Rivets vs Welds Options

[drewvw]

Most of you guys seem to be welding champs which is very cool. But one question I've been wondering is: besides the fact that it was not original approach and doesn't look as nice...what are the disadvantages to riveting?

Aren't rivets actually stronger than welds if done right? Which is the reason why airplanes and bridges are riveted?


more of a philosophical question than anything else. Couldn't find this topic in the archives.

thoughts?

[freezing14]

rivets can be almost as strong as the welding, but the finish is not so good,, if you would to rivet a car you would have to countersink everyone of them and this would take an enourmous anmount of time,, and if you look on the plane only the exterior is riveted, all the structural is milled out or welded, so for a fender rivets are OK for the longs,, I would say nop....

[drewvw]

Interesting, thank you for that....It was acutally a debate that came up at work today.

[lapuwali]

For structural purposes, proper rivets (which are not cheap, and require tooling that's not cheap, either) can be very strong. However, you really need to bond and rivet the joint. An unbonded riveted joint will "fret", slowly ovalling the holes. Every rivet hole is also a potential stress riser, which can lead to cracking.

Modern aircraft are bonded and riveted, or just bonded. Aluminum is usually the material here, not steel. Aluminum is much harder to weld correctly for structural purposes than steel is, which is one reason welding isn't used so much on aircraft fuselages. Of course, real modern aircraft are all composites, anyway, so they're all bonded. The riveted airplane body also came to be when the only way to weld was gas. MIG and TIG weren't invented until after the war, about 20 years after all-metal airplane bodies became commonplace. Designers can be a conservative lot, so they stuck with what they knew, until composites came along.

With steel, welding is faster and easier than drilling the large number of holes required to join two panels together with rivets, so it's rarely used. Welding mild steel is easy enough that it's not really considered a risk. For Al car bodies, esp. racecar monocoque tubs, rivetting was used extensively for years, very probably because the designers often had an aircraft background.

[drewvw]

Another great explanation. Thanks much! (IMG:http://www.914world.com/bbs2/html/emoticons/welder.gif)

[Mueller]

it's also easier to inspect a rivet than a weld...for aircraft the rivet can be drilled out in case a panel needs repair or replacment or you need to access something below the skin, this would much more difficult if welded..

[rmital]

QUOTE (drewvw @ Mar 9 2006, 11:25 AM)

....It was acutally a debate that came up at work today.

WorK! when do have time to work....you almost got a hundred posts in a month (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

you hit the ground running...or posting in this case.

I'm waiting for them to catch on here at my office....getting tough, the club is very addictive!

[drewvw]

QUOTE (rmital @ Mar 9 2006, 11:38 AM)

QUOTE (drewvw @ Mar 9 2006, 11:25 AM) ....It was acutally a debate that came up at work today. WorK! when do have time to work....you almost got a hundred posts in a month (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) you hit the ground running...or posting in this case. I'm waiting for them to catch on here at my office....getting tough, the club is very addictive!

so addictive! I'll be honest, I'm not new to web forums, especially for cars.....just this one.

and I'm a software developer by trade, so I am real good at multitasking with this kind of stuff.

[tat2dphreak]

MIG welders make it as easy (or easier) than proper rivets, and look better to boot... I'm by no means a great welder, but with MIG, you can get a decent looking job done... (IMG:http://www.914world.com/bbs2/html/emoticons/beer.gif)

[Eric_Shea]

Where's the 'Ricketty Racer' when you need him? (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

Come'on JP... this is right up your poop-shoot. (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)

[SpecialK]

QUOTE (freezing14 @ Mar 9 2006, 01:22 PM)

....and if you look on the plane only the exterior is riveted, all the structural is milled out or welded, so for a fender rivets are OK for the longs,, I would say nop....

