Zhongdi ZD-8936 - Hakko clone 907 (936) heating element mod - Page 1
Forum section: electronics / general

author: pilon
author_rank: Newbie
timestamp: January 03, 2017, 04:14:39 pm
content: I recently bought a re-branded Zhongdi ZD-8936 from a big re-seller here in Sweden.Haven't seen any reviews on this soldering station, so it was somewhat a "buy a pig in a poke" situation.But when I powered it up, I noticed that even though it reached/stated 300 degrees (C) in ~10 seconds, it didn't melt the 60/40 solder (even close to base), until another ~20 seconds later.So I disassembled the soldering iron (which looks quite like all those hakko 907's clones out there) and noticed the tip had a really loose fit.Anyhow, I grabbed a copper wire from a FK installation cable (7 x 0.52mm) and turned around a base of similar size (screwdriver) as the heating element for about 20mm.Then I sanded down the outer surface so that it was flat and the tip made a nice good fit (but still didn't get stuck), and then sleeved it over the heating element.With this change, when the station reaches about 200 degrees the temperature starts to increase somewhat slower, but the solder was melt after just 16 seconds (almost half the time).I haven't been able to measure the recovery-time though, but in theory it should be better. Perhaps I should waste a tip and dip it in water and see when it melts solder again (or is there a better method)?Btw, I've left a bit of the top heating element free/unsleeved since it seems that the thermocouple is placed there and I rather want it to make direct contact with the tip itself.BUT... Can I somehow damage or reduce the life of the tip/heating element/station by using this "copper sleeve" on my heating element, or is it just plain stupid for any other reason?EDIT: Altered title

author: nanofrog
author_rank: Super Contributor
timestamp: January 03, 2017, 10:05:13 pm
content: Nice work.I'd make another that goes all the way down to the end of the heating element though, as that air gap is negatively affecting performance.

author: pilon
author_rank: Newbie
timestamp: January 03, 2017, 10:46:44 pm
content: Thanks! was thinking about that too. But since I saw a video from bigclivedotcom (dunno if I may insert the link here),he verified with an IR camera that the heat (on his clone 907 heating element) was only generated at the top/end of the element.Dunno if it's the same on my heating element though, but I must assume it is.../ P

author: nanofrog
author_rank: Super Contributor
timestamp: January 03, 2017, 10:53:21 pm
content: Quote from: pilon on January 03, 2017, 10:46:44 pmLinks are fine.I'm thinking more in terms of TC response & accuracy rather than actual heating.

author: stj
author_rank: Super Contributor
timestamp: January 04, 2017, 06:08:45 pm
content: put some thermal paste on the element before you fit the tip.

author: pilon
author_rank: Newbie
timestamp: January 05, 2017, 02:10:24 am
content: Quote from: stj on January 04, 2017, 06:08:45 pmYesAs a matter of fact, I was evaluating that too (just theoretically though). But I came to the conclusion that it might have it downsides, as pointed out in this thread.https://www.eevblog.com/forum/chat/soldering-iron-tip-heat-transfer/Quote from: nanofrog on January 03, 2017, 10:53:21 pmLooking at this tear-down video from bigcliveI assumed that the tip of the heating element didn't generate any heat anyway.Hence I aimed at getting the heat from the "active" part of the element transferred onto the base of the tip, and then letting the tip of the heating element (assumably the thermocouple) touch the inner base of the tip to get the temperature reading from there to get a more correct reading and consequently get a faster TC response.I've put together a very "harsh" image of my thoughs