Yihua 907A Soldering Handle - Loose Tip - Page 1
Forum section: electronics / general

author: TLengr
author_rank: Contributor
timestamp: March 01, 2016, 08:19:01 pm
content: I have a fairly new Yihua 878AD hot air/ soldering rework station with a 907A handle. With very little use, the tip becomes loose and its temp regulation is lost. The nut on the 907A handle holding the sleeve over the heating element and tip works itself loose frequently - even when tightened firmly before use. When the nut is loose, the tip flops around in the socket and is pretty much useless. Does anyone know of a fix for this? Thanks.

author: KL27x
author_rank: Super Contributor
timestamp: March 02, 2016, 02:56:15 am
content: I'd order a new handle for it for $10.00. Then proceed to screw with the nut. Perhaps if you burred it up enough, it will stay put?

author: torr032
author_rank: Regular Contributor
timestamp: March 02, 2016, 03:20:56 am
content: Or you can order the complete station with that handle for 20$http://www.hobbyking.com/hobbyking/store/__24790__Soldering_Station_with_Adjustable_Heat_Range_with_US_Plug.html

author: KL27x
author_rank: Super Contributor
timestamp: March 02, 2016, 04:21:26 am
content: Yeah, I guess it's worth having as a backup, if it costs $20.00! Heck, buy a new one with every roll of solder, lol.

author: TLengr
author_rank: Contributor
timestamp: March 03, 2016, 01:48:45 pm
content: Yes its true that these units are inexpensive and have been the butt of jokes from those needing or willing to spend much more for a production/service grade product. However, one of these will meet my current need just fine.Building from your suggestion I think I have found an inexpensive and effective fix for the loose tip/nut issue with my iron. I wrapped the threads on the handle with a couple of layers of Teflon thread tape. What a difference. I soldered/unsoldered several devices including PCB through hole connectors with no problems at all. The tip remained tightly seated and had good heat regulation. Excellent solder flow. I can't say if the fix is applicable in general or if the fix is effective long term: time will tell. It works for me.I am a newbee to this forum, but not to this industry and hobby. Repaired my first radio in 1960. I have melted a little solder in my day.

author: TLengr
author_rank: Contributor
timestamp: March 05, 2016, 02:33:40 pm
content: I'm sorry, I failed to mention that prior to my original posting I purchased a competitors replacement iron. It did not work. I received a refund, but left with an undependable soldering station I interchanged the nuts between handles. This didn't work either. I took the iron to a hardware store and neither the threads of the nut nor the handle matched any metric or other gauge they had. And of course the threads on the handle and nut don't match each other well which is the root of the problem.There must have been tens of thousands of these units sold. Assuming there are more than a relative few units units affected, the manufacturer should have addressed this issue long ago. Perhaps they have. If so, how does one get the correct part? Meanwhile, I have plenty of thread tape.

author: amyk
author_rank: Super Contributor
timestamp: March 06, 2016, 05:59:36 am
content: Quote from: TLengr on March 03, 2016, 01:48:45 pmCareful with the Teflon - its degradation byproducts at high temperatures include hydrofluoric acid.I have a real Hakko 936 and the tip nut does get loose after a few on-off cycles - probably normal due to thermal expansion.You could try (very slightly!) crushing the nut in a vice or press if it is naturally a loose fit.

author: TLengr
author_rank: Contributor
timestamp: March 06, 2016, 04:34:03 pm
content: Thanks amyk. Your post is thought provoking.“I have a real Hakko 936 and the tip nut does get loose after a few on-off cycles - probably normal due to thermal expansion.”I think you are correct. There must be metals with different coefficients of thermal expansion used in the handle designs. When tightening the nut on my Yihua 907A one can grasp it by thumb and finger and rock it back and forth right up to the point where the torque increases rapidly. With the Teflon tape installed the rocking is much less early on - possibly because more threads are in contact.Before posting I researched the temperature properties of Teflon. Several sources state the maximum operating temperature of Teflon is 260C (500F). This would be a big problem if the nut temperature ever reached as high as the tip temperature. For my situation it doesn't come close – please see my attachment. I am not qualified to say everything here is completely safe, but I think the data speaks for itself.It would be ideal if a manufacturer's rep were to see these postings and chime-in. They should have the resources to implement a better solution if its needed.