Screws or Rivets

[NormanS]

Fair enough but note that the data in the link has reservations about the corrosion of copper- nickel rivets in aluminium in marine environments. The strength of 5000 series aluminium rivets is well above what is needed.

I try to keep my masts well above the sea.
All the other fittings on my masts, including mast head caps, spreader bases, winches, cleats and clutches, are attached with monel rivets. I see no sign of distress, and have heard no tales of failure. Have you?
Yes, we operate in a salty atmosphere, but it rains occasionally on the West Coast.

 

[Hoolie]

I'm sure it would be stronger if you welded all fittings to the mast. But you haven't, because your monel rivets are perfectly adequate. Likewise the point has been made that aluminium rivets are also adequate for this application, and offer some additional advantages.

 

[thinwater]

Anyone want to guess what the pull-out and shear strength of a 3/16-inch rivet is in a mast (yes, it depends to some extent on thickness)? How many per step the OP is installing? Configuration?

Just sayin'.

 

[john_morris_uk]

Another one for Monel rivets but make sure correct length, 3mm into section plus the thickness of step and mast, drill sizes for 3/16 rivets 4.9 and 1/4 rivets 6.5, correct size is possible 1/4" x 3/4" with dome head. at Sailspar when we used to fit stainless steps we used nylon washers under each step, this is far less messy then paste. Hope this helps.

If it’s any interest, I riveted our mast steps to our mast from a bosuns chair, Monel rivets, a lazy tong riveter and put nylon washers in between mast and step. On the advice of a rigger I have the steps half a metre apart on alternate sides but I’ve got long legs and I note that some people find that gap a bit big.

 

[Praxinoscope]

Another possibility is stainless steel blind rivet nuts which have their own internal screw thread.. Tapping ascrew thread into a mast is a bit hit and miss as the wall is fairly thin and even a find thread will have very little purchase.

 

[A1Sailor]

If it’s any interest, I riveted our mast steps to our mast from a bosuns chair, Monel rivets, a lazy tong riveter and put nylon washers in between mast and step. On the advice of a rigger I have the steps half a metre apart on alternate sides but I’ve got long legs and I note that some people find that gap a bit big.

Is Mrs M able to ascend your mast?

 

[greeny]

They are shown in the link posted by doug748. Some manufacturers/sellers call one type 'aluminium' and the other 'aluminium alloy'. RS stock both, e.g. http://uk.rs-online.com/web/p/produ...670uozEYaiw7udS8ZT4aAox7EALw_wcB&gclsrc=aw.ds

Vyv,
I notice these have carbon steel mandrels that are captive. Doesn't that introduce corrosion into the rivet that will eventually cause rust marks on the mast/fittings.
I guess that also raises the question of whether mandrels should be left in place or punched out after the rivet has been set? When I fitted some new attachments to my mast with monel rivets the local rigger advised punching them out.

 

[vyv_cox]

Vyv,
I notice these have carbon steel mandrels that are captive. Doesn't that introduce corrosion into the rivet that will eventually cause rust marks on the mast/fittings.
I guess that also raises the question of whether mandrels should be left in place or punched out after the rivet has been set? When I fitted some new attachments to my mast with monel rivets the local rigger advised punching them out.

It seems that the aluminium, either pure or alloyed, corrodes preferentially. I put some in my boom years ago and there are no rust stains or signs of corrosion. Some of the ones on my mast, not installed by me, have plasic plugs to reduce water ingress. I guess that in most cases there is not a lot of standing water on spars

 

[BelleSerene]

Tapping ascrew thread into a mast is a bit hit and miss as the wall is fairly thin and even a find thread will have very little purchase.

And you might tap into the radar cable. Don’t ask me how I know.

 

[zoidberg]

Some of the ones on my mast, not installed by me, have plasic plugs to reduce water ingress.

.... or small blobs of white CT1 or any handy equivalent.

 

[Norman_E]

How about Riv nuts or am talking out of my rear end

Rivnuts can make strong fixings but the downside is that they need much larger holes that the screws that fit them. For that reason alone I would not use them in a mast. The force required to set a rivnut is most likely greater than that required to set a rivet that would do the same job. They do however have the advantage that they can be set with a stud, nut, a couple of washers and a spanner.

 

[KellysEye]

>Monel rivets with duralac for good measure

What's right and the best thing to do, as I found. Aluminium rivets can corrode Monel doesn't

 

[cagey]

Morning Pete,
Just done same job but with mast off boat, the best bit of kit I had was a rivet gun head that fits onto cordless. It was about £17 on ebay, although I was sceptical once I got used to using it it was incredible. Pm me if you want details of supplier of rivets, folding steps and rivet gun head. I used big Monel rivets so gun wasn’t a toy although you need a good cordless.
Happies
Keith

 

[Spirit (of Glenans)]

Lidl had a hydraulic riviter for 18£ a small compressor 69 quid jobs done

A pneumatic compressor is not going to do much for a hydraulic riveter

 

[Scillypete]

Morning Pete,
Just done same job but with mast off boat, the best bit of kit I had was a rivet gun head that fits onto cordless. It was about £17 on ebay, although I was sceptical once I got used to using it it was incredible. Pm me if you want details of supplier of rivets, folding steps and rivet gun head. I used big Monel rivets so gun wasn’t a toy although you need a good cordless.
Happies
Keith

That sounds like a good option . . . . . . . I spent a long time considering the options and the costs and eventually decided to just buy a second hand Mast Mount which hoists up the sail slide groove, easy to rig and use no permanent windage either. Cost was no more than fitting permanent steps.

 

[fergie_mac66]

A pneumatic compressor is not going to do much for a hydraulic riveter

Very true. It was a pneumatic riveter