Welding and Materials - Page 3

120mm · #41 (**permalink**) 12-16-2015, 02:45 AM

Quote:

Originally Posted by alfy65

Supports the cowl, dash ,door hinges front coil over uprights and adds ridgety to the frame..I put in a bolt in backbone over transmission to add some strength.. no reason not to set a body in place and tack in support tubes..I think my gallery might show you some frame pics that might help.

I looked through your gallery and am impressed by your cobra.

Did you weld it up on a flat building table, or did you build 2 dimensional and/or 3 dimensional jigs?

alfy65 · #42 (**permalink**) 12-16-2015, 06:13 PM

I just built a heavy wood table with casters and kept it level thru the build. The CR drawings seemed to be pretty accurate for what I needed with a one off glass body that I bought. Good luck with your build...

120mm · #43 (**permalink**) 06-24-2018, 07:01 PM

This thing just followed me home.

Dual voltage, automatic adjustments and pretty good reviews from several sources. Doesn't seem like typical Chinese junk. Will give updates as I play with it.

Hoodabest · #44 (**permalink**) 06-25-2018, 12:42 AM

Not speaking without experience, just hoping you'll see the light. Your intent is to build a Cobra replica from scratch. Would you rather drop a $6,000 engine into a chassis built with a $400 mig welder, or a $2500 engine into a chassis built with a $1200 tig welder? Trust me, you'll be SO much happier with tig. And it's easier and less expensive than you'd think. Get on youtube,

MAStuart · #45 (**permalink**) 06-25-2018, 07:37 AM

A good weld with a $100. 00 mig would be better than a bad weld with a $5000.00 name brand tig no matter how much the motor cost.

120mm · #46 (**permalink**) 06-25-2018, 05:32 PM

Quote:

Originally Posted by Hoodabest

Not speaking without experience, just hoping you'll see the light. Your intent is to build a Cobra replica from scratch. Would you rather drop a $6,000 engine into a chassis built with a $400 mig welder, or a $2500 engine into a chassis built with a $1200 tig welder? Trust me, you'll be SO much happier with tig. And it's easier and less expensive than you'd think. Get on youtube,

I wouldn't touch a TIG with a ten foot pole.

I've built several aircraft with oxy-acetylene and like sound, properly soft welds, thank you. Plus, O/A alloy is easier to work. TIG creates too much of a HAZ for my taste. It's possible to get roughly ok welds with TIG, but you need an o/a torch to normalize afterwards, so what's the point? TIG is an answer to a question not asked, imo.

The MIG is for learning and building fixtures. I might try it on the 3" pieces, but the rest of it will be O/A.

120mm · #47 (**permalink**) 06-25-2018, 06:09 PM

Slightly less snotty response, but still relevant. MIG is perfectly acceptable for welding things that don't fall out of the sky if they fail. It's the industry standard for many of the Cobra kit manufacturers, in fact.

TIG is used by some industries for processes because it makes sense for their business model, or it has some capabilities which benefit their process.

O/A is how to go for ultimate strength in anything with a tube chassis. Plus it is compatible with alloy welding. It's main drawback is that it is a legacy process that is expensive and puts a lot of heat into the piece being worked, which results in dimensional instability (which then needs to be addressed, which takes time and skill).

The difference I've seen in amateur versus professionals vis-a-vis welding is that amateurs over-emphasize one process as the "one and only acceptable" process out of the fear of getting it wrong.

I wouldn't have a problem driving or riding in a MIG welded chassis cobra replica, provided the welds were done right. In fact, I already have, once. In a fairly high mileage machine that was holding up quite well.

120mm · #48 (**permalink**) 07-11-2018, 07:40 PM

It's been awhile, but I've been busy at work and only tonight was able to take the MigMax 215 out for a trial run.

I've taken courses in MIG, but frankly, sucked at it, making globs and porcupines, mainly. I'd grown up with O/A so just gave up on MIG completely.

I swear, when you try this MIGMAX, you'll realize that you barely need to be there to hold the gun. This thing basically welds on its own; the only thing you need to do is to switch it on and get the tip somewhere near your work piece and pull the trigger. The computer in the machine does everything else. It welds close, it welds far away, it welds regardless of the tip angle, and does so almost as softly as my Meco Midget N O/A rig.

Total set up was to put a roll of .030 on, adjust the tension, dial in the material and wire thickness and weld. My first welds weren't perfect looking, but they had good penetration and could be hammered without failure. This thing "feels" just like welding with O/A. Can't wait to get good at it and to make pretty and strong welds.

verticalroll · #49 (**permalink**) 01-24-2022, 04:19 AM

you can always use OA to weld aluminum too.Much cheaper to start with as a setup rig.

Andy

strictlypersonl · #50 (**permalink**) 01-24-2022, 06:22 AM

Quote:

Originally Posted by 120mm

I've taken courses in MIG, but frankly, sucked at it, making globs and porcupines, mainly. I'd grown up with O/A so just gave up on MIG completely.

If there was an instructor present, he should have told you to clean your base metal, adjust your wire speed, gas flow and heat, and check your ground. MIG welding is really pretty easy. In your case, any one of those could have caused your problem.