Best method to remove a rivet

I need to replace the rivets in the tramp frame of my Hobie 16. I found many of them loose. One will pull out a good 1/4 inch. Most will turn or lift slightly.

I replaced 5 of them today. I tried drilling the head of the rivet. The problem here is that the rivet will rotate and grind on the casting (am assuming it is cast Al).
I hacksawed some of them off, but sometimes the hacksaw grinds on the casting. The hacksaw will not get under some of the heads.

Questions:
1) What is the casting material? or rather ... If it gets scraped a bit, is this a corrosion problem?

2) What are your recommendations for removing rivets?

From this thread:
http://www.hobiecat.com/forums/viewtopic.php?f=9&t=53732&hilit=remove+rivet#p248873
my questions are:
3) Do I need to ensure the castings and crossbars are in a certain position with respect to each other? if so, how do I do this?

4) Are all rivet guns created equal as far as the end job is considered? The one I have is hard to use, but with three strokes, the rivet shaft pops and the installed rivet seems strong.

5) The Hobie manual has a size rivet for these castings. Are there other sizes that should/could be used?

Thanks!
Ted

years ago when I owned a H16, I re-did all the rivets in the corner castings. Those that spun under the drill bit were held with a file or blade under the head. drill through the head, and if necessary use a center punch to push in the rivet.

for alignment, your best bet is to keep the boat assembled while you replace rivets, or if the boat is apart, replace one rivet at a time.
unless the rivet holes have been badly galled, replacement rivets should be the same size as OEM.

the castings will not corrode if the surface is scratched.

_________________
Chris
'88 H18SE Arís

Been down this road before...
Yes a spinning rivet can be very frustrating. Try to grab it with a pair of needle nose pliers or vice grips. Sometimes you can jam a flat head screwdriver under the head to keep it from spinning.

The castings are aluminum, the rivets are stainless steel, so yes, the castings can corrode (galvanic corrosion with aluminum being the less noble metal). When you re-install, use tef-gel or even a little silicone caulk to help isolate the aluminum from stainless.

Place all rivets into their respective holes before pulling the rivets to make sure all the holes are aligned. If the holes are very wallowed out, you can install rivet casings (sold by Hobie) to take up some of the space. Or you could bump up to 1/4" diameter rivets.

All rivet guns are not created equal. The rivet guns sold by most hardware stores are for pulling aluminum rivets and are very difficult to operate when pulling stainless rivets. Harbor freight sells a nice heavy duty rivet gun which pulls stainless rivets for about $25.

sm

If you like Amazon, they have the Dorman 743-100 Rivet Gun 'used' via their Warehouse deals for $15. I used it for the rivets on my Wave traveler install.

It is certainly much easier to use than a smaller rivet gun, but whether the end result is a better installation, I don't know.

To remove a rivet, do not wallow the drill bit around to cut the head off-it leaves too much possiblilty for screwing something up. For example, for a 3/16 rivet, use a 3/16 cobalt drill bit. Keep the bit for this purpose alone, and it will last a long time. Only use the drill bit to drill a "seat" indention in the rivet head-you don't want to drill it all the way through, but at least half way. Once you have that "seat", use a 3/16" (or sometimes better 5/32") pin punch, and drive the rivet through the hole. You don't want to have to hit it very hard, which can damage/dimple the aluminum hole. It takes a bit of practice to get it just right, but it's not hard at all. I've done thousands like this, and never done any damage to the aluminum (or whatever) holding the rivet.

It's the only method I've seen that eliminates the possiblility of enlarging the original hole in the aluminum, and goes very quickly. If you have a number of rivets to remove, you can drill all the seats, and then tap, tap, tap them all out.

The rivet heads usually stick on the pin punch, but nail pulling hammer claws can tap them right off the punch.

If the rivet wants to spin, which doesn't allow the bit to cut, insert the edge of a woodworking chisel under one side of the rivet head, with duct tape on the heel of the chisel bevel, and apply enough pressure using the bevel heel as a fulcrum to keep the rivet from spinning while operating the drill.

I've replaced many corner casting rivets with 1/4" rivets sold by Murray's. If the boat has been sitting on the beach for years, there's a good possibility that 3/16" rivets won't hold well enough even with casings. It takes a real rivet gun to pull 1/4's, but the Big D makes easy work out of it. I think there are some knock-offs made these days.

There is some great advice there.
Something else that you may want to consider, is that if you completely remove one of the ends of the castings off each of the crossbars, (or if your able to do it with the casting still on) after you get all the rivets drilled out and pushed through. You will be able to get all the scrape pieces that are left behind inside the tubing by tilting one end up and shaking it to get them out.
I had a boom from a boat that had been repaired prior to owning it, and everytime in the wind when it shook, you could hear them rivet pieces moving around, finally drove me nuts to the point of drilling an end cap to get it off, just to get those pieces out of there.
It might not be that bad on crossbars, but if you like to fly the hulls, you might hear them everytime you go way up, roll all the way to the other end, and then back the other way, when you go on an opposite tack. Trust me, that rattling noise, will get annoying.

