Simple cargo bench modification (1/8" steel, using 120v MIG wire-feed welder)

[Reverser]

Re: Simple cargo bench modification (1/8" steel, using 120v MIG wire-feed welder)

Great job on that ride, Ken. :thumbsup:

I zoomed it in to see the mechanics of it. How did you know what size to make the push-pull rods and fulcrum? Did you have a pattern or do it from memory with trial and error?

 

[MinnesotaDaveChalmers]

Re: Simple cargo bench modification (1/8" steel, using 120v MIG wire-feed welder)

Overall I think the solution is a good one - bet the designers didn't think about the exhaust.

The weld in question, while not likely to break in this specific case, has some problems. (Double blue line border)

Definition: "Insufficient throat usually occurs in fillet weld and butt joint profiles that are concave. Excess concavity reduces throat thickness, which considerably reduces weld strength."

It is a very bad type of error that, in some cases, can cause a crack while cooling, or just break suddenly when a load is applied.
Like I said, with welds on four sides in this case it will likely not be an issue - but defending the weld does not make sense to me either.

Could just be a camera optical illusion - in that case, my appologies.

 

[Shield Arc]

Re: Simple cargo bench modification (1/8" steel, using 120v MIG wire-feed welder)

Could just be a camera optical illusion - in that case, my appologies.

NO! As usual Dave you nailed it!

 

[kencunningham]

Re: Simple cargo bench modification (1/8" steel, using 120v MIG wire-feed welder)

Great job on that ride, Ken. :thumbsup:

I zoomed it in to see the mechanics of it. How did you know what size to make the push-pull rods and fulcrum? Did you have a pattern or do it from memory with trial and error?

I took educated guesses mostly. I did do some calculations on paper to get an idea of the amount of handle travel in relation to the distance between the pivot points, which also was affected by the offset of the bar that the pushrods are connected to in the center section. Also, I had to remake the handles because the first set was to big for my son, his feet wouldn't touch the bottom.

 

[Sodo]

Re: Simple cargo bench modification (1/8" steel, using 120v MIG wire-feed welder)

It is a very bad type of error that, in some cases, can cause a crack while cooling, or just break suddenly when a load is applied.
Like I said, with welds on four sides in this case it will likely not be an issue - but defending the weld does not make sense to me either.

Dave as an "internet saying" I'm going to to steal that and use it too. Shield likes it. Not sure where to use it but I'll find somewhere.

 

[MinnesotaDaveChalmers]

Re: Simple cargo bench modification (1/8" steel, using 120v MIG wire-feed welder)

Dave as an "internet saying" I'm going to to steal that and use it too. Shield likes it. Not sure where to use it but I'll find somewhere.

Well I'm not sure how much of an Internet saying it is, but feel free to use that definition.
I steal that kind of stuff right from Lincoln, ESAB, Miller, AWS, welding textbooks, etc.
Often I post handy stuff right from their websites, with supporting pictures when it's helpful (and saves me from typing it).

 

[Reverser]

Re: Simple cargo bench modification (1/8" steel, using 120v MIG wire-feed welder)

I took educated guesses mostly. I did do some calculations on paper to get an idea of the amount of handle travel in relation to the distance between the pivot points, which also was affected by the offset of the bar that the pushrods are connected to in the center section. Also, I had to remake the handles because the first set was to big for my son, his feet wouldn't touch the bottom.

Yeah, I was thinking of all the factors you had to figure in to make it work right (e.g. size of your kids, sizing the fulcrum to get the right speed along with the ability to start it from a dead stop, etc.)
Looks like you got it tweaked just right. Excellent work and it looks like factory, but probably stronger. :drink:

 

[Arc weld]

Re: Simple cargo bench modification (1/8" steel, using 120v MIG wire-feed welder)

Welding 101.... Lesson #5, #6 and #7.

