aluminum welding a footpegs Honda VFR platinum: ok or not?

[Christophe]

Never in normal situation, this piece has to bear the weight of the bike. it is designed to support the weight of the pilot (and again to support the full weight of the pilot must be standing and one-legged).

Yes and small supplement:
a) It also takes the braking reaction force, the pivot (steel) of the brake pedal (also steel) being crimped on the plate
b) Finally in case of "wide" angle with violent grip (difficult to do with a VFR but possible), ie when the footrest rubs violently on the asphalt and the pilot's foot prevents lifting of the footrest , then this part can work as with a stopped fall ... but obviously with less force! (except if mega big legs blocking the climb )

The blind screws of wear I have them, they are almost new ... jouloule not like a macro me!

[Macro]

The blind screws of wear I have them, they are almost new ... jouloule not like a macro me!

No no ... You ride in Honda ... That's all They talked for a while to offer French senators these motorcycles

[Obamot]

For me ... If there was nothing to block this piece in the back .. the place where she farted was the place where the lever arm was minimum ... The point of maximum effort lying at the level of the two bindings on the frame ..

... go explain that to him

... the dedicated heating engineer is "stronger" than the engineers of the takawaar mines ...


While in reality - and it was easy to understand - the bike is on its crutch because it is located at the axis of the center of gravity (relative to the serifs).

This "point of balance" (point "0" below) is in itself the proof that the "moment" is almost zero at this point, otherwise the bike would not balance on the stand .... Logical!

In fact, at this point, with regard to a possible "lever arm", the forces cancel each other out! (In the axis of the broken foundry part => in orange, noted in "A")

So yes, we have to face the obvious, at this point the «moment»Is = to zero on the casting (if we consider the bike as a hyperstatic construction, and it is ...)!



On the other hand, yes, the force of inertia which starts its rotation very quickly, taking support on the ... tires (as a natural point of rotation ...) is indeed the one that broke the part. But it is PERPENDICULAR (in magenta above) to what Dedelco's miscalculation attempt (in the axis of the solid orange line at "A") and as he wrongly explains it here:

The lever is measurable from 1cm and the balance holds by the strength of the Holy Spirit to 20cm which replaces the weight of 5Kg [/ b] [...]

on this image :


the multiplicative factor of the flexural force F (applied on the axis ends with green arrows) is the ratio of the green lengths, (about 10 to 15cm) divided by the length Red (corrected moments of inertia) about 5mm evening a factor 20

What is arch-false ... (in your assumption lever arm: the only moment that one could have suspected, it would be 1mm, not significant ...)

Everyone will have understood that the weight of the whole has been multiplied by this force of inertia (magenta), ie = speed that the bike took during its rotation (but not by a hypothetical leverage effect, which would be transverse to it if however it existed => orange axis), moreover we can only admit that the center of gravity is ........... .................. In the center. Point bar.

[Macro]

To come back to welding and Honda ....

A craftsman who worked at my job decided to retire and not finding a buyer for his business he liquidated his gear against hard and soft coins .... There I cracked I offered myself this:

A post mig mag mma Oerlikon ....

It's a professional thing ... For the moment I only use it with argon gas + Co2 to weld steel ... but it's really a treat.

By changing the gas (pure argon same bottle as my TIG station), the filler metal and the drive roller (found on aliexpress) we can also weld the aluminum and the stainless steel, and by reversing the polarities with a toothed roller can be welded with a cored wire.

By changing the torch (but you have to use a tap torch) you can switch to the TIG process ...

The station is fully electronically controlled with a whole bunch of predefined programs for a material, a gas and a wire diameter.

easy to handle ... Disconcerting ....

So much for the welding part ....

For the motorbike part ... I didn't drop mine when it was stopped ... While driving with my moms on a TT ride, I got robbed by hitting a concrete block that probably fell from a dumpster that was unloading wild cinder block masked by the tall grass on the path ... Macro at 50 an hour hit the cinder block and go in flight followed by an uncontrolled landing of the pilot and the machine ... The pilot ok ... The machine ... A little less ...
Handlebars and crockery before twisted:

And rear loop of the frame completely crossed out on the right of 3cm

As this motorcycle is part of the museum pieces: a honda 500XR R from 1984 PE03 registered ... It no longer runs the streets ... Already there were only 2 years of production ... Then the fragility of their cylinder head has made that they have almost all finished in the scrapping ...

