Discussion in 'Gunsmithing and Repairs' started by chris in va, Jul 23, 2022.
Usually means get a new slide.
Sorry to tell you, but I think it's done.
The older SIGs and HKs (?) had their "slide snouts" welded on, back in the days of folded carbon steel (?) and pinned breech faces.
How would welding this one differ?
I can't speak to those guns, however....
To weld that with full penetration and completely re-fuse the crack, requires either a lot of heat, or to remove metal from the crack and then fill it back in with filler metal. Then that area would need machining back down. To settle for partial penetration would mean the crack could work it's way back through the welded surfaces on time. Cracks are tricky like that.
Now there are a couple problems with full penetration welding too First one is that putting that amount of heat into such a thin piece of metal, will like result in distortion and/or shrinkage at the joint as the filler material and base material cool. The other is that welding creates what is known as a 'heat affected zone' on either side of the weld. It occurs in the metal that is heated to a point high enough to change the structure of the molecules, but not hot enough to melt it. The structural change cannot be reversed unless the steel is taken to a molten state and allowed to solidify again. And it is a hard but brittle molecular structure. Not great for something thin that will take repeated rapidly applied forces.
Then there's the question of trying to match (as closely as possible) the filler material to the type of steel the slide is made from. And the question of the weldability of the base metal. Not to mention the trouble of removing contaminates from inside the crack.
That might not be what you were asking, but perhaps someone will find it educational.
I’m sorry to say, but I’ll have to agree that it’s time has come. Sorry.
That may have been an over-simplification from so inspection training I received. Thanks for the correction.
Yeah, I get it. You’re not too far off actually. When steel is heated to the point of change, it’s called Austenite, or Austenitic Cristaline state. It’s somewhere “in between” liquid & solid. Of course its still solid, but look at the steel glowing red. The surface MOVES!
Shop around for a replacement.
I think that is the first thing to do. I looked at a CZ web site, and the pistol was discontinued in 2022. There "should be" parts still available. Call Customer Service and tell them your problem, find out if the factory will warranty that pistol. There may be a secret recall, and you don't know, because its secret. And if there is not, find out how much it costs for a new slide.
Assuming, the factory won't send the old slide back, rob the old slide of everything you can take off! Spare firing pins, springs, sights, etc. Do check to see if they will send the old slide back, I doubt they will if it is warranty work. But, if they keep it, they sure won't be re using any of the old parts.
And I totally agree with the experts on not welding that crack. Do notice that the crack is along the load path from the locked breech to the breech face. And that is one thin looking piece of rail, That is support structure. Welds on primary load paths are iffy, because welds are weaker than the original material. Some of the welders can tell you how much strength is derated in an area of a weld. I recall someone saying that welds were treated as a 50% reduction in material strength. And then of course, melting the material will ruin any heat treat, and only CZ knows how to heat treat their slides.
Not true. If the correct filler metal and welding procedures are used the weld is stronger than the parent metal. Where you get into trouble is with the parent metal and how weldable it is.
I would still find a new slide or junk the gun. If it is possible to weld it and re-heat treat it is is going to be costly. Personally I wouldn't touch it with a very long stick and I made my living for years doing hi-pressure welds.
Out of stock, though.
Drat. I missed that.
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