VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > Main > Safety
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #21  
Old 05-04-2017, 10:59 AM
DanH's Avatar
DanH DanH is online now
 
Join Date: Oct 2005
Location: 08A
Posts: 6,848
Default

Quote:
Originally Posted by sprucemoose View Post
Nah, didn't run my day, but did cause me to do more research. You are of course right about the tin plated vs. zinc plated sleeves......
I might be taking Snopercod up on the offer to sell some of his excess 250 tin sleeves.
Jeff and I discussed the zinc vs tin plating issue offline. I was curious, and I had made industry contacts while researching for Kitplanes, so I promised to make some phone calls. The questions were (1) when did the standard change from zinc to tin, and (2) why?

Turns out one of my contacts is the fellow who actually wrote and submitted MS-51844, with the then-new tin requirement, way back in 1968. The change was made (as one might expect) to reduce the possibility of galvanic corrosion. Zinc is an excellent sacrificial anode. Tests found that given an adverse environment (electrolyte exposure, notably salt water), tin plated sleeves on stainless cable were superior. As a bit of trivia, nickel plated sleeves also tested well, but cost more and never gained acceptance.

Ok, so what about Jeff's problem, a bunch of stainless cables already made for a Breezy, using zinc plated sleeves? Unofficially, no difference in strength, and many, many in service, both on purpose and by accident. The issue is strictly corrosion. Given the application is a Breezy in Wisconsin, and thus unlikely to ever be flown in the rain or dunked in the ocean, a builder might make a reasonable decision to use the existing cables, rather than build a whole new set. The smart guy might squirt a little penetrating spooge on them from time to time to keep moisture out, and note the zinc sleeves in the build log, just in case it winds up on floats many years in the future. It would arguably be an unwise decision on an all-weather airplane, including an RV.

Remember, in the case of a certified airplane, you may use AC43 information only in the absence of manufacturer's guidance. Instructions from both National Telephone (Nicopress brand) and Loos & Co (Locoloc brand) are specific; the current standard is tin plated sleeves on stainless cable. The same is true for all the MIL specs. Bottom line, for certified, it's tin plated sleeves on stainless cable, no exceptions.
__________________
Dan Horton
RV-8 SS
Barrett IO-390
Reply With Quote
  #22  
Old 05-04-2017, 11:39 AM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 1,900
Default

Dan,

Did you also speak with A/C Spruce? This thread popped up a day or two after I placed an order for sleeves. I emailed Nicopress, because Spruce's page (at that time) said use either plain copper or zinc plated for stainless cable. The tin plated version was on another page, under a different name, with no reference on use.

I called them, then swapped a few emails, as they researched. Last response was that they would move the tin plated to the same page with the plain & zinc plated (which they've done). The Q&A now simply says that plated is required with stainless (which plating is still unspecified).

Charlie
-7 FWF in progress, paused to restore a Kolb Twinstar
Reply With Quote
  #23  
Old 05-04-2017, 12:31 PM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 1,900
Default

update to add new info:
Just got an email from Spruce; they will be working with marketing to update the website, reflecting milspec data.

Charlie
Reply With Quote
  #24  
Old 05-04-2017, 01:07 PM
DanH's Avatar
DanH DanH is online now
 
Join Date: Oct 2005
Location: 08A
Posts: 6,848
Default

Quote:
Originally Posted by rv7charlie View Post
Dan,

Did you also speak with A/C Spruce?
Actually I just hit "send" a few moments ago. Wrote them after the previous post.
__________________
Dan Horton
RV-8 SS
Barrett IO-390
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 06:09 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.