Hakko 850 glass/quartz tube replacement - Page 1
Forum section: electronics / repair

author: dorkshoei
author_rank: Frequent Contributor
timestamp: April 27, 2017, 07:20:30 am
content: In case this is helpful.The quartz tube in the handle assembly of the Hakko 850 I bought used was cracked.I bought "10pcs Pyrex Round Bottom Test Tube 36mL 18mm*180mm" off eBay for $8.50 shipped, they have a 1mm wall thickness the same as the Hakko quartz tube.I assume Hakko used quartz over borosilicate because it's stronger. Heat wise, I have a pyrex/borosilicate cup on my TIG welding torch and it handles that just fine.I mounted a diamond wheel to my lathe and cut the required length off one of the tubes. I tried a wet tile saw first, that didn't work so goodThe resulting piece is a perfect fit and I still have 9 tubes left

author: Dr_Ram
author_rank: Contributor
timestamp: May 18, 2021, 04:09:13 am
content: Somewhat old post perhaps but saved me a lot of trouble with a Hakko 850B I bought on ePray in rather good condition but with a broken quartz tube. A Dremel with a cheap diamond cutting wheel did the trick. Thank you!Incidentally, I found that while the diaphragm pump pushes out air quite vigorously at the base, the airflow at the nozzle end is quite feeble even with the air at max. Is this the expected behaviour? The spec sheet says 26l/min which I suppose must be the pump capacity without the hose connected.Best - Ram

author: coppercone2
author_rank: Super Contributor
timestamp: May 18, 2021, 04:13:11 am
content: the problem is when you get a big globule of solder solidifying on the tube it can crack it easily, its likely quartz is there for thermal shock not general durability

author: Dr_Ram
author_rank: Contributor
timestamp: May 21, 2021, 06:01:36 am
content: Quote from: coppercone2 on May 18, 2021, 04:13:11 amWhich is why a 18mm borosilicate test tube cut to size with a Dremel will work - borosilicate glass will not crack at the temperature of molten solder because it can withstand high thermal shock. Place an empty borosilicate test tube on a bunsen burner and you can see for yourself! All that happens is a little softening at 800C. Quartz is rated for 1000+C.

author: coppercone2
author_rank: Super Contributor
timestamp: May 21, 2021, 06:04:51 am
content: I had borosilicate (brand name) thin laboratory glassware be effected by thermal shock, I don't think its completely immune, more like there is a probability that something will happen and its reduced with quartz, its likely just a better higher durability material they specified.Solder is different then a flame also, because a flame is fairly mellow, solder will splatter on the glass randomly with random sizes as its being sucked in and have a extremely high thermal transfer rate along the random interface.

author: Dr_Ram
author_rank: Contributor
timestamp: May 21, 2021, 09:25:22 am
content: Interesting points. Anyhow, for a Hakko 850B solder splatter is probably not a concern since it is only a hot air blower, not sucker.Going back to my Q on weak airflow, in my unit I found a spring at the handpiece entry which is not in the 850B manual illustration. Removing that spring resulted in a significant improvement in airflow.

author: coppercone2
author_rank: Super Contributor
timestamp: May 21, 2021, 06:06:48 pm
content: I meant borosilicate, i never had quartz, other then in my solder extractorbut I did hear people tell me its not perfect (i.e. you can't get rid of safety precautions in a chemistry lab because you have quartz for standard setups, because there is still a risk of glass breaking from heat). So you can't decide not to have a fume hood or something because you made the perfect setup.

author: dorkshoei
author_rank: Frequent Contributor
timestamp: May 21, 2021, 06:08:51 pm
content: Quote from: Dr_Ram on May 21, 2021, 09:25:22 amInteresting. Can you post a pic.To be honest, after replacing the tube that was broken in shipping I've never used my unit as the airflow is so poor. I have a Aoyue which is much better though far lower quality.I assumed my pump had just worn out. It was an eBay buy and the seller refunded me most of the cost as it arrived damaged so I've never given it any more thought.

author: Dr_Ram
author_rank: Contributor
timestamp: May 23, 2021, 07:09:33 am
content: Quote from: dorkshoei on May 21, 2021, 06:08:51 pmPic attached showing the removed spring and its approximate location in the hose. You will need to open the handpiece to see it, and then remove the hose from the handpiece end to remove the spring.Update 30 May - I opened up the diaphragm pump too and checked for any air filter that needs cleaning. It appears this model does not have an air filter of any sort!