I beg to differ (since I assemble "planes" for a living). There are "Zero" welds on structural components, which is pretty much everything. The only welding done is on the ECS ducting, and they're isolated from the structure to prevent cracking as the aircraft flexes. Welding also alters the temper of the metal, which could be a very bad thing in a 10G turn.. (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif)

I'm going to be installing a Brad Mayeur kit with 5/32" Cherry Aerospace rivets (Aircraft Spruce) which have a shear strength of around 17,000 psi each, and high strength structural adhesive. No stress risers, no rust between the parts, and a 100% structural bond between the longs and Brad's kit.......plus I suck at welding! (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif)

[drewvw]

hmm......interesting (IMG:http://www.914world.com/bbs2/html/emoticons/idea.gif)

[Mueller]

QUOTE (SpecialK @ Mar 9 2006, 04:01 PM)

QUOTE (freezing14 @ Mar 9 2006, 01:22 PM) ....and if you look on the plane only the exterior is riveted, all the structural is milled out or welded, so for a fender rivets are OK for the longs,, I would say nop.... I beg to differ (since I assemble "planes" for a living). There are "Zero" welds on structural components, which is pretty much everything. The only welding done is on the ECS ducting, and they're isolated from the structure to prevent cracking as the aircraft flexes. Welding also alters the temper of the metal, which could be a very bad thing in a 10G turn.. (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif) I'm going to be installing a Brad Mayeur kit with 5/32" Cherry Aerospace rivets (Aircraft Spruce) which have a shear strength of around 17,000 psi each, and high strength structural adhesive. No stress risers, no rust between the parts, and a 100% structural bond between the longs and Brad's kit.......plus I suck at welding! (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif)

last time I installed a rivet I had to use a "bucking bar"....actually I had to make the bucking bar 1st with just hand tools and was graded on how accuate it was....hmmmm wonder where that darn chunk of steel is now (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

[lapuwali]

QUOTE (SpecialK @ Mar 9 2006, 03:01 PM)

QUOTE (freezing14 @ Mar 9 2006, 01:22 PM) ....and if you look on the plane only the exterior is riveted, all the structural is milled out or welded, so for a fender rivets are OK for the longs,, I would say nop.... I beg to differ (since I assemble "planes" for a living). There are "Zero" welds on structural components, which is pretty much everything. The only welding done is on the ECS ducting, and they're isolated from the structure to prevent cracking as the aircraft flexes. Welding also alters the temper of the metal, which could be a very bad thing in a 10G turn.. (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif) I'm going to be installing a Brad Mayeur kit with 5/32" Cherry Aerospace rivets (Aircraft Spruce) which have a shear strength of around 17,000 psi each, and high strength structural adhesive. No stress risers, no rust between the parts, and a 100% structural bond between the longs and Brad's kit.......plus I suck at welding! (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif)

So, just to prevent anyone else from getting ideas:

Kevin, how much is the tool you'll be using to install those rivets?

[J P Stein]

I have seen some welded titainium structures on aircraft....
Military stuff. Low production doesn't justify the expense of large forgings & castings. Never seen welded aluminum on aircraft structural stuff, but have on ships. As the man said, rivet/bond.

SpecialK: I hear ya, you like to do what you're good at, but even I can put in a plug weld with a tensile strength of 60000
PSI +......about twice the strength of the material that those stiffeners are made of......without the PITA of bonding...unless you're into bonding (IMG:http://www.914world.com/bbs2/html/emoticons/grouphug.gif) .....not that there's anything wrong with that (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)

Welding is the cats ass for steel.

