TIG help

[csmitty]

I'm staring to lay down some beads with my slightly used Maxstar 200 and I'm having some issues with the bead forming pores. I'm almost positive its due to contamination as I'm repairing a 4130 control arm, so old tubing somewhat clean, seemed ok to me, to new tubing. I've had some beads lay down just fine and others lots of sparks and arc wander/contamination. Which leads me to the metal not being clean enough. But just wanted a 2nd opinion as I was getting pretty frustrated and wasn't thinking. Plus it was the first real work out for the Maxstar on 115V power. I did some mild steel practice beads and everything seemed fine so I don't think its the welder. Had 15CFM flowing. Didn't have the right gas lens so normal collet body.

Thanks!

 

[Pneuking]

I wish I knew. My welds look horrible on a flux core.

 

[IndyGarage]

It has to be one of the following:

Dirty workpiece - clean the gap as well as the surface
Bad ground?
contaminated tungsten? Break it off above any contamination regrind it.
Bad gas - I got a tank of gas that I couldn't weld with at all. I think they filled it wrong.

I also had a nasty time awhile back when I welded a piece of galvanized steel. I ground it away good, but I think the wheel must have left some residue.

 

[t100]

it could be something like oil residue on the tubing. it's a good thing for steel yard because 4130 rusting like no other. we do rub down the tubing with acetone.

second, try bump up the gas to 25cfh, see what happens, too easy to pass up.

people do get bad gas once in a while, but since you are doing ok on the mild steel, no likely to be the gas. it happened to me once, the welding supply company filled c-25 in my argon tank.

 

[csmitty]

I moved the ground from table directly to work piece. Didn't help really. Was new 2% Ceriated tungsten. Was cleaned whenever it got contaminated. I went to 18cfm once. I'll try 25 tomorrow. might get some sand paper and try cleaning some. I've done mill fresh 4130 together with no surface prep and no problems. But this is new to 7 year old 4130. I've about struggled through it. I'll try to get some pics up in the morning. Also using Oxweld #7 but that doesn't matter much. New Argon. They gave me 75/25 on Friday. So didn't get much done on the weekend. Might try to pick up a gas lens for the WP20. This 20 is huge. Used to the 17s

 

[NASTYZEN]

Often control arms have a black oxide finish on them or some other form of corrosion protection.I just wire wheel them prior to welding.Old control arms are often corroded on the inside,that could be another issue.Make sure your filler rod is not contaminated by anything.If you go beyond 15cfm you may get some porosity as the gas will push into the weld puddle.
When welding 4130,make sure you keep the weld shielded with gas after completing the weld till the post purge timer reaches the end of its cycle.
Good luck!

 

[csmitty]

Often control arms have a black oxide finish on them or some other form of corrosion protection.I just wire wheel them prior to welding.Old control arms are often corroded on the inside,that could be another issue.Make sure your filler rod is not contaminated by anything.If you go beyond 15cfm you may get some porosity as the gas will push into the weld puddle.
When welding 4130,make sure you keep the weld shielded with gas after completing the weld till the post purge timer reaches the end of its cycle.
Good luck!

This is a fabricated control arm from raw 4130. It was primed and painted and most of that was removed. Not by me. The inside however is rusty now that I think about it. I has threaded inserts for heim joints so water could get to the interior past the threads.

I cut out the bent up section and inserted a sleeve into both open ends, then another same Dia tubing to replace the bent section. So the sleeve could have been the rust contaminating. That went ok. Not astehetically pleasing but solid. It was just going to be welded over anyways. Now my groove weld if you will on top of that is having the porosity issues. I tried turning the gas down to see if it was cavitating the pool but didn't seem to affect it. Where I'm thinking a gas lens would come in handy. I always post shield as well. Even increased the timer. My filler is a bit large for this 3/32. Really need some .065 but trying to make it work.

I've run into the problem sporadically before but can't remember how I solved it.

