silicone thermal grease + adhesive? - Page 1
Forum section: electronics / beginners

author: ledtester
author_rank: Super Contributor
timestamp: June 21, 2018, 07:32:33 pm
content: Total beginner question... what is the white stuff encasing the thermister in the attached pic?It is clearly some sort of thermal grease, but it also hardens and appears to perform an adhesive function.Is it something like:https://www.amazon.com/Super-Lube-98003-Silicone-White/dp/B0044NI2M2And a followup -- how would I find the bracket holding the thermister? (I suppose I could just make one ... it just looks like a small metal tab curled at one end and a screw hole at the other.)

author: kjr18
author_rank: Regular Contributor
timestamp: June 21, 2018, 08:21:12 pm
content: It's more likethose things sold on ebay

author: KMoffett
author_rank: Regular Contributor
timestamp: June 21, 2018, 08:45:24 pm
content: Thermal grease is just that...not an adhesive. Thus the screws. T/c clamp is probably custom, so make your own.Ken

author: David Hess
author_rank: Super Contributor
timestamp: June 21, 2018, 09:09:13 pm
content: I have seen the clamps before but do not know what they are called. Keystone might have them available, maybe a cable half clamp?http://www.keyelco.com/category.cfm/Cable-clamps-Nylon-Steel/Steel-Half-Cable-Clamps/p/1260/id/434/c_id/818Adhesive thermal compound is a standard product which is suitable where the mechanical construction will not keep normal thermal compound in place. In the past I have not bothered using it; I just epoxied the sensor in place with something like epoxy 907.https://www.miller-stephenson.com/product/ms-907-two-part-epoxy-adhesive/https://www.amazon.com/Loctite-Hysol-gram-Epoxy-Adhesive/dp/B000WXDLAQThick cyanoacrylate like from a hobby store would work also.

author: aju11
author_rank: Contributor
timestamp: June 25, 2018, 09:35:52 am
content: Quote from: David Hess on June 21, 2018, 09:09:13 pmI believe Cynoacrylate is poor thermal conductor. Won't it affect the thermal conductivity from heat sink to the thermister?

author: stj
author_rank: Super Contributor
timestamp: June 25, 2018, 03:51:22 pm
content: it's this:https://www.ebay.co.uk/itm/131516987160i use it to mount small heatsinks on i.c.'sNEVER use cyanocrylate near anything that heats up, it will vaporise and create a big mess - including sticking to your eyballs!i would like to shoot the people that use it to tack down wires for this reason!

author: David Hess
author_rank: Super Contributor
timestamp: June 25, 2018, 04:20:12 pm
content: Quote from: aju11 on June 25, 2018, 09:35:52 amThe junction to ambient thermal resistance of the thermal sensor is high so the lowest thermal resistance between the heat sink and thermal sensor is not required.Holding the thermal sensor captive is a good idea; I have sometimes seen the adhesive pop off. But there are other ways like drilling a hole into the heat sink and mounting the sensor inside or using a sensor which has its own mounting hole for a screw.Quote from: stj on June 25, 2018, 03:51:22 pmIt should not be getting that hot. I have never had a problem with cyanoacrylate when used to tack down wires and sometimes prefer it as it is easy to loosen with a heat gun if necessary although that is also the case with many adhesives.

author: schmitt trigger
author_rank: Super Contributor
timestamp: June 25, 2018, 04:34:28 pm
content: There are all sorts of thermally conducting adhesives.The better are silver filled, but also the most expensive.But they are an overkill unless your components are dissipating a ton of heat and your heat sink's thermal resistance is very, very low. Which would make the case-to-heatsink thermal resistance a significant contributor.I have only used this product once. Unfortunately like most epoxies, once that you breach the seal the shelf life is very limited, so one ends up wasting a lot of an expensive material.http://www.arcticsilver.com/as5.htm