Advice : SS Screw -vs- Monel Rivet

[SiteSurfer]

I've located a fitting which will cure my bust boom tang issue (http://www.ybw.com/forums/showthread.php?438015-Whats-this-called&highlight=whats+this+called) and I now need to consider the fitting.

My first take was to simply drill 4 pilot holes and use SS self tappers to secure it, then I got to thinking whether I should rivet it. A quick forum trawl got me wondering if the expense I'd need to go to in order to kit out redy for riveting monel rivets was actually beneficial against the holding power of 4 fairly chunky screws?

This is the part I am ordering to replace the tang:



And this is my boom:

 

[vyv_cox]

It is not strictly necessary to use monel rivets. I have many stainless steel fittings attached to aluminium spars using aluminium rivets, some probably original so 30 years old. Add a little zinc chromate paste for corrosion resistance and all will be well. A rivet is ia better fastening for this application than a self-tapping screw.

Edit: Duralac is the stuff. Horrendously expensive but it lasts a lifetime.

 

[gandy]

Glad I'm not the only one. One reason I prefer aluminium rivets is that if there were to be any corrosion, I'd rather it was the rivet and not the mast that corrodes first.

 

[Topcat47]

Whatever you use, don't use SS in Aluminium. I'm not sure what material your tang is but if it's not aluminium or an aluminium alloy, I would use Monel. Otherwise Aluminium pop rivets would be fine

 

[Fantasie 19]

My first take was to simply drill 4 pilot holes and use SS self tappers to secure it, then I got to thinking whether I should rivet it. A quick forum trawl got me wondering if the expense I'd need to go to in order to kit out redy for riveting monel rivets was actually beneficial against the holding power of 4 fairly chunky screws?

Not much expense to be fair? Monel rivets way less than a quid each, lazy tongue rivet gun about a tenner delivered (from eBay)...

http://www.ebay.co.uk/itm/32-Inch-E...op-Gun-Tool-/231413217649?hash=item35e14d7971

 

[SiteSurfer]

Oh thats quite cheap. I must have been looking at the wrong bit of gear!

The fitting is SS and the boom is Ali, so I'm thinking that the advice is leaning towards using Monel rivets (and definately rivets anyway).
As I'm a bit of a rivet newbie (ok - a complete rivet virgin) - I was looking at these:

http://www.force4.co.uk/marine-pre-packs-monel-rivets-m.html?gclid=Cj0KEQjw35-vBRD3qKz8hPezlIIBEiQAOeKNrsHWQ5ijYgrq6-jqfVbxIFKpyHDQmTfel_Cb0fIF2hoaAh4Z8P8HAQ#.Veh1VXu-2RM which come in a pack of 5, I assume that I drill a 5mm hole and go from there.

 

[macd]

Oh thats quite cheap. I must have been looking at the wrong bit of gear!

The fitting is SS and the boom is Ali, so I'm thinking that the advice is leaning towards using Monel rivets (and definately rivets anyway).
As I'm a bit of a rivet newbie (ok - a complete rivet virgin) - I was looking at these:

http://www.force4.co.uk/marine-pre-packs-monel-rivets-m.html?gclid=Cj0KEQjw35-vBRD3qKz8hPezlIIBEiQAOeKNrsHWQ5ijYgrq6-jqfVbxIFKpyHDQmTfel_Cb0fIF2hoaAh4Z8P8HAQ#.Veh1VXu-2RM which come in a pack of 5, I assume that I drill a 5mm hole and go from there.

You'll need to get the length right. Some rivets are sold with an indication of "grip range", which is the combined thickness of the two materials being rivetted. Many, including the ones you link to, offer no such information. In this case use the formula 1.5 x rivet diameter + thickness of parts to be rivetted.

And do, as Vyv advises, use Duralec (or Tefgel) to reduce the risk of corrosion. Both are horribly pricey, but last for aeons.

 

[VicS]

Not much expense to be fair? Monel rivets way less than a quid each, lazy tongue rivet gun about a tenner delivered (from eBay)...

http://www.ebay.co.uk/itm/32-Inch-E...op-Gun-Tool-/231413217649?hash=item35e14d7971

Oh thats quite cheap. I must have been looking at the wrong bit of gear!

The fitting is SS and the boom is Ali, so I'm thinking that the advice is leaning towards using Monel rivets (and definately rivets anyway).
As I'm a bit of a rivet newbie (ok - a complete rivet virgin) - I was looking at these:

.

That looks like the same lazy tongs rivet gun that I bought from Toolstation.

I used it for some smaller monel rivets. It might set 5mm ones but that'll be its limit I would think. Not complaining though. It did what I bought it for.

The two handed type of riveter is better if you can beg borrow or steal one.

