Sizes of blunt syringe needles for tacky flux (and other consumables) - Page 1
Forum section: electronics / beginners

author: FrankE
author_rank: Regular Contributor
timestamp: March 25, 2016, 03:33:10 am
content: I've got some new Amtech 559 V2 flux for surface mount and through hole repairs I have to do. The Amtech 30mL dispenser has a Luer lock so that blunt needle tips of known dimension can be screwed on the dispensing end., and a controlled amount of flux applied.What ranges (mm or gauge) of blunt syringe needles are suitable for manual dispensing of tacky flux for surface mount and through hole? I'll need to order online and I'm terrible at gauging sizes like that.I'm used to using syringes for heat txfer compound, adhesives, lubricants but this stuff is pricey and I don't want to spaff it all over a few boards.What you you folks use to control dispensed amount?While on consumables, I realised it's time to sort out my consumables when I knocked coffee over my keyboard last night, went for some IPA and sprayed the membrane with surgical spirit (in the UK=methanol + ethanol + some excipients like wintergreen + castor oil).I'm trying to find bottles that takeLuer lock caps,screw caps,atomiser caps.All the same size cap so I can swap out caps. A little faff in selection now saves repeated faff laterI had the bottles from RS with the wash caps (bendy straws). Fat lot of good they were, the caps weren't sealed withe the bottle so when the bottle was knocked over IPA leaked.

author: dadler
author_rank: Unknown
timestamp: March 25, 2016, 07:15:35 pm
content: Not exactly answering your question, but I got an assortment of these tips for cheap on eBay:http://www.ebay.com/itm/111856866201The larger of the sizes in the assortment are best for tacky flux and solder paste, in my experience.

author: KL27x
author_rank: Super Contributor
timestamp: March 25, 2016, 07:23:52 pm
content: For paste/flux, I use plastic dispensing needles. I have the 20 gauge needles. You can cut the tip to increase the size or change the angle.For vacuum pickup, finer 25-26 gauge bent steel needles will be the most useful, in my experience. For picking up SMD passives.

author: dadler
author_rank: Unknown
timestamp: March 25, 2016, 07:26:54 pm
content: I also got some Amtech flux recently--from Louis Rossman. It came in a 30cc syringe without a plunger (looks like it is intended to be used with an industrial dispensing device or otherwise). Still haven't decided how to dispense it yet.They sell hand dispensers for this type of syringe (Metcal makes one, check Amazon). But they are $60-70 which seems a bit much.

author: dadler
author_rank: Unknown
timestamp: March 25, 2016, 07:47:02 pm
content: I just measured the tips that I (primarily) use for tacky flux/solder paste. They are 1.27mm OD and 1mm ID.

author: FrankE
author_rank: Regular Contributor
timestamp: March 26, 2016, 11:20:30 am
content: Thanks everyone. I ordered a selection pack of bluntsI think I'll fill smaller luer lock syringes say 2mL, 5mL at most and use that, keeping the 30mL in the refrigerator to fill from.Those production dispensers as well as being pricey look like the don't offer much in they way of dispensed volume control

author: Cerebus
author_rank: Super Contributor
timestamp: March 26, 2016, 11:28:52 pm
content: Quote from: dadler on March 25, 2016, 07:47:02 pmI'd imagine that you probably have access to tools that let you accurately measure the OD but had to guesstimate the ID.For the benefit of those who go by gauge numbers that looks like an 18 gauge needle which has an OD of 1.270 mm and an ID of 0.838 mm.

author: zapta
author_rank: Super Contributor
timestamp: March 26, 2016, 11:32:33 pm
content: Quote from: KL27x on March 25, 2016, 07:23:52 pm+1 fit the plastic needles, they have conic internal passage for easier flow of thick paste.

author: Dago
author_rank: Frequent Contributor
timestamp: March 27, 2016, 07:13:20 am
content: Quote from: dadler on March 25, 2016, 07:26:54 pmI've always just put a plunger from a regular syringe and just used it like that. Works fine unless you are doing some actual production work or something.

author: dadler
author_rank: Unknown
timestamp: March 27, 2016, 07:24:02 am
content: Quote from: Cerebus on March 26, 2016, 11:28:52 pmI measured with my Mitutoyo calipers, but measuring ID this small involves some offset error due to the width of the caliper blades themselves/arc of tube. It was +/-0.9xx mm and I could get different readings by angling the calipers differently. The tips are also cheap from China...

