Tools/polishingwheel/induction

From rLab Wiki

Induction for the Buffing/Polishing Wheel

This is an optional induction, it is not required before using the polishing wheel if you have prior experience using one and are completely confident in your ability to use them safely

Some of the tools at the Hackspace are potentially hazardous to use, for these tools members are required to have an induction before they can use them. Inductions provide the most basic information on how to safely and effectively use the simpler functions of the tools, we appreciate that some members may have professional experience on some of these tools and in this case please tell your induction provider and the induction may be very reduced and just cover any risks or procedures specific to rLab. Some tools have multiple levels of induction in order to cover more advanced uses of that tool without making the basic induction take too long, higher induction levels will introduce some of the more advanced features of the tools but as with all inductions are only intended to provide basic information on the capabilities of the tools and how to use them safely. Some members of rLab may be willing to offer more detailed tuition beyond basic induction level or offer guided practice sessions in exchange for beer money or assistance on their own projects.

For all tools you are only required to take level-1 induction before use, after that you may perform any task that you feel confident you can do safely, higher levels of induction may be useful to you in performing more advanced operations but are not required before doing tasks covered in them so long as you're confident of your ability to handle those tasks without risk to yourself, others, or the tool.

PLEASE NOTE : All induction providers are volunteers who are providing inductions to the best of their ability but are NOT qualified instructors. Inductions are provided on a best-effort basis but you and you alone are responsible for your safety while using the tools and for satisfying yourself that you can operate the tools safely. There are professional training courses available from various providers in Reading and the surrounding area if you feel they are appropriate for the level of work you intend to undertake. Reading these notes is NOT a substitute for an in-person induction.

Note for wiki editors : Please do not edit induction pages unless you are one of of the people that gives that induction

