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  1. #1

    Exclamation Melted wire from laser tube

    Hi everyone, i am totally new to this forum (this is my first post) so please give guidance as to where the appropriate section or if I am asking a stupid question.

    I have had a 80W china laser for about 3 months. Today I was cutting some wood and my laser stopped working. I checked the tube and to my horror, the wire melted. I've attach a photo here.

    My laser machine has water cooling and air assist attached. But based on the situation, i have reason to believe the water pump is not working well? Since the wire melted, i assume it was due to overheating.

    My questions are now:

    1) Do i have to change the whole C02 tube? How do I test if my tube is still working?

    2) How do I determine if the pump is the issue?

    3) How do I change the tube/wire given the image attached? Can I just cut the wires and replace it with another wire or do I have to replace the entire tube + wire.

    I'm sorry if this has been asked many times and I seek all your expert opinions.

    Thank you!

    Bryan
    Attached Thumbnails Attached Thumbnails Burnt Wire.jpg   Burnt Wire 2.jpg  

  2. #2
    Join Date
    Nov 2012
    Posts
    1267

    Re: Melted wire from laser tube

    This is not melting, this is high voltage arcing. Electrical tape is not really suitable for insulating high voltage wires. You need to unwrap it, clean the wires and splice them properly. Here is how I usually do it:
    - smooth solder joint with no sharp edges;
    - clear silicone sealant;
    - heat shrink tube;
    - more silicone sealant;
    - one more heat shrink tube.

    Good luck, and welcome to this great forum!

  3. #3
    Join Date
    Apr 2005
    Posts
    304

    Re: Melted wire from laser tube

    Wow, what a sloppy insulation on High Voltage wire.
    Try to unwrap the red tape to expose wire connection. Find a piece of silicone tubing which has a inner diameter as the outer diameter of HW wire with thick wall.
    Redo the connection, place over the silicone tube and then test your tube.
    I guess that all will be all right.
    Make no mistake between my personality and my attitude.
    My personality is who I am. My attitude depends on who you are.

  4. #4
    Join Date
    Mar 2007
    Posts
    2083

    Re: Melted wire from laser tube

    any silicone sealent you use needs to be an electrical grade that's acetic acid free

    the usual sealents sold for household use for sealing windows or door frames etc release too much acetic acid and corrode the wire !


    I would used several layers of heat shrink sleaving

    John

  5. #5
    Join Date
    Nov 2012
    Posts
    1267

    Re: Melted wire from laser tube

    Quote Originally Posted by john-100 View Post
    any silicone sealent you use needs to be an electrical grade that's acetic acid free
    the usual sealents sold for household use for sealing windows or door frames etc release too much acetic acid and corrode the wire !
    I have successfully used regular acetic silicone (identified by strong vinegar smell) for electronic repairs - insulating wires, securing parts and connectors etc. I even potted entire circuit boards with it without any bad effects. The stuff cures before it can cause corrosion.

  6. #6
    Join Date
    Apr 2005
    Posts
    304

    Re: Melted wire from laser tube

    You can buy "neutral" silicone which takes longer to vulcanize and does not produce acetic acid. It is also known as RTV Silicone.
    I use it frequently when repairing PC Boards with factory jumper wires.

    Anyway, @Bryansglaser, repair that sloppy chinesium insulation and you are good to go.
    Make no mistake between my personality and my attitude.
    My personality is who I am. My attitude depends on who you are.

  7. #7

    Re: Melted wire from laser tube

    You guys are all amazing haha!

    I will go look out for some silicone and will let you guys know if the tube works !!

  8. #8

    Re: Melted wire from laser tube

    oh also right, this doesnt mean my water pump is damage right? just poor wrapping of the wires?

  9. #9
    Join Date
    Nov 2012
    Posts
    1267

    Re: Melted wire from laser tube

    Quote Originally Posted by Bryansglaser View Post
    oh also right, this doesnt mean my water pump is damage right? just poor wrapping of the wires?
    No, this is a purely electrical fault, not overheating. The pump did not cause it (but check it anyway).

  10. #10

    Re: Melted wire from laser tube

    Thanks!!! really appreciate your advice... just fyi, here's how the inside tube looked like previously.
    Attached Thumbnails Attached Thumbnails Tubing.jpg   tubing 2.jpg  

  11. #11
    Join Date
    May 2020
    Posts
    2

    Re: Melted wire from laser tube

    Quote Originally Posted by Bryansglaser View Post
    Thanks!!! really appreciate your advice... just fyi, here's how the inside tube looked like previously.
    I am curious is it working now? there is black burn mark on my 40w laser tube's lowervoltage connector...the machine still able to cut, but the connection got more and more burnned. so i stopped using the machine. wondering what caused it... and what should i do?

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