It is currently 29 Mar 2024 13:21

All times are UTC




Post new topic  Reply to topic  [ 3 posts ] 
Author Message
PostPosted: 17 Apr 2010 19:08 
We've all been there - half way through an oil & filter change when we realise we forgot to buy a new sump plug washer. Do we re-use the existing washer? Well, you can, and it's quick, cheap & easy!

Copper (Cu) and Aluminium (Al) are used for washers because they are soft, and when you tighten up your sump plug, the metal washer material deforms to match both surfaces, resulting in a nice tight seal. Unfortunately after being used once, they start to harden meaning next time you try to use them they will not seal as well.

Metals have a crystalline structure, being made up of thousands of tiny crystal grains, and much of their inherent hardness is actually due to the boundaries between these grains. "Working" a metal (i.e. by tightening your sump plug) will split some of the grains, resulting in an increase in the number of grain boundaries, and hence harden the metal. Conveniently, all we do to reduce the number of grain boundaries is heat up the metal and allow the grains to grow again - this process is called annealing. The trick is knowing just how hot to get them, and this is different for Cu and Al:

Cu:
  • Take the washer (cleaned) and 2 pairs of long nosed pliers.
  • Holding the washer with one set of pliers, heat it over a gas burner (like your kitchen hob or a camping stove, but not a cigarette lighter) until it starts to glow a dull red colour. If it gets hotter than that, it'll glow with a cherry red colour, and that's fine, but don't get it much hotter because it'll melt.
  • Now pass the washer into the second set of pliers, holding it by the other side and heat it again, so that the part of the washer that was underneath the first set of pliers gets hot this time.
  • Allow the washer to cool at it's own rate - don't quench it in water
  • Clean off any deposits of soot with some fine emery paper.

Al:
  • Take the washer (cleaned) and 2 pairs of long nosed pliers.
  • Hold the washer over a burning candle until it's covered in soot.
  • Holding the washer with one set of pliers, heat it over a gas burner until the soot burns off.
  • Now pass the washer into the second set of pliers, holding it by the other side and heat it again, so that the part of the washer that was underneath the first set of pliers gets hot this time.
  • Allow the washer to cool at it's own rate - don't quench it in water
  • Clean off any deposits of soot with some fine emery paper.

That's it! You may now re-use the washer, with the smug satisfaction that you could have saved as much as £0.03 - every little helps.

Disclaimer: If you decide to try this technique, don't come crying to me if you burn yourself or leave a washer-shaped mark on your kitchen worktop - things that are heated get hot, and things that are heated until they glow red get very hot, but you already know this and so it's your own stupid fault and you probably deserve all the grief that your other half will bestow upon you.

Fozberry


Top
   
PostPosted: 06 Jun 2010 01:08 
Offline
User avatar

Joined: 05 Feb 2010 20:04
Posts: 16
Location: Kent - The Garden of England
Great tip..... Thanks


Top
PostPosted: 23 Jun 2010 22:55 
Offline
I'd rather race a Honda 90

Joined: 08 May 2009 08:31
Posts: 3137
Location: Rhodesia.
From annealing position.... ;)

_________________
Spencer Racing... www.spencerracing.co.uk


Top
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 3 posts ] 

All times are UTC


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Limited