Results 1 to 12 of 12

Thread: Silvia thermocouple help needed -- maybe Gronk can assist?

  1. #1
    Senior Member
    Join Date
    Apr 2006
    Location
    Woodend Victoria
    Posts
    104

    Silvia thermocouple help needed -- maybe Gronk can assist?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Im planning on doing a Gronk thermocouple addition to my new Silvia (against my wifes wishes who thinks doing anything will wreck it!).
    Ive had the device shown in the pic for some time -- it assisted me at first in my coffee roasting, but Ive got that down pat now.
    My problem is that the long rigid stem at the end of the probe measures 6.5 inches (6cm) and that makes things very tricky ...
    I dont want to start cutting things till I know whats possible. So I need simply to know if I cut off that rigid end so I just have the flexible wire (which will then measure 1.1 metres), would I be able to solder onto whatever is exposed a screw-on thing like a small washer? AS you can tell from the way Ive asked this, I have absolutely no experience in this regard -- dont even know what to ask the hardware store for to put on the end of the wire!
    But having this thermocouple in hand must mean Im halfway there -- and it has a timer which might be useful for pulling shots too!
    Cheers

  2. #2
    Senior Member
    Join Date
    Apr 2006
    Location
    Woodend Victoria
    Posts
    104

    Re: Silvia thermocouple help needed -- maybe Gronk can assist?

    Since writing, Ive chatted to a friend who pointed out that I might inadvertently slice through the sensor part of the tip.
    So I think my best idea is to get a wide piece of wood (ie 1.5 inch diameter) and carefully, near the part where the rigid piece affixes the wife, bend it into a loop -- that will make it the right size to fit inside Silvia. Solder a tag onto the existing end, connect under the existiong thermostat connection, and all should be well ... how does that sound?

  3. #3
    A_M
    A_M is offline
    Guest
    Join Date
    Mar 2006
    Posts
    6,381

    Re: Silvia thermocouple help needed -- maybe Gronk can assist?

    Send a pic or two of what your trying to do...

    1: If it is a true thermocouple the two wires can be cut and joined with a little bit of a fiddle..

    2: If it is an encapsulated bead type... Then this may not be the case...

    3: Some systems actually use the leakage across a diode junction (can be quite liner) as the the sensor, so any fiddling can break it.

    4: In addition if you wrap / twist and or kink some of the leads you can introduce any number of errors.

    Do not prove your wife right AGAIN.... *:D



  4. #4
    Senior Member
    Join Date
    Mar 2006
    Posts
    188

    Re: Silvia thermocouple help needed -- maybe Gronk can assist?

    Anthony -

    I suggest that you do not destroy your sleeved thermocouple. *These things can be expensive, and youll probably find another use for it someday.

    Buy, or make, a simple washer-style sensor. *For this you will need a short length of type K thermocouple wire, 24AWG would be a good size. *Get the kind with teflon insulation on the two conductors with a teflon overwrap. *Youll also need a yellow, type K mini-plug for making the connection to your meter.

    Strip around 6mm from one end of the t/c wire and twist the 2 conductors tightly together. *Trim the twisted part back so there is around 3-4mm of exposed wire.

    Buy an uninsulated ring-type crimp connector at the hardware store (the barrel needs to be large enough to accommodate the thermocouple wire with insulation, and the ring opening should be around 3mm diameter).

    Pass the twisted ends through the barrel of the crimp connector so that the bare tips extend around 1mm past the end of the barrel towards the ring. *Gently crimp the barrel, just enough to secure it to the thermocouple wire insulation.

    Try and solder the bare twisted leads to the ring connector. *Use non-lead solder (for its higher melting point). *Mostly the solders purpose is to provide good thermal continuity between the thermocouple wire tips and the ring. *You will probably have trouble, however, getting the solder to flow onto the type K wire, but give it a try.

    Jim

  5. #5
    sdg
    sdg is offline
    Senior Member
    Join Date
    Mar 2008
    Posts
    368

    Re: Silvia thermocouple help needed -- maybe Gronk can assist?

    Hmm -- without the pic its rather hard to see (pun intended ;) ) what the problem is.

    But the K-type TC as used for "gronking" by myself and others is worth a whole $10 from Jaycar, and adapters can be had. Why butcher your existing probe?

    <edit> -- current Jaycar TCs list

    Bah -- dunt work -- just search on thermocouple...

  6. #6
    A_M
    A_M is offline
    Guest
    Join Date
    Mar 2006
    Posts
    6,381

    Re: Silvia thermocouple help needed -- maybe Gronk can assist?

    Quote Originally Posted by 5B4C4F280 link=1232691517/4#4 date=1232714777
    is worth a whole $10 from Jaycar
    And one then questions the issue of accuracy ;D :D :o ::)

    Oh well the Auditor and Calibration side of me must go and :(

    TG where are you :-?

  7. #7
    Senior Member
    Join Date
    Apr 2007
    Posts
    596

    Re: Silvia thermocouple help needed -- maybe Gronk can assist?

