Go Back   Home > Forums > Loudspeakers > Full Range

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 2nd February 2009, 07:02 PM   #1
freddi is offline freddi  United States
diyAudio Member
 
freddi's Avatar
 
Join Date: Aug 2005
Default is there anything to help dried/old paper surrounds?

got some very dry vintage RCF 12" whose paper surrounds look and feel very brittle - one has a crack - they don't seem to have been doped like CTS, etc. - is there any nearly idiot-proof treatment which will do more good than harm?
  Reply With Quote
Old 3rd February 2009, 06:01 AM   #2
diyAudio Member
 
Join Date: Nov 2007
I think the surround needs replacement, I dont think there is anything you can do about it short of a replacement.
  Reply With Quote
Old 3rd February 2009, 05:16 PM   #3
freddi is offline freddi  United States
diyAudio Member
 
freddi's Avatar
 
Join Date: Aug 2005
imo they have "some" life left - a suitable coating might extend life a bit - one speaker has a few radial cracks in the paper surround--- these are 12" drivers with a horrendous 2.5 ohm dcr , fs ~62, qts in the 0.7 region - dust-cap is interesting as is an inverted cone
Click the image to open in full size.
  Reply With Quote
Old 3rd February 2009, 08:51 PM   #4
diyAudio Member
 
tomtt's Avatar
 
Join Date: Aug 2002
Location: kansas city mo, and on occasion, around the world ...
Blog Entries: 15
rubber cement might be, what you may be looking for.



Click the image to open in full size.



74
  Reply With Quote
Old 3rd February 2009, 09:54 PM   #5
Speakerholic
diyAudio Moderator
 
Cal Weldon's Avatar
 
Join Date: Jan 2004
Location: British Columbia
Tom, what is the base solvent in rubber cement? I am wondering if he might want to cut it back a little before applying?
__________________
Next stop: Margaritaville
Some of Cal's stuff | Cal Weldon Consulting
  Reply With Quote
Old 4th February 2009, 12:19 AM   #6
diyAudio Member
 
e_fortier's Avatar
 
Join Date: May 2001
Location: Montreal
Not that I know them but give these guy a call;

http://www.simplyspeakers.com/2doityourself.htm

Eric
  Reply With Quote
Old 4th February 2009, 05:48 PM   #7
diyAudio Member
 
tomtt's Avatar
 
Join Date: Aug 2002
Location: kansas city mo, and on occasion, around the world ...
Blog Entries: 15
Quote:
Originally posted by Cal Weldon
Tom, what is the base solvent in rubber cement? I am wondering if he might want to cut it back a little before applying?


copy and paste from wiki -


Rubber cement is an adhesive made from elastic polymers (typically latex) mixed in a solvent such as acetone, hexane, heptane or benzene to keep them fluid enough to be used. This makes it part of the class of drying adhesives: as the solvents quickly evaporate, the "rubber" portion remains behind, forming a strong yet flexible bond. Often a small percentage of alcohol is added to the mix.

Formula

The formula for rubber cement varies according to its targeted application. Those commonly used in office and art applications are usually non-vulcanizing and seldom differ between brands. However, they have been reformulated over time due to concerns over the toxicity of the chemicals involved, especially in regard to its use by children. Consumer-grade products generally no longer contain benzene because of its link to certain cancers. Instead, they tend to be based on less toxic solvents such as n-hexane and n-heptane.


Rubber cement based on n-heptane is very popular and ubiquitous in the United States, but is generally unknown and unavailable as a consumer product in the UK and some parts of Europe, possibly due to the severe fire hazard of that formulation. A similar solvent based product called "Cow Gum" was common in the UK, but is no longer in production. Current solvent based options include Marabu-Fixogum and Platignum "Studio Gum" which are marketed in the UK and Europe.


note a difference here -


For tire patching, shoe repair, and other industrial applications, vulcanizing formulas are preferred. These contain chemical additives which enable them to cross-link and harden into a tougher, more resilient form.




http://en.wikipedia.org/wiki/Rubber_cement



132
  Reply With Quote
Old 4th February 2009, 06:17 PM   #8
HK26147 is offline HK26147  United States
diyAudio Member
 
Join Date: Jan 2008
Quote:
nearly idiot-proof treatment
It good to know that benzene is no longer used.
Still I'd be afraid about aggressive solvents and old brittle surrounds.
If the surrounds are not dirty or can be cleaned without further damage,
I would try a benign latex caulk, or a flexible fabric glue ( thinned ).

But like marchel said: replacement might be the best option.
  Reply With Quote
Old 4th February 2009, 08:08 PM   #9
chrisb is offline chrisb  Canada
diyAudio Member
 
Join Date: Aug 2002
Location: victoria BC
Quote:
Originally posted by HK26147

It good to know that benzene is no longer used.
Still I'd be afraid about aggressive solvents and old brittle surrounds.
If the surrounds are not dirty or can be cleaned without further damage,
I would try a benign latex caulk, or a flexible fabric glue ( thinned ).

But like marchel said: replacement might be the best option.

how would you propose to replace an accordion pleated paper surround?

Foam or even synthetic rubber surround kits would most likely be available in an appropriate size, but very careful cutting would be required to remove the existing, damaged surround, and more importantly, the compliance and other characteristics could be significantly affected by the new material.

If the damaged area is accessible from both sides, why not try something like patching with a sandwich of rice paper and diluted Weldbond or puzzlecoat (PVA white glue), applied with Q-tips.


You could also check with someone who specializes in repairs and restoration to vintage drivers. They may be able to recommend materials for reconditioning /doping , or have alternate methods for repairing torn pleated surrounds.

http://www.thespeakershop.com/home/speakerrepair.html
__________________
you don't really believe everything you think, do you?
community sites t-linespeakers.org, frugal-horn.com commercial site planet10-HiFi
  Reply With Quote
Old 4th February 2009, 09:30 PM   #10
HK26147 is offline HK26147  United States
diyAudio Member
 
Join Date: Jan 2008
Quote:
how would you propose to replace an accordion pleated paper surround?
Ideally, from one of several sources that carries pleated surrounds.

You do raise an issue that I also wondered about - What are the differences ( if any ) from one vendor's surrounds/kits vs another.
How much influence does it have, since it is half the suspension system?
And I wonder if we as DIYer's put more thought/concern into it than the original manufacturers.
Unfortunately there are no soft/medium.stiff options, I know of.

The comment "very brittle" made me think ( that while it may have a small tear ) it would be like patched a sun cracked worn out tire - Fix one spot apply power and another tear appears.
Is the current compliance and resiliency ( of a a brittle surround ) anything like it was when new anyway?
A surround that is torn/not shot - I have ( as chrisb said ) used small pieces of tissue/wrapping paper and soft white ( fabric glue )
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Surrounds - how should they be done? ShinOBIWAN Multi-Way 23 10th March 2008 02:01 AM
Dried out electrolytics in an amp. beppe61 Solid State 29 4th February 2006 12:24 PM
diy surrounds aarono Multi-Way 4 24th March 2005 06:40 AM
Dried Capacitors OMNIFEX Solid State 7 15th February 2005 02:55 PM
amorphous paper or Mu-metal paper can use for D/A chips for shielding or not???? siu sin man tho Digital Source 0 17th March 2004 12:31 PM


New To Site? Need Help?

All times are GMT. The time now is 03:28 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2