UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 1,730
Default Repairing self tap holes in plastic

I've a plastic cold water filter that is some 150mm in diameter and is
assembled using eight 4mm dia self tap screws. Five of the screw
holes have partially or totally stripped their thread, not so much due
to abuse - possibly in the original assembly though (!) - but I think
due to an over large hole existing in the manufacture for the pilot
hole.

The plastic is hard but I is I think thermoplastic rather than
thermosetting - what suggestions are there for a solution ?

There is not enough material to drill and plug - I could go up a screw
size but buying in a small number of SS screws is not preferred at the
moment.

I have thought of spraying the screws with silicon, filling the holes
with epoxy and then putting the screws back in. Would this work ?
Once reassembled I think is unlikely the assembly will be taken to
pieces again.

Thanks

Rob

  #2   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 519
Default Repairing self tap holes in plastic

robgraham wrote:
I've a plastic cold water filter that is some 150mm in diameter and is
assembled using eight 4mm dia self tap screws. Five of the screw
holes have partially or totally stripped their thread, not so much due
to abuse - possibly in the original assembly though (!) - but I think
due to an over large hole existing in the manufacture for the pilot
hole.

The plastic is hard but I is I think thermoplastic rather than
thermosetting - what suggestions are there for a solution ?


Obtain a shaving of the plastic, and a soldering iron.
While the iron is heating up, try melting the shaving with it.
If it does, then scrape off more, and smear it into the hole, using the
soldering iron, with a block of wood or something behind it.
Do this outside, or in a well-ventilated place.
Until you build it back up to flat plastic.
Now, screw it up.

Or more likely, repair using a nut and bolt, with the bolt screwed
through the other way from what the screws were, and then tightened.
  #3   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 9,560
Default Repairing self tap holes in plastic

On 6 Feb, 17:48, Ian Stirling wrote:
robgraham wrote:
I've a plastic cold water filter that is some 150mm in diameter and is
assembled using eight 4mm dia self tap screws. Five of the screw
holes have partially or totally stripped their thread, not so much due
to abuse - possibly in the original assembly though (!) - but I think
due to an over large hole existing in the manufacture for the pilot
hole.


The plastic is hard but I is I think thermoplastic rather than
thermosetting - what suggestions are there for a solution ?


Obtain a shaving of the plastic, and a soldering iron.
While the iron is heating up, try melting the shaving with it.
If it does, then scrape off more, and smear it into the hole, using the
soldering iron, with a block of wood or something behind it.
Do this outside, or in a well-ventilated place.
Until you build it back up to flat plastic.
Now, screw it up.

Or more likely, repair using a nut and bolt, with the bolt screwed
through the other way from what the screws were, and then tightened.


Or if you can get a rough surface on the plastic, which one pretty
much always can/does with thermosets, fill the holes with araldite,
redrill pilot and screw.

You might also be successful using plastic sleeving. Put a little in
the hole, hold it on the outside as you screw, cut off excess.

Or use those press-in fasteners insteaad of screws.


New bigger ss screws is usually the easiest way.


NT

  #4   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 9,045
Default Repairing self tap holes in plastic

Ian Stirling wrote:
robgraham wrote:
I've a plastic cold water filter that is some 150mm in diameter and is
assembled using eight 4mm dia self tap screws. Five of the screw
holes have partially or totally stripped their thread, not so much due
to abuse - possibly in the original assembly though (!) - but I think
due to an over large hole existing in the manufacture for the pilot
hole.

The plastic is hard but I is I think thermoplastic rather than
thermosetting - what suggestions are there for a solution ?


Obtain a shaving of the plastic, and a soldering iron.
While the iron is heating up, try melting the shaving with it.
If it does, then scrape off more, and smear it into the hole, using the
soldering iron, with a block of wood or something behind it.
Do this outside, or in a well-ventilated place.
Until you build it back up to flat plastic.
Now, screw it up.

Or more likely, repair using a nut and bolt, with the bolt screwed
through the other way from what the screws were, and then tightened.



Another option is a thread tapping bit..forget what they are called -
that self taps into something and has an internal machine screw thread.

If its a thermoset plastic just chars without melting) use car body
filler and redrill teh holes later.
Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Repairing large holes in drywall Smarty Home Repair 13 January 28th 07 06:30 AM
repairing a bath mixer tap Harry Bloomfield UK diy 4 July 16th 06 02:46 AM
Drilling Bath Tap Holes Steve UK diy 2 May 30th 06 12:03 AM
Repairing eavestrough holes? Ebeneezer Geezer Home Repair 10 August 13th 05 03:35 AM
Repairing Holes in Roofing Felt (tiled roof) Stephen Jones UK diy 23 February 5th 04 06:04 PM


All times are GMT +1. The time now is 01:38 PM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"