unfortunately, that is how most production buggies are made (Peter Lynn, Flexi, Kite Trike, Radsail, etc..). When they are mass produced out of China, they just fuse them together with little or no filler. That is just one of the differences between a $600.00 buggy and a $2K buggy.

It's the PL Folding+

http://peterlynn.com/products/kitebuggy-collection/folding/

http://www.vliegerop.com/index.php?inhoud=product&id=951

WOW! I'm going to have to give a Much Better inspection to my buggy! Old Kyte Tryke I believe. At 230lbs and bumpy riding mostly I suppose I had more faith in weld.. tha5 yas quickly been shattered after reading this thread. $1400 addional for decent welds seems outrageous but I would hate to break b7ggy at speed. Did break an axle bolt at speed but it didn't cause me to stop dead in mybtracks as some other failures might have. Time to start saving my pennies!

Don,
Seeing as you are reviewing crappy welds, how about this one on lower brace of fork from a supposedly reputable buggy.. I have to wonder how (well?) that buggy tracks at speed. I will leave it up to you guys to figure out which brand, but the flexi classic fork does not have a brace and the libre special isn't stainless.

S

That is another terrible weld, barely fused, too cold....probably done by somebody with an IQ of a 2nd grader. They obviously haven't welded long enough to know how to fill a gap. Looks like a PL Comp/XR to me. The welds on my brace are not very pretty but they are fused well and are not under-filled or overfilled. I trust them. Also, there is no gap between the brace and the fork tube on mine, I would guess that he welded the other side and noticed that this side was incorrectly fit so he just attempted to band-aid it instead of scrapping the part or cutting and re-welding. These people don't think about the fact that somebody could be going 30-40 mph on these little things when they're building them. Just paid to produce, not think. On the other hand, I have seen welds almost as bad as this on custom buggy's built by supposedly reputable builders who know exactly how dangerous this sport can be, that is the worst offense of all in my opinion.

I would not trust this at all, the manufacturer needs to know about this.

I would say he never tacked it all around before production welding. That is awful...
Here is my weld on my siderail to downtube connection. I gaurantee it w/ my life. Notice the difference?

Attention PL and Flexifoil :Your buggies SUCK ! Filler wire doesn't cost that much ,even in China. Have you guys ever heard of "Quality Assurance"? Obviously NOT. I have patio furniture built better than that, and it just sits there.

I'm so glad I built my own buggies, I would have been pissed beyond belief ,if I'd got a buggy with welds like that.
And I wonder if someone got hurt because of a weld failure due to deliberate malfeasance, could they file a lawsuit against them?

@ Scud, that weld looks like a third grader made it. Oh yeah, that's probably what made it.

I have had pretty good experience my flexi classic. It is on its third year at GP where it is well abused on a regular basis and it has not been to a welder yet. When you consider that Wolf wolfee had it for five years before I had it. He was jumping it on a regular basis, I think he even has few pounds on me.
S

Nice lookin bead WG.

Quote: Originally posted by WELDNGOD

Quote: Originally posted by rtz   I think Van's rails are a thicker material and not being stainless; potentially stronger: According to the Metals Handbook of the American Society of Testing and Materials, 316 Stainless has a tensile strength of 85,000 pounds per square inch. Ordinary Strength Steel is 70,000 pounds per square inch.

Be careful quoting strengths if you are not familiar with what the numbers mean. The number you give is the UTS (ultimate tensile strength). This is the load per unit area which will pull a sample apart. Long before this occurs you will be seeing plastic deformation. Engineers base their designs on the yeild strength (YS) or the load required to stretch the metal so that it will not return to its original shape.
For 304 stainless the UTS is 73 200 PSI and YS 23100 PSI. The strain to failure is 70%.
For 1018 mild steel the UTS is 63 800 PSI and YS 53 000PSI. Strain to failure is 15%.
Stainless will deform long before mild steel, but break at a higher load. Strain to failure is a measure of ductility. From these numbers stainless is between 4 or 5 times as ductile as mild steel.

