Assassin
Well-Known Member
Its been one of those days today where a mate appeared and wanted a job doing, so I thought it may be of benefit to some readers on here if they adapt it to suit their requirements.
This is fitting magnets in various drain bungs as these attract metallic swarf and give the boat owner a good visual indication of the state of their engines, transmissions, or outdrives by the amount of metallic particles they collect, and over time a DIY owner will see and note this.
These bungs were all new and came with various coatings on them and while some had a recess inside their threaded portion, some where solid; the first job is to remove the surface coatings down to bare metal and square this recess off and remove a little of the coating back to bare metal so a magnet will fit inside the recess without protruding beyond the end of the threads. Magnets were sourced from my stocks and were matched to specific bungs and the bungs were machined out to leave them with a coarse metal finish, and enough clearance for adhesive to travel up the sides of the magnets. Each magnet was put into the lathe and its outside and bottom edge was roughed up with a diamond coated cloth as many are smooth and they all had a countersunk or counter bored hole for bolt or screw fixings.
Solid bungs were drilled with a smaller drill to fit the other magnets inside by using a clearance drill, DO NOT BORE TOO LARGE OR TOO DEEP A HOLE WITH THE SOLID BUNGS.
With all the bungs and magnets prepared a little epoxy of the right type was mixed and the bottom and sides of the magnets were coated and inserted into the bungs with the countersunk/counter bored holes pointing upwards and they were inserted inside the bungs, any surplus epoxy was wiped off and the remaining epoxy was used to fill the countersunk holes to the top.
When selecting epoxy for this type of work, avoid the DIY types from high street chains as in most cases it is not designed for working in oil immersed environments and may not be rated sufficiently for the working temperatures of oil, always check the specifications of the epoxy and ensure it is rated for working in an oil immersed environment and at the required working temperatures..
This is fitting magnets in various drain bungs as these attract metallic swarf and give the boat owner a good visual indication of the state of their engines, transmissions, or outdrives by the amount of metallic particles they collect, and over time a DIY owner will see and note this.
These bungs were all new and came with various coatings on them and while some had a recess inside their threaded portion, some where solid; the first job is to remove the surface coatings down to bare metal and square this recess off and remove a little of the coating back to bare metal so a magnet will fit inside the recess without protruding beyond the end of the threads. Magnets were sourced from my stocks and were matched to specific bungs and the bungs were machined out to leave them with a coarse metal finish, and enough clearance for adhesive to travel up the sides of the magnets. Each magnet was put into the lathe and its outside and bottom edge was roughed up with a diamond coated cloth as many are smooth and they all had a countersunk or counter bored hole for bolt or screw fixings.
Solid bungs were drilled with a smaller drill to fit the other magnets inside by using a clearance drill, DO NOT BORE TOO LARGE OR TOO DEEP A HOLE WITH THE SOLID BUNGS.
With all the bungs and magnets prepared a little epoxy of the right type was mixed and the bottom and sides of the magnets were coated and inserted into the bungs with the countersunk/counter bored holes pointing upwards and they were inserted inside the bungs, any surplus epoxy was wiped off and the remaining epoxy was used to fill the countersunk holes to the top.
When selecting epoxy for this type of work, avoid the DIY types from high street chains as in most cases it is not designed for working in oil immersed environments and may not be rated sufficiently for the working temperatures of oil, always check the specifications of the epoxy and ensure it is rated for working in an oil immersed environment and at the required working temperatures..
