Narfi's Zenith CH750 Super Duty

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narfi
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Re: Narfi's Zenith CH750 Super Duty

Post by narfi » Fri Sep 18, 2020 4:43 pm

I will have to get back in practice, but I used to be really good with a pneumatic sheer, I would cut less than a blade width from the line, then second pass I could follow any curve perfectly as long as the cut was narrow enough not to bind between the blades.
The only time the router option sounds attractive is for parts with many duplicates, like the wing ribs. cut a stack of blanks and bolt the cutting template over the stack and route out several at a time.
All my experience is in repair with a little in rebuilding, so will be fun learning making all the parts new and clean to work with.

Looking at the options between electric cordless and pneumatic for both the sheer and the rivet puller, leaning pneumatic, but there are certainly some good arguments for electric.

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Re: Narfi's Zenith CH750 Super Duty

Post by Netpackrat » Fri Sep 18, 2020 5:08 pm

Router makes a horrible mess; throws chips everywhere. One key to keeping the parts nice is controlling the chips and keeping them out of your work area, otherwise they will cause scratches. I tried the router method briefly before settling on shears and snips.

narfi
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Re: Narfi's Zenith CH750 Super Duty

Post by narfi » Tue Sep 22, 2020 7:15 pm

An old friend showed up this weekend, so took him and his girlfriend out on the lake. (a lot more fun than cleaning and burning trash)

Another friend finished the video he made of the boat we made, which turned out pretty nice.(the video)

https://www.youtube.com/watch?v=cHo8aSRDKH4



Yesterday after work I was able to finish cleaning out the tent from the last projects and get some of the fiberglass dust chased out.

Just need to put some legs under the old strongback to make the table and get it leveled.


20200921_175816.jpg


Might start ordering stuff this afternoon.

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Re: Narfi's Zenith CH750 Super Duty

Post by Netpackrat » Tue Sep 22, 2020 8:42 pm

You have a lot more room in that "tent" than I had assumed... Forget what I said about dragging the strongback outside. :lol: Since you'll be doing sheetmetal and presumably not so much with sanding or solvents for a while, perhaps a stove jack and a small wood stove to take the edge off this winter might be more of an option?

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Re: Narfi's Zenith CH750 Super Duty

Post by narfi » Wed Sep 23, 2020 5:05 pm

hehe, no heat in the plans, but who knows what the future holds :)

Home Depot: $950
Amazon: $900
Aircraft Spruce $5400

Not sure how I want to separate expenses, but some of the long term tools I don't want to count against the airplane, but still I wouldn't be buying them if I wasn't building it. So I will keep two numbers I guess..... Aircraft Spruce was mostly aluminum and rivets, but also ~1k worth of tools, I will count all the HD and amazon towards tools.

Total time spent building: 0 hours
Total Cost: $8190
Airplane + consumables + project specific costs: $5340
Tools, etc.. I will keep for future projects: $2850

Next up getting some legs under the table and setting up all the tools when they arrive.
I need to make a rack for storing all the aluminum I just purchased as well.
Need to make some flanging dies similar to this,
flangedies2.jpg
flangedies2.jpg (52.88 KiB) Viewed 130 times
Something I have been thinking about, I do want to prime everything. I guess it is controversial, but I have had to clean and replace lots of aluminum during my carrier due to corrosion, so it is something I want to do.
Is there a good, thin, cost effective, epoxy primer that comes in multiple colors? would be nice to look inside a wing or tail section and be able to see the different parts contrasted in different colors.

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Re: Narfi's Zenith CH750 Super Duty

Post by BB Sig » Wed Sep 23, 2020 7:05 pm

If I remember right from my helicopter maintenance days, zinc chromate is what you want for aluminum.

narfi
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Re: Narfi's Zenith CH750 Super Duty

Post by narfi » Wed Sep 23, 2020 9:55 pm

BB Sig wrote:
Wed Sep 23, 2020 7:05 pm
If I remember right from my helicopter maintenance days, zinc chromate is what you want for aluminum.
Its gone through a few epa versions since then, but yes thats a good option. Not what I want though as it's not chemical resistant. Thats why I'll be researching a good thin application epoxy primer.

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Re: Narfi's Zenith CH750 Super Duty

Post by Netpackrat » Wed Sep 23, 2020 11:58 pm

narfi wrote:
Wed Sep 23, 2020 5:05 pm
Need to make some flanging dies similar to this,
flangedies2.jpg
That's not absolutely necessary... I flanged all of my lightening holes using a hardwood stick with a slot cut in it. Even using the dies, you'll probably still need the stick to even the flanges out after you press them in. And you only have to make the one tool; not a set of dies for each size of lightening hole.
Something I have been thinking about, I do want to prime everything. I guess it is controversial, but I have had to clean and replace lots of aluminum during my carrier due to corrosion, so it is something I want to do.
Is there a good, thin, cost effective, epoxy primer that comes in multiple colors? would be nice to look inside a wing or tail section and be able to see the different parts contrasted in different colors.
BB Sig wrote:
Wed Sep 23, 2020 7:05 pm
If I remember right from my helicopter maintenance days, zinc chromate is what you want for aluminum.
It's been a few years since I looked into where the "state of the art" in corrosion control stands, but you can't get much better than Poly Fiber epoxy primer over alodine (now called "Bonderite") conversion coating. And that's also the process we follow on the heavy iron (not that specific brand of primer though) when we have to do sheetmetal work. If you want to really be sure, you can install your rivets "wet" with primer. That's basically what I did when I was still actively building mine... Alodine followed by epoxy primer, rivets wet with epoxy primer, a wet coat of same between faying surfaces. The one exception to that being my spar caps in the rear; since they were 6061 (which has good inherent corrosion resistance) and not 2024 (which does not), I didn't bother with the alodine on those pieces. IIRC, I only assembled them with epoxy between faying surfaces, rivets wet, with the intention of using a final overall coat of epoxy primer after the spar was complete. The main spar caps, I used a different primer (that went on thinner) over the alodined 2024 spar caps with the plan of assembling them wet with epoxy primer. Never got as far as assembling the main spars though.

The main thing is to do something... most of the corroded airframes you have repaired probably got little or no anti-corrosion treatment at the factory. Also if your airframe is built from 6061t6 like many other Heintz designs seem to be, I wouldn't bother with the alodine since it is pretty resistant on its own. Maybe not even with the primer, if I were sure I wouldn't ever make a seaplane of it.

There are also corrosion control compounds that are sprayed inside structure after assembly (ACF-50, etc), But it's probably a good idea to wait until after the exterior has been painted before using that stuff.
Last edited by Netpackrat on Thu Sep 24, 2020 2:41 pm, edited 1 time in total.

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Re: Narfi's Zenith CH750 Super Duty

Post by Jeff » Thu Sep 24, 2020 11:16 am

I will really enjoy this build Narfi!!! Jeff

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Re: Narfi's Zenith CH750 Super Duty

Post by narfi » Fri Sep 25, 2020 12:24 am

couple sheets of aluminum and a few tools showed up today. Unfortunately no time to play with them.
20200924_173143.jpg
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