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Page Created August 24, 2011
Workholding Acrylic for Routing
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I have been asked a few times how I hold Acrylic while it is being routed.
Simply I use double sided tape. In the past I have tied various types of DS tape and have found the type used to secure carpet to timber or concrete floors is the most secure and reliable. There are also various types of carpet Tape and the one I am most recently using has a Fibre Glass webbing. This I found minimizes side movement. The main point of Carpet tape is that the adhesive is really, really sticky. Now a point of warning, sometimes it can be a little difficult to remove the part from the base board, I strongly recommend doing this as soon as possible before the adhesive has time to set. Try not to leave the part stuck to the board overnight.
Simply I use double sided tape. In the past I have tied various types of DS tape and have found the type used to secure carpet to timber or concrete floors is the most secure and reliable. There are also various types of carpet Tape and the one I am most recently using has a Fibre Glass webbing. This I found minimizes side movement. The main point of Carpet tape is that the adhesive is really, really sticky. Now a point of warning, sometimes it can be a little difficult to remove the part from the base board, I strongly recommend doing this as soon as possible before the adhesive has time to set. Try not to leave the part stuck to the board overnight.
For my base board I used an appropriately sized piece of MDF (Medium Density Fibreboard). I sprayed the board with several coats of clear satin to give a nice surface for the tape to stick to. I then secured the board to my routers bed using rocker clamps. These I made myself. As most of the machining I will be doing on my router will be similar I don't see having to remove this board very often at all. Hence once I locked it in place I used a V engraving tool to make some distinctive grooving that I can use for alignment of the work piece. Routing the shallow guide groves after the board is secured means that they will be in perfect X-Y alignment.
As for applying the DS Tape it is important, if at all possible, to leave the acrylics protective paper or plastic sheet on. This can aid in removal from the base board, additionaly prevents marking the acrylic while removing the tape, it also ads a little more distance (GAP) between the under side of the acrylic and the base board. Helps minimize tool cutting into the base board when the depth of cut might be a little over the material thickness. Some people might not care that much but I like to keep the surface of my base board as mark free as possible, increasing its life.
Dont use too much tape as the bigger the surface aria of tape the harder it will be to remove the work piece. Depending on the thickness of the acrylic you might need to use smaller pieces of tape but more of them to support the acrylic from flexing in the Z axis while routing. After a while you will be able to judge in your own mind how much and where best to position the tape.
As for applying the DS Tape it is important, if at all possible, to leave the acrylics protective paper or plastic sheet on. This can aid in removal from the base board, additionaly prevents marking the acrylic while removing the tape, it also ads a little more distance (GAP) between the under side of the acrylic and the base board. Helps minimize tool cutting into the base board when the depth of cut might be a little over the material thickness. Some people might not care that much but I like to keep the surface of my base board as mark free as possible, increasing its life.
Dont use too much tape as the bigger the surface aria of tape the harder it will be to remove the work piece. Depending on the thickness of the acrylic you might need to use smaller pieces of tape but more of them to support the acrylic from flexing in the Z axis while routing. After a while you will be able to judge in your own mind how much and where best to position the tape.
The images, I hope, give a good idea of what I have explained above. Sometimes the work piece can be removed by prying one side up with fingernails but other times a bit of gentle persuasion is required. I use a nicely ground wood chisel, trying not to mark the work piece or base board, very gently is the way.
I find that the leftover tape on the base board is quite easy to remove and for clean up of left behind sticky residue I use SHELLITE also known as Lighter Fuel. It dissolves the tapes sticky really well. The SHELLITE solvent does not effect or dissolve the satin finish I sprayed onto the MDF's surface. However I suggest doing a test first to make sure what you have sprayed your MDF with is OK with the SHELLITE or equivalent solvent you use.
Oh and just a note. I have not had any issue with tool cut through cutting into the DS tape, Generally if you are profiling this will happen on the final pass. Clean the milling cutter with a piece of cloth soaked in SHELLITE.
This technique for holding machining jobs works really well for me, particularly for quite thin material acrylic or Aluminium. I hope you find this information useful.
Both the Double Sided Carpet tape and SHELLITE I obtained from my local Hardware store. In Australia Bunnings and I guess in the USA would be Home Depot
I find that the leftover tape on the base board is quite easy to remove and for clean up of left behind sticky residue I use SHELLITE also known as Lighter Fuel. It dissolves the tapes sticky really well. The SHELLITE solvent does not effect or dissolve the satin finish I sprayed onto the MDF's surface. However I suggest doing a test first to make sure what you have sprayed your MDF with is OK with the SHELLITE or equivalent solvent you use.
Oh and just a note. I have not had any issue with tool cut through cutting into the DS tape, Generally if you are profiling this will happen on the final pass. Clean the milling cutter with a piece of cloth soaked in SHELLITE.
This technique for holding machining jobs works really well for me, particularly for quite thin material acrylic or Aluminium. I hope you find this information useful.
Both the Double Sided Carpet tape and SHELLITE I obtained from my local Hardware store. In Australia Bunnings and I guess in the USA would be Home Depot