Mine runs with a split cylinder head ... That I will send for repair to the only machine manufacturer on the planet who has found a solution to make them more reliable (it's expensive but less expensive and more reliable than the original in addition to that). is a French Cocorico)

I am embarking on a total restoration ...

So I completely disassembled the bike and cut the welds of the rear buckle straightened the tube which had twisted, transferred the rear footrests which had been added (while CG 1 place) and put the rear buckle back online ...

Good blank assembly after straightening pointing ... It does not seem too straight to you it's normal ... The mudguard is a bit deformed (it's been 3 years since I took the bowl and it was kept like that ...)

[Macro]

Good. First experiences of aluminum welding with semi-automatic ...

0.8 wire, pure argon gas.

already flat cords to see ...

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It's not too hard ... on the other hand you really have to be at the right intensity setting because not enough it sticks a sausage on the plate ... and too strong ... it pierces or it gives it to the limit high inside out ...

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Then ... Assembly of 2 elements and there ... It is spoiled for the beginner ...

First test tried to weld a profile of 1mm thick on a 3mm flat ... Adjustment at 1mm ca weld on the profile of 1 ca does not stick on the plate of 3..Adjustment for 2mm ... Not welded on the flat of 3..Adjustment to 3mm ... Drilled the profile of 1 ...

Then welding test of 2 identical plates in square ...

You don't have to start with the basics ...

[Ahmed]

The settings are important, but the helping hand too. I have no experience in aluminum welding, but I suppose that the management of different thicknesses is very similar to what is observed in the case of steel welding: when advancing the torch, you have to sweep lightly on the two pieces at an angle, but you have to be very quick on the thin side and insist longer on the thicker side; this avoids the collapse of the molten pool (drilling) on ​​the weak side, while having ad hoc penetration on the thick part ...

[GuyGadeboisTheBack]

I admire the effort made to explain a process that requires both practice of the tool, knowledge of the support, mastery of the gesture, coordination, and feeling!

[Macro]

The settings are important, but the helping hand too. I have no experience in aluminum welding, but I suppose that the management of different thicknesses is very similar to what is observed in the case of steel welding: when advancing the torch, you have to sweep lightly on the two pieces at an angle, but you have to be very quick on the thin side and insist longer on the thicker side; this avoids the collapse of the molten pool (drilling) on ​​the weak side, while having ad hoc penetration on the thick part ...

This is what I also thought I could do but there is a story of thermal conductivity which invites joy ... you have to be very fast because otherwise the thick side gets cold ... And you no longer penetrate .. this said it still works when the delta is less important ....

[Macro]

Here the bottom plate is 3mm thick. The vertically welded profile 5mm. I am right handed I welded by pushing from right to left. We can clearly see that at the start the bead takes better on the lower profile which is thinner while penetrating less on the thicker upper one. Then as you go along, the top profile rises in temperature and we manage to do something correct ...

So I come back to Christophe's starting problem ... On the part he had broken at the start of this post ...

[Macro]

[/ Quote]

The possibility of chamfering the broken piece is quite poor. Why chamfer ??? well quite simply to balance the two edges of the pieces to be welded so that they heat identically on the two sides to be welded ... start to make a fairly thin bead in the bottom of the chamfer and reload in two or three successive passes avoiding letting the metal cool too much ...

In view of the small distance to be welded (about 30mm) which will not give the welder much time to make his bead, and the heat dissipation which will be done on the platinum side, much greater than the footrest side (which in addition has a steel insert which will cause inertia) ... I announce a big galley for a beginner like me ... In addition this foundry piece would tend to make me doubt its homogeneity ... So personally I would say to client ... I'm not touching that ....

That said ... I will send my XRR cylinder head to a pro because, like many of these cylinder heads which suffered from a design defect, it is split between the spark plug (too big in addition to mine it was entitled to a thread) and the exhaust valve seats ... The pro in question has been repairing these cylinder heads for decades (according to him more than 5000 without any negative feedback) ... He explained to me that he smashes them completely and recharges them with solder in an oven then he reinserts the valve seats and taps a smaller diameter spark plug again ... It's not cheap, but cheaper than a new cylinder head which is no longer in the catalog anyway ....