Identify this aluminum

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Postby russell » Wed Aug 31, 2005 8:56 am

George,

The fittings that I'm writing about have what I call a laminate corrosion. The corrosion has started on the bottom edge and is similar to sort of separating into layers. Kinda like lifting the bread up on the edge of a ham sandwich, for the lack of a better discribtion.

Everything crossed,
Russell
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Postby xgary » Wed Aug 31, 2005 9:04 am

no big deal russel just buy some new 7074
or find out but i think go 25% thinker 2024 would be fine too.
But ask an expert.
7074 is not the most corrsion resitant Alum.


Shorty
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Postby Chappy » Wed Aug 31, 2005 9:56 am

Russell,

You really must replace those fittings. If I was making them out of 2024-T3, I would make them 50% thicker than the old fittings. Even if I made them from 7075-T6, I would make them a little thicker. What you are seeing is due to the fact that the higher strength aluminum alloys are much more susceptible to corrosion than the softer, weaker alloys.

There are lots of places where you can get 2024 and 7075 plate. Because you need just a little bit, you might want to try just dropping by any local machine shops or smaller custom fabrication shops in your area and see if they can sell you some of their excess (scrap). Look in your local Yellow Pages. Sometimes they will just give it to you.

I get much of my aircraft related stuff from Charley Vogelsong in Pennsylvania. He carries most anything you will ever need. He is terrific, and very fast. Give him a call:
The Dillsburg Aeroplane Works
114 Sawmill Road, Dillsburg, Pa 17019
Tel: 717/384-5865 Fax: 717/432-4589

Also you could try http://www.airpartsinc.com/ . They bring lots of small cut-offs to Oshkosh and Sun n' Fun. Give them a call.

Also there are the big homebuilt Aircraft suppliers like Aircraft Spruce and Wicks. I haven't ever tried the Metal Supermarkets, but they have stores located in the South and should have 2024-T3 in small quanities. I even found good aluminum scrap stock at local junk yards. Some will separate the better, marked stuff and sell it by the pound. That's how I got the 7075 I needed years ago, and paid next to nothing for it.

The stuffs out there, you just have to dig for it. And REMEMBER, if you are shopping at non-aviation suppliers, DO NOT tell them it's for an airplane or Ultralight! Many will not have anything to do with you if they suspect it's for a plane.

Chappy
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Postby russell » Wed Aug 31, 2005 10:23 am

Chappy, thanks for the info on Charley Vogelsong and the web site for airpartsinc and the other names. I'll definitely file these. I have exhausted all machine shops and sheet metal shops. Found one place that can get it but not less than a 4x8 sheet. Scrap yards are not catagorized as for grades, just tonage.
You mentioned not to tell anyone not aviation connected that this is for airplanes/ultralights, well around here even the vast majority of licenced conventional aircraft pilots I have disclosed that I fly an ultralight to, treat me with disdain. Anyway, George has so graciously offered to search his stockpile of spare parts for me, but should this not work out I will deffinitly try those you suggested.
Thanks much,
Russell
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Postby lazairiii » Wed Aug 31, 2005 12:54 pm

Well well, looky what I found...

I can do one of a number of things here. I can make you some up, make you templates from a piece of paper, get you the 7075-T6 .063 (factory) or .080 and trace them onto that and you could finish them up, or I could send you mine. I do like having actual pieces on hand to use as templates for those who need parts along the way.

What's your thoughts here...
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Postby lazairiii » Wed Aug 31, 2005 12:59 pm

Russell,

I'm ordering some materials for my Jury-Struts in a couple of days and can order the 7075-T6 in .071 material for you. The cost from Online metals is $14.63 for a piece 5.5" x 14". This will make the (4) pieces and is slightly thicker than the .063 that the factory pieces are. I'd do these for cost plus maybe $5 for shipping them to you if you art interested.

George
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Postby russell » Wed Aug 31, 2005 1:59 pm

George,
Rather than take your spares, I would want to order just the raw material. I found a source for it but I have to buy a 2'x4' sheet. You mentioned a place called Online Metals. I found their web site and saw that the 7075 T6 is available in the small pieces that you discribed. They had the prices listed. I went away from their site and came back three minutes later and would you believe, the price had gone up 25% across the board? Anyway, this is in the range I can feel good about. So, rather than involve you any further in my plight, I will just order it myself (gotta leave the nest sometime). Thanks for all your efforts to help me. If this should not pan out I may take you up on your generous offer to get it for me.
Thanks again,
Russell

PS: Is it acceptable to put that slight bend in these fittings cold?
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Postby lazairiii » Wed Aug 31, 2005 2:37 pm

Russell,

Personally speaking, I'd get a little bit extra...maybe 4-6 inches or so, just so you can do some bend testing before you bend the actual pieces. I think you can bend it to a certain degree before it cracks, but remember, these do NOT bent much. Use your existing brackets as templates, mark the new material, cut it out, drill the holes, then bend to perfection.

Good luck,
George
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Postby lazairiii » Wed Aug 31, 2005 4:40 pm

Russell,

You can try making them out of .063 Titanium and never have to worry about them again. I did this on 8 different pieces on my plane. Scroll down the page on this website and you will see some .063 in various sizes. There are a couple of pieces that are about $32. This would be a great way to go. I bought my Titanium from this guy and he was very easy to do business with.

You would be able to cut and bend this yourself.

George

http://www.titaniumjoe.com/6al4v%20sheet.htm
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Postby Chappy » Wed Aug 31, 2005 10:39 pm

Russell,

The bending is done cold. Heating will reduce the strength of this tempered material. Just try to bend it over something to keep the same small radius as these original parts.

If you were making sharp bends in soft aluminum, then you would heat it just enough to relieve the work hardening of the metal as you were bending it. That's a whole 'nother subject.

Chappy

PS. GET THIS BOOK:
http://www.aircraftspruce.com/catalog/b ... achdbk.php (Standard Aircraft Handbook) It's cheap, and will teach you most of what you'll need to know to work on your Lazair. EVERYONE that owns and works on an aircraft airframe should have and study this book! Matter of fact, I think I'm going to order a new one myself, as the two copies I own are loaned out, and were printed over thirty years ago.
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