[TimmyTheClub]

I am going to be building a truck bumper, and the bumper kit is 99% 3/16th. The kit also includes shackle mounts that are 1/4 inch. when welding the 1/4 to the 3/16, do i weld on a setting for the 1/4 or for the 3/16? I need it to be strong, as that is what i will be using to pull my truck out of sticky situations, but also do not want to blow through the 3/16. any information would be greatly appreciated!

as a second question, any insight on the lincoln 125 amp flux core welder? I am using a 90 amp Harbor freight to teach myself currently, and already bought it when i realized the shackle mounts were 1/4 in, unlike the rest of the bumper.

[exnailpounder]

I would look at the amperage difference between 3/16" and 1/4" on the door chart and go somewhere in between. It won't hurt to weld the whole thing at a 1/4" setting. You will get more penetration but you will have to play with the wire speed. You also might have to adjust your wire speed depending on what kind of weld you are doing. The door chart is a starting point. You will have to adjust your parameters accordingly. You will pick it up as you get more experience.

[Farmwelding]

Well both machines are underpowered for doing any 1/4" in my opinion. In this case you will just have to make sure to put multiple passes in to gain as much strength as possible. Now in my experience I have never had an issue blowing through metal that was thicker than 1/8" so I would go through with welding like it was all 1/4". Also, you aren't going to blow through 3/16" with 90 amps or even 125. If it is still worrying you I would pick up some spare plate to try it in and double check but no matter what with the machines you listed you are going to need multiple passes to ensure strength.

[Mike]

Timmy, welcome to the forum.

[TimmyTheClub]

Thanks for the reply's everyone! the reason for sticking with the small welders for myself is that i do not have a 220 in my garage, and my house panel is full, so i am unable to even run one. any recommendation for a flux core wire that will provide a strong but not brittle weld? it seems like the Harbor Freight stuff is a little brittle.

[Farmwelding]

Thanks for the reply's everyone! the reason for sticking with the small welders for myself is that i do not have a 220 in my garage, and my house panel is full, so i am unable to even run one. any recommendation for a flux core wire that will provide a strong but not brittle weld? it seems like the Harbor Freight stuff is a little brittle.

I know that weld.com came out recently with a video that you might want to watch. Lincoln wire is pretty good for self shieled flux core.

[ex framie]

Welcome Tim.
Welding aside, the design of the bumper should have the recovery points secured to the chassis rails by suitable bolts and then go through the bumper.
Nothing 1/4" welded to 3/16 without being secured to the chassis as well will handle the forces of a vehicle recovery without failing catastrophically possibly causing injury or death.

As to welding dissimilar thicknesses, practice on some scrap the same thicknesses first and see what your machines will do, what penetration you get etc. Get your settings worked out on the practice pieces, clean the weld areas down to bare shiny metal, clean the area the earth clamp will connect.
Your welds leg length should be 1/4 " on both legs.

Cheers

Exnailpounder,
You owe me a beer

[exnailpounder]

Deal!

[homeboy]

I had a Lincoln 100 -120 volt wire feed flux core welder for lot of years and it worked flawlessly. I used Lincoln E717-11 all position and very satisfied. It seemed fine on up to 1/4in but slow going .I used to have a 220 -ac-dc stick for the heavier stuff anyway. Biggest problem with the 120 v is very short duty cycle because anything over 1/8 you have to crank it up fairly high. With the Lincoln you will need a 20A circuit if you are welding any more than fairly short periods at a time. They say 15A but that wouldn't cut it so we just ran a dedicated 20A and changed the welder plug to a 20A plug to prevent someone plugging into 15A and popping breakers. Hopefully you have enough spare juice to handle that. As for the tow attachment I also would be leery to tackle it with your machine. Any chance of fabbing and tacking the parts in place and having someone with the proper equipment complete it.?

[homeboy]

I had a Lincoln 100 -120 volt wire feed flux core welder for lot of years and it worked flawlessly. I used Lincoln E717-11 all position and very satisfied. It seemed fine on up to 1/4in but slow going .I used to have a 220 -ac-dc stick for the heavier stuff anyway. Biggest problem with the 120 v is very short duty cycle because anything over 1/8 you have to crank it up fairly high. With the Lincoln you will need a 20A circuit if you are welding any more than fairly short periods at a time. They say 15A but that wouldn't cut it so we just ran a dedicated 20A and changed the welder plug to a 20A plug to prevent someone plugging into 15A and popping breakers. Hopefully you have enough spare juice to handle that. As for the tow attachment I also would be leery to tackle it with your machine. Any chance of fabbing and tacking the parts in place and having someone with the proper equipment complete it?

[TimmyTheClub]

Thanks everyone! Yes, that was my other thought. I want to do as much as i can on my own, since i completely rebuilt my truck, and want to be able to say i did almost everything, but the recovery points i will likely just take to the local fab company and have them process it through, but i will complete the rest of it myself.

I just ran my first test T-weld on a scrap of 3/16, hit both sides of the T, and it holds my 280 pound frame jumping on the 3"x3"x3/16 T. I would think that that is acceptable for an $89.99 harbor freight welder

I know the welds aren't the prettiest in the world, but... not to bad for my first attempt at real welding, instead of just hitting fast spot welds on body panels for my truck

[homeboy]

Looks not too bad. If you want a big visual improvement and much easier cleanup try a light coat of anti-spatter spray. My old mantra. Just dampen the area -don't need a lot. I don't know if they are all the same but I get mine at TSC in Canada and it works awesome.

[TimmyTheClub]

I definitely was planning on getting some when i started on my bumper build, i just did not want to waste any on practice, until i get better at the beads.
is it safer to run a strait bead, and then a second bead over the top of that to the top layer? better penetration, or just wasting material?

