Skymaster Forum  

Go Back   Skymaster Forum > Messages
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
Thread Tools Rate Thread Display Modes
  #1  
Unread 11-09-16, 12:11 PM
AP AVM AP AVM is offline
Registered User
 
Join Date: Feb 2016
Location: Waterloo,ON
Posts: 82
AP AVM is on a distinguished road
Any STD on removal of sound dempering material on 67Bs?

Was there a STD for the removal of all sound dempering material/charcoal gray pads from the internal structure of the fuselage of 67 337Bs and O-2A/B by FAA due to corrosion build up between the pads and aluminum skins or panels.

I have been asked by a 337 specialist to remove these from the side walls, top and from the floor of my AVM. This stuff has been glued pretty good for last 49 years and is giving hard time to come off by using lacquer thinner.....

Last edited by AP AVM : 11-10-16 at 12:56 AM.
Reply With Quote
  #2  
Unread 11-10-16, 12:19 AM
Skymaster337B's Avatar
Skymaster337B Skymaster337B is offline
Registered User
 
Join Date: Jun 2004
Location: New Mexico
Posts: 508
Skymaster337B is an unknown quantity at this point
I thought those pads were more than sound dampening, but also for harmonics control. But I'd be curious of any documentation to remove them.
Reply With Quote
  #3  
Unread 11-13-16, 05:30 AM
skymstr02's Avatar
skymstr02 skymstr02 is offline
Ace of the Atmosphere
 
Join Date: Apr 2002
Location: Madison, MS
Posts: 329
skymstr02 is an unknown quantity at this point
After you removed the items, how did you account for them on your weight and balance? The total weight would not have been negligible.
Reply With Quote
  #4  
Unread 11-14-16, 07:05 AM
LostKiwi's Avatar
LostKiwi LostKiwi is offline
Registered User
 
Join Date: Jan 2016
Location: Canada, eh.
Posts: 56
LostKiwi is on a distinguished road
From the maintenance manual...

3-43. SOUNDPROOFING.
3-44. DESCRIPTION. 337-Series aircraft are insulated with spun glass, mat-type insulation. Two types of vibration dampening materials are used.
A brush-on type compound on the inner surfaces of the baggage and cabin area and a sheet type that is held in place with an epoxy adhesive.


Ipso facto... be very very careful in just yarding it out and then going flying. You're essentially making your aircraft unairworthy.

I've seen people talk about how its in there as a vibration thing, now we have a manual reference that confirms it.

As an A&P / IA would I recommend taking it all out to check the structure for corrosion? absolutely! Its held on with glue! Thats a recipe to trap water and set up a corrosion cell. By all means, take it out - BUT you need to fit new stuff (or a modern equivalent).



DrDave, I tip my hat to you sir. That is not a small job.
Have photos of the finished product?




Leighton.
Reply With Quote
  #5  
Unread 11-14-16, 03:20 PM
DrDave DrDave is offline
Registered User
 
Join Date: Nov 2010
Location: Seattle
Posts: 115
DrDave is on a distinguished road
I've heard that some people have removed the little gray patches that are glued on. I've also heard that the best way is with a heated pressure washer. Here's the old sideways picture thing. I have limited abilities at posting pictures I rarely try.

Dave
Attached Thumbnails
Click image for larger version

Name:	IMG_5386.JPG
Views:	1201
Size:	137.7 KB
ID:	1693  

Last edited by DrDave : 11-14-16 at 03:34 PM.
Reply With Quote
  #6  
Unread 11-14-16, 03:21 PM
kilr4d's Avatar
kilr4d kilr4d is offline
Registered User
 
Join Date: Mar 2016
Location: CNC3
Posts: 265
kilr4d is on a distinguished road
Check out Herb's refurbishment thread:

http://www.337skymaster.com/messages...ead.php?t=2309

Read the whole thing, but he starts discussing those stick on dampeners in post #21.
Reply With Quote
  #7  
Unread 11-15-16, 06:00 AM
LostKiwi's Avatar
LostKiwi LostKiwi is offline
Registered User
 
Join Date: Jan 2016
Location: Canada, eh.
Posts: 56
LostKiwi is on a distinguished road
Looks like you're doing a real nice job, Dave.

Nothing more demoralizing that cleaning 40 year old goop from inaccessible areas, but the end result looks great.


