fuchs weld repairs?

[mb911]

Ok I am not really looking for the typical response of "I wouldn't do it? But wondering why the fuchs wheel is amoung the strongest wheels ever made supplied from any automotive factory but they are considered junk if you tweak them or have any cracks in them. However the rest of the automotive world often repairs and welds them etc to bring them back to factory specs etc.. So my question is why more people are not welding the 9X16 fuchs which are most prone to cracking? Is the welding of a crack on a wheel causing extreme stress risers not seen on any other wheels in the world Please explain? I think that most the cracks that I have seen on the forum pics of fuchs could be easily repaired but really looking to see what everyones thoughts are on this. Now cracks are not always as small as they appear but once heat from the weld is applied you can follow the crack.. Just help me see this. make it simple for me please..

[island911]

The heat of welding will Soften the Aluminum near the weld.

Tho ' Welding (having a weld there) will certainly be better than having the crack

(saw your post on the g b. site.. was going to ask for a pic.. maybe post a picture here when this site is back to 100%)

[cgarr]

Doesn't someone make these wider by welding two together?

[jorian]

I'm with Craig on this one. Lindsey welds up entire wheel sets that have been used extensively on the track with enormous loads.

[PatrickB]

I may be wrong, but I thought the most stressed out area is the one that normally cracks... On the pedal near the lug nut... Lindsey welds where 2 wheel halves are put together, not on the high stress area that normally sees cracks...

Of course, now someone will post a picture of where the weld broke of on the wheel section...

[dvkk]

Originally Posted by PatrickB

I may be wrong, but I thought the most stressed out area is the one that normally cracks.....

The crack could originate from the weakest part of the wheel where the localized stress isn't necessarily the greatest.

[ianc]

As island said, a forging gets its strength from being stamped at a specific temperature which allows the grains of the metal to stretch. When they cool, they have built in stress which makes them stronger. Think of the grain structure of a forging as like spaghetti, while a casting has the grain structure of oatmeal; very homogenous small grains.

When you heat the metal to weld it, this stressed grain structure relaxes and the grains coalesce to a smaller size, and a great deal of the inherent strength goes with it.

ianc

[cgarr]

Maybe you could have the wheel heat treated? Maybe these keep cracking in these areas because of the working stresses (work harden) and constant heat cycling from braking, don't know but these wheels are getting old.

[mb911]

Well for street driving I would think the cracks could be repaired without major issues. The crack in question is 1/2 inch long right buy the center cap.. it is a hairline crack and almost just looks like a small scratch and does not look to be completly through to the other side. I have seen this type of crack on a lot of fuchs. One thing to note is typically the weld area(HAZ) is harder then the base material.. Interesting. Do you know what lindsey uses for filler wire in their welds? any one? 4043 or 5056?

[island911]

The HAZ is softer.

My theory is, that type of "center cap" crack gets started from abuse to the center cap mounting surface. That is, a new wheel has a nice smooth surface, where old wheels are often gouged. That area (as new) should NOT be a stress riser of any sort. If it's cracking there, it is most likely something else causing the high stress in that area. (tire machine?)

SO, if you know anyone who can lay a decent bead I say go for it. Clean it up, and keep an eye on it. Let us know how it goes.

[mb911]

Originally Posted by island911

The HAZ is softer.

My theory is, that type of "center cap" crack gets started from abuse to the center cap mounting surface. That is, a new wheel has a nice smooth surface, where old wheels are often gouged. That area (as new) should NOT be a stress riser of any sort. If it's cracking there, it is most likely something else causing the high stress in that area. (tire machine?)

SO, if you know anyone who can lay a decent bead I say go for it. Clean it up, and keep an eye on it. Let us know how it goes.

It is getting closer to the end of the season here anyhow but I am going fix it in the morning. Grind the hairline crack out and weld it up . the crack starts from the center cap "boss" and goes inward 1/2 of an inch.. I don't track at all so strictly street driving.. I will see what it does for the next 6 weeks or so and maybe start looking for replacements. even thought about some Rh's but those are uber expensive.. maybe rota's?? either way I will report back.. I know there are a bunch of regular cars that have this type of repair last years and years. so maybe I am over reacting..

[Racerbvd]

What about the guys who everyone sends their rims to to be refinished, what do they have to say on the subject??

[mb911]

Originally Posted by Racerbvd

What about the guys who everyone sends their rims to to be refinished, what do they have to say on the subject??

They fix em!

[Zeke]

Ben, how hot will you preheat the wheel and how will you control the cool down? This, to me seems like 80% of the problem with the rest being how to exactly match the graining of the original wheel (can't).

[chrisp]

Are Fuchs heat treated?

[island911]

Milt, I think he's okay to weld there. As far as I can see that center cap area shouldn't be highly stressed. Well, except for those tire bead-breaking machines that grab the wheel by it's center cap mount with a big wedging cunk of steel, whilst a enough force to pull the tire off the bead is quickly applied.

[mb911]

Originally Posted by milt

Ben, how hot will you preheat the wheel and how will you control the cool down? This, to me seems like 80% of the problem with the rest being how to exactly match the graining of the original wheel (can't).

This is way more important with cast items mostly with cast iron.. I have welded many many rims(wheels) with 100% success. so this would be the first "structural" fuch repair