.

You could possibly cut a piece out with an angle grinder or similar and you would need to prep the joining edges by removing the galvanised coating. Welding will remove move of the existing coating through burning. There will be a grey blue flame and heavy fumes as you weld so wear breathing protection.

There are a number of cold galvanising products on the market and you would need to treat the welded surface with this. It may last a few months but will show through and rust quite quickly.

I've done this in a number of non marine applications for industrial use and that deterioates after time.

Could you not fill the hole with epoxy or metal filler and coat it?

Hope this is helpful.
JJTOP

 

[PCUK]

You could weld it, then paint the entire pulpit with epoxy after priming the rest of the galvanised sections.

 

[Topcat47]

I've tried welding and my skills aren't up to it, the zinc invariably B*&&$£s up the weld. Brazing on the other hand works very well...you could try that.

 

[Lakesailor]

I built up my arc welding skills on scaffolding pipe, which is galvanised. It does take a bit more current and you have to be wary of the galvanising generating it's own heat and taking over the control of the weld.

I would think for a corroded bit of light gauge tube it's not worth the hassle; corroded metal having it's own weld problems. I would go with grinding back and using a metal repair paste, perhaps bonding a patch of tube wall into the original.

 

[the_wanderer]

It can be done but beware of the fumes that the burning zinc gives off. You can end up with what you may think is a dose of flue. Whilst it is not dangerous you can feel bad for a few days afterwards. Tell me about it! Bin there dunnit!

Regards.

Alan.