What size square tubing for building a frame?

[brrymnvette]

I'm going to be starting on my frame for my 88 Mustang Notch. I am basically back-halving it sort of.

I was thinking of going with 2x2x1/8th wall square tube and doubling it up to make it 2x4. Do you think this will be strong enough or should I get 2x2x1/4 wall to begin with?

Car will have at least 700 to the wheels and a cage.

Either size of tube won't be too much money, I have a hook-up of sorts. Which makes me wonder why I'm even asking. I should get the thicker anyway if it's cheap.

Thoughts? Would 1/4" thick be enough? Would 1/8" thick be enough?

[Mathius]

I'm going to be starting on my frame for my 88 Mustang Notch. I am basically back-halving it sort of.

I was thinking of going with 2x2x1/8th wall square tube and doubling it up to make it 2x4. Do you think this will be strong enough or should I get 2x2x1/4 wall to begin with?

Car will have at least 700 to the wheels and a cage.

Either size of tube won't be too much money, I have a hook-up of sorts. Which makes me wonder why I'm even asking. I should get the thicker anyway if it's cheap.

Thoughts? Would 1/4" thick be enough? Would 1/8" thick be enough?

What would be the point or advantage of buying 2x2x1/8" and "doubling it up" ?

I would not use anything less than 3/16" for a frame unless you're an engineer. Particularly with 700hp to the rear wheels.

2x4x3/16" is a common size for frames, and heavy enough if you sufficiently gusset the proper areas and put your crossmembers where they should be. Going up to 1/4" is probably just adding more weight.

Mathius

[parsonsj]

Morrison's 2x4 frame rails are .120 thick. 2x2x.120 times two would easily be sufficient, but why not use 2x4x.120 ?

p

[brrymnvette]

2x4x3/16th" is ordered. 20ft cost me $80.

[highschool70ss]

Where did you get your steel from? Is it in the STL area.

[brrymnvette]

Yes in the STL area. The place I used to work for sells/stocks square, round, solid pipe and tube.

National Sales Company
4201 Duncan Ave
St Louis, MO 63110
314-531-3200

[highschool70ss]

Thanks, I will have to check them out.

[JMarsa]

What would be the point or advantage of buying 2x2x1/8" and "doubling it up" ?

I would not use anything less than 3/16" for a frame unless you're an engineer. Particularly with 700hp to the rear wheels.

2x4x3/16" is a common size for frames, and heavy enough if you sufficiently gusset the proper areas and put your crossmembers where they should be. Going up to 1/4" is probably just adding more weight.

Mathius

I'm not an engineer although I play one at home :-)

I've read somewhere that "Doubling Up" has a huge factor increase in strength because of the added corners.

--JMarsa

[Mathius]

I'm not an engineer although I play one at home :-)

I've read somewhere that "Doubling Up" has a huge factor increase in strength because of the added corners.

--JMarsa

The idea you're suggesting is that by stacking the tubing and welding them together is that the horizontal bracing will provide more inherent strength. I believe you're putting twice the amount of potential stress into your welds. It's hard enough to properly engineer a frame capable of racing where you can get good welds, but you're talking about a structural weld basically the length of the frame.

A lot of non welders or home taught welders don't realize that in order to lay a good weld down on tubing you should either sleeve the weld, or purge the inside, otherwise you risk impurities on the inside of your weld.

And again I would like to present the example that you can take a piece of 1/8" steel and bend it with your bare hands. If you get the design wrong, there's a pretty good chance that frame will fail and you could very well die from the experience. Is it worth taking the chance?

I've been welding for something like 8 years now, but I'm not an engineer. That's why I overbuild everything or follow the prints. I'm not willing to put my own safety or someone elses at risk based an idea I think _might_ work.

Mathius

[LateNight72]

I'm going to be using 3x6 for the Chevelle. But I over-engineer stuff.

[parsonsj]

A lot of non welders or home taught welders don't realize that in order to lay a good weld down on tubing you should either sleeve the weld, or purge the inside, otherwise you risk impurities on the inside of your weld.I disagree. I've read and read and read about all kinds of welding: the vast consensus is that the only common tube material that needs to be back purged is stainless steel.

Here's just one example from Miller Education:

http://www.millerwelds.com/education/articles/articles70.html

There is not a single mention of back purging.

Back purging your non-ss tubes isn't harmful. Just unnecessary.

jp

[gto406]

For those not familiar with 'back-purging' is there any good sites that discuss the process?