Here's what I'm working with. Didn't get any weld pics this morning as I was running behind. Plus I don't really want to put my name on it. If anyone is familar with the SAE Mini Baja, or Baja SAE as its now called this is what its for. About a 400lb off road race vehicle.

 

[NASTYZEN]

The a arm almost looks to be zinc plated.This can create havoc for sure.You can tell because of the strange colours when you weld it as well as it popping and sticking to your tungsten.Another note,are you sure your filler is for t.i.g.?If you use filler for gas welding,the carbon content is much higher than for t.i.g. and bubbles to no end.

 

[csmitty]

Def. not zinc plated. I more than likely built that originally 6-7 years ago. We had two guys doing the welding. It was just primed and painted. So visually inspecting it seemed pretty clean to me.

Here is the rod i'm using. the 32.
http://www.aircraftspruce.com/catalog/mepages/oxweld.php
It is a bit to large at 3/32 though but doable. I walked back and verified the rod as they brought out the 7 before.

Some sections have welded just fine. While others are creating the pores and sparks. This eveing I can get some photos of the decent and the bad. I might grind them out just to make me feel better about it. Then clean up the edges more.

 

[Mad4wd]

How are you sharpening your tungsten and what are you using to sharpen it? The inner tubing still has mill scale on it? Was it painted and or powder coated before? We run around 18-20 on the gas but we use diffuser lens and have a lot more control over the arc with the Dynasty.

 

[7 second chevelle]

Are you welding near a magnet? The magnet will really mess with the arc..

 

[IndyGarage]

Surely you cleaned it up from what's shown in the pictures?

That inner tube hasn't been cleaned at all, and the outer one has dirt all over it other than the cut surface.

If not, there's your problem.

 

[csmitty]

Using an 80g Silicon Carbide wheel to sharpen tungsten. In line with the wheel to keep the grind lines running down the axis of the tungsten. Airgas didn't have the larger gas lens so gonna be stuck with a normal collet body.

I'm not denying that its not the cleanest of surfaces. However I think the original tube is the problem. I haven't cleaned the scale on some 4130 T joints and its gone just fine.

I'll still get some pictures but I'm pretty sure I'm just going to start over and get that parent material cleaner. What would one recommend besides a clean flap wheel? trying to keep the stress risers down. However that section would have a thicker wall. Its 7/8x.058 with 3/4x.065 as the sleeves. Couple mils off but not to bad for what it'll be used for.

 

[tool whore]

I am going to be in the minority here, but I would turn the air down to around 5cfm and slow way down on the process. Turn the heat up and take a little more time.

With the 110 it should take longer. With the air jacked up you will get porosity from the blowing of the puddle. Since some welds are good and others not, cleaning seems to be the difference. I would not use the silicon disc on the tungsten. Also, whatever the disc, you should never use it for anything else. We all do, but shouldn't.

 

[bobadame]

I think that 4140 and Mini Baja are not compatible. Mild steel a arms will bend and keep on going. 4140 tends to snap next to the welds when it fails. I know the competition is all about power to weight but it's more about how many laps you can complete.
If all else fails, and I hate to suggest this, weld over the bad spots with 308 ss filler or silicon bronze.

 

[Vicegrip]

Not even close to clean enough for me for Tig YMMV. I like things to be eat off it clean befor I Tig. Any dirt or oil will just mess up the weld and the torch. I could be wrong but most of the other welds look like Mig. You can Mig 4130 that is less than .25 thick. why use 4130? Have it on hand?

 

[csmitty]

I am going to be in the minority here, but I would turn the air down to around 5cfm and slow way down on the process. Turn the heat up and take a little more time.

With the 110 it should take longer. With the air jacked up you will get porosity from the blowing of the puddle. Since some welds are good and others not, cleaning seems to be the difference. I would not use the silicon disc on the tungsten. Also, whatever the disc, you should never use it for anything else. We all do, but shouldn't.

I'll give it a shot. I haven't had any problem getting a good pool going. Whats wrong with the silcon carbide wheel? Should be better than aluminum oxide. Its a dedicated wheel. I've got a general Aluminum Oxide on the other side I could try.

