bumper welding tips

So I understand that for a structurally sound bumper I should use a good welder. I have a good welder, except its only a 110V (Millermatic 135).

Currently I am looking to buy a bumper... if the sale doesn't go through, I am thinking about making my own bumper to stock XJ bumper specs, except with clearanced and wrap around corners (as well as weld through recovery points). MAYBE extend it out a bit an add a winch down the line, but that is a different design, I just want to keep it stock for now

My big question is regarding the welder. I know that for a bumper it is recommended to have a 220V welder for a good, deep, wide weld... If I were to try and weld up a 3/16ths bumper with my welder, is it possible/worth doing? I was thinking that I would hit every weld (except 2) from both sides if necessary.

Yes I know it would be a PITA due to the fact that I would need to run the welder at full power (and with 20% duty cycle..that means it would be a long project). But I am talking in terms of strength... I am also planning on learning (or teaching myself) torch welding... but I figure the mig plus torch set is enough for now. I cant afford a big mig or tig for the time being

So opinions? is this a do-able project or should I just save my money and wait until I have a better welder?

If you are looking for a good looking and strong bumper you can weld up youself, check out IronScorpion.com.

He lives not far from me and his bumpers are the nicest design I have seen. You almost can't buy the steel for what he sells them for.

old_man said:

If you are looking for a good looking and strong bumper you can weld up youself, check out IronScorpion.com.

He lives not far from me and his bumpers are the nicest design I have seen. You almost can't buy the steel for what he sells them for.

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I have checked out iron scorpion and liked the looks of the bumpers.. to the point that I almost bought one recently. But I decided that if I am buying a bumper it will be custom through AJ's.

I would rather design/build my own. I started this thread to ask if my welder could (in 2 passes, one per side) create a solid enough weld to hold up to a good beating. Yes my welder is rated to 3/16ths but I know it isn't an ideal welder for this type of project which is why I mentioned hitting every [critical] weld from both sides, PM or ask if you want details on my idea of what I will be doing (passing out now, but will have time to explain tomorrow )

I may just end up building what I have planned and tacking all the pieces in place until a local welder can do it right (if a couple passes with my mig wont be enough).

Not trying to bash on your post, I do like iron scorpions work and I have had a tab open in firefox for a month now to keep reminding me to check their site and see what is in stock... I just have different plans rigfht now

It's plausible but not very recommended. If you do attempt it this is what I would do.
1. I would get some .023" diameter wire and 100%CO2. 100% CO2 will give you the most penetration.
2. Bevel all of the welding joints with a grinder. Run multipass welds.
3. Preheat all of your welding joints with your torch.
4. If you are a proficient welder try to weld all of the joints in the 3G/3F up position.
Fabrication is typically about 90% fitup, and 10% welding.

That welder will be fine, and I agree with go1lum and use 100% co2 for a hotter weld, but I would use .030 wire. My buddy's Hobart 140 does great. Prep is real important, but you won't need to preheat. Just make sure you are getting enough heat in there. The .030 wire will help that. I used it to weld up my 1/4 inch wall control arms for my XJ.


Here's the 140:

Yeah .030" wouldn't be a bad choice either.
And those tips are more just general guidelines when trying to weld thicker metal with small 110v units.
I've welded 3/8" plate successfully using the proper procedure.

go1lum said:

Yeah .030" wouldn't be a bad choice either.
And those tips are more just general guidelines when trying to weld thicker metal with small 110v units.
I've welded 3/8" plate successfully using the proper procedure.

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I'm glad .030 isn't bad, I have 10 lbs of it sitting with my welder now so I am glad that I don't need to buy more wire.

Thanks for the info. So I have been thinking about it and I guess that I have 2 options.
Either I do it myself and hopefully get good penetration, or I just do all the prep work: cut all the steel & tack everything in place, and call up my buddy who's job is welding. Have him swing by and do the actual welds with his equipment (or give the tacked bumper to him and have him do it while he is at work). As much as I wanted to do it myself, I am starting to lean toward the 2nd option just to be sure I have it as good as possible

I used a 110v mig for over 20 years. I fabed just about everything. I didn't use the mutiple pass method. My technique was to work the puddle until it was the size required. It means the linear progress on the weld is much slower and you get great penetration. It gives the metal you are going to weld the time to adjust its temperature. I never had a problem with one of my welds. The biggest thing to watch for on building a bumper is the warping due to welding.

old_man said:

I used a 110v mig for over 20 years. I fabed just about everything. I didn't use the mutiple pass method. My technique was to work the puddle until it was the size required. It means the linear progress on the weld is much slower and you get great penetration. It gives the metal you are going to weld the time to adjust its temperature. I never had a problem with one of my welds. The biggest thing to watch for on building a bumper is the warping due to welding.

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Meh, I'm not worried about warping. Like I said, I want to build it to look like a stock XJ bumper... A little warping might add to the effect and make it look more like my current bumper :laugh:

Thanks though. I have some 3/16" or 1/4" flat stock I was going to use to fix my drivers side door hinges. Maybe I will cut off a couple short pieces of that and see how well it goes together.

Now I just have to find someone to fill my CO2 on a weekend. I know the local fish/bait/gun shop used to have a C02 tank to fill paintball guns, I would guess that they still do.. Would that work for filling the welder tank or is there a difference? (other than maybe needing an adapter to connect to the welder tank).

Make sure the ragulator is compatible with Co2. For some reason, my 220 Lincoln mig's regulator did not like 100% co2. Not sure why. It also has a different connector on the tank than argon mix, if I remember right.