1. A larger/wider weld does not give more strength. It gives an over estimation of strength. 2. Fillet weld leg length only needs to be the size of the thinner material to achieve maximum strength. This of course is based on a flat or slightly convex fillet and not a concave fillet. Too convex causes a notch effect at the toe. Too concave doesn't provide proper reinforcement and can fail as mentioned already. 3. A properly done weld should break in the weld, not the heat affected zone or the toe of the weld. Fillet weld break tests will confirm a proper welding technique.

General life lesson #1.

Don't tick off the craftsmen with years of experience that are willing to share it. :duh: They'll go away and people wanting advice will have to rely on wannabe's that can only wish they had the experience.

 

[Furu]

Re: Simple cargo bench modification (1/8" steel, using 120v MIG wire-feed welder)

No, not at all. I'm just asking for civil responses, please! I would like to note that anyone can test weld penetration by cutting the weld at 90 degrees and etching it. This will provide a visual representation of the weld penetration. I know just enough about welding to know that I will never know enough. Technique and process have to work together. Actually, the more I learn about welding, the more I realize that I dont know all that much. I am on a personal crusade to see the nice person that I bet you are

Ken
You will not meet a nicer, more helpful person than Shield Arc.

He has invited and had several of us over to his place for personal one-on-one instruction to try to improve our welding skills.
He told me once and I paraphrase, so no quotation marks:

I had a lot of help when I was learning and it is now my time to help others who are trying to learn.

He also told me that he gets a lot of enjoyment from helping those of us that he has helped.

The following quote is from an email that I received from him.

"....don't give it a second thought about me helping you learn, I enjoy it!"

He means it.

I don't think that we as a human race get much from always being told we are a winner. Look at what is happening to our society where everyone is a winner, no one loses and everyone gets a trophy.
I think telling folks about the quality of their welds is more important than making them feel good about them if they don't deserve the praise. I have seen SA tell many folks that their welds look good or that they are really improving in their skills. He gives positive praise/comments when they are deserving.
SA will tell you if the weld looks good and also if it does not look so good.
Would you rather be misled into thinking that what you have is better than it is? Me not so much.
Of course I value safety a lot. I also value honesty in the people around me.
If they can't be honest with me then I can't trust them to tell me when I am screwing up. Maybe that is because I work in a field where if I screw up I kill folks.
Maybe that makes you look at things from a different perspective. Me I like honesty.

I truly value the help and assistance that folks like SA give to folks here on TBN. Over on WW help is not always quite as friendly as it is here but help is available there as well, just takes a thicker skin.

 

[paulharvey]

Holy crap... first I think everyone gets a bit butt hurt quick. Everyone needs to step back, apply some ointment, and relax.

Second, and this kinda goes both ways; it's a modification that makes something work that didn't before, so by just that the weld made something work that didnt. Is it possible that it's not text book, sure, but it's not on the space shuttle.... now not entirely sure why Sodo took it all personal in the other thread, but everyone can learn at bit more about anything. Can't ever hurt to learn something simple that can make you better at something you do. The nice thing about welding on your own stuff is if it breaks... you re weld it, no harm no foal.

This probably would be more effective of an argument if you didn't start it by looking for a fight. I agree partially that many professional welders (guys who get paid to weld) have a 120 volt mig welder for use when appropriate (guys who are called to fix stuff; not pipe liners, ship fitters) because they work for some applications. They have there place; as do $5000 machines. Guys who can slap 4 pieces of scrap together too make something half way useful have there place as do the welders who have two helpers prep every piece and weld only, but build 5000 psi tanks.

I do think that shield sometimes comes off as a self promoter (thread: OP: I'm a 70 year old lady who wants to make two pieces of metal into one... SA: here's 7 pics of something I did for nasa) but I do think there's a lot to be learned from him. You just have to tune out the (perceived) bragging.

And if the cargo frame works, it works. Doesn't matter if it's liquid nails and drywall screws holding it together.

Now I know someone will bring up "but think of the children, he's going to kill everyone on the road, and only an engineered DOT approved, blah blah blah"