    In reference to Jims method of making a washer type t/c, would just cutting the ball off a ball type t/c and joining the two wires together work, also if soldering is difficult would using heatsink plaster(sets like silastic) do.

  8. #8
    A_M
    A_M is offline
    Guest
    Join Date
    Mar 2006
    Posts
    6,381

    Re: Silvia thermocouple help needed -- maybe Gronk can assist?

    Quote Originally Posted by 233C36273A34383027550 link=1232691517/6#6 date=1232743737
    In reference to Jims method of making a washer type t/c, would just cutting the ball off a ball type t/c and joining the two wires together work, also if soldering is difficult would using heatsink plaster(sets like silastic) do.
    As Jim and I have implied... It can be a fiddle, but can be done.

    If you read my other posts on Accuracy of Thermocouples etc I also mention the how and why they work... Thus due to the reaction and small voltages the dis-similar metals generate...

    A GOOD contact is required... If not, your readings may be inaccurate but could be all over the place as well and not stable..

    While I use silastic for many reasons the gases it gives of when curing and its chemical make up can be quite corrosive...

  9. #9
    Senior Member
    Join Date
    Apr 2006
    Location
    Woodend Victoria
    Posts
    104

    Re: Silvia thermocouple help needed -- maybe Gronk can assist?

    Experimentation shows I can fit that thermocouple in without bending
    -- except I cant get it to reach the thermostat screw. I can however
    just secure it to the top of the boiler with either heatproof tape or
    putty, or even solder it on. Ill give that a go ....
    Pics will follow.

  10. #10
    Senior Member
    Join Date
    Mar 2006
    Posts
    188

    Re: Silvia thermocouple help needed -- maybe Gronk can assist?

    Quote Originally Posted by 637C76677A74787067150 link=1232691517/6#6 date=1232743737
    In reference to Jims method of making a washer type t/c, would just cutting the ball off a ball type t/c and joining the two wires together work, also if soldering is difficult would using heatsink plaster(sets like silastic) do.
    If by a "ball type t/c" you are referring to one with a little bead joining the ends of the wires, then you would want to leave the ball/bead in place. *This bead accomplishes the same thing as twisting the wires, only it is made using a special welder and does a much better job.

    Quote Originally Posted by 547B72706758747B74727078707B61150 link=1232691517/7#7 date=1232746448
    If you read my other posts on Accuracy of Thermocouples etc I also mention the how and why they work... Thus due to the reaction and small voltages the dis-similar metals generate...

    A GOOD contact is required... *If not, your readings may be *inaccurate but could be all over the place as well and not stable..
    Dont know about you, but I was a little disappointed when I learned that it wasnt magic that made them work *;)

    We are measuring micro-volts to get accurate temperatures, so anything that inhibits electrical continuity at the sensing tip can really mess up the readings.

    Jim

  11. #11
    Senior Member
    Join Date
    Mar 2006
    Posts
    188

    Re: Silvia thermocouple help needed -- maybe Gronk can assist?

    Quote Originally Posted by 2922202B24293A232D480 link=1232691517/8#8 date=1232750585
    Experimentation shows I can fit that thermocouple in without bending
    -- except I cant get it to reach the thermostat screw. I can however
    just secure it to the top of the boiler with either heatproof tape or
    putty, or even solder it on. Ill give that a go ....
    Pics will follow.
    It is hard to know exactly what your probe looks like. *But most sleeved probes suffer from "stem effect." *To avoid this, the sleeve needs to be in full contact with the thing being measured*for several "stem diameters." * This type of probe is really better suited for immersion in a liquid or gas.

    Avoiding stem effect is going to be quite a challenge in this situation, I think. *Im afraid youre going to end up measuring some random combination of the boiler temp and the temp of the surrounding air.

    Jim

  12. #12
    Senior Member
    Join Date
    Jul 2008
    Posts
    323

    Re: Silvia thermocouple help needed -- maybe Gronk can assist?

    Gday Anthony

    Sorry I only just stumbled across this thread.

    Looks like you got all the good info needed from the other posters

    Cheers :)



Similar Threads

  1. Fitting a bead type thermocouple (to a Silvia).
    By Toad in forum Brewing Equipment (non-machine specific)
    Replies: 3
    Last Post: 28th August 2012, 09:18 PM
  2. Are you adequately prepared to assist me with my purchasing decision?
    By IPYF in forum Brewing Equipment - Entry level (sub $500)
    Replies: 45
    Last Post: 12th April 2012, 10:15 AM
  3. Do assist me in my quest to become accredited.
    By IPYF in forum General Coffee Related...
    Replies: 5
    Last Post: 28th March 2012, 09:20 PM
  4. My Gronk silvia thermocouple (with pics)
    By ajhclarke in forum Brewing Equipment - Midrange ($500-$1500)
    Replies: 3
    Last Post: 25th January 2009, 08:43 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •