6061 T-6 angle vs. Home Depot alum. angle??

Pretty sure I already know the answer to this but I want to probe the A&P/AIs out there on this...

This is for part FL-406A ( RV-8), which is fabricated from AA6 125 11/2x2 airgrade grade angle. This is part of the fortification and installation of the flap piece that is actually connected to the extension rod. With airloads and such on the flap, I would imagine there is a lot of stress in this area of the flap.

Since I cannot locate my original piece to do this, I either need to procure another piece either from Vans or another aircraft parts supplier, or run over to Home Depot and but some similarly sized angle and move on..

The difference I see from the good stuff and the HD variety is the inclusion of an inner radius on the aircraft grade, whereas the HD angle does not! Also, not sure if the manufacturing process of the HD version would be of the same standard as aircraft grade. This appears to my amateur thinking as a potential weak spot for cracking and coming apart at a later date thus possibly rendering one with an assymmetric flap condition and an interesting landing.

Am I on the right track here to be suspicious of the HD variety for this particular application, or does it really matter??

Thots?

jdmunzell said:

Am I on the right track here to be suspicious of the HD variety for this particular application, or does it really matter??

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To put it bluntly....

You shouldn't even consider using any aluminum angle from Home Depot for anything thing that could be considered at all structural.


I could tell you a very sad story about a guy who bought some surplus aluminum from an aircraft parts outlet for a project he was rebuilding.
Even though it was aircraft grade material, it was not the correct material and he died because of it.

'Nuff said by Scott.
Don't do it.

Vic

The inner radius aside, it's not even the same alloy. Menards (like Home Depot in the upper midwest) sells aluminum angle but it's 3000-series stuff.

For some interesting reading, check out the differences between the various aluminum alloys. Large differences in strength, fatigue, and corrosion characteristics.

Aircraft Spruce and Spec. Carry about all the sizes and spec needed by A/C builders. And they will cut any length you need . Don't know about your location but I can order on line and it will be at my door by the end of the next day

You need that specific alloy and heat-treatment that Van's specified. Commonly available aluminum is MUCH weaker.

Dave

All of the above is true, however, you can get the right material from your local steel supplier in many larger towns. Hint: Get the RIGHT material!

Our local steel suppliers in Evansville have 6061-T6, with the right profile, for less than $1/foot.

AED Motorsports http://www.aedmotorsport.com/ in Indianapolis has 4130, 2024, 6061 and other metals and is usually less $$ than our favorite big box airplane store... especially if you pick it up in person.

I have no affiliation with AED, just a happy customer. Tell Al Lowe that Vince from Flyboy sent you.

YMMV!

rvbuilder2002 said:

To put it bluntly....

You shouldn't even consider using any aluminum angle from Home Depot for anything thing that could be considered at all structural.


I could tell you a very sad story about a guy who bought some surplus aluminum from an aircraft parts outlet for a project he was rebuilding.
Even though it was aircraft grade material, it was not the correct material and he died because of it.

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What Scott said and then some and a lot more. Van has all that stuff in stock per the plans. We have gotten extra in the past where needed. STRUCTURAL parts are known quantity "TSOed" material put in by the book or plans in this case. Please don't! Yours, R.E.A. III #80888

rvbuilder2002 said:

Even though it was aircraft grade material, it was not the correct material and he died because of it.

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Scott,
Could you explain to me what exactly aircraft grade aluminum is? I deal with lots of different extruded alloys everyday and not once have I ever seen any alloy called aircraft grade. 6061-T6, 6063-T6, 7075 are all alloys we use.

Now the Lowe's here stocks some 6061-T6, but it's all architectural (square inside corner) not structural. My 9A has a significant amount of structural 6061-T6 in it.

Paul,

I don't think the square inside corner material is 6061-T6.

PaulR said:

Scott,
Could you explain to me what exactly aircraft grade aluminum is? I deal with lots of different extruded alloys everyday and not once have I ever seen any alloy called aircraft grade. 6061-T6, 6063-T6, 7075 are all alloys we use.

Now the Lowe's here stocks some 6061-T6, but it's all architectural (square inside corner) not structural. My 9A has a significant amount of structural 6061-T6 in it.