I boguht aluminium rivets from B&Q but ended up buying prepacks of Monel ones from Force 4. It's an expensive way of buying them but when you only need a small number probably the most sensible.

 

[SiteSurfer]

Thanks all. Great advice as usual.

 

[alan_d]

Seascrew sell monel rivets singly, so possibly the cheapest way to buy.

 

[Rum Run]

That looks like the same lazy tongs rivet gun that I bought from Toolstation.

I used it for some smaller monel rivets. It might set 5mm ones but that'll be its limit I would think. Not complaining though. It did what I bought it for.

The two handed type of riveter is better if you can beg borrow or steal one.

I boguht aluminium rivets from B&Q but ended up buying prepacks of Monel ones from Force 4. It's an expensive way of buying them but when you only need a small number probably the most sensible.

I have done 1/4" Monel rivets with a lazy tongs riveter. It helps to be working from above the job but hooking an arm round the boom for counter-pressure should work.

 

[SiteSurfer]

Without wishing to derail the thread into a discussion on "how to" - is it possible to operate the lazy tong version single handed with a larger rivet? I'm thinking of the practicalities of trying to do this on a moving boat. (As in berthed up not close hauling when I say moving...) - I also need to add lazy jacks at some stage and the most obvious method of attaching the mast eyes would seen (now) to be rivets and being up a mast sounds to me like a one handed job.

 

[VicS]

I have done 1/4" Monel rivets with a lazy tongs riveter. It helps to be working from above the job but hooking an arm round the boom for counter-pressure should work.

It is whether or not the cheap tool will be up to the job of setting larger Monel rivets that I was doubting. Its a bit flimsy. Nicely made but not strongly made

Without wishing to derail the thread into a discussion on "how to" - is it possible to operate the lazy tong version single handed with a larger rivet? I'm thinking of the practicalities of trying to do this on a moving boat. (As in berthed up not close hauling when I say moving...) - I also need to add lazy jacks at some stage and the most obvious method of attaching the mast eyes would seen (now) to be rivets and being up a mast sounds to me like a one handed job.

It needs a pretty powerful push to set monel rivets and when the mandrel snaps the nose of the gun can go skidding off with the end of the broken mandrel damaging the work unless you have hold of it. So the work needs to be well supported and you need one hand to push with and the other to grip the nose of the gun, and you need to be sure you dont go "base over apex" when it snaps.

smaller sizes of aluminum rivets are no problem and a good plier type tool will set them easily.

 

[xeitosaphil]

Without wishing to derail the thread into a discussion on "how to" - is it possible to operate the lazy tong version single handed with a larger rivet? I'm thinking of the practicalities of trying to do this on a moving boat. (As in berthed up not close hauling when I say moving...) - I also need to add lazy jacks at some stage and the most obvious method of attaching the mast eyes would seen (now) to be rivets and being up a mast sounds to me like a one handed job.

When I fixed my lazy jacks on my previous boat I used one of these type, easily used one handed up the mast from a ladder and cheap enough :

http://www.halfords.com/workshop-tools/tools/hand-tools/halfords-hand-riveter-kit

The saddle clips used for fixing the pulleys don't really have that big a hole in them so 4.5mm should cover it

If you could borrow a lazy tongue one for your other job, this might be a cheap option for your mast job.

 

[VicS]

When I fixed my lazy jacks on my previous boat I used one of these type, easily used one handed up the mast from a ladder and cheap enough :

The saddle clips used for fixing the pulleys don't really have that big a hole in them so 4.5mm should cover it

.

I am surprised you can set medium sized Monel rivets with one of those. You must have a much stronger grip than I have.

 

[xeitosaphil]

I am surprised you can set medium sized Monel rivets with one of those. You must have a much stronger grip than I have.

I was younger / stronger then Vic, and before two Carpel Tunnel op's, boat was smaller H22, so size of saddle holes only about 4mm and I chose to use Aluminium rivets as the stresses were only in shear with no load other than the weight of the boom and sail.

Actually I was wrong, I did use Monel rivets, because I still have two left in the Holt's Packet- " Senior moment "

 

[Fantasie 19]

Thanks all. Great advice as usual.

You were in Emsworth YH for a while?? If you're still there the chandlers on site does rivets singly, you can also have a look and confirm what size you'll need....

 

[William_H]

I would advocate a completely different attachment of the bale to the boom. Just buy 4mm metal thread in stainless steel. Buy a tap to suit the screws. Get Duralac to coat the screws and the bale where it rests on the ali boom. A low speed battery powered drill is ideal for driving the tap in assuming you have drilled the correct sized hole. The reverse function and low speed make it easy. As said you need something more than pop rivet pliers as pictured to set anything but ali pop rivets in 4mm size. I had some as pictured and manged to snap the handle before the monel rivet set. good luck olewill