I found the following for TIG welding, but I am not sure this is what you guys are talking about:

http://books.google.com/books?id=RKPBv1ECHz0C&pg=PA107&lpg=PA107&dq=weld+back+purge&source=bl&ots=bHO4aUTHW2&sig=zWxTQ3S1Es2NnoT0k93UPchG82g&hl=en&ei=4rQWSo-yOZOWMsqssLEI&sa=X&oi=book_result&ct=result&resnum=8

With respect to the first post in this thread...
I would recommend to anyone building a frame (or any structure like a roll-cage, etc.) to examine the rule-book of an auto-racing sanctioning body that runs a class (or type) of vehicle _similar_ to what is planned. For example, if the plan is to do solo events or the odd track-days, the SCCA would be a good place to start (formal rules can be found here - http://cms.scca.com/documents/Club%20Rules/09%20GCR/GeneralRegulations.pdf). These sanctioning bodies will provide (in there rule books) alot of good details on race car construction. I am sure you could also contact one of their stewards to clarify the information (if required). The nice thing about going this route, is that the sanctioning body has the benefit of input from race car constructors, stewards, standards bodies (like SFI - http://www.sfifoundation.com/), all providing input. Also note that these bodies are typically liable (if something happens at an event) so you know the emphasis will be on the safety aspect.

Thanks,
Brian.

[parsonsj]

Here's one of my favorite articles from Lincoln:

http://www.lincolnelectric.com/knowledge/articles/content/chrome-moly.asp

One of the questions addresses back-purging in 4130 welding.

As for me, I back-purge when I weld SS exhaust tube for headers and such. I have a separate tank (100% argon) and regulator. I have it connected to a ball valve assembly with 1/4" pipe thread on one side. From there I make adapters to the diameter of tube I'm welding. I cap one end of the tube and make some small holes in it (aluminum foil and wire works well). Connect the other end of the tube to the regulator, flow as low as your regulator supports (10 cfh or so) through the tube, give it a minute or two to purge the oxygen and replace with argon, and weld as normal. I use the ball valve to stop the flow of argon when I'm not welding.

Back-purging is a real pain in the ass, actually. :)

jp

[parsonsj]

I believe 3/16 wall thickness in tube is overkill. .120 is more than adequate, and is what is commonly used in race car fabrication.

If it gives you peace of mind, then fine. It certainly won't make the resulting product less safe.

jp

[gto406]

It sounds like back-purging shields the 'inaccessible' portion of the weld area by basically surrounding it with shielding gas (which is why I assume you need to create an air-tight cavity of the tubing you are welding on).

Yes, the process does sound like a major PITA!

Thanks for the clarification JP,
Brian.

[parsonsj]

I dug up some data about tubes. I remembered that, in general, the sectional area of a tube determines the strength of it. Wall thickness has a negligible effect, but I didn't remember exactly how to calculate that.

The basic way to compare is calculate the difference in section modulus. Section modulus is the measure of the resistance to bending, loosely speaking.

S = [x * y (raised to the 3rd power) - x1 * y1 (raised to the 3rd power)] / 6 * y

where
x is the short side of the tube (2 in this case)
y is the long side (4)
x1 is the remaining short side minus wall thickness (1.75 or 1.625)
y1 is the remaining long side minus wall thickness (3.75 or 3.625)

For a 2x4 x .125 tube, the section modulus is 5.17 square inches. For a 2x4 x .375 tube, the section modulus is 5.19 square inches.

So, in general, it means that the heavier wall tube will resist bending through its long wall side by about .05 percent more than the thinwall tube. Note the decimal point. (somebody check my math, please!)

Given that the heavier wall tube weighs nearly 2 lbs per foot more, it doesn't seem the higher cost and weight for .05 percent more "strength" is worth it.

jp

[parsonsj]

t sounds like back-purging shields the 'inaccessible' portion of the weld area by basically surrounding it with shielding gas (which is why I assume you need to create an air-tight cavity of the tubing you are welding on).

Yes, the process does sound like a major PITA!That's right. The idea is to remove the oxygen from the back side of the weld.

jp

[brrymnvette]

Lots of good info in this thread. Thanks for the tips/help/suggestions. I went with the 3/16th thickness b/c I like to over do some things too.

[Mathius]

I disagree. I've read and read and read about all kinds of welding: the vast consensus is that the only common tube material that needs to be back purged is stainless steel.

