OzVMX Forum
Clubroom => Bike Talk => Topic started by: utsman on January 31, 2009, 08:28:09 am
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I need to weld a crack in my CR500 frame . It is right at the bottom and easy to access. What do i need to be carefull of ie, can I damage the ignition etc, splatter on the cases. Any thoughts appreciated.
STU
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pull the motor out stu and do it properly. use either Mig or Tig
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Hey UTSMAN, I agree to a large extent about removing the motor, The point i would like to highlight is the frame material. Many of the old Mxers are made of cromoly (yz125e, cr250m, etc) if you use mig with a steel wire then you may not get a strong weld. Ask around to find out what material your frame is. If it is cromo then you should use tig with the correct filler rod. If you have little welding experience then dont put it to chance... OLDYZMAN
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I reckon its best to remove all electrical components completely from the bike when welding. Better to be safe than sorry.
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Oh NO - I certainly won't be doing the welding. Motor out eh. What a mission but still, must treat the old girl right'
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hey utsman, if you r sydney based maybe i can give you a doods number to weld it...
OLDYZMAN
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disconnect the electrics, if you want to do it motor in the frame make sure the earth is on the frame next to where you are welding so you don't arc through the bearings. TIG is the only kind of welding that counts, MIG will crack about the edges usually if the parent metals and wire are not the same. I use stainless TIG rods, never had problem.
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if you want to do it motor in the frame make sure the earth is on the frame next to where you are welding so you don't arc through the bearings.
Yes, very important.
I have welded cases while the motor was still in the frame at times, very awkward.
but the worst thing is the customers complain about having to remove the oil as its fresh :o
TIG is the best option for welding, normal TIG wire will interchange with cro-mo allright but obviously the cro-mo wire will be the stronger weld.
MIG will do the job also but you will need some experiance to tackle it properly, its too easy to lay down a big bead of weld with MIG thats not burnt in, these would be the welds that crack at the edges.
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GMC, iIf you weld with CrMo do you need to stress relieve by heat treating? I asked John LeFevre of Vintage Husky about welding CrMo Husky frames once and he said he used mild steel filler wire. Its not the weld thats the weak point in these frames...or is it ??? ??? My 2 cents...
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As Geoff said welds crack in the Heat Affected Zone(HAZ) that is the bit in between the filler and the parent material. Weld ductility is greatly enhanced by stress relief after welding but not essential for just 1 weld, maybe for a frame welded on a production line in quick time . For this you just have to gradualy heat the area, weld, then slowly cool it makes a ductile weld. The only time I would say you have a frame problem if a frame is welded and it cracks again in the same spot.
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When tig welding chromo I always used 346 stainless steel wire and never had any problems.
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Hey firko is that 316 or 346 s/s filler rod, genuine question?
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Oops...I meant 316. My old brain must be fading fast. Sorry to anybody who'd gone looking for 346 rods as they may just have had a bit of a tough time finding 'em. :)
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Thats interesting to know firko, I guess chromolly has a certain amount of chromium and so does 316 s/s
Never really thought of it that way
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I had read on the subject and seems I was incorrect in my assumption that normal triple deoxidised filler wires are no good on CrMo/4130 tube. They are OK but not as good as CrMo filler, sorry to play bad cop agin on you firko but it took me a while to find it here is what John Bradley in the Racing Motorcycle Vol2(what I usualy refer to) has to say on the stainless filler on CrMo subject.
(http://i155.photobucket.com/albums/s297/Lozza85_2007/IMG-2.jpg)
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Thanks for the tip Lozza. I expect all of those frames I've welded over the years should all start falling apart soon. I'd better check. :o
With due respect to you and Mr Bradley Lozza, the best tig welder I've ever seen, Chris Ellis uses stainless filler rod on chro-moly and I'd prefer to go with his advice on the subject, . ;)
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Okly Dokely then,
I have been away from the net again ( why me). Man you guys know a lot about welding. :D
and the verdict is
If I get an experienced welder and make sure the earth is right near (how close?) to the weld and I disconnect all the electrics and they use the right type of welding can I get it done without stripping it down or is it too risky??
