Which rivets to use - yet another rivets topic?

[slawosz]

SS or monel? I need to reattach gooseneck fitting to mast and to do this, I need to remove riveted attachment. I wonder what type of rivets should I use - monel or SS. I don't know what metal attachment is made of. Photo of part for reference.

 

[doug748]

The gooseneck fitting appears to be extruded aluminium alloy set with alloy rivets. It also looks to have a stainless strap attached which may not need to be disturbed.

I would use aluminium alloy rivets which are cheap, readily available and compatible with mast. Just drilling the heads off and belting them through with a pin punch means you can use the same diameter, if you are careful.
It would do ho harm to use monel; in either case don't forget the jointing compound. I would avoid stainless steel.

.

 

[Boathook]

I would use monel. If the aluminium was a suitable alloy it would do but possibly difficult to obtain. Any spare monel rivets can be kept for another job in the future.

 

[vyv_cox]

Aluminium rivets come in two descriptive grades - 'aluminium' and 'alloy'. The latter is a 5xxx alloy, good corrosion resistance and widely used by spar makers. RS sell them, probably many other suppliers also.

 

[iamtjc]

It would do ho harm to use monel; in either case don't forget the jointing compound. I would avoid stainless steel.

I'm new to this game. I recently replaced a couple of halyard exit sleeves on my mast using monel rivets but didn't think to use jointing compound. (I've since found out what it is for).
How big a deal is this likely to be? The sleeves are plastic so the rivet head is against plastic, it is only the body of the rivet that will be against the aluminium of the mast.
Do I need to drill them out and re-do?
Thanks

 

[Concerto]

I'm new to this game. I recently replaced a couple of halyard exit sleeves on my mast using monel rivets but didn't think to use jointing compound. (I've since found out what it is for).
How big a deal is this likely to be? The sleeves are plastic so the rivet head is against plastic, it is only the body of the rivet that will be against the aluminium of the mast.
Do I need to drill them out and re-do?
Thanks

You only need to use a jointing compound like Duralac if you have 2 different metals like stainless steel and aluminium. The compound is to create a break between the metals so electrolosis cannot corrode the aluminium. On my old spinnaker pole someone fitted a stainless steel eye for the pole lift but did not use Duralac. The end result can be seen in the photo below. That mistake cost me £400 for a new pole.

 

[doug748]

I have some recent experience of this because I did some work on my boom about 6 ish years ago and did not have any Duralac on hand so I improvised with Bostic..........
Taking the boom off this winter all of the ss fitting showed some degree of corrosion around them. Not very bad but it gets under the surface finish and is unsightly. As far as I could see, around the monel rivets was pretty good but it's difficult to be sure. Stainless without any form of barrier can cause havoc, the monel rivets not so much and, as you know the plastic not at all.

So my advice is to consider redoing it, but not necessarily right now. it is not going to scrap your mast, or make it fall down.
Your attitude might depend on if you have a new expensive boat or a well used oldster.

.

 

[slawosz]

Thanks. I understand that duralac protects 2 different metals. Will buy the tube - or I can get replacement in screfix?
I understand that monel rivet won't cause mast to corode?

 

[iamtjc]

Thank you Doug, that's helpful. These plastic sleeves seem to break quite easily so I may just wait until the next time I have to replace them.

 

[BabaYaga]

How big a deal is this likely to be? The sleeves are plastic so the rivet head is against plastic, it is only the body of the rivet that will be against the aluminium of the mast.
Do I need to drill them out and re-do?

I would also not worry too much.
The photo below shows a hole in my boom that had a 6.4mm monel rivet for 40 years, rivet head against the extrusion surface.
Some corrosion, but not too bad in my view. I could see no corrosion at all on the inside of the goose neck casting (also aluminium).
I replaced with new monel rivets, but with a nylon washer under the head.

 

[Boathook]

I would also not worry too much.
The photo below shows a hole in my boom that had a 6.4mm monel rivet for 40 years, rivet head against the extrusion surface.
Some corrosion, but not too bad in my view. I could see no corrosion at all on the inside of the goose neck casting (also aluminium).
I replaced with new monel rivets, but with a nylon washer under the head.

I like the idea of using nylon washers under the rivet head.

 

[bigwow]

I like the idea of using nylon washers under the rivet head.

We used bits of plastic milk bottles under our riveted fittings.