I have to assume my welding friends are unfamiliar with benefits of autogenous tig welding (no filler). Often used when welding thin wall tubing as it gives a smaller HAZ and less problems with composition gradients that can be associated corrosion at welds..

S

Quote: Originally posted by Scudley

Quote: Originally posted by WELDNGOD   Quote: Originally posted by rtz   I think Van's rails are a thicker material and not being stainless; potentially stronger: I have to assume my welding friends are unfamiliar with benefits of autogenous tig welding (no filler). Often used when welding thin wall tubing as it gives a smaller HAZ and less problems with composition gradients that can be associated corrosion at welds.. S There are no benefits, only rejections. It is NOT allowed except on sheet metal. The concavity created is called undercut, it is rejectable. Unless you are welding a spatula together or some galley sheet stainless, you better add filler or you will get FIRED ! I actually weld everyday, all day. You name a system on a ship ,and I have built one or dozens. All that book mumbo-jumbo don't mean jack on the deck plates Bro'. And BTW,that aluminum buggy I built is still kickin' sand. I even loaned it to Ragden @ WWBB. He has put some miles and some stresses on it. Guess what... Not a crack anywhere and still rock solid.:P "Strength by design,not material" WG Now go back to your desk,I got weldin' to do!

Oh yeah, if your buggy bends all to heck. It's still broken..... Even if it did not break in two..

Quote: Originally posted by WELDNGOD

Oh yeah, if your buggy bends all to heck. It's still broken..... Even if it did not break in two..

Yes Don, absolutely true. This why is dangerous for you to use UTS as a design spec. It why engineers use yield stress.
Now there things that can be done to raise YS (work harden, heat treat) so yield stress number will will often state the material history. Ie as drawn tube or annealed.
S

All they need to do is NOT use BORDERLINE material for the given application.So it costs a little more,weighs a little more. A humans butt is literally riding on it.
If Peter Lynn's grandma was gonna ride it,you can bet your a$$ it would be welded proper.

The more I see in this industry, the more I love the fact I built my own rides. I feel for you folks riding around on what I consider a deathtrap waiting to fold up on ya ! It's just a matter of time. And that little Chinese kid who welded your buggy and a hundred more just like it that day, until the sunglasses could no longer protect his eyes from the UV radiation(like they ever could) ,won't give a rats behind that his weld failed and you got hurt.
Maybe a buggy should not cost $500,maybe it takes a thousand to get it safe enough for grandma.

Do you have a $500 body/life or a $2500 body/life?

Quote: Originally posted by Demoknight

But Stainless is definitely far more brittle than non-stainless. At least the tubing I would use if I still had access to my old iron-working stuff.

The specs for 304 stainless give a strain to failure of 70% and for mild steel (1018) 15%. Which one did you say is far more brittle?
Why would you choose to use a brittle material in an application of subject to tensile loads.
S

Yes, stainless is more brittle but not so much so that it's gonna crack when you hit it with a hammer, even a really big one. Tungsten, on the other hand, would. For our purposes, in my opinion, stainless is better because of the corrosion resistance and greater strength. Tensile strength isn't a factor, in my opinion, on a buggy unless you're building it with way too small diameter tubing, like .0625" welding rod lol. I bet you could measure the oldest, most beat up buggy out there with the most bad ass Mitutoyo Vernier calipers or digital micrometer out there and you will find nothing has elongated even .0005" (half thou). I could be wrong but I don't think so. I would think that impact resistance would be a greater factor than tensile strength for our purposes.

Try this, take a piece of 12"x1"x.125" stainless and mild steel tubing, weld them both to a metal table and then hit them with a hammer and see which one moves/cracks/bends/breaks etc. Then make your choice. Stainless is the obvious choice, for me, after working with different types and grades of materials for a while. The only thing that might factor in for me is the cost.

Sean, you are looking at it from the engineers standpoint. You make choices based upon what you see on a spec sheet and what you learned in school. We make choices based upon real life scenario's and experience in the field. This is why office people (you Sean :P) and the people that actually build the product don't often get along. Two completely different crowds at the Christmas party lol.