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Thanks
STU
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Yeah well I suppose you can but when your mate Chris can write a 1000 pages on motorcycles and fabrication then have HRC purchase a 100 sets, have every Pommy frame manufacturer seek his advice, be a Uni lecturer and Mechanical Engineer and have his opinions stand up against peer review, then I'll be quoting from Mr Ellis' book, but until then........................... ;D
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You go your way Lozza and I'll go mine. All I know as a lowly tradesman without a book to my credit is that using stainless rod on chromo or mild steel has worked for me as a boilermaker/welder for thirty years with no failures to my knowledge. I was licenced pressure welder and often ran a stainless root weld on steel pressure pipe with no knockbacks by the inspector to my memory. Chris was the head welder at Qantas and the only welder in Australia licenced to weld jet engine rotors at the time. He's also the welder that did every big fin head for Ballards XRs Only and is the choice of welder when it gets too hard for everyone from Laurie Alderton where Chris worked part time for years welding engine cases and broken frames right through to welding the Honda team bikes for the Australian Safari for years and a shitload of other big time racer work. Geoff Ballard has quoted in ADB that Chris was the best in the business.
Mr Bradley's theories are not going to change my opinion of what works or doesn't work after 45 years as a tradesman. I know what works for me, Chris knows what works for him and Mr Bradley knows what works for him. Viva 'la differeance!
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All I know as a lowly tradesman without a book to my credit is that using stainless rod on chromo or mild steel has worked for me as a boilermaker/welder for thirty years with no failures to my knowledge.
Respect Firko. No sarcasm intended. I once had the privilige of working with a bunch of boiler makers (as an electronics engineer) and I hold their skills in high esteem.
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Thanks Tim....I loved my years with a big hammer and chisel. The old skills still come in handy in the shed.
I was just in the mall doing the weekly shopping and while sitting having my Donut King Capuchino and complimentary donut recalled visiting expat Kiwi chassis builder Ron Butler at his Los Angeles workshop back in 1977 and distinctly remember him using stainless steel filler rod while tig welding a Pro Stock Chassis for the legenary Sox and Martin Mopar teams new Dodge Colt (Galant). I was new to TIG welding in those days so asked him why he used Staino instead of Chromo rods and he replied that it was the way he'd learned in the aerospace industry and that using staino rods prevented contaminating the electrode and therefore the weld. Later on I got a part time job with LA midget speedcar chassis builder Ace Nofsinger and took note that his Mexican chassis welder Luis also used stainless rods. Many years later I assisted then Aussie Compact Speedcar Champion Warren Wright build a new chassis for his car. Once again...stainless filler rod and that chassis is now celebrating its 20th year on the track!
Obviously none of these guys have read John Bradleys warning them of the evils of stainless steel but managed to make a living doing quality work despite that lack of knowledge. Funny that. ::)
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One of the benfits of working in the nuclear "industry" is that the standards are extremely high. I once shared a liftclub with a boilermaker who produced a short circuit plate for an RF resonant cavity the quality of which left me breathless. I mean this workpiece transcended the border between craftmanship and art. It was a thing of beauty.
Another mate of mine, a classic enthusiast, picked up a wrecked fastback commando and restored it. He ran the maintenance division at the nuclear institute concerned so when he wasn't in a state of mild panic he could do as he pleased (which was most of the time). Nuclear institutes, if you don't know, use a lot of stainless, so Geoff's Fastback had an instrument binnacle machined from billet stainless. Again it was a thing of beauty.
One collegue (I hesitate to call him a mate) was a superb machinist but had the habit of filing every machined surface of the workpiece and making it look like crap. Philistine!
Mike, the aforementioned boliermaker, turned his attention in the evenings to building a Lotus Seven and after its completion the joke running around was: "Why doesn't Mike's Lotus have windscreen wipers?". Answer: "They're not a stores issue".
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To UTSMan,
Sorry to get off the subject, Over the years i have tig welded many very hitech packaging machines, scales, wrappers and labellers where it was not possible to strip down - never had an electronic failure due to welding. If it were me And you could access the break well enough to get a good weld round the frame then i would leave the engine in the bike, get the earth lead within 2 or three inches of the weld, and certainly only tig weld the job. Consider radiant heat therefore shield if needed. As far as the filler rod goes there seems to be enough advice out there.
