The wrong way vs. the right way

[Doug Chase]

Let's say you need to make a mount. This happens all the time when you're doing any sort of custom fabrication. It could be a motor mount, an accessory mount, or anything else.

THE WRONG WAY:

Many times brackets start and finish like this:



You get it to this point, install it wherever it goes, discover that it works (woohoo!) and move on to the next thing because you're so excited about the project. You tell youreslf you'll get back to this bracket later and clean it up a little bit. STOP. Once this thing is installed you'll forget about it and by the time you remember it will be burried somewhere hard to get at. It will never progress beyond this.

BETTER:

Take it out as soon as you do the test fit and clean it up. It only took 20 minutes to make this piece a lot nicer:



And it only takes a can of paint to make it nicer yet:



Is this mount perfect? No, far from it. In an ideal world I would have calculated loads, picked the most appropriate material, and designed the piece for maximum strength to weight ratio.

Most of us don't have the resources to do that for every single piece we make. And that's ok. At least take the time to do a nice job.

This has been a public service announcement from Chase Race.

[eHoward]

Want to explain double shear vs single shear and stress risers Doug? ie what makes the right way the right way.

[whipped]

Half assed jobs are the american way! So there! :thumbleft:

[Doug Chase]

Want to explain double shear vs single shear and stress risers Doug? ie what makes the right way the right way.

Not really.

You see, my degree was in EE and not ME. Given my now chosen profession and the fact that I never used my EE degree even once, I probably picked the wrong one. Oh well.

I (like to think that I) have a fairly intuitive understanding about the different types of stresses and loads on a piece, and I can pick out "bad" from "good." I know what single shear, double shear, and stress risers are, but I don't think I can give a proper engineering explanation using all the correct terms.

I'm sure you can. Go for it.

I'd also like to point out that I never said my finished piece was the right way, just that it's better than the wrong way. IE: not making crap that looks like it was hacked from a chunk of angle iron with the only engineering done being making sure the pieces with bolt holes were somehow attached to each other, and then bolted to the car rust, sharp edges and all. I'm sure this piece could be improved. If you want to point out how I'd love to hear it.

[The Fieromaster]

Who let the person who made that near the welder??? That is an EXTREME lack of penetration!
I will have to add the fact that when most people make stuff they use there home 110 Volt welders... For thick mounts this is NOT sutable... trust me, welding is what i do for a living... at none other then the worlds largest Lincoln Electric (i basically weld welders... lol)

[eHoward]

Really only one way to tell for sure: Put the thing on the bandsaw.

Who let the person who made that near the welder??? That is an EXTREME lack of penetration!

Sounds like a cool job. I use all Miller stuff btw :blah5:

[eHoward]

My degree is in Commerce Engineering. I think that's worse!

You see, my degree was in EE and not ME. .

I'll put it on my list of crayon drawings to make, but non-engineer-speak, you don't want to put a bending load on a bolt or rod end and that's what mounting in double shear prevents.

[Doug Chase]

Who let the person who made that near the welder??? That is an EXTREME lack of penetration!
I will have to add the fact that when most people make stuff they use there home 110 Volt welders... For thick mounts this is NOT sutable... trust me, welding is what i do for a living... at none other then the worlds largest Lincoln Electric (i basically weld welders... lol)

There's actually quite good penetration there, it's just on a little thick in spots.

No 110V welder here. This was using a Millermatic 185 turned up to 5 (out of 6) with 0.030" wire. I weld for a living, too.

I've excavated a number of welds just to see what they look like inside. Maybe that would be something interesting to post, too. I'll see when I can find the time.

[Doug Chase]

My degree is in Commerce Engineering. I think that's worse!

It sure sounds worse! What's that? A business degree from the Engineering college? :blah5:

I'm sure FSAE would have helped me. Too bad I didn't discover it until a few years out of college...

[The Dark Side of Will]

Want to explain double shear vs single shear and stress risers Doug? ie what makes the right way the right way.