Topic Detailed Contents Rationale
Proper Clothing
  • Short Sleeved shirts or shirt sleeves rolled up and secured.
  • Overalls only if you can roll up and secure sleeves.
  • Old clothes are a good idea if you're doing more than a very small amount of work, the wheels tend to fling dirt and grit at you.
  • No watches, no rings! Nothing that might get caught, search for "degloving" if you need to know why and have a strong stomach.
Staying safe and not getting pulled into the wheels
PPE and why
  • Goggles are required, the wheels fling out fragments and grit
  • Hearing protection is a good idea if doing a lot of polishing, the wheels aren't THAT loud, but loud enough over long periods to merit protection
  • Dust mask is required, some of the abrasives will produce dust that causes serious lung disease and fine dust gets into eyes. A full-face mask is best if available but at least a basic dust mask is compulsory when using this tool
  • NO GLOVES! Yes your hands are going to get dirty, it's a lot better than the alternative
Protection from the specific hazards
Area Safety
  • Check the area around the wheels for anything flammable, the scotchbrite wheels can fling sparks and the residue from previous polishing operations is extremely flammable
  • Make sure no-one else is working too close to the wheels
  • Check the area around the wheels to make sure there's nothing that might fall into them
  • Don't use the wheels while others are using the small linisher or mini-mill, the vibration will affect their work.
  • Make sure the downstairs air-cleaner is turned on to keep dust down
Keeping other people safe around you
What are these wheels good for
  • These wheels are for use on metals only, for polishing wood or plastic you can use the wood lathes
  • The Scotchbrite wheels can perform fine deburring of metal parts but can only remove very small burs and will round-over edges
  • Your work will have to be well smoothed out and free of any substantial scratches before you start
  • You have to be able to hold your work securely so very small items are best polished by hand
  • Polishing works well on steel, stainless steel, brass, copper and jewelry metals
  • Polishing aluminium is possible but it's easy to remove too much material too fast
  • These wheels are for polishing only, they are NOT suitable for paint or rust removal or for re-shaping work. For paint/rust removal maybe try an angle grinder with a wire wheel. For re-shaping work the a file is a better choice.
What you can and can't do on this machine
Setup and changing wheels
  • A selection of wheels are kept in the box behind the polishing machine
  • Don't leave the lid off the box, dust and other dirt getting onto the wheels can ruin your finish
    • Be careful reaching over the wheels, Don't bump the power switch!
  • We have a selection of wheels usually available, if we're out of stock of any of these please contact the maintainers to arrange re-supply.
    • Scotchbrite wheels in Coarse, Medium and Fine
    • Green sisal wheel which is used with Grey cutting compound
    • 2 close-stiched mops which are used with Pink and Blue medium polishing compound respectively
    • A loose-cloth mop for use with the white polishing compounds
  • Use Scotchbrite on the left spindle and polishing mops on the right spindle
  • Wheels simply screw onto the ends of the shafts by hand, no tools are needed
    • Note the left-hand wheel mounts using a left-handed thread
    • Try to keep the wheels on as straight as possible when fitting them, having them wonky will increase vibration and make it much harder to use
    • Tighten them on has firmly as you reasonably can by hand, they'll tighten up further when you start using them
  • If you're using a new wheel it will fling a LOT of loose threads off when started for the first time
  • When you spin up a wheel after having changed it, it's wise to stand off to the side the first time as if it's ever going to fly apart, this is when it'll happen
Getting the wheels properly mounted is vital for safe use
Selecting suitable wheel for your job
  • This is a polishing machine, it'll put a shine on things but it cannot remove significant scratches or marks
  • You'll have to finish your work with emery paper up to about 220grit before you start polishing
  • The Scotchbrite wheels will leave a satin brushed finish, ranging from visible brush pattern for the coarse wheel to a soft satin for the fine one
  • For a nice shine on your work you'll have to start on the Scotchbrite wheels and then move up through the polishing wheels
    • The coarse sisal wheel will leave a dull shine
    • The medium close-stitched wheels will leave a bright shine
    • The fine loose-leaf mop can polish to a mirror finish.
  • You have to remove all marks cause by the previous wheel before you move up to the next one.
    • E.G. when using the medium wheel, you're not done and ready to move up to the fine wheel until all traces of marks from the coarse wheel have been removed
  • When moving from a coarser wheel to a finer one, clean the work carefully. It's best to use a solvent like IsoPropanol or Acetone to remove all trace of the previous compound and watch out for areas that can trap the old compound. If you don't remove traces of the old compound you'll contaminate the wheel and won't be able to get a good finish.
  • Getting a real mirror shine on something, even small items, can take hours
Using the right wheel for each job
Handling your work
  • You need to be able to keep a firm grip on your work as the vibration and friction will make it hard to hold
  • Your goal is a firm grip but still with enough flexibility to move it gently into the wheel
  • You have to be able to move your work around the wheel without risking your hand coming into contact with the wheel, if you do touch the wheel it can cause second-degree burns from the friction in less than a second!
  • Small or difficult to hold items can sometimes be held by screwing them onto a wooden block but make sure they're securely held down
  • Watch out for heating, there's a lot of friction involved in polishing and the work will get quite hot, quite fast, consider where that heat is going to go and make sure it's not into your hand
  • Beware of loose threads on the wheel, they look like soft cotton but once they're spinning at 3000rpm, they're cheese-wires travelling at 90 mph
  • Consider how you'll handle curved surfaces, you want to be able to hold the work such that you can trace the inverse curve to the one you're trying to polish.
Proper workholding is a major safety issue!
Addressing the wheel
  • Before you use the wheel you may need to apply compound to it
    • Scotchbrite wheels are used dry and never need compound
    • The other wheels all need polishing compound
      • Only use the compound that matches that wheel, using the wrong compound is a problem because it's impossible to remove it all and so the wheel will never be able to be used for it's original purpose and will have to be replaced.
      • The green sisal wheel uses the grey coarse cutting "medium greasy" compound
      • The multi-coloured close-stitched mop uses the pink medium grade cutting compound
      • The wide white close-stitched mop uses the blue medium grade compound
      • The white lose-stitched mop uses the white fine polishing compound
    • Very little compound is needed, if the wheel looks at all "matted" or greasy then no more compound is required
    • If the wheel looks dry then a little more can be applied but you'll probably only need to press the polish blocks to the wheels for 1-2 seconds every 5-10 minutes
    • If the wheel is leaving a dark greasy residue on the work then it's got too much compound, you can't do anything to remove compound from the wheel and will just have to keep using it, but don't add any more!
  • The wheel can grab and fling your work quite easily, you need to be aware of how you're holding it and how you're presenting it to the wheel to make sure that when it does grab, it'll be flinging it away from you and other people, not into you. This is the greatest danger that you face using a polishing wheel, if the work kicks towards you, it will do so at 90mph and the risk of serious injury is high
  • Avoid the work touching the wheel above it's half-way point, always the bottom half of the wheel
  • You also need to consider how the work might twist in your hands, draw an imaginary line from where you're holding the work to where the work is touching the wheel and continue that imaginary line on, if it passes above the hub of the wheel then you're in danger of the work being thrown at you!
  • Consider if the work can get pinched between the wheel and the table, if it can you're doing something wrong and risking getting the work flung at you!
  • Keep a firm grip but press the work into the wheel gently, not much force is needed, pressing too hard will wear out the wheels MUCH faster and make a lot of heat
How to polish safely
Finishing and cleaning up
  • Once you're done it's polite to fit the coarse scotchbrite and wide close-stitch mop back to the wheels as they're the most widely useful
  • The wheels will have flung dirt and threads and grit around the bench, please clean up thoroughly as we won't keep the polishing wheels if they result in too much mess.
  • Make sure other wheels are put away in the box and the lid is back on it to keep dust out.
  • Turn off the air-cleaner if there's no-one else working downstairs, or put it on timer.
We're only keeping these if there's not TOO much mess