I thought I had my breakage problems with the PL Bigfoot buggy worked out by switching over to Flexifoil parts. I had everything Flexi except for the BF front fork so I could use a Bigfoot light tire. I even managed to use a Flexi downtube and connect it to the PL Bigfoot fork. Then yesterday I was making a slow turn on a gradual incline and....

The siderails must have already been cracked underneath from previous bumps.

I was able to splint together the two halves with a piece of wood I found and my two ground stakes so that I could tow it back to the truck a quarter mile away.

You and TheKidd are in the same boat. This is where he broke his custom built buggy at WBB. Except he didn't break the weld. He broke to tubes themselves. I would contact Van at VTT (you most likely know him) and get a set of side rails made up. You'll be kicki'n up sand in no time!!!

That close up pic is interesting in how it separated. If you can find somebody local who can TIG stainless; you can get it reattached. Or order a new set of side rails.

Do you buggy in SPI? I was looking at it on a map and it seems one could head north easily but not so easy heading back south due to the angle the beach runs and the typical wind angle. Where do you ride at?

These pics have me more and more worried every time I go out now....I expected this from some manufactured parts but not the one you are mentioning. (see how I didn't mention names so I don't catch any crap).
I wouldn't want to be cruising down the beach or a field at 30 mph + and have this happen...
Is there anything you can do to prevent this? I guess mine has lasted so long due to my weight in the buggy but I do think I ride rather hard for a little guy...

I'd just inspect the welds before or after a session and look for hairline cracks in the welds. The shiny stainless makes them easy to see.

Rocfighter,

That is also how I finally destroyed my first buggy, a Rockville, only the siderails simply bent to the ground untill I was dragging so much I couldn't go anywhere. I bent them back in shape a couple of times but the metal was too fatigued to hold for very long.

Thank you for the VTT suggestion.

rtz,

My experience with having things TIG welded locally is that it seems to weaken the metal, make it more brittle and cause problems sooner rather than later. I have not had Flexifoil SS re-welded and maybe since it is better SS than PL SS I would get better results.

Yes, I buggy SPI and have been kicked off of both the dunes and the beach by local authority. You are correct about the prevailing SE winds. There are, however, east wind days that allow you to buggy the beach both directions. That is, of course, if the tide is low enough to give you a beach to buggy. The east wind days are fairly rare and hard to predict. You can usually assume that the wind will swing through east after a Norther, but when and how long is something you have to be here to catch. Since I have lived here, August has been a good east wind month, but I would never bet on it.

BEC,

My lighter buggy friends don't have nearly the the trouble I have with breakage. I am 6'3" and weigh 215. I also seem to have a knack for hitting a rut or drop off exactly wrong. I should have a job as a buggy test pilot! I do not mind giving details on brands. I have absolutely nothing against, Rockville, PL or FlexiFoil. I have had such a blast in each of my buggies. It's just too bad I am so fat and stupid.

I think Van's rails are a thicker material and not being stainless; potentially stronger:

http://www.bigmikeskites.com/VTT/XR-Rails/XRRailKit.html

You might be able to get a deal on just the rails if you don't also need a new seat:

http://www.vantantech.com/

Quote: Originally posted by rtz

I'd just inspect the welds before or after a session and look for hairline cracks in the welds. The shiny stainless makes them easy to see.

Don't look at the bead, the cracks WILL happen right next to the weld. I mean right NEXT to it. There is something called the" heat affected zone" ,that is the metal on the edge of the metal that melted. But this metal got ALMOST hot enough to melt but did not. As a result it became weakened . Even the "weldngod" creates a HAZ, it cannot be helped . But, it can be reduced by keeping the heat input down to a minimum. These are production buggies and the guys that weld them are not in the same category of welder as me. They may even get paid by the piece. Which means they are gonna "throw the coals"at it to get as many done as they can. Which WILL create a huge HAZ. Also if the re-entrant angle is too steep it will create a STRESS RISER, and that can create a crack as well. Put both together and disaster ensues.
Just my professional opinion
WG


edit: Also ,by getting stainless too hot. It creates carbide precipitate on the backside of the tubing/pipe. It looks like black sugar, and it is a defect.

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.

I'm curious where they get these parts made, cause this is a NASTY weld ,complete with undercut. Whomever welded this,is no welder. Looks to me like a child welded it. Do they make them in Bangladesh, in a child labor sweatshop???

So Don, how would you go about repairing this? MIG or TIG? Grind the crappy welds off of the flange and clean up the tubing or start with new material? Would there be any sense in making two smaller passes with a TIG versus one thicker one?

Thanks:wee:

Not that I have broken my Flexi, or any buggy I'm just trying to pickup some welding tips!:wee:

Quote: Originally posted by Crash then swim

Not that I have broken my Flexi, or any buggy I'm just trying to pickup some welding tips!:wee:

I have an idea on how to repair it. But it is metric and I'm not sure if I could come up with the right material to make the repair with. Basically, a heavier wall sleeve that fits inside of the tubing then getting beveled and welded to the flange. With a couple of plug weld holes in the tubing to help it become one.