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I was speaking in very general terms (I should no better ) of aluminum that is commonly used in aircraft construction.

The point was, an alloy commonly used for aircraft was purchased but it was not the alloy that was specified. The rebuild apparently assumed that since it was aluminum that was used in aircraft, it should work for what he was making.

Even if Lowes or Home depot had extrusion that physically matched the desired shape and specification, I don't think I would use it for structural purposes in my airplane unless they were able to supply tracking history docs back to who ever is certifying it to be 6061-T6, and I bet you would just get a blank stare if you asked for it.

jdmunzell said:

Am I on the right track here to be suspicious of the HD variety for this particular application, or does it really matter?

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Well done Jeff. Here ya' go:

http://www.aircraftspruce.com/catalog/mepages/aluminfo.php

It's where a lot of us got our first exposure to alloy and temper. Click and study the charts at the bottom.

If you get really curious about some fine detail, try this at...

http://everyspec.com/MIL-HDBK/MIL-HDBK-0001-0099/MIL_HDBK_5J_139/

....or here:

http://www.abbottaerospace.com/wpdm...and-elements-for-aerospace-vehicle-structures

Aluminum

On one hand, you may be thinking, Hey, its experimental, I can do what I want. Not knowing alum properties and misusing the wrong type of alum can be deadly either for you, your passenger, or the next guy who buys your mistake.

Its important to understand that not all aluminum is the same. There is a reason the alum at Home Depo is lower cost than aircraft certified alum. As was stated above, different alum series and heat treatments has different hardness and strength depending on the applications. Aircraft engineers rely on their material knowledge of aluminum to determine what type to use and where to use it. In some places, 2024-T3 is used. Sometimes, 2024-0 is formed then heat treated to 2024-t4. Other places may need 6061-T6. Welded areas may need the 50 series. Some places require 7075 and nothing else. One type will have superior corrosion resistance while another may have better strength. Alum at home depot could possibly be used in a non-structural capacity in the cabin somewhere whereby if it failed, nothing would become of it. On the RV designs, there are a lot of areas that are structural because Van's Engineers are really good and eliminating waste and redundancy in the design. At the end of the day, use what is called out for.
Good luck on your project!
Kindest regards,

Aluminum angle

Any aluminum extrusion that's worth buying from ANY source will have the alloy (6061-T6 is a common grade and Vans specifies it in some locations, 2024-T3 is a common aircraft alloy, as is the higher strength 7075 series) ink stamped along one leg, usually including a QQ-X-XXXX quality specification. But even if you could find the right dimensions, right inside radius and right alloy at HD, Lowes, or an industrial metal supplier, they don't treat the stuff like their life might depend on it. I bought some aluminum angle from an industrial supplier and told them "no scratches please". OK. Guess what? Lots of scratches from mishandling. I didn't use the piece on my airplane.

Many thanks for the responses!

Thanks everyone for chiming in! This bird might be "experimental" but it's still my @$$ strapped into it, or anybody else for that matter.

I figured as much but wanted to see what you all thought. Since earlier in the day, I have already been able to get hold of a proper piece from my hangar mate ( RV-8 driver..), who happened to have some extra stock laying around in the hangar! Who knew!

jdmunzell said:

Since earlier in the day, I have already been able to get hold of a proper piece from my hangar mate ( RV-8 driver..), who happened to have some extra stock laying around in the hangar! Who knew!

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You'll find that to be the case more often than not. We all have extra materials, parts, fasteners, scrap, etc laying around the hangar. Seems almost every RV builder/flyer in our local area shares parts and help from time to time. Isn't it a great community?

rapid_ascent said:

Paul,

I don't think the square inside corner material is 6061-T6.

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I really don't know whether HD or Lowes is 6061-T6 or not. I do know that I have a huge selection of both structural (radiused inside corner and edges) and architectural shapes (all square corner) in 6061-T6 and yes I do have all the QC mill test reports for both.

As to the question at hand, I would NEVER use any aluminum in my plane that was called out as structural from someplace that couldn't confirm or supply the test reports. It's too easy to call Van's and have a piece shipped. The small cost is worth the piece of mind.

I dunno. seems legit and made from garage supplies.

https://www.youtube.com/watch?v=ORhBz998GeM