Well, I did learn in school that unless you chose your filler very carefully welds between austenitic steels and ferritic steels are always brittle because unless the filler has lots of chrome and nickel the fusion zone of your weld is going to contain martensite at the mild steel end of the weld and martensite is really brittle. You when combine mild steel with 304 and you let the fusion zone get below 17% chrome and 7% nickel, the fusion zone get the the same chemistry as some grades of readily heat treatable tool steels.
Any other questions?
S

Blah -blah -blah. Any WELDER knows if you are going to weld stainless to steel ,you only have a few choices of electrode to use. It ain't rocket science Sean. You obviously never weld, or you are a rod burner. LOL So ,you know your elements and compositions of metals ,let's see your custom self made buggy. Let's see your bead. Let's see you weld a pipe, looking in a mirror around a corner. You are one of the people that have me putting a 7/16" fillet weld on a 1/2 " piece of material, and wonder why it warps....
Typical desk jockey, book smart ,and no practical knowledge.

I've only seen one kind of pipe in Sean's hands...

Quote: Originally posted by RonH

I've only seen one kind of pipe in Sean's hands...

laughed my ass off and then fell out of my chair funny.

This was a fun read! I'd want to talk to Sean and the welders if I had to spec materials and weldments for my personal buggy or one I wanted to sell with my name on. I think both sides have knowledge to offer. Just can't let one know you've been talking to the other!

Got it welded:

nice!

Hardwire stainless shortarc (a kind of MIG welding) . better than production.

Should have had him go ALL the way around it.

That's a good idea. I should have. If it cracks again; I will.

Nice! Definitely better than it was. I wouldn't wait for it to crack before I had it welded the rest of the way.

BB was right this was an interesting read... Just some thoughts though, feel free to tell me I'm wrong.

I have both a Peter Lynn buggy and a mild steel VTT Hybrid buggy. Van provided me with rails and the current edition of my buggy has a homebrew downtube and back axle and the PL front fork. I'm am by far no Weldngod, but I do know how to weld mild steel, make it reasonably strong, and look pretty. http://www.powerkiteforum.com/viewthread.php?tid=27299

I was just thinking about this from the standpoint of USAGE... I'm not a speed demon and I'm not doing tricks (esp with big air). I live about a bazillion miles from Ivanpah, and I'm only on a beach for a very short amount of time during the year. My riding spots are all pretty small and I'm about 90% sure that I will never get over 30mph in a buggy (see my current PB below). As fast as 22 mph feels, I don't have much intention of going too far past that.

That said, is it reasonable to assume the most stress and force I put on a buggy is when I put my big fat 200 lb backside into the seat? ... Or is it reasonable to assume that if you intend a buggy for relatively light use, a Peter Lynn buggy (subpar welds and all) may be a reasonably well suited ride? It would seem to me like anyone who decides to take a PL buggy out to go 40-50 mph+ has some very bad decision making skills. I'm not sure if it's how they are marketed, but most people in the sport would tell you that a PL bug is a "starter" ... At least that's the terminology I heard A LOT, when I was shopping. I would think that when guys are making the decision to go out at excessive speeds and putting more strains and forces on a buggy, they have already moved into something that costs $1200 or more (Apexx, MG, Ivanpah, PTW, etc). If not, they may not be the brightest bulb in the box. It only takes a few seconds of stupid to undo years and years of learning, right. Or are the stresses and forces at 15-20 mph enough to do significant damage to a buggy?

It's obvious that there is something wrong with some of the welds on some of the PL buggies, otherwise rtz and yeldarb and some other folks wouldn't be having this problem because they didn't stand up to typical abuse. But there seems to be a higher percentage of PL buggies that are just fine.

And what about buggies made of mild steel? Are they significantly weaker? My VTT feels pretty stout, and I know there are a lot of Ivanpah's out there of mild steel. Are they more likely to get wrecked under the strains of high speed?

Just some thoughts I'm having about the discussion,... am I out of line? How much does the usage factor play in the durability of a buggy relative to what it's made of?