Tig welding 4130 tubes, neeb question

[kakarot]

I am a college student at Polytechnic University of Brooklyn.

I am doing a project called Formula SAE. Its a basically a formula 1 car but smaller and slower.

Anyways, I am doing a 4130 steel frame from 1", 0.75", 0.625", 0.5" tubes thickness from 0.035" to 0.095" (mostly 0.035"). I have a Tig welder, it goes up to 325Amps on the dial.

I need to purchase gas, filler rods, and tungsten/cup.

I was wondering if anyone know which one should I get. Which filler rods, tungsten and cup size and type, what gas I need. Any help and tips would be appreciated.

[fun4now]

welcome to the site.
you will need strait argon for gas. the tungsten, cup and torch will all be dependant in part to the welder you are using, be it transformer or inverter. so what is the welder you will be useing ??
and you just have to show us some pic's of this project as it progresses.
Miller has an excelent TIG book free to download in its literiture section, i would atleast download and read it but i recomend the student package for $25 you cant go wrong, i got it a wile ago and its a great packet.

[kakarot]

I have a Heliarc 252, Solid State AC/DC TIG Welder Transformer/ SCR, that what it says.

Ye, I will post pics as soon as I start welding the thing.

[Jetmekdc-10]

I am also fairly new to welding. I am finishing up a roll cage made of 4130 and used 1/16 ER70 rod. One thing I learned that may help is to clean the inside of the tubing just as good as the outside surfaces. I bought some different diameter wire brush wheels and would sort of hone the inside up about 3/4 inch. There is a site called JD2.com that sells a great little tube notcher for $200. Good luck

[kakarot]

So, looks like argon gas.
and Use ER70S2 or S6 filler rods.

What tungsten should I use? type, size? and cup for it?
How many amps should I squeeze, and what flow should I am at?
I am in low air travel area, Indoors.

I got a present, temporary, the tube notcher

I will need to get wire brush things

[fun4now]

i would use 2% lanthanated or 2% cerated tungsten ( i prefer lanthanated). its becomming more commen for transformer welders to start useing the new better tungsten mixes as aposed to pure tungsten however you could use pure if you wanted.
size would be 3/32" or 1/16" tungsten cup could be from a #4 to #8 depending on the tungsten and the personal preferance. i would highly recomend you read the above mentioned TIG book first and get a lot of practise befor atempting this especily if some one will be driveing this thing when done. TIG is not simple and you dont want to trust your life in a race car to bad tig welds. its easy to get a good looking weld that is not going to hold anything, you need expereance to do some thing like this. looks can be decieving and you dont want it falling apart on you.

[kakarot]

I go with a 3/32 tungsten lathinated, probably #6 cup. The manual says #8, but I try to use a smaller one to limit the flow. Reading more online, looks like I should shoot for 5 to 10CFH, but not sure, looks a bit too low.

[fun4now]

i have a gas lense on mine and run it right about 12cfph, when i dont use the lense and have a standerd TIG cup setup on i run about 20-25cfph. 5-10 with a standerd cup setup dose sound low.

[Aerometalworker]

Ahhhh Formula SAE, I know it well.
To prevent fatigue cracks in your welds, anneal them with a torch after welding. Also dont be tricked into "tiny weld" syndrome, keep large nice looking welds. Watch the part cooling rate on thin sections.
Tig works OK on 4130 providing you post weld anneal.
If you want some hands on help go to your local aircraft mechanic that works on antiques. They will be more help then any manual for technique, although they may look at your electic welder kinda funny and hand you a real torch.

-Aaron

[fun4now]

although they may look at your electic welder kinda funny and hand you a real torch.

LOL. thats funny, but probly true.
good luck, some first hand help would be a good idea.