Welding Tips and Tricks

I'm repairing a boat trailer in which i will remove 4 damaged tubing cross members, then i will install 4 new cross members of 4" 3/16" channel iron. the new cross members are about 6 feet long and will be cut in the middle to form a V shape. Good welds in the V are important. To weld i have at hand two options, 1. a 295 amp stick welder and 2. a 90-105 amp century wire (with gas) welder. I think the stick will give me the best penetration but will also be messy. my other option is to borrow a large (higher amp ?) wire welder but not having ever used a large wire machine i don't know if it will be as penetrating as the stick and it will be a big deal to borrow a large machine as it's vary big and heavy . . like maybe 400-500 lbs and 3'x4'x4'. just don't know if its worth the trouble. I could use some other opinions, thanks for any input.

Donald,
I used to have to replace quite a few cross members in truck beds on (Cement) block trucks. They were V'd in the middle similar to a boat trailer. I would only cut a notch from the top down to the bottom flange of the channel leaving the bottom flange intact. This adds an incredible amount of strength to the joint over mitering it and welding. The ones I would have to replace were mitered and welded and would crack next to the weld every time. Once I started leaving the bottom flange un-molested, problem solved.

Now to your original question. I personally would weld them with the stick welder and would use a 7018 rod, 3/32" starting @ around 90-105 amps, vertical uphill. You didn't mention if your machine is A/C or A/C-D/C but they make 7018's for either, I prefer D/C reverse personally. Now don't think that 90-105 amps with a stick welder translates into the same weld being dished out with a wire feed welder, different animals.

Can it be welded with the small wire feed, yes, but should it , probably not.

Those are my opinions and others here will have theirs, but if you brought it to me and asked me to repair it, that's how it would be done.

Len

Braehill wrote:Donald,
I used to have to replace quite a few cross members in truck beds on (Cement) block trucks. They were V'd in the middle similar to a boat trailer. I would only cut a notch from the top down to the bottom flange of the channel leaving the bottom flange intact. This adds an incredible amount of strength to the joint over mitering it and welding. The ones I would have to replace were mitered and welded and would crack next to the weld every time. Once I started leaving the bottom flange un-molested, problem solved.

Now to your original question. I personally would weld them with the stick welder and would use a 7018 rod, 3/32" starting @ around 90-105 amps, vertical uphill. You didn't mention if your machine is A/C or A/C-D/C but they make 7018's for either, I prefer D/C reverse personally. Now don't think that 90-105 amps with a stick welder translates into the same weld being dished out with a wire feed welder, different animals.

Can it be welded with the small wire feed, yes, but should it , probably not.

Those are my opinions and others here will have theirs, but if you brought it to me and asked me to repair it, that's how it would be done.

Len

This advice it on point. I have built and repaired many trailers over the years and Len's advice is exactly how I would make this repair with the tools at hand.

Kevin

Same advice here, only if the steel is thick enough, use a 1/8 7018 at 125 amps.
I'll kill you if you try and use that mig.

Good luck,
Please post pics of your progress.

John

So what if the stick weld is "messy"? That's what spatter-spray and grinders are for. (No, I don't like to grind my welds, but I'll knock spatter off with one!)

I agree with all the above. The stick machine has the power for the job, and Len's right, vee out to the lower flange, and bend, rather than miter the whole thing.

Steve S

very good input. I originally thought a notch in the v leaving the bottom intack was the best way but cutting was complicated to get the right angles as my only cut options was with a power horizonal band saw so at this point i have already cut all 4 crosse Vs throught. (now have two pieces each) now that its been said a full cut is not so good, I guess my only option now is adding a 1/8" thk X12" long strap across the bottom to beef up the V. Ive never used 7018 but ill sure buy some tomorrow. as of today i have tacked welded each peace in place to get a perfect fit. ill try to add photos before i do any more tomorrow. thank you very much for the help.

here are some photos as of today

more photos

more photos again

the welder. now im starting to think i should buy a plasma cuter and make v plates, say 4" by 12" 3/16 thk and weld on one side of each channel v. now im weired about the v weld.

You can make a gusset if you are worried about the v welds but I don't see a problem with what you have done. Weld the channel on both sides and head to the lake.