good insulator that glues good for heatsink TO can pin holes - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: March 23, 2024, 07:44:25 am
content: I have a heatsink I made for a TO transistor but I want to glue little tubes into it so that the leads are kept away from the copper.I can slide tubing over the leads cut to lenght but I thought a better solution would be to actually glue something in there.What is the best material that adheres to glue the best that can be bought in a rod stock (and drilled) or tube form that I can use for this purpose?I have teflon super glue primer etc, but its not super necessary here. I thought I can optimize the design by choosing which material will glue the easiest, not necessarily the best insulator.Part of me thinks that maybe some kinda rough ceramic would be best? The glue should have really good adhesion to alumina I think. But some sort of plastic would be OK too.These typically annoy the shit out of me and break circuits when the insulator slips out, so I want it in there really good.Maybe filling them with epoxy and drilling it out would be the best way actually.

author: wraper
author_rank: Unknown
timestamp: March 23, 2024, 07:49:51 am
content: How about just using heatshrink tubes. As of adhesive, don't reinvent the wheel and use neutral RTV silicone, preferably electronics grade. I suggest ordering 70x (701-708) from China as those are the only types I know that can be bought in small tubes. I always have a few types of different viscosity stored in moisture barrier bag with desiccant. Don't use random glues on electronics as it will come back to bite you eventually.

author: coppercone2
author_rank: Super Contributor
timestamp: March 23, 2024, 07:52:10 am
content: I want it on the heatsink that I use for prototyping not on the transistorI think I will just counterbore it ALOT on both sides and then fill it with epoxy and drill it out, it actually seems like a solid idea. Drill it with a fresh sharp carbide drill so it dont get disturbed.

author: wraper
author_rank: Unknown
timestamp: March 23, 2024, 08:04:04 am
content: QuoteLike spend 10x more time to do that than you'll ever spend by adding tubes during prototyping.QuoteSounds stupid.BTW Soviets always used non-heatshrink plastic tubes and wire soldered at 90oat the end that prevented tube movement.QuoteThere are many TO-x packages, the vast majority plastic. So your post did not say anything about it being metal can and heatsink with holes.

author: coppercone2
author_rank: Super Contributor
timestamp: March 23, 2024, 08:10:24 am
content: yeah this heatsink is full of western decadence like not requiring extra work with adding bushings

author: coppercone2
author_rank: Super Contributor
timestamp: March 24, 2024, 07:02:01 am
content: alright I ultrasonic cleaned it for 10 min with alnox then I dried and heated up with a torch, filled the thing with DP270, baked 2 hours and drilled it out with carbide. So long you mind the air bubbles (bit of a pain in the ass) it seems to work OK if drilled with SHARP (new).not gonna be dealing with little wire sleeves like some 1984 factory bullshit

author: wraper
author_rank: Unknown
timestamp: March 24, 2024, 06:16:05 pm
content: QuoteWhy do that "bullshit" if you can do 100x greater bullshit.

author: edavid
author_rank: Super Contributor
timestamp: March 24, 2024, 06:25:15 pm
content: You just buy plastic shoulder washers and force fit them into a slightly smaller hole.If they ever get damaged, spend a few cents to replace them.https://www.digikey.com/en/products/detail/keystone-electronics/341/16011

author: coppercone2
author_rank: Super Contributor
timestamp: March 24, 2024, 07:43:16 pm
content: Quote from: edavid on March 24, 2024, 06:25:15 pmI considered this but its to-3 8 pin so you need to remove ALOT of copper and do flat counterbores if you want them to seat in the socket flush