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Aluminum welder sought

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From my knowledge 7075 is categorized as a non arc weldable (tig, mig, etc.) alloy due to its chemistry. You would need to find someone who is well versed in exotic welding practices like friction stir welding to help you out.
 
Q - I come into contact with two aluminum alloys of which I have found difficulty in obtaining information about arc welding. These alloys are 2024 and 7075. Can you provide me with information on how to weld these alloys with either the GMAW or GTAW process?
A –
The reason you are having difficulty finding information on welding 2024 and 7075 is that both of these materials belong to a small group of aluminum alloys that are generally considered as being unweldable by the arc welding process. These materials are often found on aircraft, sporting equipment and other types of high-performance, safety-critical equipment and are not usually arc welded on the original component. Probably, the two most commonly found aluminum alloys within this category are 2024, which is an aluminum, copper, magnesium alloy, and 7075, which is an aluminum, zinc, copper, magnesium alloy. Both of these materials can become susceptible to stress corrosion cracking after welding. This phenomenon is particularly dangerous because it is not detectable immediately after welding, and usually develops at a later date when the component is in service. The completed weld joint can appear to be of excellent quality immediately after welding. However, changes which occur within the base material adjacent to the weld during the welding process, can produce a metallurgical condition within these materials which can result in intergranular micro cracking, which may be susceptible to propagation and eventual failure of the welded component. The probability of failure can be high, and the time to failure is generally unpredictable and dependent on variables such as tensile stress applied to the joint, environmental conditions, and the period of time which the component is subjected to these variables.

It is strongly recommended that great care be taken when considering the repair of components made from these materials. It must be stressed that if there is any possibility of a weld failure becoming the cause of damage or injury to person or property, do not perform repair work by arc welding on these alloys and then return them to service.
 
I know it is supposedly un-weldable however I also know it can be done and seek someone with the necessary experience. There will be a demonstration pretest after the Q&A interview.

My project is a 60yr old AR lower receiver, I need to tig weld the trigger well channel, the front and rear halves of a bandsaw cut de-milled lower. Trigger well has a 6061 block inserted to back the weld and needs to be penetrated by the weld so it can be milled out later. Wall thickness is .100" +/- 040". If anyone here knows who John Norrell is he was the pioneer in this twenty years ago but is no longer accepting these types of projects.
I have to agree this would be a very difficult thing to do. I tig weld a lot! I only do gun stuff and rewelding parts kits is a large majority of the stuff I do. A lot of the older AR receivers were 6061. So are you sure its 7075? I'd be happy to look at it and do the welding if I think it's possible but I'm not cheap and it's gonna cost a lot more than a new 7075 receiver will.
 
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