Here's just one example from Miller Education:

http://www.millerwelds.com/education/articles/articles70.html

There is not a single mention of back purging.

Back purging your non-ss tubes isn't harmful. Just unnecessary.

jp

John, you can disagree if you want to, but experience tells me otherwise. Even with back purging, I've had tubes fail to pass a visual inspection inside during a cert practice.

Depends on the process of course, stick welding provides its own flux, but think about what you're dealing with... The whole idea of a shielding gas is to "shield" the weld from impurities in the air while welding. I believe in some cases like argon, the gas actually removes impurities. IIRC argon removes oxygen from the weld... but I digress, it's not import to understand how the gas works to understand what I'm getting at.. If you're going for 100% penetration on a tube, you're technically welding top and bottom. What's removing the impurities from the weld on the inside of the tube?

Also, you don't know what might have happened on the inside of that tube. What chemicals were run through to clean it... was it stored somewhere where it got wet inside? Was it just bad steel?

Personally I prefer plugs. They're much easier to deal with. But there's a whole extra science involved to using them as well. Solid plugs should be used when going from a large to small diameter pipe. Otherwise hollow plugs should be used. You should put holes in the adjoining tubes and use rosette welds. Some will argue that a diagonal weld along the tube is better, but I've never seen a convincing argument that that is necessary.

Mathius

[parsonsj]

Depends on the process of course, stick welding provides its own flux, but think about what you're dealing with... The whole idea of a shielding gas is to "shield" the weld from impurities in the air while welding. I believe in some cases like argon, the gas actually removes impurities. IIRC argon removes oxygen from the weld... but I digress, it's not import to understand how the gas works to understand what I'm getting at.. If you're going for 100% penetration on a tube, you're technically welding top and bottom. What's removing the impurities from the weld on the inside of the tube?Argon or any other shielding gas does not remove impurities. Shielding gas is to shield the puddle from oxygen so that the molten material doesn't oxidize while it's liquid.

As far as reading your links from the Chopper Underground site, I have to be a member to see them... so I can't read them. My only comment since I can't read them is that my links were from Lincoln and Miller, the two biggest domestic suppliers of welders. Between message board comments and welder companies, my money would be on the welding companies.

Back purging structural welds will certainly do no harm, and I do understand why some people would go to such lengths. My take is that it is unnecessary, and I'm backed up by a wealth of professional welding educational material.

jp

[parsonsj]

Personally I prefer plugs. They're much easier to deal with. But there's a whole extra science involved to using them as well. Solid plugs should be used when going from a large to small diameter pipe. Otherwise hollow plugs should be used. You should put holes in the adjoining tubes and use rosette welds. Some will argue that a diagonal weld along the tube is better, but I've never seen a convincing argument that that is necessary. I remember a post about an incredible truck project somebody was doing (an off-road deal). The fellow did beautiful welding work, and said the same thing: he capped all of his tubes before welding them, and pie-cut all of his bends so that the whole chassis was done with straight tubes all welded together. Seemed like over-engineering to me, but he swore by it.

jp

[Mathius]

Argon or any other shielding gas does not remove impurities. Shielding gas is to shield the puddle from oxygen so that the molten material doesn't oxidize while it's liquid.

As far as reading your links from the Chopper Underground site, I have to be a member to see them... so I can't read them. My only comment since I can't read them is that my links were from Lincoln and Miller, the two biggest domestic suppliers of welders. Between message board comments and welder companies, my money would be on the welding companies.

Back purging structural welds will certainly do no harm, and I do understand why some people would go to such lengths. My take is that it is unnecessary, and I'm backed up by a wealth of professional welding educational material.

jp

I removed the links because you have to be a member to see them. You must have been posting while I did the edit.

Again, you're entitled to your opinion and you can use whatever method you want. I will use what I have been trained with and what I know to work. What I have seen with my own eyes.

I used to do work at Lincoln Electric (their world headquarters) and I can tell you they are not perfect by any means. They are among the leaders in their industry and they make fine equipment, but their information is not always correct or for practical application. They also say things like you can use their 110v unit to weld aluminum. Technically you can, but you should use a dedicated machine or change out the sleeve every time, and you will also probably deal with birds nests. Even then, the power output won't be enough to do any aluminum getting anywhere close to 1/16".

I've had guys on boards tell me you can't weld steel using argon as a shielding gas. But I've been doing it for 8 years now.

I've seen guys say you can't gas weld aluminum. But there's a whole forum of guys on Metal Meet that are doing it, and there are old timers I've seen do it (although never in person, usually in a video).

