Hi I need to make some precise holes big enough to get the wire feeds and plastic plug thingamajigs for Kato Unitrack stuff in my extruded foam insulation board. Can anyone suggest a good tool to do this without making a mess?
You can get pretty good results up to 1/2" by usinga standard HSS bit (NOT a spade bit.) Run the drill slow and keep it pointed exactly where you want it to go. The smaller the hole, the easier.
BNSF4ever,
You could also look into, hole reamers, you may have to do, both sides,for the hole to be uniform, if it matters, but in foam, it would be like, going through butter, plus no mess. Even a rat tail file. [:)] Old fashion, ice pick.
Cheers, [D]
Frank
…screw driver, pocket knife, sharp stick…
Depending on the size of the hole, you can use an awl or even a #2 pencil. Then, take a cylindrical coffee stirrer or a common drinking straw and line the hole with that.
For a larger, neater hole, use a drill.
I don’t use foam but it should be possible to cut a piece of brass tubing and bevel the edge with a file to make a cutter that could be chucked in a drill. Alternately it might also be possible to make a point that could fit in a piece of tubing like a bullet that could be reused leaving behind a piece of tubing in the hole.
I made a “sewing needle” out of a wire hanger. One end was ground to a point. I flattened the other end with a ball peen hammer on the anvil of my bench vise. Then I drilled small holes in the flattened end. When I want to pull wire through for feeds, I thread the “needle” with some stripped wire, pulled through and twisted. I push the needle through and pull it through from the bottom. I’ve used this tool to pull wire through foam 12" thick.
Does your Unitrack wire have a plug on both ends? If not, one end should go through a lot easier pushing it down through. If both ends have plugs you will need a much bigger hole for the plug than for the wires. You could cut out a larger chunk, put the wire through, then replace the chunk, it will give enough to push by the wire easily. For my feeder wires I put a drinking straw in a 1/4" drilled hole. Plug the end of the hole with Sculptamold and smooth over. Alternative method would be to cut the wire, push it through a small hole/straw then reconnect the wires. Good luck, Richard
I am of two minds on this one. Normally, I drill. I have used the extruded foam in the past, and it takes tree armatures and utility/telegraphy poles nicely in suitably sized holes. However, the holes don’t stand up well over time in foam. Knock a utility pole askew, and it’ll need a new hole…sorry. If you can find a knitting needle that you can force into the foam about one full inch, and then wait for it to close up some once the needle is removed, it would be stronger around its ‘cylinder’ with the compressed foam. Maybe one of the thicker bamboo barbeque skewers with the fine point would be better for that initial thrust.
If you want to screw somehing like fascia to the sides of layered foam, pre-drill with an appropriate diameter wood bit, not a spade one, but the other spiral one, and then insert a large plastic drywall anchor, the ones you get in the clear plastic small boxes at the hardware store with the three-tipped spade tongue on the front of the cone. Nip the blade off at the base first, then drive the cone into the foam to ‘snug’ only. It will hold for years.
Great idea! I’m just getting ready to wire a new 2" foam extension to the layout (the rest of which is plywood) and I was thinking about using a sharpened wire hanger to make the holes. I wondered if there was a better way. I also liked the idea of keeping the hole open with straws or tubing of some type, but for simple wiring, it’s probably overkill.
use a hot wire, like you use for cutting foam.
I employed a method similar to a previous post. Used brass tubing from Micro Mark. Put the tube into a drill press and beveled the outside edge with a file. It made a clean hole into the foam equal to the outside diameter. Made a push rod from a coat hanger to push out the foam plug. Secondly, on the opposite end, I used a chamfer bit to bevel the inside of the tube. This makes a hole equal to the inside diameter of the tube. This is the way I made holes in the 2" foam to route my track wires.
Correction to my previous post. The outside bevel will create a hole equal to the inside diameter of the tube and visa versa for the inside bevel.
Yup me too. Made a special “attachement” tip for an old soldering gun that does this.
Be warned if you linger too long the hole will get bigger and bigger.