But, this may only move the stress riser to the end of the heavier pipe.

The real problem is "fatigue" and the material is borderline for this application. There is a lot of flex right at that point and all the flexing is breaking down the metal. Just like bending a piece of wire over and over until it breaks. The heavier you are ,the sooner it will happen. Or rugged terrain could do it as well. There is a reason my stainless "Homebrew" buggy weighs 131Lbs. It is NOT made from thin wall tubing. I wanted it to be built like a tank. Even my Aluminum buggy that I was told was not a good idea and would not last ,weighs 87 Lbs. and it is still going strong 4-5 yrs. later.
Strength by design !:alien:

WG

Fixing it is not your answer. The thin wall stuff will break again under your weight and riding style. I would recommend thicker wall tubing. Come to DBBB this year. You can try out the thicker side rails and see what you think.

I just got back from SPI and found a crack on the lower end of my swan neck (aluminum)
the dunes and beach were very bumpy and were probably the cause.
I would agree Van is your best bet on getting your bug back up and in the sand.
About a 7 hour drive for you and probably well worth your time.
See you and Bert this coming spring.
Good luck
Bob

Bob, what grade of aluminum is it?

WELDNGOD

Thank you for the frank assessment and ideas on the weld picture. That was an eye opener. I didn't understand some of the terms but, I get the idea. You and Vann saved me a few bucks because I will not try and have the side rails repaired.

bobsalinas

Sorry about the crack. Welcome to my world. That was as bumpy as I have ever seen it. I think it was the result of incredible wind after an unusual amount of rain. It seemed to turn the dunes liquid and formed sand waves.

BRAD, Sorry for your buggy loss I guess there is a price for FUN. The east wind days were the best amazing how
the dunes contour changed with the help of the great mother.
Youve got the kites dialed. time to upgrade the buggy. see ya in the spring.

KAZEDOKA

Glad you and Bob made it home safely. I kept thinking while you were here that you hit it right this fall. Your were here for the second best buggy day of the year. You also got a bunch of other east days, two Northers and some big sail southeast. Quite a nice mix!

I had a bunch of PL parts. I put together a Big Foot with a straight Flexi downtube. I hope it will last until I can get something really good going. Take care.

We have replacement frame rails in stock if you need to get it back together quick.
http://www.awindofchange.com/product/plframerails.html

awindofchange

Thank you Kent. What I broke were both Flexifoil siderails. Even though PL siderails fit a Flexifoil regular and extra wide back axle without the nylon bushings, I didn't want to do that. I had enough PL parts to put together a Bigfoot. I guess I'm saving the last Bigfoot downtube I got from you for a special occasion.

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.

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.

Depends on the grade. But that's not the problem, overheating the THIN WALL stainless (which I am certified to weld) IS the problem. That , and they want to keep the weight down. If you overload it ,or cycle it really hard on rough terrain , it's gonna crack.
It's just a matter of time.

I don't have time to read through the whole thread but I've noticed that bad welds seem to be a trend in the buggy building industry. Even my MG has some terrible looking welds on it. It seems that some of these guys decide to build buggies with no knowledge of how in the hell to weld it properly. Some, thank God, have progressed in their welding skills over the years. I think it's total BS to risk somebodies life just because you wanna make some money. IF YOU CAN'T WELD, DON'T!!! There's a lot more to it than you might think.

WELDNGOD - Thanks for your input, it is very much appreciated.

Just sharing my knowledge with my kite family. I don't want to see anyone hurt ,and if I can teach someone enough to do it better/right ,then I have been a benefit to the community.

The results from todays ride:

Looks to me Like someone A: Does NOT know how to properly weld Stainless Steel and/or B: Used WRONG parameters when welding. Either way, I BET he/ she does not hold a Certification for that alloy. JMHPO

WOW, that is absolutely horrible. I'm sorry you have to deal with that. If I were you, I would take it to an experienced TIG welder and have them cut a groove (die grinder, dremel, etc.) in all the welds and then weld them again. I would only feel comfortable until I did that. This looks like they used the wrong parameters and not even close to enough rod or too small dia. rod. They just stuck the rod in and ran it down instead of dabbing it. Dabbing it creates ripples which make the weld stronger and much less prone to cracking. Of course, YMMV.

Chris, after some magnification, it was just fused. No filler added at all. It's undercut all to heck. The world needs more of us !

rtz, what brand is that? I would like to personally call them out on this .That is disgraceful.... And extremely unsafe . A weld needs certain things in it's make alloy. That is where "filler wire " come in,but it's not just filler. Some things make it more durable,less prone to cracking. Without it you get what we have here.

NAME AND SHAME the culprit. They should NEVER be allowed to sell another P.O.S. to anyone else.