Hi all, first post here and super new to CO2 lasers!
I bought a used K40 machine (had my pants pulled down but we live and learn) turns out the laser was knackered. I have a new one coming today which has the cables pre-soldered onto the laser so I just need to attach them to the existing wires on my machine.
My question is, what is the safest way to do this? IE insulation? Will heat shrink be ok or do I need something more substantial?
I was thinking heat shrink then a piece of water hose filled with silicone?
The āK40 Introā in the top navigation should be very helpful to you. Itās a summary of a lot of hard-won experience with K40-class lasers. Note that it has valuable information on how to keep your brand-new tube from also becoming knackered!
Heat shrink definitely wonāt be enough. Thereās around 20,000 volts going to the laser. The dielectric strength of heat shrink is in the hundreds of volts, not the tens of thousands of volts; itās two orders of magnitude too weak. If by āwater hoseā you mean silicone hose of the type used for water in the laser, thatās OK, and you donāt need to fill it with more silicone. You can use heat shrink around the joint, but then encase it with silicone hose for 5cm or more on both sides of the joint. You can hold the silicone hose to the wire with zip ties. Make sure it canāt slip, and err on the side of more hose around it. Be generous!
Thank you for the reply! Can I use a crimp connector instead of solder?
Okay great so: connect the cables together with (hopefully a crimp?) something, cover the joint with 10cm+ of silicone hose, heatshrink the whole thing and everything is ok?
Should I heat shrink a couple times before the silicone hose? As obviously the hose has a greater diameter than the cable.
All you need to do it wrap the wire around the post. This is extremely high voltage and a gas-tight connection is not needed.
Itās not necessary but you can use a connector of some sort that slides over the post but crimp it on the wire first.
Do not solder!
Forces on the post in the tube can crack it.
Slide a piece of silicone tubing over the joint and then fill it with silicone and let it set up for 24hrs.
Slide a peice of silicon tubing 2+ inches long on one end of the wire. The tubing needs to be larger than the wire so you can get silicon inside. The bigger the better.
Solder the two wires together. When you solder do not leave points in the joint. You want a smooth ball joint.
Slide the tubing over the joint and then fill it with silicon.
This stuff works https://amzn.to/3dccu2N
If you canāt get that stuff choose an RTV with a high dielectric strength.
I canāt find the specs but I think it will be fine. In this case more silicon is better. Use the largest diameter tube in the order of 1/2" you can and insure that it extends at least 1" from the joint (2ā would be better) on each side of the joint.