Pop Rivet Material

[vizwhiz]

So what pop rivet material do you use when riveting items to the aluminum boom and mast?
Is there a particular type of rivet you look for/buy?
Where do you buy them, do you buy them in bulk, small quantities, etc.?
How do you ensure that you have the right diameter and length?
I have done some pop-riveting before, but never the different things I will be doing on this boat, so I wanted to gain from the experience of others before I start.
Thanks!

[Russ]

Good question.

I've always just used whatever they sold at the hardware store. They seem to be made of aluminum.

Diameter? I drill them slightly larger than the rivet. Longer rivets, within reason, will expand. Short ones won't work. For me, the end of the rivet needs to extend slightly further into the hole so it can expand.

[Russ]

http://www.go2marine.com/category/14005 ... #questions

http://www.go2marine.com/category/14005/pop-rivets.html

I also prefer aluminum riviets because they are easily drilled out. Now if I needed a lot of holding power, I might go with SS rivets.

[nedmiller]

You're better off going with similar metals, whenever possible. Even stainless steel and aluminum will get corrosion at the interface. Although strong right at first, they will weaken over time, especially if exposed to saltwater. Just buy your rivets at the hardware store, and the package will tell you what size drill to use. I usually take that size drillbit and store with the rivets so I don't have to search for it every time. As with all hardware, avoiding Chinese made hardware is advisable when possible.

[mastreb]

Unless you need the strength of stainless, you should go with aluminum to avoid bi-metal corrosion. I'm rebuilding my mast right now and can confirm that the factory used aluminum for the mast cap and masthead light, but stainless steel for the gooseneck. The gooseneck rivets are indeed beginning to corrode on my three year old mast. I don't believe there's much difference in grade of aluminum rivets between West Marine and the hardware store.

Also, the stainless steel hounds have corrosion underneath them between the hound and the mast--a fine white uniform layer.

It's my belief that the most common mast breakage on these rigs (breaking at the spreaders hound) is caused by bi-metal corrosion from the hounds and bolts at the drilled bolt-holes. I'm looking for permanent solutions to this problem on my current mast build.

[seahouse]

As a matter of routine, on assembly I put a drop or two of oil on any fittings and fasteners that are going to be exposed to a moist, outdoor, or corroding environment.

Pop rivets in particular, being hollow, will benefit from this; capillary action will "feed" oil to the joint over time, making it less important to replenish it with a drop or two every few years.

Galvanic corrosion will be greatly reduced (pretty well all oils are dielectric for this purpose) as long as oil is present at the margin between the metals.

Though done after assembly, every joint, connection and fastener on my trailer has received this treatment twice so far, takes just a few minutes. I have made special needle oilers for this purpose for precise placement and quantity, but any needle type oiler will do the trick. Apply too much and you could make a mess, but it wipes off easily.

I would expect you to see a difference after just one season in a salt environment, Matt, it will prevent the white dust of corrosion you are seeing, if the crevise is small enough to retain the oil. If you are willing to risk one half of your fittings (the untreated half) treat the fittings on only one side of your boat and see after a year.

A detail that seldom gets attention in production environments is the finish on the inside of the hole drilled in the metal. An incorrect feed rate, drill rpm, angle, lubricant, bit sharpness, chamfer, poor operator training, etc can leave a rough micro-cracked finish that, in a location like the spreader bolts, can increase the likelihood of early cracking and failure of the mast.

You have an advantage when you can do this yourself and know that it was done with a higher priority on quality and lower priority on time ( and = money).

-B.

[mastreb]

Thanks Brian, that's simple enough. Since I've got my existing mast for evidence, I'll just oil everything and then look at it in three years for comparison

[seahouse]

Yeah Matt - I'd like to know what you see in time.

And regarding hole size for the rivet, Viz; you want to keep the clearance to the bare minimum, as more clearance reduces the integrity of the joint.

The dimensions (and grade) will be called for on the package, but what I've done in the past (but haven't done lately) is to use the nominal drill size for the rivet – so use a 3/16” drill bit for a 3/16” rivet, for example. The clearance will result from the small amount of runout from the drill, so you should be able to easily push the rivet through.

Using a fractional drill to drill a 1/64” oversize might give too much clearance, especially in the smaller diameters, so a number drill size might be a better choice, and might even be suggested on the package. You don't normally use hole clearance to allow for expansion and contraction between the two parts with rivets the way you would for some other fasteners.

Pre-fit the pieces before you rivet to make sure the two surfaces are evenly matched in profile (bend them a bit to suit if they aren't), and leave no burrs to interfere with a flush connection (cleco pins can be handy at this point if you have them available, but of course not required for the few rivets we have here on booms and masts). I point this out because it's pretty easy to just allow the rivet to pull the parts together instead - not good because this uses up some of the breaking strength of the stem to do - strength that might fracture the stem before the head has been fully formed on the backside.

-B.

[jbgibbs99]

I use Monel rivets as they don't cause corrosion. A bit more expensive but I've ony needed a hadfull.

[bartmac]

Second that....Monel rivet is the go for anything important...although google it and find NOT with steel and salt

[vizwhiz]

So what about rivet guns...what do you use and do you need the swivel head?

[kmclemore]

Second that....Monel rivet is the go for anything important...although google it and find NOT with steel and salt

Where possible I drive out the remaining internal pin ends after riveting (using an old rivet pin) and then I 'mushroom' the head on the other side to match the front side using either a hammer and punch or a Vice Grip. This increases the holding strength of the rivet and also prevents those long,nasty, ugly rivet backs from sticking out the back of your work.

[Steve K]

Seahouse.......... Great info/advice !

I just wanted to add that I read where the white Teflon pipe dope is used by many sailors, during assembly of SS fittings to aluminum spars (comes in a small tube and is used where one would use Teflon tape on plumbing fittings). I've used oil, as you say, in the past, but tried the Teflon this time when adding some fittings to the boom and mast. I had a tube sitting around, so thought I'd try it.
I can't seem to find the article I was reading. It also suggested using it on aluminum pop rivets and this seemed to make them seat tighter. not sure.

As you said above, I also use the same sized drill bit as the pop rivet, for the reason you state. It is almost impossible not to get some drill run out in aluminum when using a hand drill. I usually use my cordless and at lower speed. This helps to get an accurate hole............. Always center punch before drilling

Best Breezes,
Steve K

[Steve K]

So what about rivet guns...what do you use and do you need the swivel head?

I use a cheap no name rivet gun. Had one for about 30 years. Just had to get a new one about a year ago. It's not something I use often.

I did notice it's getting harder to squeeze this newer one (or my old grip is getting weaker). Suggest getting one with the longest handles you can find

BB,
SK