Heartbreak-broken rear shock mount

[Ulrich 3.0 CSA]

Hello all,

for the ones who are interesetd I offer a metal part for the cracked domes. It is made by pressed steel and lookes like the original dome!

The broken top part must be cut off - than you weld the new part on.

Price is EUR 40 for one pice...+ postage from Germany.

Paypal is possible (without any fees for me please).

If interested please PM.

Regard Ulrich

 

[Peter Coomaraswamy]

Ulrich, that looks great, have you had any comments regarding welding the back side or do you weld from underneath?

Thanks, and has anyone had "failure" below the dome?

 

[Stevehose]

Update

Shock towers cut in preparation for the metal piece (edge will be cleaned up before welding):

Latest design and measurements (the piece will be 40mm tall and go into the tower about half way):

Here's my question, the welder suggests doing 8 welds along the top each about an inch or so long to prevent metal weakening from the heat, then alternating with a drilled spot weld on the sides for strenght in that direction. What say you guys - should I just do a bead along the entire top or is the alternating idea a good one?

 

[adawil2002]

I am not a welder but have watched welders work and one of my friends is a metal sculptor.

Doing it as your welder suggests is good. Weld in small segments because on such a small area the metal will pull or shrink towards the weld. Alternating sides like tuning a drum head, mitigates the shrinking. Eventually the bead will run the whole way around the tower.

 

[dang]

Any concerns with moisture getting through the non-welded areas? Of course this would mean you're driving your coupe in the rain. ;-)

Dan

 

[saltydawg]

Steve,
For an overlap joint like you you have designed here you might wat to consider pre-treating the blind areas with something like Wurth zinc rich weld-thru primer to get at least some rust protection. I have used this with good success in applications like this.

JNL

 

[Ulrich 3.0 CSA]

Hello Peter,

you simply cut off the top part (shown in a later foto) put the new part on top of the existing dome - than weld from the outside 360° around the dome.
Should take 1-2 hours on each side.

I have one last set of these parts left....

Reagrds Ulrich

 

[Nicad]

I'd do the spot welds on top of the circumference weld. Looks like a good plan of attack. Do you know if it will be Mig or Tig welded?

 

[Ulrich 3.0 CSA]

Hello all,

all sets of these parts for the dome are sold.
Thanks to the buyers.

Ulrich

 

[Gazz]

This thread is getting hijacked (sort of) so we can start a new one about the strut housing repair if you want. Here's my thoughts... The load needs to be transferred to the walls of the can and bottom edge as much as possible. It seems like the only solution should come from the bottom and I think it would be better to do it without any welding. A support "sleeve" could be bonded to the inside of the strut can and provide plenty of additional support. The trick is the shape being close enough to the original to slide in and bond, but it only needs to hold it in place since the strength comes from bottom edge and thicker top surface.

I like this idea, though what type of bonding agent would you use that would resist the vibrations from the damper?

 

[Stevehose]

I don't see how this would work better than welding. The top section is not thicker than the walls, it's all 2mm except the center ring where the bushing fits which is folded over in the stamping process to 4mm. I think the folding process is strike one in the design flaw, making the center 4mm section weak to begin with.

The top section takes a lot of abuse over the years so I think welding to the sides is the strongest solution. Either with a cap or a sleeve.

I like this idea, though what type of bonding agent would you use that would resist the vibrations from the damper?

 

[Stevehose]

Not sure but I think Mig. Is there a preference?

I'd do the spot welds on top of the circumference weld. Looks like a good plan of attack. Do you know if it will be Mig or Tig welded?

 

[Stevehose]

I have read mixed reviews on primer affecting the quality of the welds so probably will go with waxoil, seam sealer, and paint. Although the idea makes sense.

Steve,
For an overlap joint like you you have designed here you might wat to consider pre-treating the blind areas with something like Wurth zinc rich weld-thru primer to get at least some rust protection. I have used this with good success in applications like this.

JNL

 

[Nicad]

Not sure but I think Mig. Is there a preference?

Tig when done right is stronger and heats the metal up less. A well done Mig weld will hold just fine though. Roll cages are Tig Welded.

 

[Stevehose]

Weld question

How thick can the replacement piece be in order for the welds to be successful?

The shock tower is 2mm thick, what is the max thickness the replacement piece can be in order for the weld to be good and not destroy the thinner piece, or is there a limit?

Like Sgt Schultz, I know nuthink!

 

[Luis A.]

Steve,

I'll let real welding experts chime in but from practical experience MIG welding, it's not so much a function of maximum thickness but minimum, at least in this scenario where you are not butt welding them. The degree of difficulty is predicated on the thinnest piece of the two you are trying to join, not the thickest one. Don't you have a welder who will be doing this for you? What does he think?

 

[Stevehose]

I havent asked him yet, I want opinions first so I can speak (reasonably) intelligently about it.

Right now the piece wall is 15mm thick. This would be welded to the 2mm tower. Should I bring the thickness down to say 5mm?

Wouldn't you need a big ass MIG welder if it's 15mm thick in order to get the bead to stay?

Steve,

I'll let real welding experts chime in but from practical experience MIG welding, it's not so much a function of maximum thickness but minimum, at least in this scenario where you are not butt welding them. The degree of difficulty is predicated on the thinnest piece of the two you are trying to join, not the thickest one. Don't you have a welder who will be doing this for you? What does he think?

 

[Luis A.]

This isn't like soldering or brazing where you have to bring the temperature of the piece to a high temperature relatively slowly and the large mass acts as a heat sink. The electric arc is a pretty local phenomenon and heats the immediate area where it strikes to a very high degree very quickly and melts it locally without having to heat a large mass. In fact, I feel it makes it easier to weld to a large piece since you mostly have to worry about the thinner side of the weld.

 

[Stevehose]

I see, but why do MIG machines have different settings for metal thickness if it only has to penetrate a small portion of the steel?

My fear is that a 15mm piece welded to a 2mm piece will have a crappy quality weld due to not enough amps into the big piece, or are you telling me this is unfounded? If so, then what thickness metal would the machine be set for? Wouldn't a 5mm piece weld better to a 2mm piece then a 15mm piece would?

Sorry for all the stupid questions.

This isn't like soldering or brazing where you have to bring the temperature of the piece to a high temperature relatively slowly and the large mass acts as a heat sink. The electric arc is a pretty local phenomenon and heats the immediate area where it strikes to a very high degree very quickly and melts it locally without having to heat a large mass. In fact, I feel it makes it easier to weld to a large piece since you mostly have to worry about the thinner side of the weld.

 

[Luis A.]

You would set the machine to produce a sufficient amount of heat on the larger mass, the new top piece, to create the molten pool there and walk it/wave it briefly into the thinner piece in order to melt that into the pool, without dwelling too long or the thinner piece could melt through. In addition, one would not go all around in one continuous weld to start with but as you mentioned before in interrupted segments. I'd like to know from your welder if he would ultimately go all around or not. I would be inclined to do so in order to seal it and for appearance, if once I am underway I feel I can do it reliably without eating away the thinner tower metal. In this case the thinner piece isn't all that thin either, only relative to the thicker piece. Making the new piece thinner buys you very little, if anything, in terms of welding to it, is my feeling.

And no, they're not stupid questions at all, great to think about this in that level of detail now.