There is a lot of information out there, and people can do what they want with it.

The links I was going to post from the chopper site was not member information, it was articles that a member had scanned and posted, along with diagrams to go along with it. There was some fantastic information on plugs, rosette welds, etc.

There are guys on that site that have been building bikes for years that will tell you to just start cutting, measuring, and welding. Then there are other guys who have been building bikes for years who tell you to research, find someone who can do it and teach you, or don't bother because you'll put your life in your own hands.

There are guys who will weld tubes to tubes and be done with it, and guys that insist you will die if you don't put a plug between your tubes and do it properly.

There are always going to be opposite ends of the spectrum on all issues and sometimes there is no right answer. For all I know, when my welded tubes failed the visual inspection there were other factors involved that I didn't know about at the time. But I do know that purging the inside of the tube will make double sure my welds won't fail. I don't like welding things when I'm not 100% positive I'm not putting someone's life in danger.

I was going to leave the links because the information is very good, but I figured that most people wouldn't bother to take the 10 seconds it takes to register to read so they can read the stuff.

You confirmed my belief. I don't want to be offensive John. I saw your Nova, I read your posts, I know that for the most part you know you're sh*t. But you're telling me I'm wrong, but you wouldn't even take 10 seconds to read the information that i posted.

Anyways, like I said, you can use the technique that works for you. I'm not trying to start a p*ssing match, I'm just trying to put out what I believe is the safest technique.

Mathius

[Mathius]

I remember a post about an incredible truck project somebody was doing (an off-road deal). The fellow did beautiful welding work, and said the same thing: he capped all of his tubes before welding them, and pie-cut all of his bends so that the whole chassis was done with straight tubes all welded together. Seemed like over-engineering to me, but he swore by it.

jp

Like I said in my other post, I'm not an engineer. So unless it gets to the point where I'm adding an incredible amount of weight to my project, I will ALWAYS over-engineer and take every precaution necessary.

This is a hobby and these projects are fun, but the fun quickly disappears if your frame breaks free and you end up in a wreck.

You discounted the "chopper forum" guys that I had originally linked to in your previous post, but chopper frames have to be engineered a lot better than a car frame. You can get away with a lot more when you have 4 wheels pulling you along than you can with two. If a chopper frame breaks, you're probably going down. If you go down on a bike vs. a car crash? You have a good chance of surviving the car crash. Motorcycle fatalities are a lot more common. These guys need to know their stuff.

Not everything has to be doom and gloom though. Another example.. I will ALWAYS cap every tube I weld to ensure the inside is 100% sealed. Why? Rust can't accumulate where there is no air. You can't count on coating the inside of a tube to prevent rust without some kind of space age fiber optic camera inspection or something.. but if you can properly seal the air out of the tube it won't rust from the inside out.

Most guys will tell you it doesn't matter, that the part will never rust through in your lifetime. But I hate rust with a passion, and I believe in doing things right.

Anyways, this is just my 2 cents.

Mathius

[parsonsj]

was going to leave the links because the information is very good, but I figured that most people wouldn't bother to take the 10 seconds it takes to register to read so they can read the stuff.

You confirmed my belief. I don't want to be offensive John. I saw your Nova, I read your posts, I know that for the most part you know you're sh*t. But you're telling me I'm wrong, but you wouldn't even take 10 seconds to read the information that i posted.Peace. Please.

I draw the line at registering on message boards I'll probably never visit again. I've got nothing against chopper forums... really. Don't turn this into my issue. This isn't about me or my 10 seconds. You could have taken the time to snag the links within that forum and posted them directly. It isn't reasonable for you to expect all of us to register on a different forum to see that information.

I apologize if I've offended. I certainly didn't mean it that way.

Anyway, this isn't about us, and my intent is not to convince you. I know better. One of my jobs as the moderator of this forum is to make sure that strong-willed members don't overwhelm all the other members with opinions presented as fact. That's why I'm very careful to make sure when I present a different solution or an alternate viewpoint, I have data to back it up.

I'm happy to have civil discussions about these differences (which we've managed so far), but I won't let it become personal. I can't... I gotta stay above the fray.

We can talk about capping tubes and wall thickness and material and rust as long as anybody wants (I will, because I enjoy the discussions). But let's keep it from being me vs you. That's not my intent at all.

jp

[parsonsj]

Assuming everybody is still here... :)

It is a good idea to cap tubes to keep the moisture out of them. I don't have any open tubes on my car for exactly that reason. But I didn't cap every tube as I went: I just capped all the exposed ends when I was done.

