[jdmwnnb]

dammmmmmmmn love the suuuubie sweeeeeeeeeeeeeeeeeeeeeeeeeeeeet looking nice
keeep update hope to see more pixxxxz waannna trade lol

[wdb]

That has to be the all-time champion, king of the hill, top of the heap, rear strut tower bar.

Nice work! Great pics, thanks for sharing. I've been starting to think about roll bars/cages, but seeing how far you stripped your car down has me wondering if that's really where I want to go...

[98ss]

This looks great!
However if you had access to your friend, wouldn't it be better to ask him seam weld the whole car instead of doing cage?
I wonder which is stiffer, seam weld the whole car vs weld in cage?

[Tweeter]

Not bad.

Most people use white to paint cages to check for cracks or tears as well. I doubt you'll have any issues. I noticed there were a few dead tubes but on a paved surface I don't think it'd be an issue, wouldn't rally it though that's for sure.

When you paint it, I would just cover the whole interior (stripped) with newspaper and masking tape. Takes a long time but worth it. Also, if you dig the bare look you could clear coat it or use linseed oil. Used to race class 12's in MDR and that's what we would use.

[mug23]

Thanks a lot for the comments. I would love to seam weld the car but this car is not going to do any hard-core rally, mostly road racing so the cage will do just fine. However, I will seam weld the trunk, under the hood and anywhere that I can see it next year where I will finish learning how to weld. It's in the plans.

I really love to paint the interior white but that would mean A LOT of more work to take all the wiring and other stuff out. I think I will just going to keep it satin black. I was thinking of rattle can but I just may use the stuff called POR-15 which you can brush on and still look good. Anyone have any experience with POR-15 stuff?

Can you please point out which one are the "dead tube" you mention? I love to learn more on cage design as I will also be building either a spec bmw e30, spec 944 or of course, the spec miata.

I know buying a used race car is easier way to go, but I like to build my own so I know the car inside out...

Please keep the comments/recommendation coming. I have learn a lot on building race cars.

[Tweeter]

If you're taking the time to seam weld it, painting it is kind of a mute point IMO. Takes twice as long to prep the metal for welding than it does actually welding it. You could try and knock out both at the same time, that's what I'd do.

These are the dead tubes I was talking about:



Also the misalignment of these tubes stood out to me as well:



^^^
It's best to tie tubes together in junctions so the load is shared between the two, rather than the individual tubes being exerted.

Definition: “T” junctions are called a dead tube junction, as one tube dead ends into another. This should be avoided whenever possible, because the dead end tube will bend the other one when the loads are along the dead tube.

Basically means a tube welded in the middle of another tube without the junction of at least 1 more tube causes more stress on that area, therefore making it more likely to bend, crack, or tear. Being that I come from an offroad point of view the trucks/cars I've been it have been over-built because forces of a car crash of a road course can be calculated somewhat, while the desert is much more unpredictable.

What'd you make it out of?

Mild, DOM, or 4130?

.90, .120, etc?

I'm not talking crap on your friends welding or design at all, so don't take it that way please. I've had a lot of experience in the cage building department and just trying to help.

[mug23]

Thanks for your reply. By no means I'm taking it badly. I totally understand triangulation and in cage design, triangles are the name of the game and always join at ends at a single point so it can all share the load.

Half the cage was pre-fab, so we couldn't do anything about the tubes where they were. I'm using DOM 1-3/4" tubing and .120 wall which is pretty strong for that car since I was following SCCA rule about the car being in the 3000 lb range.

I believe the cage is well build and very strong for road racing. If I were to take it off road racing or rally, maybe I would have design few things differently.

I will be adding a few more bars where it will help to share the load, so this is not a 100% complete.

Again, thank you for your input and I appreciate your experiences on pointing me out some of the weakness of the design.

[Tweeter]

Alright cool, some people get butt hurt when constructively criticzied.

That should be plenty strong for what you're doing. It's just best to tie in tubes wherever possible. The triangulation on the A-pillar and windshield bar was a very good call, those things make all the difference. (And I'd guess SCCA requires them.)

I wouldn't call it "weak" by any means just take in consideration where I'm coming from lol. Knowing that it was a pre-fab cage now it came out pretty well! Props to your friend for working with that. Hopefully you'll never have to test out the strength of it

If you're not big on painting it linseed oil would be your best bet to prevent rusting. Where are you mounting the harnesses?

What I raced:

Porter built Class 12

That's me in the hat lol

[mug23]

I always take constructive criticism as a way of positively looking at things. I mean, take what you need and throw away the ones that will not fit your needs...

I will be painting with stuff called POR-15. I heard they are very strong and easy to use. I still may consider using a rattle can spray paint in stain black. I'm not sure which way to go.

I like to hand brush because I can be more detail on where to paint and don't have to deal with masking it. But, it seems like spraying it would come out better looking and faster too. So, I'm still up in the air for that.

I will be mounting my harness on the main hoop which is pretty standard. Do you have any suggest any other place to mount the harness?

