| Author |
Message |
captain ron (Captain_ron)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 03, 2006 - 5:18 pm: | |
I got my steel today and will raise the roof tomorrow. I can get .040 painted aluminum 4x10 for 67.00 a sheet or 16th inch for 97.00 a sheet.
which should I use. also I would like ti find the same rivets used on the lower skin on my MCI. Where? |
Jim Ashworth (Jimnh)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 03, 2006 - 5:53 pm: | |
Go for the .062" aluminum. It will be a lot less dimpled and smoother around the rivets than the thin stuff. Rivets from MCI will match and they are a lot cheaper than pop rivets. I think the setting mandrels are still available from them for use in an air impact chisel.
Jim |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 03, 2006 - 7:24 pm: | |
I have never seen an air impact chisel that had the equivalent of a "variable" trigger, they're either "on" or "off". You can't properly drive a rivet with such an air impact chisel. |
Donald Lee Schwanke (Dontx)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 03, 2006 - 7:49 pm: | |
You can get bonnets or umbrellas for pop rivets, nobody ever knows the difference. First you can do it without a helper, second plenty easy to do, third I like them better. Get a Harbor Freight rivet puller or your hands are gonna get mighty sore! |
John MC9
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 03, 2006 - 8:09 pm: | |
Olympic Bulb-tite Rivets |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 03, 2006 - 11:44 pm: | |
If you're covering the window areas you should have backside access and there's no reason not to use a standard rivet.
If you're dealing with the skin thicknesses mentioned above, you could use flush rivets to boot!
I'd still consider reading Chapter 7 of Dave Galey's Bus Converter's bible. Steel is cheaper, has the same co-efficient of expansion, avoids electrolysis. As Dave mentions, |
Jim Ashworth (Jimnh)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 04, 2006 - 5:27 pm: | |
"You can't properly drive a rivet with such an air impact chisel."
That's quite a strong statement that I disagree with. My wife & I did hundreds of them on my MC-8 with no trouble. The secret is not using 125psi unregulated air to the chisel. Back down the pressure and it is an excellent tool to use.
These rivets were $.04 each compared to $.20 each for pop rivets at the time. And they go in just as fast, hold many times better and rarely loosen up and have paint chip off around them.
Jim |
Donald Lee Schwanke (Dontx)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 04, 2006 - 7:07 pm: | |
I can agree Jim, but this guy is mostly alone and in a big hurry, so I thought pop rivets may well suit his needs better. |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 05, 2006 - 1:08 am: | |
Jimnh,
I guess I should define what I meant by "properly".
Regardless of whether you reduce air pressure, the cycle interval between blows for a impact chisel is way too short (fast) for "properly" driving an aluminum rivet. When you upset a rivet the best scenario (strongest rivet, best clamp, less distortion of surrounding sheet metal, etc.) is to squeeze it in a single operation. Use a hand or air powered rivet squeezer. The next best is to upset the rivet with as few blows as possible.
Each time you strike the rivet it work hardens, instead of forming around the structure it seeks to fasten, the shank swells and stretches and enlarges the hole the rivet is filling, causing distortion and reducing the quality of the assembly.
Air chisels will reduce impact force with a reduction in pressure but not cycle time. They cannot be controlled down to a "plop", "Plop" every 1/2 second or so, something I can easily accomplish with settings on my rivet gun.
Does your method work? - yes; Will it be as strong as 'my method'? - no; Will it be strong enough? only time will tell; Does it give me some type of bragging rights? only if I'm a small minded [ ] [ ] (fill in the blanks) which I believe I am not.
At the same time, if it was something important, I'd take the extra effort to do it "properly" by using a squeezer or a rivet gun.
Onward and Upward |
Gary Stadler (Boogiethecat)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 05, 2006 - 3:26 pm: | |
Interesting about the work hardening point... so a question...
Will a *cold* rivet that is squeezed into a given end-shape be more work hardened if it's done in many steps than one which is taken to end-shape in one step?
That would be the only difference between doing it with a single squeeze and an air chisel, at least unless someone enlightens me further.
From what I understand, it's the amount of distortion of a metal that work hardens it, not now many increments you take to get it there..
and last, it is exactly the fact that the shank of a rivet compresses (not stretches) and fills the hole that it's in, even distorting it a bit, that makes a rivet so strong. It's not just the mushroomed head that you're looking to for strength,,, the shank becoming "one with the hole" is an important part of riveting...
Onward we go.... tag..... |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 05, 2006 - 11:14 pm: | |
Gary,
I tried to set out that a single deformation to the finished clinch is the optimum situation.
Each time the rivet is deformed, no matter how slightly, it work hardens. The rivets going thru normal temperature cycles day to nite, will eventually harden virtually equivalent to the hardness of the deformed state.
A rivet won't "mushroom" until the shank is constricted by the surrounding sheet metal. This is a chicken vs. egg argument, in a way. What you want to do is get the shank trapped before the hardness of the shank exeeds the stiffness of the surrounding sheet metal.
As the rivet shank gets increasingly harder, until "trapped" by the surrounding sheet metal, it approaches and can exceed the strenght and temper of the surrounding sheet. Continued bucking of the rivet swells the shank more and more until it stretches and distorts the sheet metal, compromsing strength and appearance.
Best rivets I ever "drove" in my T-18 project came from freshly annealed A17 rivets, stored in dry ice after quenching. 40# air pressure and 4 gentle "pops" about one second apart from just "tickling" the trigger on the rivet gun.
Couldn't catch the edge of the flush rivet with a fingernail, etc. just a little irregularity.
Standard "store bought" rivets took 80# and a 3-4 second "brrrrrrp" burst from the gun and while very satisfactory, still showed some signs of distortion and would catch a fingernail.
I learned my riveting from employees of the Vega division of Lockheed and the course instructor at an A&P college. I've done riveting on Grumman F-8 Bearcats, Hawker Sea Fury's, North American AT-6s, Mooney's, Cessna's and my own T-18 project. Easily more than a complete MCI-9 project. |
Gary Stadler (Boogiethecat)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 05, 2006 - 11:46 pm: | |
Wow, interesting!! I know that riveting is more of an art form these days- all the old dogs that knew how to do it have mostly retired or gone away, and it's probably much easier to do a bad rivet job than a good one unless you really know your stuff.
Thanks for the education Marc! What you say makes perfect sense.
Cheers |