Struggled to get his done and checked if anybody had the same problem of the "pop bottle top effect" found the answer on the 701 forum,was to anneal the section first and slowly form the lip.

What I wanted to add to this great tip was how to know when the alumimiun was at the correct annealing tempurater.Simply rub the backside of the section you heating up with regular bath soap, start gently heating the section until the soap turns BLACK, you have now reached the correct tempurater, allow to cool and form that perfect 3 mm lip on the rib nose.

Views: 616

Reply to This

Replies to This Discussion

Hi Raymond.

I built a 601XL from scratch. The 601 has a similar build requirement of  bending the 3mm LE ribs.

I found I didn't need to anneal. I bent around 1/8" Aluminium former screwed onto 3/4" MDF. You may have to use a harder hammer to prevent the bottle top effect.



Thanks for this tip, I am going to give it a try with some scrap ali and see how it comes out.

How do you get it back to the T6 condition that it started with?

Hmmm ok this was not mentioned in the topic I picked up on the build forum, if it is only the tip thats annealed would it require to be at T6 spec, an interesting point you make, can somebody elaborate on this option of annealing the tip if one was to use this method

The easy way that I found to make these is to form them full size and then trim them off to the 3mm, toy will have to flut them but keep the flut away from the bend.

Hi All, I spoke about this problem early in my build, well having done a lot more forming of parts I can now get this edge done perfectly. The answer was simple, just make 100% sure the material on the edge to be formed doesnt excessed the 3mm measurement. Was dreading forming the flaperon ribs but they came out perfectly. if you have a tricky section add in a tiny crimp to help the forming.

The build continues, the addiction to build at every spare moment can be tricky at times when family/friends/school functions requires your attention.

Sweated this for weeks before I spoke to Chris Heintz personally about this when I met him at Sun-N-Fun. Even had a flaperon nose rib with me. The annealed part does not have to be brought back to original hardness it just helps support the nose skin. Many designs use "fish mouths" in that type situation; no metal at all. The problems I encounted was not in the 3mm nose section but at each end of it; small cracks would develop during the forming process. It was my understanding in my conversation with him that the section in front (the nose) of the two first rivets, one at the top one at the bottom, hardness was not that critical you just could not have a crack.

Hi Chris, I did anneal the tip of the rib in the begining as I was really struggling, but now after doing quite a lot of forming it comes out nicely, like a said if you struggling just put in a small crimp at either end of the 3mm lip area and it comes out almost perfectly every time, I agree with CH on the support of the skin, but if you fit the skin and try push it in on the radius you will see just how strong it really is, so a fish mouthed rib would also work, as the design calls for a 3mm edge I will do it as per plans. Really looking forward to forming the wing ribs as I am quite confident to do it now after doing those tiny flaperon ribs, big wing ribs NO problem now, just practice and it comes.

You can use a 50/50 solder bar to form your ribs. it is sometimes refered to as a 'Slapper'. I have found them for sale on Ebay for $5. They are usually about 3/4"x1/2"x 12" long. The solder will grab the aluminum and stretch the flange around the form block.



Here's a pic I got from Ebay item # 160921328095

I think the old lead bars are what is desirable as these were used to form the ribs back in the 60's. I can check mine, but it is pretty beat up and has been hammered back into shape several times. 



New from Zenith:

Zenith Planes For Sale 

Classified listing for buying or selling your Zenith building or flying related stuff...

Custom Instrument Panels
for your Zenith

Custom instrument panels are now available directly from Zenith Aircraft Company exclusively for Zenith builders and owners. Pre-cut panel, Dynon and Garmin avionics, and more.

Custom Upholstery Kits for your Zenith Aircraft:

Zenith Vinyl Upholstery Kits

Zenith Apparel from EAA:

Zenair Floats

Flying On Your Own Wings:
A Complete Guide to Understanding Light Airplane Design, by Chris Heintz

Builder & Pilot Supplies:

How to videos from

Developed specifically for Zenith builders (by a builder) these videos on DVD are a great help in building your own kit plane by providing practical hands-on construction information. Visit for the latest DVD titles.

Aircraft Insurance:


West Coast USA:

Pro Builder Assistance:


Transition training:

Golden Eagle Aviation

Pianosa Flying Farm

Aircraft Spruce & Specialty for all your building and pilot supplies!

© 2021   Created by Zenith.Aero.   Powered by

Badges  |  Report an Issue  |  Terms of Service