jfkal
Active member
Is monel the right material to be used for screws and rivets on Aluminium or is there any better material for this taking the corrosion effect into account??
Rivets & Screws
- Thread starter jfkal
- Start date
vyv_cox
Well-known member
There are two different requirements here. Pop-rivets need to be relatively soft and ductile to allow them to function, whereas screws need to be strong to enable them to be tightened.
Monel is soft (at least, when unhardened) and has extremely good corrosion resistance, so is good for aluminium. Aluminium rivets should also be good but in general they don't perform well, perhaps because the precise composition is not known.
300 series stainless steels are widely used for screws and bolts in aluminium. In temperate climates they will last almost indefinitely. In tropical climates it is common for electrolysis to occur between aluminium and stainless steel fittings, normally overcome by bedding onto a non-conductive interlayer/sealant. If you are really bothered, apply some sealant to the screw/fitting to keep the water out as long as possible.
Monel is soft (at least, when unhardened) and has extremely good corrosion resistance, so is good for aluminium. Aluminium rivets should also be good but in general they don't perform well, perhaps because the precise composition is not known.
300 series stainless steels are widely used for screws and bolts in aluminium. In temperate climates they will last almost indefinitely. In tropical climates it is common for electrolysis to occur between aluminium and stainless steel fittings, normally overcome by bedding onto a non-conductive interlayer/sealant. If you are really bothered, apply some sealant to the screw/fitting to keep the water out as long as possible.
oldsaltoz
New member
Re: Rivets
G’day jfkal
I used Monel (blind) rivets on my mast spreaders 6 or 7 years ago, looked pretty good when inspected about 4 months ago, I’m told the Monel rivets are much stronger than the aluminium ones, with less corrosion than aluminium and a blind rivet is better than standard in shear, its stronger an lets less water in.
Avagoodweekend Old Salt Oz……
G’day jfkal
I used Monel (blind) rivets on my mast spreaders 6 or 7 years ago, looked pretty good when inspected about 4 months ago, I’m told the Monel rivets are much stronger than the aluminium ones, with less corrosion than aluminium and a blind rivet is better than standard in shear, its stronger an lets less water in.
Avagoodweekend Old Salt Oz……
ccscott49
Active member
Monel rivets are the correct things to use in alyy masts etc, blind ones prferably. I haven't seen many monel screws, except in oilfield equipment used for their anti-magnetic properties. Totally non-magnetic.
G
Guest
Guest
I replaced the aluminium rivets on a friends mast five years ago with cheap stainless rivets from my tool box (standard industrial) when we checked the mast in November they looked like new and the aluminium around them showed no signs of corrosion (ie the anodising was intact). The original aluminium rivets had all deforded in around two years.
ALLAN
ALLAN
Ralph
New member
Monel is the approved material for pop rivets in aluminium. However when fitting anything with dissillilar metals to a mast it is imperitive that you the jointing compound. It is available from good chandlers as is a nasty greeny/yellow colour and I am assured is bad for your skin. Can't remember what it's called but it's about a tenner for a tube. If you don't use it then you'll be setting yourself up for bi-metal corrosion which can be very bad news on a mast or other spars.
