Help with Monel Pop Rivets please

[lenseman]

Is there any method of testing to see if pop-rivets are the common pop-rivet ones as sold by Halfords or the marine rivets made of Monel alloy?

I have bought some Monel rivets and want to check that they are genuine before I use them.

The second interesting question relates to the shearing steel 'pin' left inside the pop-rivet. If this is steel inside a Monel rivet, how is it that the galvanic action and salt water does not effect the Monel part of the rivet. Monel and steel apparently are very aggressive as far as corrosion is concerned.

 

[sailor22]

David

Monel Rivets should be harder and the mandrels are a different colour. But as far as a definitive test is concerned, I cannot help other than to suggest buying from a trusted source.

Mandrels - Knock out the mild steel mandrel that has sheared and is left in the rivet. Collect the bits from the botttom of your mast along with all the swarf. Squirting a hose down the mast does a lot to clear them out.

 

[davidej]

If you get one of each beside each other the difference is obvious.

I don't really know how to describe it, but the monel are shinier and pewter colour.

If you have a penknife (or nailfile) in your pocket, the ally will scratch very easily.

I doubt you will find monel at Halfords but I have never looked.

 

[lenseman]

Thanks sailor22 and davidej.

If you get one of each beside each other the difference is obvious.

I don't really know how to describe it, but the monel are shinier and pewter colour.

If you have a penknife (or nailfile) in your pocket, the ally will scratch very easily.

I doubt you will find monel at Halfords but I have never looked.

When you said "ally, did you mean 'aluminum' or did you mean 'Alloy'?

I suspect you mean aluminum as Monel has a copper content which is harder than aluminum?

Some of the shear-pins (mandrels) are a golden purplish colour, rainbow effect, so I presume these just might be Monel.

The reason I asked is that I bought some really expensive equipment from a reputable manufacturer to hold my Garmin 18HD aloft and I wanted to make sure that I have been supplied the correct rivets as their quality control on the remainder of the mounting is absolutely rubbish with incorrect drillings, 15° out of alignment. Having sent it back to them, after 9 weeks, they sent me another which was just as bad and could not be assembled due to fabrication drilling errors. I spend many hours with a Ward file and a reamer to get the two main stainless steel components to marry up correctly!

Having had the above problems with this company, I just wanted to check the rivets were correct and fit for purpose?

 

[davidej]

Thanks sailor22 and davidej.



When you said "ally, did you mean 'aluminum' or did you mean 'Alloy'?

I suspect you mean aluminum as Monel has a copper content which is harder than aluminum?

Some of the shear-pins (mandrels) are a golden purplish colour, rainbow effect, so I presume these just might be Monel.

The reason I asked is that I bought some really expensive equipment from a reputable manufacturer to hold my Garmin 18HD aloft and I wanted to make sure that I have been supplied the correct rivets as their quality control on the remainder of the mounting is absolutely rubbish with incorrect drillings, 15° out of alignment. Having sent it back to them, after 9 weeks, they sent me another which was just as bad and could not be assembled due to fabrication drilling errors. I spend many hours with a Ward file and a reamer to get the two main stainless steel components to marry up correctly!

Having had the above problems with this company, I just wanted to check the rivets were correct and fit for purpose?

You are quite right I did mean aluminium - though is is an alloy (as is monel). It is quite soft and you can almost scratch it with your finger nail

Slightly bluish sounds right for monel though I doubt you can get these at the usual hardware places. I would try a fastener supplier or a swindlery

 

[vyv_cox]

Ehow http://www.ehow.co.uk/facts_6371309_monel-metal_.html says that monel is slightly attracted to a magnet. This might be difficult to detect with a steel pin at the core, but maybe you can get one out? Aluminium certainly will not be attracted.

As said, there is a considerable difference in the appearance of monel and aluminium, a known aluminium one should be relatively easy to obtain for comparison. It will look more white.

 

[Martin_J]

and then after doing what Sailor22 suggested, knocking the inner piece through (and then collecting it at the bottom of your mast)..

... you can plug the hole that is left with the small plastic cone shaped plugs that might have been supplied with the rivets!

 

[Seajet]

'Duralac' zinc chromate anti corrosion paste between fittings and mast is also a good idea, standard with alloy aircraft; I heard somewhere it may be carcinogenic though, so wear surgeon style rubber gloves and don't try tasting it.

 

[AngusMcDoon]

Is there any method of testing to see if pop-rivets are the common pop-rivet ones as sold by Halfords or the marine rivets made of Monel alloy?

If you have one to spare, you could have a test pop. If you have to puff and grunt a bit, it's aluminum. If you have to bounce up and down on the riveter with all your weight and strength, explete in a high pitch voice, go purple in the face, and feel like a lie down to build up the strength before having another go, it's monel.

 

[VicS]

Just to add to the confusion

I have Monel rivets (Holt Marine pre-packs) that have steel mandrels

I have aluminium "Stanley" rivets bought from B&Q which have non magnetic mandrels. Softish but not easily bent. An aluminium alloy I'd guess.

I have ordinary aluminium rivets, Halfords probably, which have steel mandrels

I have what may be stainless rivets with steel mandrels.

