DIY Wire grabbing hemostat mod#2 (Insulation saver version) - Page 1
Forum section: electronics / projects

author: robrenz
author_rank: Super Contributor
timestamp: April 20, 2014, 10:28:15 pm
content: Onthis earlier threadI show hemostats modified for grabbing wires like this. These work great on high temp insulation that does not melt at normal soldering temperaturesbut when soldering wires with low melting temp insulation into high thermal mass solder cup connectors these are not good enough. The insulation get completely trashed.Here is a modification that I mentioned in that thread applied to a pair of hemostats that keeps the insulation in good shape. First I get a piece of copper tubing with an ID that matches the wire insulation diameter. Then take a diamond mandrel with a diameter that matches the tubing OD in a dremel or flex shaft and grind the pocket in the hemostat tip to receive the tubing.Tubing in place held by the latched hemostat.Brazed with high temperature silver solderVery thin jewelers saw blade used to....Saw the tube in half in line with the hemostat jaws.Jewelers saw frame, sanding sponge, abrasive bristle brush, fabric buff, files etc used to debur and polishTo end up looking like thisHere holding the wire ready to solder.Shown holding a wire ready to reflow into a pre filled solder cup in the heavy connectors.

author: 128er
author_rank: Regular Contributor
timestamp: April 20, 2014, 11:00:15 pm
content: Congratulation!Realy - that looks awesome! Now i know what to do with my bunch of jewelry saw blades.Many times i have tried to solder with high temperature silver solder. Each time it ended in a mess. Well, my pieces had more thermal mass then yours. I think my blowtorch has not enough capacity to heat up huge things.

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: April 20, 2014, 11:41:05 pm
content: Did a lot of silver soldering in gunsmithing , 1st is enough heat - Ox Acetylene welding tips .And just like some electrical soldering jobs , preheat in oven and last bit of heat to solder .

author: Vgkid
author_rank: Super Contributor
timestamp: April 20, 2014, 11:49:07 pm
content: That is really cool, I wish I had a fraction of your skills.

author: nanofrog
author_rank: Super Contributor
timestamp: April 21, 2014, 12:18:47 am
content: Very nice work rob!Yet another great idea tostealborrow.Seriously, a great big thanks for sharing your ideas with us.

author: SeanB
author_rank: Super Contributor
timestamp: April 21, 2014, 05:44:40 am
content: Very nice.

author: Kjelt
author_rank: Super Contributor
timestamp: April 21, 2014, 03:16:13 pm
content: Excellent craftmanship. Would be a nice kickstarter project

author: robrenz
author_rank: Super Contributor
timestamp: April 21, 2014, 09:35:33 pm
content: Thanks all for the kind words. There are anti wicking tweezers already availablehere.These are actually better in that they have two internal diameters. One to grab a short section of the conductors to minimize wicking and another to grab the insulation. I could have made these like that but just needed to make something quick and the tubing was handy.

author: nanofrog
author_rank: Super Contributor
timestamp: April 21, 2014, 10:17:05 pm
content: Quote from: robrenz on April 21, 2014, 09:35:33 pmWow! I didn't even know Clauss still made tweezers.Don't even see mention of them poking around on theirwebsite.

author: BravoV
author_rank: Super Contributor
timestamp: April 22, 2014, 03:34:54 am
content: Robrenz, thanks for sharing this, an excellent post as always.Noob question, about the high temp brazing with the silver solder, does butane torch workable ? My torch is those with separated butane canister, not those tiny refillable pocket size one.Similar to this one

author: robrenz
author_rank: Super Contributor
timestamp: April 22, 2014, 03:47:57 am
content: Thanks, Yes the butane torch will generate enough heat for things the size of the hemostats. It will actually work very well since it will be a neutral flame. If you are going to buy flux get the black higher temperature flux as it is more forgiving. Also if you are going to buy silver solder get easy flow 56 as this has the lowest melting temp of the hard silver solders that don't contain cadmium. It is important to have the flux on the joint before applying heat and heatvery gently/slowlyuntil the water evaporates out of the flux and starts to go to a liquid state. when the flux goes clear you are at temp to add the solder. If you heat too quickly the flux boils and jumps off the joint leaving spots that will oxidize.

author: BravoV
author_rank: Super Contributor
timestamp: April 22, 2014, 04:00:11 am
content: Great tips, especially on the slow heating and watching the flux state, thank you Sir !Btw, "neutral" flame ?Whats that ?

author: Vgkid
author_rank: Super Contributor
timestamp: April 22, 2014, 04:07:47 am
content: For the flux, would it be acid core, or normal electronics flux?

author: robrenz
author_rank: Super Contributor
timestamp: April 22, 2014, 04:29:52 am
content: Quote from: BravoV on April 22, 2014, 04:00:11 amOn oxy-acetylene: oxidizing flame = excess oxygen, reducing flame = excess acetylene, neutral = perfect mix.since the butane torch gets its oxygen from the atmosphere it is inherently neutral.

author: robrenz
author_rank: Super Contributor
timestamp: April 22, 2014, 11:21:44 am
content: Quote from: Vgkid on April 22, 2014, 04:07:47 amNeither,this is the bestIt is significantly better than the more common white flux.

author: robrenz
author_rank: Super Contributor
timestamp: April 22, 2014, 12:50:59 pm
content: Here is some silver soldering from my Ultimate Kelvin clip part 2 video.http://youtu.be/0wbC8fOKswM?t=9m7sThat is the black flux and easy flow 56 solder.