electro polishing s/steel

[Peter]

A couple of questions on electro plating s/steel bits for my boat. What is the best grade of s/s for electro plating, ie 304, 316L s/steel. What sort of finish do these guys want, ie all welds dressed etc. Is it cheaper to fabricate in s/s first then electro polish, or fabricate in polished s/seel and finish off by locally polishing. Finally any address of electo polishers out there, preferable in the north west.

Thanks

Peter

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[dickh]

316 is marine grade - don't use 304 - and all bits should be polished, including welds. Not sure about polishing before or after fabrication. I would have thought that it would be better to use polished material and then locally polish welds etc.
Sorry don't know anyone who can do it. Try yellow pages under stainless fabrication - there must be someone familiar with ss for marine use in your area.

<hr width=100% size=1>dickh
I'd rather be sailing... /forums/images/icons/smile.gif

 

[charles_reed]

Confusing

It is unusual to plate stainless, though Jaguar do so for some of their trim.(It's 303 and is mirror-finish cold-rolled before plating).

Usually one polishes stainless using jewellers rouge and a buffing disc, tho' I've found a 3M metal finishing pad faster.

It's easier to finish if you start with pre-polished tube - dress the welds then polish them up.

304 is OK for above waterline work, but will weep rust-stains if it has a lot of sea on it. It's a lot easier to work, less likely to work-harden and has a slightly lower tensile strength than 306.
Whatever you do don't use it below the waterline (it's known as A2 when used for fixings).
316 is the most common stainless for marine work, known as A4 when used for fixings - it's prone to fatigue failure, anaerobic and crevice corrosion. It's a pretty unsatisfactory mechanical material when compared to many other steel alloys.

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[Birdseye]

If you want to know how to polish / buy polishing materials etc then the place to look is in the mags which sell to the custom bike freeks ie Hardly Dangerous. They do a lot of this sort of fabrication and subsequent polishing.

Since polishing involves removing metal until you get a mirror smooth surface, it stands to reason that its best to start with as smooth a surface as you can. So welds should be dressed, and angle grinding kept to a min.



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