I think that 4140 and Mini Baja are not compatible. Mild steel a arms will bend and keep on going. 4140 tends to snap next to the welds when it fails. I know the competition is all about power to weight but it's more about how many laps you can complete.
If all else fails, and I hate to suggest this, weld over the bad spots with 308 ss filler or silicon bronze.

We've always used 4130. And yes if anything fails its usally around the weld. We heat treat the frame usually and sometimes suspension components if they're finished. They've taken quite a beating over the years. The 05 car has the most jacked up rear lower arms imaginable. I mean creases in the impact area. still held up for years post comp driving. This is off an 04 car and I should have taken a pic of the deformation before.

we only had one fatigue failure that I'm aware of when i was on the team. and that was due to the wrong material selection in fabrication, which happens.

If your going to have a 400lb car, and you have to to be competative. Your going to use an alloy steel frame. We were top 10 almost every race from 04-07 with a win in SD in 07. We also had a good race team and structure though. Unfortunantly that seemed to have droped off after I left that year.

 

[bobadame]

I'll give it a shot. I haven't had any problem getting a good pool going. Whats wrong with the silcon carbide wheel? Should be better than aluminum oxide. Its a dedicated wheel. I've got a general Aluminum Oxide on the other side I could try.



We've always used 4130. And yes if anything fails its usally around the weld. We heat treat the frame usually and sometimes suspension components if they're finished. They've taken quite a beating over the years. The 05 car has the most jacked up rear lower arms imaginable. I mean creases in the impact area. still held up for years post comp driving. This is off an 04 car and I should have taken a pic of the deformation before.

we only had one fatigue failure that I'm aware of when i was on the team. and that was due to the wrong material selection in fabrication, which happens.

If your going to have a 400lb car, and you have to to be competative. Your going to use an alloy steel frame. We were top 10 almost every race from 04-07 with a win in SD in 07. We also had a good race team and structure though. Unfortunantly that seemed to have droped off after I left that year.

Sounds like you've got it figured out. When you are welding a tube structure make sure that there is a hole drilled somewhere through the tube so that heated, expanded air can escape. Otherwise it wants to come out through the last bit of the bead you are welding. Also make sure the inside of the tube is clean especially if it's thin wall. Might help to back purge the tube. Once bubbles show up in the bead you need to grind the bad area out or it will continue through the bead. This can be a frustrating problem for sure. One other thing I'd suggest, where your shock mount is welded to the A arm you have a long continuous weld. If that starts to crack it will continue along the weld. A better way is to use shorter, interrupted beads. This way if a crack starts it will usually stop at the end of the short weld. Also you have to add up all your welding beads somewhere in the cost report. You will do better points wise with less welding.
GOOD LUCK at the competition!!

 

[welder4956]

From the photos, it looks like more cleaning is needed in the weld area. The mill scale needs to be removed to bright metal using sanding disc, flapper wheel, sand blasting or grinding. Also, the Oxweld wires are intended for gas welding (such as oxy-actylene), not for TIG. TIG wires have significantly more deoxidizing elements (Si, Zr, Ti, Al). There are none in Oxweld wires, save for a small amount of Si. You might try switching to ER70S-2 or ER4130 TIG wire.

 

[csmitty]

Not even close to clean enough for me for Tig YMMV. I like things to be eat off it clean befor I Tig. Any dirt or oil will just mess up the weld and the torch. I could be wrong but most of the other welds look like Mig. You can Mig 4130 that is less than .25 thick. why use 4130? Have it on hand?

The other welds are all TIG, however 04 (when these were made) was the first year with the TIG. I had about a years experience with TIG welding and some of the others were just starting out. The year before that they were MIG and it looked terrible and heard lots of bad stories. I can imagine it would be pretty hard getting a good continuous bead. Having the adjustable amperage makes a huge difference IMO. 4130, for this repair its what it was made out of. For the car that year it was for weight savings. With 10hp you gotta cut the fat.