Actually it's not (I only used CO2 briefly with it though, now I have flux). I remember noticing that when I bought the welder. The P.O. apparently just ignored the fact that the regulator was for Argon mix only :dunno:

Does running 100% CO2 through a Argon mix regulator damage the regulator at all? If so I will have to pick up a new one once I get some Argon mix.. I am definately getting a CO2 regulator as soon as I refil the CO2 tank... I'm just curious if I need to get both or if my Argon mix should still be OK.

Another question since you mentioned different connectors: I bought oxy/acetylene tanks the same day I got my welder. I bought a torch set and IIRC the oxygen regulator goes on fine but the acetylene regulator needs an adapter (or the other way around). I think it looks like the oxy tank may already have the adapter I needed.

I havent looked at them in a while, but I think both the tank and regulator have male threads so I need a F-F adapter. Does anyone know where you can pick up these adapters? would somewhere like home depot have them? Granted I need to find the correct adapter for my threads... but any recommendations on where to look for one?

Edit: I need something like this, does anyone know where I could pick one up today so I don't have to order from the internet (esp because I am not 100% sure what I need... Not exactly positive what fittings I have on my cylinder and regulator. It seems that CGA-200 or -300 is pretty standard for the cylinder fitting and CGA-510 or -520 is pretty standard for the regulator fitting... is there any way to measure or check which I have?

http://www.google.com/products/cata...k+adapter&cid=10594604633202407382&sa=title#p

themangeraaad said:

Does anyone know where you can pick up these adapters? would somewhere like home depot have them? Granted I need to find the correct adapter for my threads... but any recommendations on where to look for one?

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I got mine at Airgas (welding supply) when getting the gas bottle itself.


Edit: I had to buy that same piece to run co2, cost $10 or so.

if you are going to weld 3/16 material with a welder that is rated for 1/8, i would go with c02 argon mix. I have the same welder by the way, love it to death, its never given me a problem.

old_man said:

I used a 110v mig for over 20 years. I fabed just about everything. I didn't use the mutiple pass method. My technique was to work the puddle until it was the size required. It means the linear progress on the weld is much slower and you get great penetration. It gives the metal you are going to weld the time to adjust its temperature. I never had a problem with one of my welds. The biggest thing to watch for on building a bumper is the warping due to welding.

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Very good advice!

Just picked up the adapters i needed at a local weld shop. had to leave work early to get there before closing, but there was no problem with that :laugh:

buzzbombxj said:

if you are going to weld 3/16 material with a welder that is rated for 1/8, i would go with c02 argon mix. I have the same welder by the way, love it to death, its never given me a problem.



Very good advice!

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No 100% CO2 will give more penetration than Argon/CO2. There will also be more spatter.
Also OP would you like some tips on the operation of torches.

go1lum said:

No 100% CO2 will give more penetration than Argon/CO2. There will also be more spatter.
Also OP would you like some tips on the operation of torches.

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Sure, tips are always a good thing!

And update: Got home, got set up, went to crack the tank and blow out the valve before attaching the regulator... 02 = fine, acetylene = empty. Oh well, looks like it's another trip to the welding shop next wk.

themangeraaad said:

Sure, tips are always a good thing!

And update: Got home, got set up, went to crack the tank and blow out the valve before attaching the regulator... 02 = fine, acetylene = empty. Oh well, looks like it's another trip to the welding shop next wk.

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Well do you know the correct procedure to light and extinguish the flame?

gas on first, gas off last. Once gas is burning adjust the Oxygen

Well for maximum safety it's good to always try to do it this way.
1. Make sure that your regulator pressure adjustment screws are backed out with no resistance on them. *Even more important with oxygen. If the regulator fails on a high pressure oxygen tank the adjustment screw makes a good bullet.
2. Place your body behind the cylinder and out of the way in case of regulator failure.
3. Crack the oxygen cylinder slowly so that the high pressure gauge on the regulator becomes pressurized. Now be sure to open your oxygen cylinder all of the way. There is a seal in the valve that only seats if it is opened all of the way. Otherwise they can leak.
4. Now open your acetylene valve slowly until the regulator becomes pressurized. Then open it a quarter turn more.
5. Now adjust your working gas pressures with the regulator adjustment screws. *15p.s.i. is the maximum pressure that acetylene is considered safe to work at. (15psi is the standard for safety reasons but acetylene does not actually start to disassociate until ~29-30psi) Make sure that the valves on your torch are close when adjusting the pressure. (For cutting applications I tend to have my acetylene working pressure between 5-8psi, and my oxygen pressure between 25-50psi)
6. Now if you have a torch that has 2 oxygen valves and 1 gas valve, open the oxygen valve on the bottom of the torch all of the way. The oxygen valve up on the body of the torch is your fine adjusting valve.
7. Crack your acetylene valve and light your torch. Adjust the flame until the black soot is no longer produced by the flame. Now open the fine adjusting oxygen valve on the torch body. Adjust until you get a neutral flame. *A neutral flame can be tested by pressing on the oxygen cutting jet lever, there should be little to no change in the flame.
8. Shut down is pretty much the same procedure in reverse. When I shut down my torch I turn the fuel gas on the torch off first. If the gas is off then no flame can be sustained. When the oxygen is turned off first the acetylene still burns. *Once your torch flame is out turn off the tanks and then bleed the pressure out of your hoses. Then adjust your regulator pressure adjustment screws back out.