Welding questions - lower radiator core support

[wwwdotgov]

I'm going to be outsourcing most of the welding that's needed on my project because I don't have the equipment or the skills to do it myself. But I'm still going to be buying, measuring, cutting, and sometimes tacking the steel here and there.

My question is about welding steel together that differs so much in thickness.
For example, The lower core support is weak spot and needs replaced. Looks like others have welded a thick 1/4" plate on top of an area that is nothing more than thin sheetmetal (or maybe 2 layers sandwiched).
lowerradiatorsupport17 (1)_kindlephoto-280679886.jpg
Can you get good penetration joining such dissimilar size metal?
I know there's a couple of bolts going through the plates, but they are just clamping down to more thin sheet metal.
I was reading in welding forums how hard it is to weld 1/8" thick (.125) plates for roll cages to sheet metal floors.
Yet the plates I see being used here on the core support are twice as thick at 1/4". Idk how you'd keep from blowing out the sheet metal when welding?.
Are the 2 bolts taking up most of load then? And if you ad gussets to the back side, again, aren't you again going to be welding gussets to thin sheet metal that differs greatly in thickness?

I guess I'm just kinda surprised not to find more substantial structure up front (especially when the lower core support is playing multiple duties) in the Festiva.

Thanks for any insight!

[FestYboy]

Work the pool from the 1/4" to the sheet steel, going the other way will not penetrate the plate and be a weak weld.

[mikemounlio]

Yes u Can! Look up Lucifer gets a new turbo.

I just did this. I even used a flux core 110v welder to do it. I had help but I could do it now myself after just a bit of practice

[mikemounlio]

The metal for the actual support is weak. The frame area is actually pretty strong. Once I had weld that hit the actual frame and not just the thin sheet crap my 1/4 PLATE became totally solid. Don't worry about the thickness. Just know its strong down there.

[Advancedynamix]

I use 1/8" thick plates. I drill multiple holes through the plates and plug weld them to the existing body sheet metal. I then stitch the outsides with a tack and cool method of welding. It's best to use spaced out stitches on the parameter of the plates, rather than a continuous weld. this is to reduce warpage and reduce the HAZ area around the plate. Welding steel actually makes the steel weaker around the welded area, so you want the minimum amount of weld necessary.

[wwwdotgov]

Thanks y'all for the tips.
I've been living at wrecking yards every weekend collecting parts Now it's time to go to the metal yard and get busy on this side of things.

[mikemounlio]

I did mine like Gomez. I added my own thing to it tho. I have pictures in my Lucifer buuld.

[scitzz]

I use 1/8" thick plates. I drill multiple holes through the plates and plug weld them to the existing body sheet metal. I then stitch the outsides with a tack and cool method of welding. It's best to use spaced out stitches on the parameter of the plates, rather than a continuous weld. this is to reduce warpage and reduce the HAZ area around the plate. Welding steel actually makes the steel weaker around the welded area, so you want the minimum amount of weld necessary.

All of that is 1/8th, not 1/4? Also, what about doing the upper support as well, would there be any advantage to that?

[Fecomatter]

charlie pretty sure #1 rule on the forum is no witchcraft. please and thank you.

[william]

Charlie is that lip under the angle iron to suport the bottom of the bumper?

[Advancedynamix]

All of that is 1/8th, not 1/4? Also, what about doing the upper support as well, would there be any advantage to that?

Yeah, on this car I made it all from 1/8" thick material, the the bottom of the angle is doubled up with a 1/8" strap. There may be benefits to the top support area, but I can't see it being necessary for what I do.

charlie pretty sure #1 rule on the forum is no witchcraft. please and thank you.

Funny, this car is named Cauldron.

Charlie is that lip under the angle iron to suport the bottom of the bumper?

Yeah, and it runs completely under the entire support. I laminated the angle iron with flat strap to give it strength but be lighter than a full 1/4 angle support.

[mikemounlio]

Yeah, on this car I made it all from 1/8" thick material, the the bottom of the angle is doubled up with a 1/8" strap. There may be benefits to the top support area, but I can't see it being necessary for what I do.


Funny, this car is named Cauldron.


Yeah, and it runs completely under the entire support. I laminated the angle iron with flat strap to give it strength but be lighter than a full 1/4 angle support.

I went with the 1/4" on everything to try and help traction out as much as possible. Charlie how did the car do with only 1/8" thick material? Would you do 1/8th again or go back to 1/4"?

[Advancedynamix]

This car has a lot of gussetting on the front frame rails as well. We basically boxed in the front crumple zone. I did this more to protect the chassis during bump and go racing. We can't afford to have a minor bump with another car throw off the alignment.
My next version will be tubular, and incorporate trailing links. This car was done as quick and cheap as possible. It's a LeMons car, so it didn't need to be perfect, just good enough to be track worthy.

[wwwdotgov]

When rebuilding the lower core support, is there any reason why nobody really is permanently welding them in? What's the purpose of bolt-on removable crossmembers?
For easy replacement in direct center accidents or ?

[Fecomatter]

It's way better to be able to remove it. But mine is welded in because I'm a lazy shit.