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Hubitom1

Member
Just installing the steps on my RV7A, and was wondering what you guys did with respect to metal protection. I've seen them painted, and I believe I've seen them shining with chrome.

What is the better protection, and what is more likely to rust? Does the riveting process damage the chrome layer more easily than the paint??

Any input is welcome.

Thomas
 
chrome

I had my steps chromed, they looked great. Riveting them on did no damage to the finish. Then I came to my senses and took them off and put on a tailwheel, best thing I ever did.
 
I painted, but getting some rust thru..

I primed and painted mine like the rest of the plane, but after 5 years I have some very minor rust showing through. I'd recommend powder coating or chroming to avoid. (and I live in a dry climate..)
Also, look at the threads about step cracking and consider a reinforcement below the top weld line before you install and paint...

Seb Trost
RV-7A
Boulder City, NV
 
Hubitom1 said:
Just installing the steps on my RV7A, and was wondering what you guys did with respect to metal protection. I've seen them painted, and I believe I've seen them shining with chrome.

What is the better protection, and what is more likely to rust? Does the riveting process damage the chrome layer more easily than the paint??

Any input is welcome.

Thomas
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I wouldn't chrome. I don't recall the particulars but it seems chrome can cause some sort of embrittlement of the base metal. The steps take a beating as it is without adding any tendency for failure. I painted mine with the same automotive paint as the plane and it has held up perfectly.
 
Try Nickel alone without chrome

Mine are nickel plated, not chrome.

I have used nickel plating to corrosion protect steel parts that take a beating in industrial setting. I expect it to do fine on the step.

I did not do anything to reinforce the lower portion of the weld (because I learned about it too late). Since there are so many failures on unplated steps, I will not be able to blame a future failure on the plating.
 
Oh No!

C-FAH Q said:
I had my steps chromed, they looked great. Riveting them on did no damage to the finish. Then I came to my senses and took them off and put on a tailwheel, best thing I ever did.
Click to expand...

A-H-E-E-E-E-E-E Terrible ,Terrible, disgusting, Ha-Ha, I guess I can't knock it until I beat you.

Anyway, I instaled mine with rivets in the original build and flew with them zink cromate primed (yellow green) and wingwalk grit paint on the steping surface for one year from 2004 until 2005, then had them painted with the rest of the airplane with Imron in 2005. In 2008 I drilled out all the rivets and mounted the steps with stainless steel screws so I could remove them and install a cover plate for racing. I have had no rusting of the steps in all these years. With reasonable care and attention you should be able to use paint and not have a problem. It is easy to touchup as well.

Bob Axsom
 
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Powder coated white, I think it was 20 bucks or so. Installed with pulled rivets with proseal behind the plate on the top and sides only.
 
Thanks so much for your inputs, guys! Although the choices a great, I know I have to make a decision on what I believe will be the best solution.

However, what I was not aware of, is the problem of steps cracking. I will definitely see and find out if a local welder can add a strap on the underside of the step tubing.

Thanks again!

Thomas
 
I powder coated with pop rivets. I sprayed zinc chromate on the skin before installation.
 
Sam Buchanan said:
I wouldn't chrome. I don't recall the particulars but it seems chrome can cause some sort of embrittlement of the base metal. The steps take a beating as it is without adding any tendency for failure. I painted mine with the same automotive paint as the plane and it has held up perfectly.
Click to expand...

Your probably thinking about the term hydrogen embrittlement. This only happens on high strength steel, ~38 Hardness Rockwell C Scale or more. I doubt the step is made from that hardness of material, if it is, then a post bake is needed to resolve that issue.

All your high strength cad plated fasteners will suffer the same risk and if manufactured correctly will have the post bake in the process.

Chrome wouldn't scare me at all in this case.
 
rzbill said:
Mine are nickel plated, not chrome.

I have used nickel plating to corrosion protect steel parts that take a beating in industrial setting. I expect it to do fine on the step.
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Normal "decorative" chrome plating is actually nickel plating with a very thin (flash) plating of chromium on top to provide the mirror finish. A good commercial decorative chrome plating with nickel base should provide adequate corrosion protection. Just look at all the car bumper bars that were done that way in years past....most of them lasted for decades without corrosion.
 
Captain Avgas said:
Normal "decorative" chrome plating is actually nickel plating with a very thin (flash) plating of chromium on top to provide the mirror finish. A good commercial decorative chrome plating with nickel base should provide adequate corrosion protection. Just look at all the car bumper bars that were done that way in years past....most of them lasted for decades without corrosion.
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Thats true. My following comments are more related to hard chrome (meaning thick coating) rather than decorative.

Chrome is brittle in inself, not including the hydrogen issue. Microscopic observation of a chrome surface will frequently reveal microcracking invisible to the naked eye. I decided to avoid coating with stress risers.

Nickel is considerably more ductile plus, while there is hydrogen generation during the process, it is at a 5% rate of hard chroming.

Nickel will have a yellow tinge tarnish. I'm OK with that.
 
ty1295 said:
Your probably thinking about the term hydrogen embrittlement. This only happens on high strength steel, ~38 Hardness Rockwell C Scale or more. I doubt the step is made from that hardness of material, if it is, then a post bake is needed to resolve that issue.

All your high strength cad plated fasteners will suffer the same risk and if manufactured correctly will have the post bake in the process.

Chrome wouldn't scare me at all in this case.
Click to expand...

The step is 4130, don't know if that falls within the group you referenced.
 
The real issue

Hydrogen embrittlement of the vans steps is a non issue as far as decorative chrome plating goes. Regardless of the coating system you'll eventually get cracking adjacent to the upper weld if hefty pax jump off the wing onto the step. I've seen lots of RVs with step cracks (it's a very common problem) and none of them were chrome plated. The steps are a very lightweight construction and will not tolerate sustained abuse...so they need to be used accordingly. Enforcing proper disembarkation techniques that do not put dynamic loads onto the step is the key. That's the real issue.
 
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