Where can I buy thermal glue? - Page 1
Forum section: electronics / repair

author: hansibull
author_rank: Regular Contributor
timestamp: April 22, 2018, 06:39:36 pm
content: Hi!I'm currently repairing an old Altec Lansing 9444B amplifier, and I want to replace a few TO-220 heatsinks with some larger ones. Problem is, there's a few zener diodes glued to the heatsinks with some kind of thermal glue. Does anybody know where I can get this? Canthis gluebe used?Thanks!

author: GEOelectronics
author_rank: Regular Contributor
timestamp: April 22, 2018, 06:56:11 pm
content: Hello. If you mean that white stuff, it's not glue but heatsink compound.Do a search for "wakefield thermal joint compound type 120"George Dowell

author: hansibull
author_rank: Regular Contributor
timestamp: April 22, 2018, 07:05:53 pm
content: Thanks. Shipping from Digikey to Norway is pretty expensive though..The white stuff between the zener and the heatsink is pretty hard. It's not porous, but not soft either.I'm pretty sure it's not just regular heart sink compound that's dried out.

author: mariush
author_rank: Super Contributor
timestamp: April 22, 2018, 07:10:17 pm
content: I don't even think it's heatsink compound or thermal glue, i think it's just that "selastic" material , silicon compound that hardens after application and holds stuff in place, used just to prevent vibration of the components inside the case.Doesn't do anything special for heat transfer and should be obvious by looking at the component legs that they intend to isolate the parts from others and if they block leads with those things they don't really care much about heat transfer.Note that some of these solutions as they dry out from the heat they can become slightly conductive and cause problems ... so if you see the substance dark yellow / brown that portion could be a bit conductive - if the amp. has issues, may want to separate the part from the heatsink and break any potential paths that could affect circuit (like if substance would cause a short across the diode leads which doesn't seem to be the case here) and test again and see if that solved something

author: hansibull
author_rank: Regular Contributor
timestamp: April 22, 2018, 07:14:44 pm
content: QuoteIt's strange that they want to all that effort (isolating legs, gluing the diode to the heatsink) if they could just mount the diodes flat on the PCB with no additional isolation or glue.

author: kizmit99
author_rank: Regular Contributor
timestamp: April 22, 2018, 07:14:55 pm
content: I would think it's something like this:https://www.ebay.com/p/10g-Thermal-Conductive-Plaster-Viscous-Adhesive-Glue-for-PC-Heatsink-GPU-IC-Chip/848135406?iid=121292809947&chn=psNote, there are tons of folks selling this stuff (probably a lot cheaper than this) -- I just grabbed the first one I saw on ebay...I've used it, it hardens into a rubbery consistency and does provide thermal conductivity.Edit: This is the actual stuff I used (from AliExpress):https://www.aliexpress.com/item/3pcsx5g-Thermal-Pads-Conductive-Heatsink-Plaster-Viscous-Adhesive-For-Chip-CPU-GPU-VGA-RAM-LED-IC/1996938004.html?spm=a2g0s.9042311.0.0.MG0MhA

author: hansibull
author_rank: Regular Contributor
timestamp: April 22, 2018, 07:18:31 pm
content: Awesome! Do you know if the glue is electrically conductive when dry?

author: kizmit99
author_rank: Regular Contributor
timestamp: April 22, 2018, 07:19:26 pm
content: It is not (electrically conductive).

author: hansibull
author_rank: Regular Contributor
timestamp: April 22, 2018, 07:25:04 pm
content: Thanks for the links! Ordered!

author: tecman
author_rank: Frequent Contributor
timestamp: April 22, 2018, 07:29:53 pm
content: QuoteThe diodes are attached to the heat sink (of a transistor) so that the 2 devices are thermally tracking. This is a common practice used to maintain a constant transistor bias in the amplifier.BTW a filled epoxy, like JB Weld is a good choice for the attachment.paul

author: Samogon
author_rank: Frequent Contributor
timestamp: April 22, 2018, 09:50:08 pm
content: 10g Thermal Conductive Silicone Plaster Viscous Adhesive Compound Cooling Glue For L...https://www.amazon.com/dp/B072MSXHJD/ref=cm_sw_r_sms_c_api_Mkq3AbZ2GDQGMIt sets hard

author: ChrisLX200
author_rank: Unknown
timestamp: April 23, 2018, 09:54:38 pm
content: It also sets hard in the tube after an inconveniently short time - a few months - so don't bother stocking up on the stuff..

author: ovnr
author_rank: Frequent Contributor
timestamp: April 23, 2018, 10:22:49 pm
content: After getting fed up with some cheap chinese thermal glue setting in the tube and not setting well when actually gluing something, I ended up buying some fine pure copper powder and mixing it with two-part silicone - about 85-90% copper by weight. It's definitely not as good as a proper thermal paste, but it works surprisingly well and ended up being non-conductive. It's also just the right mix of robust and removable - it'll rip off if you try hard, but it's not going to fall off. Plus it cures consistently.And it was a lot cheaper than buying aproperthermal adhesive - like $2.50 for 30 grams of copper, and I already had the silicone.

author: cellularmitosis
author_rank: Unknown
timestamp: April 23, 2018, 10:54:59 pm
content: I've had good luck with the two part Arctic Silver thermal epoxy. Its on the expensive side, $10 to $15 for the two small tubes.

author: uy2618Mc01
author_rank: Newbie
timestamp: April 25, 2018, 10:23:47 am
content: "The white stuff" comes in two consistencies. One is just thermal paste as you allude. The other is thermal GLUE. Readily obtained via Ebay or similar in 5ml tubes. It looked to me like the thermal paste in a silicone matrix. Its fairly effective, but deteriorates in a semi-outside environment and becomes no longer elastic.I just searched on "thermal glue" on Ebay and came up with reams of ads.

author: uy2618Mc01
author_rank: Newbie
timestamp: April 25, 2018, 10:24:45 am
content: Very NOT conductive.