[ex framie]

Pam cooking spray is apparently a great anti spatter without the noxious fumes.
This is pure here say on my part as we don't get Pam over here.
Still it gets mentioned on most welding forums I visit, for a couple of bucks its worth a try.
Then you can post your results, worse case, you have something to stop eggs sticking to your pan.

[homeboy]

I heard of the Pam spray but never tried it. My concern was cleanup because almost everything I make is painted. The spray I use costs $6 a can and I used less than one can on a complete utility trailer build. It is paint compatible by the time I do my paint prep--wire wheel etc. it pretty much disappears and I have had no paint issues over many projects. When I started using it I felt that the weld appearance actually improved and cleanup is just a zip with a wire wheel. My take anyway-

[cj737]

is it safer to run a strait bead, and then a second bead over the top of that to the top layer? better penetration, or just wasting material?

Stacking beads over beads doesn't improve your penetration, it only adds build up. Penetration comes from your root pass, strength comes from cover passes (overlapping and offset to increase the width).

If you are seriously considering fabbing your own bumper as a first welding project, then you might want to understand the forces encountered during any collision. Your 280 pound frame jumping on it isn't even close to the 3 tons of truck and force created by inertia. So let's just get that out there-

If you want to truly understand the penetration you're getting, perform a fillet weld on some material of the equal thickness as your bumper. One side only. Let it cool, then cut it in sections, 1" long. Polish it and etch it. That will reveal the "penetration" and also show you where you have voids in your weld due to improper technique, heat, or fill.

For a first bead, sure its fine. But its not even close enough to be good enough to weld a safety product in my opinion. Have someone you know that is a competent welder, help you. This should not be a "wing it" project.

[TimmyTheClub]

Thank you for your honesty. Unfortunately the only person I know who i thought was a competent welder, i found out is nothing more than a drunk who talks a big game. I am going to do a rear bumper first, and i have a hitch on the truck, which is what will be stopping any car that rear ends me, so i will give that a try, and see how it holds up to trees and other impacts i encounter when driving off-road. when i go to do the front, I may just take it in, as that will have to withstand the most force. it will be a winch mount and also have the 1/4 inch hoops.

[TimmyTheClub]

I guess i should also be a little more clear on what it is that i am building. here is a link to the company that sells what i am buying for a bumper kit. https://www.movebumpers.com/
I figure this will give the best idea of what i will be working with. I have a 98 Chevy K3500

[cj737]

I completely understand what you're building and why you're undertaking it. I just can't stress enough the importance of it being welded properly.

If you can essentially weld the bumper from the "backside" also, then I might even suggest you stick weld it (given your limited power sources) and then wire weld the front for aesthetics, grind that flush, and then you can paint it. This way, you'd have better strength, and a fully welded in piece.

My opinion, new welders that opt for wire feeders do so as they are easier to weld with. This is true. But that belies the fact that wire welders are also not as strong as Stick or TIG welding. So you end up defeating yourself somewhat in terms of the objective (strength and safety) to achieve your goal (DIY). This is NOT to say it can't be done properly and fully safely with a wire welder, it can. But that requires someone with experience in welding and the proper gear.

Since you are limited to 110v, I believe that the gauge of steel you are working with is outside the capability of your equipment for a single, full penetration pass, even two-sided. I would never rely on multiple passes in this situation to achieve sufficient strength, only to increase the strength. But multiple passes also create weakness away from the welded seam. So its a Catch-22.

This is all I'm saying. I have no wish to disuade you or discourage you, or demotivate you. Simply to encourage you to understand the importance of what you're undertaking and the steps to having it be safe, affordable, and allow you your DIY pride. If it fails, quite possibly a lot more than your pride is at risk of injury.

[PeteM]

The talk about penetration can be deceiving. A good weld only has to be approximately 30/70 mixture of parent metal to filler metal, and a 1/4 to 3/16 weld does not need some super deep Heat penetration.

If you can make a weld to size with good fusion (wet toes) it should be fine. Its a bumper, not a sky scraper. If you hit a tree and it falls off, you get some more practice.

[TimmyTheClub]

that is what i was thinking, weld it, abuse it and fix it if it fails, repeat, then proceed with paint. I also do not intend on grinding the external bead unless it looks really bad.

when i welded what i took the picture of, the back sides of both pieces were glowing a nice bright red, I assume that means i was getting good penetration.

[PeteM]

More than likely, sure. On a simple visual inspection, the thing that should set off a red flag is cold lap (lack of fusion), inconsistent deposition (gaps, holes, thin/thick spots), and porosity.

It might be a good idea to get some pieces and mock up the same type of weld and position to find a good setting, then beat them to death to see if the actual weld or parent metal breaks. If the weld breaks=bad. If parent metal breaks=good.

[TimmyTheClub]

Definately a good Idea! being as it is 3/16th, what do I do if i cannot get either to break?

[cj737]

Definately a good Idea! being as it is 3/16th, what do I do if i cannot get either to break?

Definitely buy a lottery ticket. One or the other will break.

[homeboy]

I have always strived to build or possibly overbuild to be on the safe side with any project. It would drive me nuts doing something without great assurance that it would do the job with lots of redundancy built in. In your situation I would picture myself in the middle of nowhere stuck to the frame -winch hooked to a tree and front bumper laying forlornly on the ground totally useless!!! If I had done all reasonable due diligence and this happened -ok crap happens-go to plan "B". If I had known that I was taking a chance from the start and got caught serves me right-my bad. It is always more work and more costly to try to repair an improper job. My 2 cents worth.