Corrosion treatment products in SEQ

[Timbot]

Hi All,

 

I'm presently dealing with some intergranualar corrosion on a 2020 T3 spar cap extrusion. I need a very small quantity of Deoxidine 624 and Henkel W01 to clean up, 100ml of each one would be heaps.

 

Does anyone know where I might be able to find this in SE Qld? Henkel don't sell deoxidine in less than 20L. If a member has some I could purchase a smaller quantity off that would be great.

 

Also I'll likely need to talk to a CAR35 (or Part 21 section M I think it's now referred to!) engineer - can anyone recommend one that is GA experimental friendly. I've had to take 0.030" at the deepest spot off the top of the 0.190" T extrusion.

 

Cheers

 

Tim

 

 

[Dafydd Llewellyn]

Hi All,I'm presently dealing with some intergranualar corrosion on a 2020 T3 spar cap extrusion. I need a very small quantity of Deoxidine 624 and Henkel W01 to clean up, 100ml of each one would be heaps.

 

Does anyone know where I might be able to find this in SE Qld? Henkel don't sell deoxidine in less than 20L. If a member has some I could purchase a smaller quantity off that would be great.

 

Also I'll likely need to talk to a CAR35 (or Part 21 section M I think it's now referred to!) engineer - can anyone recommend one that is GA experimental friendly. I've had to take 0.030" at the deepest spot off the top of the 0.190" T extrusion.

 

Cheers

 

Tim

A CAR35 (now 21M) engineer has to make a finding of compliance against a design standard. There is no design standard against which he can do that, for an amateur-built experimental aircraft - so your chances of getting an approval for such an aircraft are not good. Do you mean 2024 alloy? If it's an extrusion, it won't be T3; that only applies to sheet material. Could be T3511.

From a basic engineering standpoint, the questions are:

 

(1) Where along the wing span is the damage? Most aircraft are critical at the wing root, if it's a cantilever wing, or at the lift-strut attachment, if it's strut-braced, and usually have some margin in the spar cap away from the critical locations. So whether or not your repair is permissible will depend on these factors.

 

(2) The issue is not how deep you had to go to clean-out the corrosion, but by how great a percentage is the cross-section area reduced (and mainly, that applies to the top of the T, ignoring the vertical leg)

 

(3) Is it on the top or the bottom cap ? (i.e. is it normally loaded in tension or compression in flight)

 

(4) Does the aircraft have any fatigue life limits?

 

You'd have to provide that sort of info to an engineer, to get any sort of answer.

 

You also have a problem in QLD, because one cannot legally give engineering answers without being registered with the QLD Board of professional Engineers.