Sounds like you've got it figured out. When you are welding a tube structure make sure that there is a hole drilled somewhere through the tube so that heated, expanded air can escape. Otherwise it wants to come out through the last bit of the bead you are welding. Also make sure the inside of the tube is clean especially if it's thin wall. Might help to back purge the tube. Once bubbles show up in the bead you need to grind the bad area out or it will continue through the bead. This can be a frustrating problem for sure. One other thing I'd suggest, where your shock mount is welded to the A arm you have a long continuous weld. If that starts to crack it will continue along the weld. A better way is to use shorter, interrupted beads. This way if a crack starts it will usually stop at the end of the short weld. Also you have to add up all your welding beads somewhere in the cost report. You will do better points wise with less welding.
GOOD LUCK at the competition!!

I've been out of the game since 07 unfortunately. Would love to go back though. This is for a retired car.

From the photos, it looks like more cleaning is needed in the weld area. The mill scale needs to be removed to bright metal using sanding disc, flapper wheel, sand blasting or grinding. Also, the Oxweld wires are intended for gas welding (such as oxy-actylene), not for TIG. TIG wires have significantly more deoxidizing elements (Si, Zr, Ti, Al). There are none in Oxweld wires, save for a small amount of Si. You might try switching to ER70S-2 or ER4130 TIG wire.

Interesting. I didin't know the oxweld was a gas welding rod. We used it for many years on these type frames. I've got some ER70S-2 I was thinking about trying with. Guess I will.

Here's some rather horrid pics for your viewing/commenting pleasure. I wonder if I could post under someone else's name

Didn't get to work on it tonight. To busy putting up my gladiator stuff. I couldn't wait.

I'll have some fresh 120g flap discs tomorrow so will use those. Those "welds" will also get ground out.

 

[JSGAuto]

Oh...BAJA.....

Sounds like we were in it at the same time, I finished up in '07. We weren't as sucessful as you, but I'll blame funding and school politics!

I rescued an old frame as well, someday I'll have to put it back together. I'm not sure I could live with the 10hp anymore though!


Jim

 

[csmitty]

Nice! What school? I was Auburn. It seems funds and politics are the common inhibitors to a successful Baja SAE program. We always had great support from the COE and had multiple SAE teams throughout. Formula, of course, were the nemises. We got along ok though. I'm sure we've got quite a few SAE alums around as well.

Since 04 all our cars have gone to former team members. Before that they were cut up. 04 was our turning year so they're all good quality cars, some more so than others. I'm trying to save 07, our winning year car, from destruction from newbie drivers. Its to the point where the current team doesn't have the means to keep it up so to keep it from rusting away in storage I want to refurb it back to its glory days and resist the power upgrade. Its def. a piece of our Baja history so I'd like to run it some more, then eventually give/loan it back to the COE as a display piece. We shall see.

 

[JSGAuto]

New Jersey Institute of Tech.

From what I hear the Baja team has dissapeared. Kinda sad, considering its been around since the '80s. Reguardless of finish (The best we did was in the 20's), the education was so valuable, especially for me, since it more or less decided my carear path.

I do bump into baja/formula alumni every now and then. It seems when I run into them in the professional setting they seem to have a better grip on design-for-manufacturing then the others!

I helped mfg a few parts for the last FSAE team a couple years ago, but since then lost touch.


I'd love to get my hands on an old FSAE car too!

 

[csmitty]

Well go to work on it tonight. Ground out alot of the junk then flap wheeled it and the outside. Was still having problems but it was better. Ran through a couple settings of gas flow, used the ER70. I think its still some kind of **** in there. Even after I sanded the weld back down smooth you could see how the pores had formed down in the weld. I think I settled around 12CFM. Here I made a little sleeve to beef up the bend a bit and got away from where I cut the original straight out and it did much better.

Didn't turn out or go as well as I planned/hoped. But its also been a while since I picked up a torch. Looking forwarding to burning some more metal.