Simple Roll Bars

[Daniel Peterson]

The pace at which I complete anything as become the stuff of legend, but I do actually start suff.

I pulled out a GT350H Mustang and figured I could whip it up as a box stock build just to get the juices flowing again...but of course, I started thinking about modifications shortly after putting it on the bench. I'm now gathering parts to make it a 70's street machine of sorts.

But I digress...the topic here is simple roll bars.

I know this technique is not new, but it's new to me and I was flabberghasted at how easy it was.

First thing I did was get some 3/32" (2.4mm) Plastruct styrene tubing. It looked a little bit too small in the store, but I think it scales out nicely for a believable roll bar.

Second step was to root around for some aluminum wire. I don't know where I originally got it, but I'm going to guess it was purchased at a craft store, probably in the jewelry or floral section.

Here are the two side by side.

The idea is to insert the wire into the tubing for strength, which will prevent the tubing from kinking and to help the final form retain its shape.

The wire has to fit the interior diameter of the tubing, and fortunately this size tubing and the wire I found were perfect for each other. Yeah, I know this is pretty simple, but that's the point.

Now that we have covered "theory", let's get to the actual fabrication process.

I personally have a terrible time sizing a custom roll bar to the interior...mostly because I can't crawl in there with some tubing and a tape measure. I discovered that using this wire to form a "dummy" roll bar was (again) waaaaay too easy. I simply took a length of wire, estimated the location of the first bend to get the proper height so I'd clear the roof and slipped it into the side window of the model (body on chassis with the interior tub in place). The rest was trial and error until I got one side of the roll bar to the shape I wanted. Remember, I've only got one or two bends on one end of the wire, with the rest of the wire sticking out and being used as a handle of sorts. Once I got the primary shape for the hoop "right", I placed the wire on a piece of paper and traced the form I made. I used that tracing as a template to get the other side bent the same as the original, and cut off the excess wire.

Remember, this is not the roll bar, but rather my "dummy" for mock-up.

Now that I have the form shaped correctly, I need to make the real roll bar. Rough out how much tubing you need, and leave some excess wire sticking out. Part of the reason for doing that is so you don't lose the wire in the tubing, but there's another purpose as well. You'll see what that is later.

As you see below, the wire serves its purpose and holds the bend you make in the tubing. Without it the tubing wants very much to go back toward its original shape unlesss you heat it. Heating this stuff to bend it seemed too much like work to me.

Take your wire-filled tubing and bend it by hand to match it to the shape of the "dummy". I can't offer much more instruction than that. You do want to remember that you'll want to expose some excess wire once you have everything sized the way you want it. Those exposed wires will eventally serve as locating pins.

The photo below shows how I prepped the interior tub for the main hoop and rear braces. Again, I eye-balled this, but actually measuring things for location and placement can't hurt.

Those little holes in the bottom of the interior tub are going to accept the excess wire I told you to leave exposed. (The holes in the back are for the bracing...this is a simple 4pt bar.) It's a good idea to leave an inch or so of the wire exposed until you fine tune all the bends. The excess sticking through the bottom of the tub will keep things located while you tweak. Once you have the shape finalized, double check that it clears the seats and anything else in the interior that might interfere. Now is the time to double check the fit of the body over the interior and roll bar.

To make the rear braces, all I did was cut a pair of pieces of tubing, eyeball the angle I wanted and drill those holes in the back of the interior tub. I notched one end of each tube and raduised it to give it a fishmouth so I could glue it to the main hoop. I slid the tubes through those holes toward the hoop and glued them to the hoop with liquid cement and let it cure overnight. You want to leave some excess tubing at the rear as well so you can manipulate them while getting the cement to set. I did not cement the tubes to the interior tub, because I want to be able to remove the assembly to paint it and reinstal it later. You could create mounting plates out of styrene instead of cutting holes in the interior as I did, but in this case I want the illusion of these tubes passing into the trunk area and being attached to something of substance.

This is the resulting assembly. You can see the little pins I left at the bottom of the main hoop.

And this is what it looks like in interior. I'm thinking a cross bar behind the seats might be in order, but other than that, I call it ready for paint.

You can get as crazy as you want with roll cages, but this shows you the basic process I used and is just intended to give you an idea of how to fab your own simple roll bars and not have to rely on the parts box to supply one that "kind of" fits.

[GOTH KUSTOMS]

WOW! Daniel, that looks so much easier then what I had planed to do, with nails and heat, thanks....

[Clay]

How did you get the wire in the plastic? If you explained it in your post I must have missed it, so please explain.

[Daniel Peterson]

How did you get the wire in the plastic? If you explained it in your post I must have missed it, so please explain.

Since the tubing is hollow, I just slid the wire in there. I wish I had the label from the package of wire I bought, but I don't so I can't tell you the exact diameter to hunt for. It measures out to about 1/16th, but I don't know if it was originally marked in inches or a wire gauge. It was sold in about 15" lengths rather than on a spool.

[Clay]

Oh I guess I could have seen that if I could see all the pictures, sorry about that.

[Daniel Peterson]

Oh I guess I could have seen that if I could see all the pictures, sorry about that.

If that's all you missed, then you read more than half of what I said. That's a more favorable ratio than I'm used to...I have a teenage son.

[Clay]

The idea is to insert the wire into the tubing for strength, which will prevent the tubing from kinking and to help the final form retain its shape.

I guess thats what this says, thought there would have been some drilling

Oh well, I will have to try it.

I can't see the one of them side by side.

I actually read the whole post, just didnt quite comprehend it. But I got it now.

Edited January 10, 2009 by Clay