Leighton.
Reply With Quote
  #8  
Unread 11-15-16, 02:26 PM
DrDave DrDave is offline
Registered User
 
Join Date: Nov 2010
Location: Seattle
Posts: 115
DrDave is on a distinguished road
Leighton:

When you get down into the inside of the belly with a pressure washer you can uncover years of grunge that has been coated in hydraulic fluid. You can make the inside look brand new. You will also find enough loose nuts, screws, clamps, etc. to start a small hardware store. There are a number of unpleasant smells lingering in the belly of the plane. All of those will be washed away.

It is so much nicer to work on a plane that is clean and goop free. When I figure out how to post a picture that is not turned 90 degrees I'll send more.

Dave
Reply With Quote
  #9  
Unread 11-15-16, 07:46 PM
JAG JAG is offline
Registered User
 
Join Date: Jun 2014
Location: Texas
Posts: 260
JAG is on a distinguished road
Pictures come out okay.

Hi Dave,
When I click on the thumbnail, it opens up correctly (O2 bottles on the top) on my computer! Keep the photos coming.
JAG
Reply With Quote
  #10  
Unread 11-15-16, 07:54 PM
DrDave DrDave is offline
Registered User
 
Join Date: Nov 2010
Location: Seattle
Posts: 115
DrDave is on a distinguished road
I wonder why it's off 90 degrees in the thumbnail

Dave
Reply With Quote
  #11  
Unread 11-16-16, 11:40 PM
AP AVM AP AVM is offline
Registered User
 
Join Date: Feb 2016
Location: Waterloo,ON
Posts: 82
AP AVM is on a distinguished road
I don't have a facility to power diesel wash the inside of the fuselage at my airport to remove them. I'll use heat gun to warm up the glue and try to scrape them off with plastic spreaders.

After reading through all the comments, I think it's wiser to remove most if not all.
Reply With Quote
  #12  
Unread 11-17-16, 12:24 AM
DrDave DrDave is offline
Registered User
 
Join Date: Nov 2010
Location: Seattle
Posts: 115
DrDave is on a distinguished road
That sounds like a long messy day. Once you get the interior stripped out you will likely want to scrub the belly out as well. You may be surprised at how yucky the belly is.

Dave
Reply With Quote
  #13  
Unread 11-17-16, 12:42 AM
DrDave DrDave is offline
Registered User
 
Join Date: Nov 2010
Location: Seattle
Posts: 115
DrDave is on a distinguished road
After you clean everything it's a good idea to carefully rinse the areas where you've cleaned. You want to be as gentle as you can. Here's how I did it.

Dave

https://youtu.be/kbOyOf4A8EM

This is exactly how interior of my C337B is currently, it's all gutted and I even took more out of it to it's bare bones. There are no instruments or radios , yokes in the cockpit, just wires, cables, couple old heat ducting hoses, mechanisms for yokes and trimming dials. All my floor panels will be replaced as they all are corroded but it looks as inside the belly is still pretty good yet full of dirt n grime from sitting out in elements for last 12-15 years..


AP-AVM

Last edited by AP AVM : 11-17-16 at 11:18 AM.
Reply With Quote
  #14  
Unread 11-17-16, 03:12 PM
DrDave DrDave is offline
Registered User
 
Join Date: Nov 2010
Location: Seattle
Posts: 115
DrDave is on a distinguished road
If you are gutted down to the bare bones I would really make an effort to get in there with the corrosion treatment and a hot water pressure washer in the whole thing. It will pay dividends for years to come. I'm sure you can rent the things too.

Dave
Reply With Quote
  #15  
Unread 11-20-16, 10:07 PM
Skymaster337B's Avatar
Skymaster337B Skymaster337B is offline
Registered User
 
Join Date: Jun 2004
Location: New Mexico
Posts: 508
Skymaster337B is an unknown quantity at this point
I like the way a good pressure washing looks, but I don't remember anything during my formal A&P training about pressure washing. I never read anything in the maintenance manual or the old AC 65-15 about pressure washing. I'm not judging, but I'm curious about tech data for cumulative fatigue on aluminum during a pressure wash....I'm sure it's dependent upon pressure, metal thickness, area, etc. Not to mention, that not all Skymasters are equal...pre 1973 used thinner aluminum. Looking for a discussion, not a shooting match.
Reply With Quote
Reply


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

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 Off
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 04:25 AM.


Powered by vBulletin® Version 3.6.9
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.