Brett
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Thanks Oldyzman and everyone for their thoughts.
One last question. how do I tell if my 93 Cr500 has a chromo frame or a steel one?? Then I know what rod to suggest to the tig welder guy.
You guys rock
STU
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There should be info on that model from honda to id material as it is not really that old. I will be interested to hear opinions on this. Hey guys my yz125e has a chromoly frame is it my imagination that where it is scratched doesnt really seem to be rusting somethin to do with the cromium content? Can this confirm material for utsman
OLDYZMAN
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Back in "Ye olde days" when I first learnt to argon-arc weld (as TIG was then known) in the late seventies it was common to use stainless filler for odd jobs. Copper coated triple deoxidized filler was a rarity that no one had. TIG welding with oxy wire would produce a weld with lots of porosity rendering it useless, where as stainless would produce a good weld even when TIGing gal.
I prefer to weld my frames with Cro-Mo filler rod as it is made to suit the material.
Cro-Mo will rust a bit slower than steel but will still rust just the same.
Many frames, if not Cro-Mo may be made from other high spec. steel. It won't matter too much what it is welded with so long as it is welded by someone of some competence. No matter what you use a Cro-Mo frame will become brittle in the heat affected zone (next to the weld). For any serious work on a frame I recommend having the frame heat treated (normalized) afterwards for longevity & peace of mind, but it depends on wether your trying to hold the engine cradle together or just putting back a sidecover bracket.
When repairing something like this you have to remember that the welder can only make it as good as it was in the first place, which probably wasn't good enough as it broke in the first place.
If it breaks again you have to be careful you don't confuse poor welds with poor design.
TIG is now known as G.T.A.W. ( Gas Tungsten Arc Welding)
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What ever happenrd to TIG tungsten inert gas - the things we learn every day......
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When I started work all the old guys called it argon-arc. At trade school they called it TIG, I told the old guys to get with the times, its called TIG. They told me to F off.
Now life has gone full circle, it's now called GTAW but I still call it TIG & I tell the kids to F off when they try to tell me different ;D ;D
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I have been following this topic with interest, esp regarding the normalising post weld repair. For a major repair to the structure, in this case where the downtube connects to the steering tube i would assume heat treatment would be necessary to return the frame to "as good as new condition." Do you have a furnace to do this work GMC?
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Depending on the repair, normalizing may or may not be of benefit.
But, if its old stressed material that may have also work hardened over the years, then heat treatment may be what the material needs to give back it's youth.
I send all my frames & most of my frame repairs to companies that specialize in this service.
Up to $110.00 will get it done professionally.
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The tips & tricks guy seemed to rabbit on a bit, some of it was American based but other wise it was mostly good advice.
"when you seal up the joint, often times pressure builds up and blows a hole and disrupts the gas shielding and causes porosity. You can either drill a small vent hole in a place that will allow or stop right before you seal it up and let cool for a minute before coming back and hitting it quick to close it up...or 309 stainless rod will let you overcome the porosity..if the application will allow for this."
This "blow out" is common on any sealed tube, no matter what the material & is worst when the tube is sealed & you try to weld a gussets in the middle of the sealed tube. People often ask me why my frames have a small 3mm hole drilled in every tube in my frames, this is why. I would dispute that the stainless would cure this though.
When the pressure from the heat builds up it wants to break through the weakest point, being the molten weldpool. Usually when it blows through it deposits a great lump on the tungsten electrode forcing you to stop to clean it.
I have had this "blow through" on many stainless jobs so I can't see how stainless filler would cure it.
The lower grade stainless makes sense as they have less nickel in them, but few firms stock the lesser grades as they can't afford to mix the lower grade filler into 316 jobs, but 316 filler is fine with most grades of stainless.
As well as Argon-arc, TIG & GTAW being the same thing, Heliarc is also the same. It's the American name. You can use either argon or helium as the shrouding gas, both are inert gases & shield the weld from the atmosphere.
I believe Helium burns a bit hotter & is suitable for some special applications.
I hear Argon is common out of Bass Strait whereas the USA Helium comes out of some fields in Canada so it's mostly the economics of gas prices why our countries use different gases