Opinions wanted on welding core support

So yeah....I'm welding in a new radiator core support.

Using a harbor freight titanium 140 mig flux core....

I need to know, from those who have welded a core support in before, what kind of wire, speed, amperage, etc. that you used and any other general advice.

I'm told the best way to avoid warping is to either :

1) keep heat low and wire feed slow or

2) higher heat with barely a trigger pull as I work my way around from weld to weld.

Experienced opinions welcomed.

 

you'll get all the welding nerds over in the welding thread:
https://www.tacomaworld.com/threads/anything-welding.113957/page-1410

speaking as someone that tried and miserably failed at attempting to plug-weld some holes in a 2014 trunk lid with a 0.030 flux core welder(i started with a 1/4" hole to fill, now i have a 2" hole to fill), it's a dangerous job with mig or flux, as it's easy to burn all the way through and open a larger hole. many newer vehicles, the metal is thinner, which makes it much harder to weld without blowing through.

the first aspect that i like to look at is to first understand the techniques/processes at how the factory assembles it. specifically, the factory uses spot welding. your best chance at success is to attempt to match the technique with cleaning the metal, and use clamps, with specified predrilled holes that would be filled with weld where a normal spot weld would go. this is not going to be a spot where we want to lay a bead of weld down. this will help control the heat introduced, but also maintain the design intentions of the panels stiff/flexible parts(engineers designed it to move some)

you didn't specify the welding wire, in this case, you'll want to be using 0.023 welding wire. 0.030 is likely going to be too large. if you check inside the welder door, it has some baseline recommended settings for metal thickness. realistically, you're going to be towards the lower end of the spectrum. likely somewhere near 15-16v, with a wire speed around 150-190.

and as it sounds like you're not extremely familiar with the technique, i'd also recommend you cut up the old core support and use the pieces for practice to perfect your cleaning/clamping/drilling/hole-filling techniques. that will also allow you to properly dial in the welder to your preferences, and more importantly, get your motions practiced, as welding is really 25% welding machine settings, and 75% welder using it.

as far as the heat aspect, that's actually the easiest part to control. just get a medium-sized soaking wet rag. after you fill a drilled hole, quench the welded area with the rag, rotating through different areas of the rag every 10-30 seconds to best dissipate the heat introduced, on both sides of the weld surface if possible.

importantly, this is a technique that goes for much further than only while welding. if you heat up any section of a metal panel with a torch, it expands--left to itself, it will stay expanded. but if you quench the hot metal with a wet rag, it will shrink. add/subtract heat as needed to get the metal to maintain the shape desired. you don't need to get the metal red-hot, most of the time hotter than anyone would care to touch is more than enough to achieve the effect.