Contrary to what Vyv says it is impossible to distinguish the aluminium ones from the Monel ones by appearance.
However easy to tell apart by scratching with the point of a pocket knife blade. Monel scratches but aluminium scratches easily

 

[savageseadog]

Thanks sailor22 and davidej.



When you said "ally, did you mean 'aluminum' or did you mean 'Alloy'?

I suspect you mean aluminum as Monel has a copper content which is harder than aluminum?...................

Monel is a Nickel alloy not an Aluminium alloy, Monel is closer to a stainless steel than anything else.

 

[Retired in Crete]

and then after doing what Sailor22 suggested, knocking the inner piece through (and then collecting it at the bottom of your mast)..

... you can plug the hole that is left with the small plastic cone shaped plugs that might have been supplied with the rivets!

If you do this just remember that you are reducing the shear strength by 50% plus!

All breakstem rivets (Pop is a trade name) are designed to retain the stem for maximum strength.

John

 

[vyv_cox]

Contrary to what Vyv says it is impossible to distinguish the aluminium ones from the Monel ones by appearance.
However easy to tell apart by scratching with the point of a pocket knife blade. Monel scratches but aluminium scratches easily

Maybe depends on the age and surface tarnish? I have several boxes of many types and don't find it difficult to tell them apart.

 

[AngusMcDoon]

If you do this just remember that you are reducing the shear strength by 50% plus!

All breakstem rivets (Pop is a trade name) are designed to retain the stem for maximum strength.

Monel rivets come with a plastic plug that can only be inserted after the stem is pushed out, suggesting that it is intended to be. It also seems strange to me that the shear strength of the fixing is designed to be dependant on a loose part that can fall out anyway.

 

[johnphilip]

Test Method

1) Buy a set of lazyjacks.
2) Buy a poor set of pop rivet tongs (poor not cheap as they came from the chandlery)
3) Up the mast to fix the eyes each side with the rivets.
4) Struggle with the job due to the force needed to pop the rivets.
5) Come back down with broken riveter.
6) Chandlery says riveter not intended for Monel rivets

QED Those were monel rivets!

 

[Retired in Crete]

Angus,
Breakstem rivets, like most things, come in many types and qualities. If you buy only on price you will get a poor quality (made in China?) product with a stem that will fall out if you look at it!

Before you buy from a reputable fastener distributor ask to see a data sheet. It will show the shear strength and the stem push out values. “Positive stem retention”, i.e stems that do not push/fall out and retain their shear strength, is a major selling point of quality rivets!

Another is “Hole fill”. Does the rivet expand to fill the hole or only expand behind the workpiece. Better ones fill the hole.

Consider also the grip range. Most rivets are grip sensitive. If you have an “elephants trunk” at the back it is too long. The more expensive rivets are “multigrip” and cover a much wider grip range. These also give excellent hole fill and positive stem retention. This is achieved by laser band annealing which gives different metal hardness in bands around the rivet shell. This means that they collapse in bubbles (sort of woman shape) rather than the plain expanded tube seen on low quality products.

Cheap rivets are made from tube with the end "bashed" in a cold heading machine. Decent ones are made from solid rod which goes through a 5 or 6 stage machine.

As I said, you get what you pay for!

PM me if you want more information.

John
(Ex marketing manager of a fastener manufacturer with 9 factories around the world)

 

[VicS]

Maybe depends on the age and surface tarnish? I have several boxes of many types and don't find it difficult to tell them apart.

I was comparing some aluminium ones with some Monel ones that I bought at about the same time 2 years ago. I really cannot tell them apart by appearance. ( except that the aluminum ones have slightly larger heads) Both lots, or at least what's left, are still their original packaging.
Appearance cannot therefore be relied upon.


BTW regarding a rivetter I bought an inexpensive lazy tongs type from Toolstation (click picture for details)

Seems well made and I've used it for for Monel rivets up to 3/16" .

 

[davidej]

I was comparing some aluminium ones with some Monel ones that I bought at about the same time 2 years ago. I really cannot tell them apart by appearance. ( except that the aluminum ones have slightly larger heads) Both lots, or at least what's left, are still their original packaging.
Appearance cannot therefore be relied upon.


BTW regarding a rivetter I bought an inexpensive lazy tongs type from Toolstation (click picture for details)

Seems well made and I've used it for for Monel rivets up to 3/16" .

Bl**dy hard to use up a mast on a bosun's chair.

I had to borrow a large lever trpe from the boatyard

 

[johnphilip]

A Boat will always make things difficult

Bl**dy hard to use up a mast on a bosun's chair.

I had to borrow a large lever trpe from the boatyard

I had borrowed a pair of similar Lazy tongs for use up the mast but the front end was too thick and would not fit between the hole I was riveting and the hoop of the fitting. See link. Hence the purchase of a chocolate teapot rivetter

 

[VicS]

Bl**dy hard to use up a mast on a bosun's chair.

I had to borrow a large lever trpe from the boatyard

I'd not try using it up a mast.

I bought it because I was having difficulty hiring one. At the price it was an attractive option.
Ive done a couple of jobs and i have a riveter should I need one again, without spending a shed load of cash. I probably won't and it'll just go in a skip with everything else when I pop my clogs.

Thought people might be interested thats all.