[Tweeter]

Never heard of POR-15. Is it paint or like a rhino lining sort of deal? I found that Rustoleum flat black is more durable than the gloss black, but for looks the gloss black is pretty p.i.m.p.

Painting it by hand would be VERY tedious! It's not as bad as you think masking it off would be. My only advice if you do be careful with the newspaper afterwards that has paint all over it. My buddy almost burned his shop down after throwing it all in the corner and it going up in flames lol. You could try handpainting a small section and spraying a small section and see which one you like more...?

No I don't have any other suggestions where to mount it. The bar right behind the seats is the best place. Some people like to mount it on the floor and you can really **** up your back doing that. But thank you for putting harnesses in a car with a cage. Most people don't realize without a cage, harnesses are designed to keep you upright and when you roll with no protection, you can't duck down.

PS is your friends welder a Miller? If so, he picked a good one!

[mug23]

Originally Posted by Tweeter

Alright cool, some people get butt hurt when constructively criticzied.

That should be plenty strong for what you're doing. It's just best to tie in tubes wherever possible. The triangulation on the A-pillar and windshield bar was a very good call, those things make all the difference. (And I'd guess SCCA requires them.)

I wouldn't call it "weak" by any means just take in consideration where I'm coming from lol. Knowing that it was a pre-fab cage now it came out pretty well! Props to your friend for working with that. Hopefully you'll never have to test out the strength of it

If you're not big on painting it linseed oil would be your best bet to prevent rusting. Where are you mounting the harnesses?

What I raced:

Porter built Class 12

That's me in the hat lol

I had a few of those type of buggies but they are radio controlled.. They are very fun to drive i can see.

Yes, he's a certified welder that can weld almost any metal. He loves his Miller TIG and MIG welders and have like one for certain thickness of the metal to be welded plus a plasma cutter which I'm looking to buy as my next tool.

Here's the web site for POR-15.

[Tweeter]

Damn, the POR-15 stuff looks pretty intense. If you can afford it, I'd say go for that instead of Rustoleum in a can.

If you like the bare metal look I'd go for this stuff:

GLISTEN PC-POR-15 Inc.

[token-negro]

Por15 is what some of us call, liquid powdercoat, the stuff is just awsome, mean what ever u want to use to discribe it. Wear gloves do not let it dry on your skin as you wont get it off without wearing it off meaning in time it will come off. The other known issue is that it does not have any protection from UV rays built in, so if you plan on any part of it being exposed to the sun it will need a clear coat to protect it.

[hellomyles]

I used por-15 on my 75 Bronco and it is great stuff. But as others have said it is uv sensitive. It will faid from the sunlight if you use it on your cage. It does brush on pretty well, but I would not recomend brushing on the cage. I think it would look much, much better being sprayed on. Just remember a little extra time now and you will be happier later. If it was me I would spray is with regular car paint and not por 15. Por 15 is more of a rugged paint for old 4x4's or a rust stopper for old cars and hot rods. Just my .02. Good luck with your project.

[MGizzle]

The few things that I noticed on that cage that made me question are:

1: the bars going to the rear strut tower point into an area where almost no stress is seen, which means going there will not make the car stiffer. I think the right way to do it is to actually weld the bars to where the faces change planes, meaning weld the bars to the edges of the strut tower. I have seen guys bend the flat plate around (looks almost like a L beam but rounded at the corner).

2: The center roll hoop is way too far behind the B pillar. It doesn't serve a purpose so far back because the stock frame reinforcements (lateral cross member and roof cross member) are in line with the B pillar. I think you can see them in one of the pictures slightly. The Roll hoop should be in the same plane as well and welded to the lateral members because even in roll over it will serve a better purpose. I know that you probably did it this way because the seat bar for the harnesses wouldn't go forward any more but that is why most profesionall cages don't have a seat bar. The mount the harnesses way back on a different bar etc.

3: The top bars conecting the center roll hoop to the front run right across your head. Disaster in roll over.
motorgeek.com :: View topic - Project RSCoupe - Now with crash update...

The guy is lucky to be alive. The bar actually moved his head down into his body and he turned blue because he couldn't breathe.

4: The plates that conect to the A pillar....what are they for?? That right there is one of my main vision points and those look like you have no vision into corners anymore. They don't look to be doing much so you could maybe just take a couple square half inch bars or something and weld them at the top and bottom to connect to the A pillar for NVH or whatever it is there for.

5: I am not sure what that lateral bar in the trunk does because again, there is no loading going into that area from the suspension. The links are mounted to the rear subframe and the damper to the tower above so by the time stress distributes you will not see the energy at that spot.

6: It looks like you should have a bar coming from the bottom of the center roll hoop to the rear strut or somewhere because it looks like you have a lot of weight at the top of the cage instead of at the bottom. I don't think you have anything unnecessary at the top but the chassis look slike it would be further stiffened if a bar was coming into the center hoop node.

Anyhow, just constructive criticsm to help us all. Maybe I am missing some things and would love to know.

PS: Check the guy with the audi on the link above and how he did his side impact bars. Those suckers will take a side load. The ones you have could fail similar to how his roof failed. The bars would just buckle and that is it.