Jet Engine Turbine Scrap Discussion

[snoman701]

Except for the fuel manifolds and twin blades, you should be able to easily see the braze joints. For example, in your 1st photo, you can see the braze.

So is that the right color for the gold braze? That is actually reactive with nitric, which I wouldn't expect if it were greater than 50% Au.

 

[goldsilverpro]

Except for the fuel manifolds and twin blades, you should be able to easily see the braze joints. For example, in your 1st photo, you can see the braze.

So is that the right color for the gold braze? That is actually reactive with nitric, which I wouldn't expect if it were greater than 50% Au.

No, I'm just saying it's braze, of some type. The color is usually masked by the coating or corrosion.

Sometimes, on stators, they seem to have used way too much braze. It's all over the place. A friend of mine calls those stators "training day."

If the coating is aluminum, which used to be quite common, you can put on a few drops of HCl, which will dissolve the Al and, after rinsing, will expose the braze.

 

[snoman701]

THANK YOU EVERYONE!

Special thanks to Justinchase & GSP.

I think I've got enough information to be dangerous now.

I'm no where near skilled enough to even think about recovery, but should be able to recognize when I should be looking for PM presence.

I have considered your statement that some stators have some, lots and none. Any possibility the gold braze is used to balance the stator?

Is LazerSteve still a participating member?

 

[Lou]

Not used to balance, just to hold dissimilar metals together.

FYI, happy to buy those materials from you snoman701. My business processes A LOT of braze material.

Lou

 

[Justincase]

THANK YOU EVERYONE!

Special thanks to Justinchase & GSP.

I think I've got enough information to be dangerous now.

I'm no where near skilled enough to even think about recovery, but should be able to recognize when I should be looking for PM presence.

I have considered your statement that some stators have some, lots and none. Any possibility the gold braze is used to balance the stator?

Is LazerSteve still a participating member?

I have read about a pure gold brazing being used to repair turbine blades that have shown slight cracking.
This surprised me as on propeller air craft if any thing shows a crack you bin it immediately.
Hard to tell if it ever had much use but there may be the odd front compressor turbine blade that has a gram or two from such repairs.

 

[4metals]

I have read about a pure gold brazing being used to repair turbine blades that have shown slight cracking.

I would guess this all depends on where on the turbine the cracking occurs. If it is on an existing brazed joint I can see a repair being effective because the old braze melts and a new joint forms which in theory is as strong as the original. The alloys used are eutectic alloys so they are selected for their ability to form a strong super-lattice joint with the material they are bonding.

 

[snoman701]

Well, I checked them all...couldn't find any brazed parts except a few stators that I brought home. I will check them for values when I have time. I have a feeling however that they are the cold end.

Some of the stators had a red "tape" around the outside of it, with two spot welds and no filler. I'll be on the lookout now though.

 

[Justincase]

Well, I checked them all...couldn't find any brazed parts except a few stators that I brought home. I will check them for values when I have time. I have a feeling however that they are the cold end.

Some of the stators had a red "tape" around the outside of it, with two spot welds and no filler. I'll be on the lookout now though.

don#t forget to check the fuel lines.I have wound some good brazing on them.
Strange I did put "don't forget to check the fuel lines I have found some good brazing on them"
But {don#t forget to check the fuel lines.I have wound some good brazing on them.[/quote]} was put up instead.
The code I put in is different to what is published.

 

[lazersteve]

Is LazerSteve still a participating member?

Yes, I'm still here.

As already mentioned, there are a lot of combinations of brazes and part assemblies. For this reason, pretty much anything posted is speculation, some based upon real world experience, some based upon the information you provided. My observations are pretty much in line with GSP's. The obvious brazed areas are where the values may be, depending on the braze used.

There are some parts that have 'hidden' values, that are not visible to the naked eyed. I always approach the problem of precious metals recovery from a reverse engineering perspective. In other words, I ask: how do I undo the assembly process as efficiently as possible into the discrete components from which the item was constructed. This in turn leads to questions of how the parts are assembled at the manufacturer and real world experience with the various types of parts assemblies and brazes. The choice of solutions to treat the parts with is not only determined by the braze content, but also the type of alloy the part is constructed of. There is a fine line where mechanical recovery is a better method than chemical recovery, depending again on the specific scrap you are dealing with.

The above paragraph applies to all types of scrap in my opinion, not just jet engine turbine scrap.

Other parts in the turbine engine where values are located, are the air seal, fuel nozzles, various bearings, wiring, and seals. I have seen a lot of silver plated items in many of the engines that I have recovered values from.

Steve