Roll cage sectioning??

[chuck baader]

I am helping a friend move a cage from one car to another. He has cut the cage in various places (not the main hoop) to facilitate installation. My question is although we have sleeves to reinforce the cuts and holes drilled to plug weld, what else is required? Is there a diameter hole that should be drilled to plug weld. As always, thanks, Chuck

[Greg Amy]

GCR 9.4.G.7, p113 in the August PDF, "Removable roll cage bracing..." Otherwise I suggest full welding around the entire perimeter of both ends of the section sleeve.

As you noted, the main hoop must be contiguous.

[Chip42]

in the case of door bars etc... I'd be inclined to replace them after installing the recovered main and front hoops or halo and bracing.

Very likely, this is an opportunity to upgrade the design, is a small cost vs. a new cage, and these are the beams most likely to see bending loads which you do NOT want to see fail. reconstituded beams don't deform as cleanly as whole ones.

[chuck baader]

We have door bars both sides. I read the GCR 9.4.G.7, p113 in the August PDF about bracing but it does not address welding. It does, however, address modifying the main hoop but there is nothing to link the two together. My plan is to butt weld the two tubes with an inner tube plug welded in position equidistant from the center weld. Anyone see any problems with that? Thanks, Chuck

[tom91ita]

Chuck,

That sounds like the way to do it. Maybe have a 1/16" gap so you are welding the inner piece in as you butt weld it.

Then if you have a couple of 3/8" or so weld-plug holes about an inch from that seam would mean the inner section would be about 3" long.

[jhooten]

May I suggest you consult the local tech inspector who will be the one to issue the log book for the new car and see what he will accept?

[betamotorsports]

When joining two tubes to make one tube use a straight taper or a fishmouth on each end of the sleeve and weld it carefully. The sleeve should fit tight (less then 1/16" gap) and have a wall thickness at least as great as the original tubes. The original tubes should also butt against each other inside the sleeve.

FYI... the above is not a SCCA spec but is a normal practice in aircraft tubular fuselage repair..

[cschimmel]

When joining two tubes to make one tube use a straight taper or a fishmouth on each end of the sleeve and weld it carefully. The sleeve should fit tight (less then 1/16" gap) and have a wall thickness at least as great as the original tubes. The original tubes should also butt against each other inside the sleeve.

FYI... the above is not a SCCA spec but is a normal practice in aircraft tubular fuselage repair..

I've moved a couple of cages from car -to-car using this method.I was very disappointed that teh SCCA doesn't have this very strong method listed as an approved method. I'm wondering what trade spec we could cite to have this included as an "approved method of joining cage tubes?
Worth the effort? Look at their approved methods and I think this is vastly superior to what is in now .
Chris

[betamotorsports]

FAA:

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/list/AC%2043.13-1B/$FILE/Chapter%2004.pdf