<VV> Re: Floor Pans (Kinda Long)

[Scott Cable]

For those of you that are discussing rivet installation of floor pans, please allow me to shed some light on the process:
 
1. Rivet types:  Since the panels to be riveted are cold rolled steel, this forces you into one of two rivet material choices:
 a.) Stainless Steel or 
 b.) Steel
You cannot use aluminum because of galvanic corrosion.
Since commercially available pop-rivets are 1100 series aluminum, these are quickly ruled out.  Cherry-Max or Cherry-Lok makes a pull type rivet in stainless, but they're very expensive, and very hard to find. You also need special equipment to pull this type of rivet, which is very expensive also.  You may luck out and find some at a local FBO at a small airport, but they will most likely be the aluminum (7075, or 7050 series aluminum) which won't do you any good either although stronger, you still have the galvanic corrosion issue.
 
This leaves you with solid steel rivets, that must be bucked.  IF you can find some, then of course, you'll need the proper tools to install them with.
  A good 4x rivet gun, and various shaped bucking bars. A good used rivet gun alone will lighten your wallet by a couple hundred bucks... 
 
2. Rivet spacing:  For a structural application, the rivet spacing should be held between 
  4 - 6 D. (that's 4x to 6x the rivet diameter) Thusly, if you were using 5/32" rivets and riveting two panels together that are 6 feet long,  @ 4d spacing=115 rivets, @ 6d=77 rivets.  Since 5/32 and smaller is not considered a structural rivet, you will more likely need to choose a 3/16 or 1/4 inch size, spaced as shown below:
using 3/16ths" rivet @ 4d=96 rivets, @6d=64 rivets
using 1/4" rivets @4d=72 rivets, @6d=48 rivets.
With the Corvair floor panels riveted on, you could easily double the 72 inch rivet seam length.
that's alot of rivets....
  If you have never bucked rivets before the process goes something like this:
Trim and fit panel
Prep and deburr all faying surfaces and edges
Layout the hole pattern
Mark (center-punch) the hole pattern
Drill locating holes
Cleco part into place
Drill hole pattern, cleco-ing every 4th or 5th hole
Remove clecos
Deburr all holes (both sides of both panels)
Apply sealant (or panel adhesive)
Reinstall panel with same amount of clecos
Starting from the center wet install rivets (with sealant), removing clecos as you go.
If you are using countersunk rivets, then you have to add the process of countersinking all the holes before you de-burr the holes.  Which would be worth your while to purchase a drill stop, as it would easily triple your drilling time sizing each countersink.  Again the proper tools aren't cheap.
    So you plan on installing a hundred or more steel rivets PER panel.  Sure hope that you have experience doing this, because Lord help you if you happen to screw one up as you go- 
Which is almost guarenteed working within the close confines of a chassis- because now you have to remove the rivet head, and drill out the shank, and pray to the sheetmetal gods that you don't double drill or egg-shape the hole when removing the rivet shank.
If you egg shape the hole, then you'll have to oversize it for the next rivet size up.
 
Here's a list of tools you'll need:
Air Compressor
Air Hoses
Drill
Drill bits (Number sizes not fractional)
Center punch (perferably an automatic type)
Drill guide
Clecos (probably around a hundred of the correct size)
Cleco pliers
De-burring tools
Countersink
Countersink stop (adjustable drill stop)
putty knife
Panel adhesive gun
Rivet gun
Bucking bar
File(s)
Sheetmetal shears
Hearing protection
Safety glasses
Rags
Lights, Lots of lights and even more lights (to see where you are working)

 
Not to discourage anyones intent here, this is the reality of tackling a job of this magnitude.
One could easily drop a grand alone in tools to do this job.  So what is my advice?  If it were me, I'd purchase a wire feed welder or MIG. Harbor Freight sells one for about $200 bucks.
 
    I just did this job on my VW / Porsche / Corvair kit car project this last weekend and got excellent results using an Acetylene and Oxygen torch set-up.  I "tacked" the pans every two inches. It's important to note that there is a distinct difference between the Corvair and the VW.  The VW chassis has a tunnel down the center of the chassis in which the pans attach to.  When I applied the heat, I aimed or directed the heat onto the tunnel  and let the puddle flow onto the pan.  I also placed a soaking wet towel on the pan near the area I was welding, to minimize heat distortion.
    It's also important to know that the chassis has been stripped of all fuel and brake lines, it's just a bare, glass-beaded clean chassis (no fire hazards).   When I flipped the chassis over to weld the outboard rear fittings, you could see on the center tunnel where the heat had penetrated to the lower part of the tunnel. YEA!!!
  Hope this sheds some light on the subject and best wishes on your project.


Scott Cable
Jamestown, ND
s2cable1 at yahoo.com
		
---------------------------------
Discover Yahoo!
 Stay in touch with email, IM, photo sharing & more. Check it out!