Glue to temporarily attach thermocouple wire to fixtures? - Page 1
Forum section: electronics / general

author: julian1
author_rank: Frequent Contributor
timestamp: September 21, 2020, 01:38:41 am
content: Kaptan tape works to a point.But are there any glues available, that could withstand higher temperatures (up to 300C) , and could also be easily cut away or removed with common solvents (isopropyl/ acetone). Maybe silicone based or rubber-like plasticity with some give.

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: September 21, 2020, 02:31:32 am
content: Not sure about glue, but why not use a washer/eyelet thermocouple like:https://au.rs-online.com/web/p/thermocouples/2000615/

author: SMTech
author_rank: Frequent Contributor
timestamp: September 21, 2020, 09:38:10 am
content: If you are using them for profiling, the other option is to solder the thermocouples in place using high temp solder, there are several with melting points around 300C which is way past anything you should see when reflowing SN100 or SAC.

author: julian1
author_rank: Frequent Contributor
timestamp: September 21, 2020, 10:32:01 am
content: I'm interested in attaching to boards, so the mechanical strength needed is almost nothing. Anything ghetto style would work. I was thinking about modelling clay, but figure there must be something better.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 21, 2020, 05:05:32 pm
content: There are high temperature cements. There may be not easy solvent, but the mechanical strength and adhesion to metal is usually poor. So it can usually be scraped off and small residue may be removed with acid. The is also sodium silicate solution, but here is may be a little more tricky to remove.

author: Mangozac
author_rank: Frequent Contributor
timestamp: September 21, 2020, 08:34:42 pm
content: We just fasten the wire in place with some kapton tape and put a dob of heat transfer paste where the thermocouple tip touches the PCB.

author: elecman14
author_rank: Unknown
timestamp: September 21, 2020, 08:47:36 pm
content: Could you use peelable solder mask? Seems like that is used for component adhesion in some applications.

author: pickle9000
author_rank: Super Contributor
timestamp: September 21, 2020, 08:55:55 pm
content: High temp RTV silicone (red) in an automotive store.

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: September 21, 2020, 11:07:35 pm
content: Quote from: Mangozac on September 21, 2020, 08:34:42 pmThis will work for a bit, but after X many thermal cycles your paste will dry out and make an air cavity between the tip and board, which will eventually lead to underestimated temperature readings

author: pickle9000
author_rank: Super Contributor
timestamp: September 21, 2020, 11:53:19 pm
content: This stuff works very well.https://www.emisupply.com/catalog/supply-emi5005-food-grade-silicone-sealant-aluminum-103oz-p-9731.html#.X2k8b3tlBPY

author: Mangozac
author_rank: Frequent Contributor
timestamp: September 22, 2020, 03:01:50 am
content: Quote from: ANTALIFE on September 21, 2020, 11:07:35 pmYeah, that's why it's only a temporary solution

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: September 22, 2020, 03:56:44 am
content: Quote from: Mangozac on September 22, 2020, 03:01:50 amOh lol, completely missed the "temporary" part from OP...

author: CatalinaWOW
author_rank: Super Contributor
timestamp: September 22, 2020, 04:17:04 am
content: Quote from: ANTALIFE on September 21, 2020, 11:07:35 pmAll temperature readings must be regarded as estimates. The thermocouple, its wires and any hold down material modify the thermal paths. If you really need to know the precise temperature it requires a lot of thought and thermal modeling. Or perhaps remote sensing with a pyrometer or thermal camera. Those options don't modify the thermal environment, but tend to be lower precision.Drying thermal paste can lead to either high or low temp estimates, depending on which side of the thermocouple the air gap forms. And can lead to low estimates early if the thermal paste acts as a spreader.