[LvSteveH]

I think bonding fender flare is a neat idea, but you'd never convince me to rivet/bond Brad's kit in lieu of welding. The whole point of the kit is to eliminate ANY shifting of the panel and tie it into the existing chassis. Rivets typically have some give in the joint which makes them great for an aircraft that sees huge fluctuations in pressure and temperature, but not so good for a structural automotive panel. Obviously the idea is that by bonding and riveting you get that 100% union, but there are still enough issues to make that inferior to welding that I can't take it seriously. Good luck with that. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

[SpecialK]

QUOTE (lapuwali @ Mar 9 2006, 06:05 PM)

QUOTE (SpecialK @ Mar 9 2006, 03:01 PM) QUOTE (freezing14 @ Mar 9 2006, 01:22 PM) ....and if you look on the plane only the exterior is riveted, all the structural is milled out or welded, so for a fender rivets are OK for the longs,, I would say nop.... I beg to differ (since I assemble "planes" for a living). There are "Zero" welds on structural components, which is pretty much everything. The only welding done is on the ECS ducting, and they're isolated from the structure to prevent cracking as the aircraft flexes. Welding also alters the temper of the metal, which could be a very bad thing in a 10G turn.. (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif) I'm going to be installing a Brad Mayeur kit with 5/32" Cherry Aerospace rivets (Aircraft Spruce) which have a shear strength of around 17,000 psi each, and high strength structural adhesive. No stress risers, no rust between the parts, and a 100% structural bond between the longs and Brad's kit.......plus I suck at welding! (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif) So, just to prevent anyone else from getting ideas: Kevin, how much is the tool you'll be using to install those rivets?

Good point James. I already have the CherryMax installation tools from my Saberliner contractor days, about $340 for the gun, $60 or so for the different size heads, I've got the grip gauges, the de-burring tools, etc.... I do need to make a correction on the CherryMax rivets too, I mistakenly rated them at 17,000 psi shear, when they actually (according to the mfg.) 75,000 psi (IMG:http://www.914world.com/bbs2/html/emoticons/tongue.gif) . And as you said, "so nobody gets any ideas", bonding and fastening structures together is what I've been doing for the last 20 years, so I'm absolutely confident in my abilities to do it "to spec", and know for a fact that something I've bonded will be a helluvalot more structurally sound than something I've welded with my POS flux-core welder (IMG:http://www.914world.com/bbs2/html/emoticons/cool_shades.gif) . The "structural adhesive" is used in areas of the aircraft where they don't want any flex, everywhere else they use a fuel resistant liquid rubber type adhesive that allows for movement (flex) between parts, and prevents dissimilar-metal corrosion. So if you're not sure of the proper proceedures, prepping, and materials, you'll end up blowing a bunch of money, make a huge mess, and want to kick my ass the next time you see me (IMG:http://www.914world.com/bbs2/html/emoticons/spank.gif) . I think I will however have to photo-doc the proceedure so the critics will have something to hammer on me about......I love abuse! (IMG:http://www.914world.com/bbs2/html/emoticons/whack_3.gif)


Just for the record, a monel cherrymax is a corrosion-resistant steel self-sealing pull-type blind fastener (fancy name for a pop rivet....but bad-ass), the mandrel snaps off when pulled, and remains in the rivet (self-sealing), and is held in place by a locking ring......it ain't gonin' anywhere, and they're a bitch to drill out....so get it right the first time or (IMG:http://www.914world.com/bbs2/html/emoticons/headbang.gif) .

[Jeroen]

QUOTE (LvSteveH @ Mar 10 2006, 01:57 AM)

Obviously the idea is that by bonding and riveting you get that 100% union, but there are still enough issues to make that inferior to welding that I can't take it seriously. Good luck with that. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

well then... how about the lotus elise?
the chassis is all bonded aluminium (not even rivited)

trouble is (I think) that it's easier for the average DIY-er to get a decent weld than a good stong bond through glue/rivets

[Eric_Shea]

I'd like to put a rivet in that Bronco's cheerleader... (IMG:http://www.914world.com/bbs2/html/emoticons/blink.gif)

[SpecialK]

QUOTE (Eric_Shea @ Mar 9 2006, 08:20 PM)

I'd like to put a rivet in that Bronco's cheerleader... (IMG:http://www.914world.com/bbs2/html/emoticons/blink.gif)

Yeah! A self-sealing pull-type! (IMG:http://www.914world.com/bbs2/html/emoticons/wub.gif)