Another question about steps

[Robert M]

I'm having, what I believe to be, a step alignment problem with the passenger step. I can get the side plate of the step flush with the skin of the fuselage (mostly) but the pipe isn't perpendicular with the baggage rib. I get the pipe perpendicular and the plate is at an angle and it sticks out a lot to wards the front.

Anybody else seen this?

While I'm on the subject..... There is a vertical column of rivets that are supposed to go into the F-724 rib flange. Are they suppose to be back drilled through the flange where the other rivet holes already are or am I supposed to drill all new holes based on the dimensions on the instructions?

Continuing with my confusion, the illustration in the instructions shows 5 rivet holes in that F-724 flange column and the photograph shows six. I can only work it out to line up with 4 of the holes. Are 4 holes going to be enough or will I need to make six? If I need to make six, should I space them between the already existing rivet holes?

Whew!

 

[carguy614]

step issues

Bob,

You won't get off that easy. Center up the mounting pipe, and be sure you are at the right angle as far as the step itself is concened. You will have to carefully shape the plate to fit the skin. I ended up with a tiny void at the bottom of both steps that I filled with tank sealer. Painted up, and you can't tell. OK to use the exising rivet line for the rearmost vertical rivets. Get as many in there as you can. I had room for another line of rivets at the front of both of my steps for some reason, so I installed a doubler on the inside of the skin with keeper rivets, and drilled another row. They turned out great, but require a lot of work to get them fitted properly. I used button head rivets for my steps, but I see that some folks have CS rivets to make the attach. focus on getting the actual step angle correct, and the same on both sides if you mare installing 2.
Time spent here is worth the effort. Everyone sees the steps when they board the craft!!

Hope this helps,
Chris

 

[Robert M]

Thanks carguy.

The alignment thing was in my eyes and not the parts, I got that straightened out.

So, if I understand you correctly, I SHOULD use the existing rivet holes in the F-724 flange??!!

I will go with the 470 rivets. All that extra work to countersink for 426 is more work than I want.

 

[N941WR]

Robert,

Don?t forget to powder coat the step or paint it and the aluminum where they touch. Using primer isn?t enough as it is porous.

 

[Jamie Aust]

Robert,

Don?t forget to powder coat the step or paint it and the aluminum where they touch. Using primer isn?t enough as it is porous.

I was told that powder coat can crack over time, Im going to use 2-pack paint.

Im also working on my steps as we speak.

 

[Robert M]

I'm not ready to do the final install on the steps, I just want to get them ready.

What type of paint should I use against the fuselage?

 

[roee]

As others have said, make sure the tube is positioned where it should be, and adjust the step flange as necessary to match the skin.

At the F-724 column, I opted to leave the existing flush rivets in there and add four new rivets through the step and the F-724, adequately spaced from the existing ones. True, had I drilled out the existing ones I could have probably put five or six rivets through the step and the F-724. But rivet holes that have been previously drilled out, and especially since these were dimpled for flush rivets, would not be nearly as strong as newly drilled and installed rivets, especially in shear which is what matters here. I reasoned that four good rivets were better than five or six not-so-good ones.

And don't take the rivet pattern shown in Van's drawing for the steps too literally. That drawing was done for the RV-6, and the dimensions on the RV-7/9 are a little different. Adjust as needed.

Not all primers are created equal. I sprayed AKZO epoxy primer on the step weldment as well as the Al skin at the interface. This is a true corrosion-inhibiting primer-sealer, and should do the job just fine. Bill R. is correct though that most rattle can primers that people often use are not sealing primers, and are designed to promote top coat adhesion, not provide a moisture barrier on their own. Whether they're effective at all for corrosion protection is another topic for discussion ("primer wars") that we don't need to get into here.

My steps: http://www.kalinskyconsulting.com/rvproj/cabinsteps.htm

 

[Robert M]

I'm not setup for mixing epoxies and spraying with a gun. Is there a rattle can primer/paint that I could use?

 

[roee]

I'm not setup for mixing epoxies and spraying with a gun. Is there a rattle can primer/paint that I could use?

There may be, but none that I can recommend.

With respect to epoxy primer though, there's really not much to be set up. Mixing is 1:1 by volume, which I do with disposable picnic cups that I buy at the supermarket. To spray you obviously need a compressor, which I assume you have. And a $15 paint gun from Harbor Freight is more than adequate:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?itemnumber=86-7VGA&Submit=Go

 

[Lionclaw]

I pro-sealed my steps and wet riveted them on. I masked off the plate and painted the tube with 7220 before applying pro-seal. I'm not flying yet, so no idea how it will hold up in the long run.

 

[Robert M]

possible drill pattern for steps

What about those zinc chromate spray in a rattle can - would that work for anticorrosion protection?

This is what I came up with as a possible drill pattern for the steps. Anybody see any problems with this?