One tip: if you do cap tubes, be sure and drill a small vent hole (1/8" is fine) in the tube somewhere away from the weld. Otherwise you'll have difficulty with your weld puddle blowing out from the hot gas trapped in the tube. Then after the whole tube cools down, do a quick cosmetic weld to fill the vent hole.

jp

[gto406]

Agreed, there is more than one way to 'skin a cat'. A good friend of mine (an auto mechanic with over 35 years experience) once told me while we were working together on our cars and I ran into some issues - 'it is all in the way - you hold your head' - this as I sat underneath the car!

I thought he was nuts, but after thinking on this some more, what he was talking about is 'perspective' (your angle or view on a particular topic). Sometimes all it takes is a 'small movement' over to the left (turning your head) to see that YES, there is another way to accomplish the same thing.

I am by no means a mechanic or a mechanical engineer, however I have been a computer/software engineer for 21 years - and if there is one thing I have learned, each way to do things have pro's and con's. You need to look at the application, weigh your pro's and con's against your criteria (and the problem at hand) and make your choice. Obviously, safety plays some role or criteria in those decisions.

My $0.02.
Brian.

[Mathius]

Peace. Please.

I draw the line at registering on message boards I'll probably never visit again. I've got nothing against chopper forums... really. Don't turn this into my issue. This isn't about me or my 10 seconds. You could have taken the time to snag the links within that forum and posted them directly. It isn't reasonable for you to expect all of us to register on a different forum to see that information.

I could have posted the stuff here directly, but I figured the stuff is already on the internet, why take up more resources on this board here, when I can just link it?


I apologize if I've offended. I certainly didn't mean it that way.

I'm not offended, but you presented a counter argument that Miller and Lincoln are better sources. I don't necessarily find that to be 100% accurate in all cases.


Anyway, this isn't about us, and my intent is not to convince you. I know better. One of my jobs as the moderator of this forum is to make sure that strong-willed members don't overwhelm all the other members with opinions presented as fact. That's why I'm very careful to make sure when I present a different solution or an alternate viewpoint, I have data to back it up.

As do I. I'm not presenting an opinion, I am giving facts. I am telling you what I have personally seen and used in the last 8 years since I began welding. Just because the experience was something that happened to me personally doesn't mean it's an opinion, John.

And yes, I'd certainly agree with your assessment of me as a "strong willed" individual, but if you don't present your arguments with conviction, how is someone to take you seriously? Anyways, it's up to the user to read the information I've provided and come to their own conclusions.

Your way? May work. May work every time for you, for all I know. But my way provides additional insurance. And for all I know the reason your way works has to do with you using a different approach than what I do. Like my other example that I usually weld steel with argon instead of the 75/25 that I think most people use. I don't see the advantage in paying for an extra bottle when I get results just fine this way.



We can talk about capping tubes and wall thickness and material and rust as long as anybody wants (I will, because I enjoy the discussions). But let's keep it from being me vs you. That's not my intent at all.


It's not "me vs you" John, it's your argument against mine. And for me, I can understand your presenting the information that Miller and Lincoln is putting out, because they are obviously large companies, but the idea that you want to present that someone should take less precautions is something I can't agree with.

Again, when I weld something I want to know that I'm not putting someone's life at risk by my welds. If there are extra precautions I can take within reason, I will always try to do so and I don't know or understand why anyone else would want to do less.

Mathius

[Mathius]

Assuming everybody is still here... :)

It is a good idea to cap tubes to keep the moisture out of them. I don't have any open tubes on my car for exactly that reason. But I didn't cap every tube as I went: I just capped all the exposed ends when I was done.

That is how I do it as well, but one thing people often neglect to do that I will do (and again is overkill, but I despise rust), is that they fail to deal with holes that they have in the frame.

On a stock frame there are tons of holes from factory jig alignments or other reasons. I cap all these.

If I run a bolt through the frame, I will drill the hole oversized, sleeve it with a tube, and run the bolt through the tube.

On c-channel type frames.... what I mean is like on a factory pickup truck where you basically have a square tube with the inside wall missing, people will often box the frame for strength, but some people will run their lines inside there to "neaten" things up. I like to box my frame, but I will deliberately weld angle iron at key locations to give my lines somewhere to sit and be mounted. And again I will weld them all the way around. Not because it's necessary for strength, but we've all pulled a bracket off of our frame and saw the rust that formed behind the bracket.

