• Registered: 2019-03-06
  • Posts: 1

Topic: Cage Build, Spreader Plates & Rust

1st time lemon here, building a cage and want to run a few ideas by the hive before I make a mistake.

The A-pillar bars terminate on a weak section of the floor that also happens to be a bit rusty.  As such, we've devised a plan to build a small plinth that spans over the rusty thin part.  We will put a spreader plate on the inner rocker (solid) and span to the cross-member in back, spot welds in the front, and solid metal seam on the inside (w/ vertical plates to make up the elevation difference).  With this method, I don't plan to replace the rusty part of the floor as we are completely bypassing it w/ the plinth. 

Two questions:
1) good idea or bad?  Does the floor actually add any strength in this area?  It could be replaced after the fact from below, but would be more difficult.
2) Would this cause some consternation w/ the judges? 

Pics:
https://i.imgur.com/GSdgRf9.jpg?1
https://i.imgur.com/ymFVDCg.jpg
https://i.imgur.com/TUyNO8n.jpg
https://i.imgur.com/OWhEdRG.jpg

  • From: SF BayArea/Land of Enchantment
  • Registered: 2012-01-22
  • Posts: 901

Re: Cage Build, Spreader Plates & Rust

Your best source for all information regarding safety is to email those pictures and questions to John Pagel...
.His is the only opinion that really matters....

pagel@24hoursoflemons.com

45+x Loser.....You'd think I would learn......
5x I.O.E  Winner   1 Heroic Fix Winner   1 Org Choice Winner
2x  I Got Screwed Winner    2x Class C Winner
(Still a Class B driver in a Class A car)
  • From: NH
  • Registered: 2010-01-20
  • Posts: 3,299

Re: Cage Build, Spreader Plates & Rust

Agree to talk to John.

however, tying into the sill like that is a good idea, because it's a stronger place than the floor. I suspect you will be told that you need 360degree welds on the spreaders, so you still need to make the spreader match the floor and weld all the way around. or smash the floor flat in order to make that work.

20+ Time Loser FutilityMotorsport
Abandoned E36 Build
2008 Saab 9-5Aero Wagon
Retired - 1989 Dodge Daytona Shelby 2011-2015 "Lifetime Award for Lack of Achievement" IOE, 3X I got screwed, Organizer's Choice
  • From: Newport News, VA
  • Registered: 2015-12-23
  • Posts: 620

Re: Cage Build, Spreader Plates & Rust

[Voice=Marvin the paranoid Android]Rust... Don't talk to me about rust [/voice]

That guy
  • Registered: 2015-05-13
  • Posts: 122

Re: Cage Build, Spreader Plates & Rust

I would 360 weld both plates and once you land the tube on the spreader I would add a piece of spreader plate vertically between the tube and the rocker.

  • Spank
  • Utter Madman
  • Offline
  • From: Escondido, CA
  • Registered: 2009-06-10
  • Posts: 5,863

Re: Cage Build, Spreader Plates & Rust

Pagel has addressed similar issues with me, but as others have suggested certainly best to contact him directly for his input on your specific needs.

What he has said in the past is that when I have had a plinth box that welds onto a vertical spreader up the sill, then the spreader plate on the floor "doesn't really add anything". He has told me to just take the inboard (trans tunnel) face of the spreader plate and angle it to the base of the sill making a wedge-shaped perch. 

That said, I have always chosen to just make a normal rectangular plinth and use a large spreader plate like you have proposed there. 360 welds, yadda yadda.  If I'm particularly concerned, I will run a length of 1"x2" .095 or .120 that spans the fore-aft distance from spreader plate to spreader plate and along the sill. I'll stitch weld it directly to the vertical of the sill as well as fully to each vertical spreader plate. Why? Because AFTER meeting the written requirements of the rules, I figure the point of the spreader plates is to spread the load. In my head, the 1x2 helps spread that load even further. But this is NEVER in place of the required elements; always in addition to the required elements.

That 1x2 then also becomes something I can weld cross beams to spanning the width of the car (or 1/2 width just to the tunnel) and mount the seat to.

YMMV.

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