If you don't intuitively understand that, put the welder down and step back slowly. :blah5:

[eHoward]

uh, one step below that... engineering degree from the business college.

My degree is in Commerce Engineering. I think that's worse!

It sure sounds worse! What's that? A business degree from the Engineering college? :blah5:

[eHoward]

you wouldn't believe how many senior MEs I had to explain those concepts to.

If you don't intuitively understand that, put the welder down and step back slowly. :blah5:

[The Dark Side of Will]

No, I probably wouldn't.
Did they have welders?

[p8ntman442]

no penetration and too much throat.

[eHoward]

they gave drawings to the machine shop.

No, I probably wouldn't.
Did they have welders?

[The Fieromaster]

I am sorry but i still agree (with P8ntman) that there is not enough penetration on those welds, and not to be rude but if you own Chase Race, it makes me concerented that you would build things that require structural integrity with such a weak weld, not to mention with the look of the weld you used flux cored. Do you tig any of your products? If so do you purge inside the tube too??

I not only do production mig welding for Lincoln but i also am a robotic tech and program all the recent new robotic welding jobs. I (not to be rude) could pop off an example of what a weld like that should look like for those who are curious. Weak welds are no joke and even a pretty LOOKING weld can have no penatration.

[Doug Chase]

I am sorry but i still agree (with P8ntman) that there is not enough penetration on those welds

That's fine. You are entitled to your opinion. I'm pretty sure there's nothing I can say to convince you otherwise. I wish you could inspect the weld in person so you could see it close up.

not to mention with the look of the weld you used flux cored

Nope. C25.

Do you tig any of your products?

Yes.

If so do you purge inside the tube too??

When I weld stainless I use Solar Flux Type B instead of back-purging.

I (not to be rude) could pop off an example of what a weld like that should look like for those who are curious.

Me too. How's this? The plate is 3/16" and the tubing is 0.120" wall.

[Shaun41178(2)]

Holy crap Doug I love you.

Looks nice.

[Doug Chase]

Thanks Shaun.

Fieromaster, perhaps I should explain a little more about the part above. Sorry this is long, that's why I hadn't typed it sooner.

I make a bunch of parts like this (front mount for a removable trailer hitch, see: http://www.chaserace.com/fabrication/fabrication.html ) and they are admittedly difficult to get perfect.

The problem is those welds. There are a couple things here that make it difficult. First is that I'm welding into a fairly tight 3-way "V". Because of this, all of the spatter tends to collect on the pieces near the weld (which is most of them).

Second, is that to minimize spatter, one thing I've tried is to crank up the heat and then start from the bottom of the corner. As the weld progresses I point the cup away from the corner and then move out so the spatter is going away from the part.

This is the way I welded the above piece. The fact that I turned up the heat gives me good penetration at the start, but it's a smaller area since that's the thickest part of the angle iron. Because of the high wire speed necessary for this much heat the weld tends to build up at the start. As you proceed, the part heats up and the area of penetration gets a lot wider. Look at the weld towards the edge of the angle iron.

I've tried welding this piece the other direction, but there's a lot more spatter since I'm aiming and moving the gun into the corner. This is a problem particularly on the inside welds, because it's difficult to clean off so I can get a heim joint in there. I have inspected the welds carefully and determined that they are actually quite good despite their appearance.

I have a couple ideas that I haven't tried yet. One is to go down to 0.025 wire so that with this much heat I may be up into spray mode and wouldn't get spatter.

Another idea is to try TIGing it. I haven't tried this yet because it will be difficult to get the torch clear into the corner. Perhaps the corner will hold the argon so I could extend the tungsten farther out of the cup than you can normally get away with.

Another idea is to turn it up even hotter and be prepared to move very quickly as I move out toward the edge of the angle iron.

Do you have any thoughts on making things better?

[Kohburn]

Weak welds are no joke and even a pretty LOOKING weld can have no penatration.

and a bulky weld could have penetrated but have too high a feed rate/too slow movement