Heat Resistant Plastic - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 8th March 2011, 04:13 PM   #1
lpd is offline lpd  Canada
diyAudio Member
 
Join Date: Nov 2003
Location: BC
Default Heat Resistant Plastic

Hello there. I have a Stax DA-80 amp that was damaged on transport. The damage is to where the heat shields mount to the chassis. The heat shields mount to a piece of heat resistant plastic which is mounted to the chassis. I am guessing the heat shields can't be mounted directly to the chassis due to grounding??

Anyone here know of a suitable plastic that could be used? The strips are about 6 inches long, 1/2 inch wide, and half inch deep.

Thanks,

Peter
  Reply With Quote
Old 8th March 2011, 04:51 PM   #2
diyAudio Member
 
Join Date: Feb 2010
Location: Back in CT!
The highest temp 'plastic' I am aware f right now is PEEK.

Just be sitting when you get the quote...

We use it a lot for non-conductive parts of plasma guns. It takes 400F (if memory serves) continuous pretty well.

Of course Teflon is quite a high temperature insulator as well. Plus it doesn't melt- it sublimates to gas. It is a bit soft however. PEEK is much more solid- similar to Delrin (maybe a bit harder?)

Now, if you want a thermally conductive plastic that does not conduct electrically, that is something I am not aware of. This may be what you need for this application?
__________________
"When the world is running down,
you make the best of what's still around."
  Reply With Quote
Old 8th March 2011, 05:20 PM   #3
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Many of our modern plastic are "thermo-plastic". They soften as they get warmer.
A lot of our older plastics (bakelite) were "thermo-setting". They set when heat is applied. They say set once that cure has been achieved.
When heated they retain much of their mechanical properties, but as with all organics, heat them sufficiently and they burn/smolder/give off noxious fumes. By then the vast majority of the thermo-plastics will be a puddle in the bottom of your chassis.

There may be some grades of formica/phenolic composite that meet your requirement.
__________________
regards Andrew T.

Last edited by AndrewT; 8th March 2011 at 05:30 PM.
  Reply With Quote
Old 8th March 2011, 06:02 PM   #4
diyAudio Member
 
wrenchone's Avatar
 
Join Date: Feb 2004
Location: Silicon Valley
A picture of the part in question would work wonders. Since the part carcked in transit, I would guss that it might be something like bakelite, which tends to be brittle. It also hold up to heat fairly well. I assume that this is a heat shield around some tubes - correct me if I'm wrong.

I looked this thing up, and the Stax DA-80 appears to be a SS amp, in which case you might be talking about a heat sink suppport. Am I right? In that case, I would use glass/epoxy composite of necessary thickness, unless the part is some tricky molded piece of nonsense. Glass-epoxy is strong, reasonably cheap, and will stand up to the temperature of a properly designed heat sink. It can be drilled and tapped. McMaster-Carr and other suppliers sstock a wwide variety of forms and thicknesses.Anyway, pictures first!

Last edited by wrenchone; 8th March 2011 at 06:12 PM. Reason: some checking + extra thought.
  Reply With Quote
Old 8th March 2011, 06:04 PM   #5
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
A picture would indeed help. There are a lot of good materials options, but they all have tradeoffs. If I can understand what the exposure is and what mechanical stresses are expected, I can probably give you a good recommendation.
__________________
The more you pay for it, the less inclined you are to doubt it.- George Smiley
  Reply With Quote
Old 8th March 2011, 06:28 PM   #6
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
They're for damping, and primarily for raising the heatsinks above the chassis (distribute the air flow from the inlet slots).

Plain nylon would suffice, imo.
__________________
The buck stops Here
  Reply With Quote
Old 8th March 2011, 06:31 PM   #7
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
SS heatsinks? So the temp range is probably not much above 100°C. Easy. Glass epoxy if there's any structural stresses. Nylon is OK except for its tendency to shrink and swell with changes in humidity.
__________________
The more you pay for it, the less inclined you are to doubt it.- George Smiley
  Reply With Quote
Old 8th March 2011, 06:41 PM   #8
lpd is offline lpd  Canada
diyAudio Member
 
Join Date: Nov 2003
Location: BC
Thanks guys. I can post pics of the plastic pieces tonight and the damage. The amp looks electronically perfect, no damage to the circuit just the mounts. I was concerned that the amp was grounded through the heat sinks and that they were mounted on the chassis to isolate it from the chassis? Looks good if they are just for dampening and to raise and support...I can easily rebuild something if that is the case.
  Reply With Quote
Old 8th March 2011, 08:59 PM   #9
lpd is offline lpd  Canada
diyAudio Member
 
Join Date: Nov 2003
Location: BC
Quote:
Originally Posted by SY View Post
SS heatsinks? So the temp range is probably not much above 100°C. Easy. Glass epoxy if there's any structural stresses. Nylon is OK except for its tendency to shrink and swell with changes in humidity.
Looks like what I have is bakelite. Why didn't they just use metal? Is there an advantage to a heat resistant plastic/bakelite?

Thanks
  Reply With Quote
Old 8th March 2011, 09:03 PM   #10
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
Nonconductive, for one thing. Maybe cheaper, though I can't imagine that it's anything significant in the BOM.
__________________
The more you pay for it, the less inclined you are to doubt it.- George Smiley
  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
Can I make paper cones water resistant? MikeHunt79 Multi-Way 11 30th January 2008 09:50 AM


New To Site? Need Help?

All times are GMT. The time now is 01:54 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