Because air=rust.

Mathius

[80proZ]

. Like my other example that I usually weld steel with argon instead of the 75/25 that I think most people use. I don't see the advantage in paying for an extra bottle when I get results just fine this way.



Mathius
The addition of the CO2 to argon does two things.Helps with arc stability and helps to increases the width and depth of the weld penetration.

[parsonsj]

I don't see the advantage in paying for an extra bottle when I get results just fine this way.


If there are extra precautions I can take within reason, I will always try to do so and I don't know or understand why anyone else would want to do less.

So which is it? On the one hand you say it's good enough (just use 100% argon), but on the other other you say you will take extra precautions?


As do I. I'm not presenting an opinion, I am giving facts. I am telling you what I have personally seen and used in the last 8 years since I began welding. Just because the experience was something that happened to me personally doesn't mean it's an opinion, John.Yes it does. You've given no corroborating information to back your argument. It is your opinion. I'm always open to learning new things, but one person telling me something without additional data is not going to change my mind. It shouldn't change anybody's mind.

jp

[Mathius]

So which is it? On the one hand you say it's good enough (just use 100% argon), but on the other other you say you will take extra precautions?

How is using 75/25 an extra precaution when I am using a method that I was taught with and has worked for 8 years?


Yes it does. You've given no corroborating information to back your argument. It is your opinion. I'm always open to learning new things, but one person telling me something without additional data is not going to change my mind. It shouldn't change anybody's mind.

jp

Ok, now I'm taking offense and taking it personally, so this will be my last post in this thread, because you'll just lock it anyways.

An opinion is something that is not concrete. It is someone's perceptions of a situation.

We're not talking about my perceptions of the situation, we're talking about concrete results. Experiences are NOT opinions.

Enjoy your holiday, John.

Mathius

[parsonsj]

An opinion is something that is not concrete. It is someone's perceptions of a situation.We agree. That's exactly what I believe too. And since you can't have your experiences directly input into my brain, we're left with your written descriptions. Those written descriptions constitute your opinion. It's just your perception of reality.

As I said above, one person's methods are not going to convince me, and shouldn't convince anybody. You need to bring independent sources to bear to back up your case.

Anyway, thanks! (holiday wishes) My holiday will be spent underneath my car scraping the 3rd member gasket off my rear housing. Somehow it bonded itself and became one with the housing. Yuck. Anyway, I hope your holiday is better than mine.

jp

[80proZ]

How is using 75/25 an extra precaution when I am using a method that I was taught with and has worked for 8 years?




Mathius
Because useing 75/25 is the proper sheilding gas when mig welding carbon steel.How can you argue about back purging on carbon when the gas your using is wrong for the material to begin with.
I'm not trying to start a pissing match,just trying to give people the right info.Just because you've been using straight argon and it works does not mean it's correct.Theres a good reason why they mix the gases the way they do for each application.Do some research.

[parsonsj]

useing 75/25 is the proper sheilding gas when mig welding carbon steel.Every welding source I've seen has said the same thing. That's what I use, and what everybody I've ever talked with uses for MIG welding steel, though I've seen some people use 80/20.

jp

[gto406]

Yes, I agree with that as well, argon (in and of itself) is inert - meaning you need something to move it out (hence the Carbon dioxide). I believe for TIG you can use pure Argon, but most gas suppliers (source: http://www.boc-gases.com/products_and_services/by_product/welding_gases/index.asp#_Shielding_gases) make use of a combo of argon and something like helium or helium/CO2.

Interestingly, when I went to refill my cylinder (Autoweld) two weeks ago my supplier said many welders that come in there (Linde) to request new cylinders don't even mention (or check) the type of gas cylinders they are replacing. Once I mentioned MIG (for regular steel - auto application) he said 'okay Autoweld is what you need' (Autoweld is 75 Argon/25 CO2).

~B.

[jevonniespapi]

I am so curious, was a frame ever built? I'd love to see some pics!

[brrymnvette]

It's in the process of still being built. Getting married and doing a house reno, has put the car down towards the bottom of the list. Hopefully soon I'll be able to get back to it and finish the frame.

[fordsbyjay]

You never did mention if there is going to be a roll bar in the car. All I ever use is 2x3x0.120 wall. It is plenty strong enough if tied into everything else around it. Your suggested method of stacking seems complicated and very heavy to me.