_________________
79 H16 #46803

I can replace these one by one. How do I tell if the holes are wallowed out? I can see the surface of the Al casting, but that is about it.

Thanks for the great advice.
Ted

you won't need to tap in a new rivet in the used hole, but, any seemingly excess slop, side to side, or angular deflection, when inserting the new rivet could mean an up size. if you not sure on the tolerances here, get some local advice on rivets, does not have to be about sailboats. it is best to have someone show you examples. kind of hard to describe bad vs okay fit.

ask a local auto body expert for advice. many body parts are riveted in.

If the holes are enlarged too much, then the rivet won't grab and it will just fall out after it has been "popped." In that case, you need to go up to 1/4" diameter rivets.

sm

OK. When I initiated this thread, I had replaced 5 rivets. I got stuck on the 6th due to it turning. I have sailed the boat maybe three times in pretty good wind. Today I went back to replace the other rivets. I had luck keeping the rivets from turning. I used a sharp bit, and was able to replace 6 more. I was trying for 7, which would have made a total of 12, and ended up spending 13 of my rivets.

Here are my problems:
1. One of the rivets seemed to have its shank pulled too far out by the gun. I could see bite marks on the shank, and then it broke off with a stub above the rivet head (which will snag clothing and skin).
2. A second did the same, but has barely any of the shank above the head. You can see the shank, which on a proper pull, is completely buried.
3. A third hole ate two of my new rivets. The first rivet would not be pulled by the gun, and when removing the gun, the shank fell into the boat. Thinking this was a defective rivet, I drilled it out (it must have partially engaged), put a second in, and the second did the same thing. I left that one in. The temperature was in the 90s today.
4. I then noticed that several of the 5 rivets I sunk in May, are loose.

Note: when putting in the new rivets, there was some slop or play - it was not a glove fit. After pulling the rivet with the gun, the rivets were tight (at the time they were sunk; excluding item 3. above).

Any idea what is going on?

Thanks!
Ted

Ideally, the hole is just marginally larger than the rivet and the rivet is appropriately longer than the depth of the hole.

Unfortunately, this is rarely the case - especially when you're replacing rivets you've drilled out.

If the shank breaks off above the rivet head, then the hole was too large. The solution is to just tap the shank back down into the body of the rivet with a nail set. Unfortunately, if the shank pulled that far, the rivet will be loose, too.

If the shank falls back in, again the hole was too large or the rivet was too long - and the shank didn't set into the rivet in the first pull and/or your rivet tool didn't grab it well enough. The solution is to make sure gravity helps you when pulling rivets. Try to pull rivets from below, not above. Make sure the shank is as far into the tool as possible when you start pulling.

Rivets (really, the hand tools) aren't that good at pulling material together - which results in loose rivets. The factory uses pneumatic rivet tools that are far superior to any hand-operated tool you can use.

Bottom line - the quality of your rivet tool, the dimensions of the hole and your technique make a lot of difference in the quality of the attachment.

You will also have better results if you make sure you push the rivet gun firmly against the part you're riveting and hold it as square to the work surface as possible.

The other thing to keep in mind is that the rivets on the H16 tramp frame are really just there to hold the castings on. They don't really provide frame stiffness (that would be asking a lot of the rivets). So if they are loosening up, it means there is relative movement between the castings and crossbars and overall your boat is not stiff. It may be time to consider shimming or epoxying the frame.

sm

To keep an old rivet from spinning while drilling it, I put the cutting edge of a woodworking chisel under the rivet top, with the bevel down on the chisel, and pry up a little. Put some blue masking tape on the sharp corner of the chisel bevel to keep from scratching the anodizing. With a sharp bit, it doesn't take much upward pressure to keep the rivet from spinning.

Don't think about using 1/4" rivets unless you have a Big D rivet gun, or something similar capable of pulling a 1/4" rivet. A regular rivet gun, and even most that will pop a 3/16" stainless rivet won't come close.

As everyone else has said, use a wedge or pliers to hold the rivet and drill.

I replace all my stainless rivets with larger aluminum rivets. The issue with the stainless is galvanic corrosion. The aluminum that touches the rivet gets eaten away, until the rivet is loose. On my 1972 H18 the rivets on the mast base were so loose that I could lift them out with pliers, no drilling required. In that instance, I used the next size up in aluminum, and added two more rivets.

So far I have never had issues with my replacement rivets.

Joe