author: dadler
author_rank: Unknown
timestamp: March 28, 2016, 04:01:19 am
content: So just an aside on the tacky flux:I have been using Kester RF741 tacky flux (http://www.kester.com/products/product/RF741-Rework-Flux/) for the past few SMD projects, and had just sort of gotten used to it.Today, I decided that I'd try the Amtech NC-559-V2-TF Flux that I received a while back (purchased from Louis Rossman @https://mailin.repair/amtech-nc-559-v2-30-cc-16160.html)As I mentioned above, the 30cc syringe does not come with a plunger (nor any tips, for that matter).I used what appears to be an 18 gauge tip (per one of the posts above), and I can say this stuff is incredibly thick and difficult to dispense without a plunger!I just pressed the back of the syringe with my thumb/fingers, which leaves a mark--because you have to press *hard* as this stuff is thick. Prior to heating, it's not a thin gel like the Kester flux--it seems more like a wax/oil emulsion of some sort. I am going to have to find a more appropriate dispensing mechanism... a plunger that fits the hole on the back of this syringe, or perhaps one of those pricy gun dispensers.Anyways, this flux is absolutely amazing. There is no comparison to the Kester flux.It's much thicker even at high heat, it's entirely clear which aids visibility, and it yields beautiful joints/pads.Hot air still does blow it around, but much less than the Kester flux. It doesn't smell/burn as awful as the Kester flux, either.The primary win is its viscosity though... This stuff stays where you put it.

author: nanofrog
author_rank: Super Contributor
timestamp: March 28, 2016, 04:19:04 am
content: Quote from: dadler on March 25, 2016, 07:26:54 pmA cockroach bait gun will do exactly what you want for $26.00 shipped (Masterline Bait Gun).; BTW, cockroach baits use 30ml syringes.There are also inexpensive dental impression mixing guns if you want one for 2 part epoxy (available in1:1/ 2:1, and4:1/10:1).

author: dadler
author_rank: Unknown
timestamp: March 28, 2016, 04:48:14 am
content: Quote from: nanofrog on March 28, 2016, 04:19:04 amAh, this is excellent. I had previously searched a lot, and even found a couple that look like those (@ China sellers of questionable repute), but didn't think to search for cockroach bait gunhehe!Thanks!

author: FrankE
author_rank: Regular Contributor
timestamp: April 03, 2016, 03:09:27 am
content: What size syringes do people use 2mL? 3mL? 5mL? 10mL?

author: KL27x
author_rank: Super Contributor
timestamp: April 03, 2016, 06:56:49 am
content: I bought 3mL syringes, because I initially wanted to use them for solder paste, and 3mL is the smallest diameter syringe that I could personally find with a luer locking tip.A flux pen is 10mL, FYI.A 3mL syringe of flux lasts a pretty long time, although when I am doing certain pcb assembly, I can go through 2-3 in a day. I will fill 5-6 syringes at a time, in that case. But under more ordinary use, 3mL of flux could last months.I'd suggest 5mL or 10mL might be ideal for a flux dispenser.

author: FrankE
author_rank: Regular Contributor
timestamp: April 03, 2016, 10:11:10 am
content: I've ordered these syringeshttp://www.ebay.co.uk/itm/280769928169http://www.ebay.co.uk/itm/281338157051and these tips[EDIT: WHICH AREN'T STANDARD SIZES]http://www.amazon.co.uk/Plastic-Dispensing-Needle-Blunt-Assortment/dp/B01AXWFHE8/ref=zg_bs_1938358031_14I'll see how I get on with the different sizes before considering longer or angled tips (account a little for the length / bend)I can always use spare syringes in the greenhouse for dosing tomato feed.

author: nanofrog
author_rank: Super Contributor
timestamp: April 03, 2016, 12:22:31 pm
content: Quote from: FrankE on April 03, 2016, 03:09:27 amFWIW, most of the commercial products I've gotten tend to use 10ml or 30ml (fits dispensing equipment).That said, CML Supply here in the US breaks down larger containers of Kester RF741 flux and Easy Paste 256 (6ml & 12ml respectively). Perhaps there's such a company in the UK/EU market?Quote from: FrankE on April 03, 2016, 10:11:10 amVery wise IMHO.

author: FrankE
author_rank: Regular Contributor
timestamp: April 03, 2016, 05:54:41 pm
content: Quote from: nanofrog on April 03, 2016, 12:22:31 pmI meant to use on the bench (easy to handle size and to get under the 'scope) rather than to the size of the syringe the flux/paste is supplied in. I buy the size that gives best value accounting for one's usage and for the shelf life plus estimate of the safety margin. I got 30mLI've spent a small fortune on the 'little' bits and pieces this week syringes, tips, scalpel blades, bottles, brushes, wipes, tapes and I've still got leaky bottles to replace. It all adds up and I've barely put iron to copper.Oh, I did treat myself to some new stainless steel and some glass.

author: nanofrog
author_rank: Super Contributor
timestamp: April 04, 2016, 12:22:40 am
content: Quote from: FrankE on April 03, 2016, 05:54:41 pmMakes sense.FWIW, I haven't sprung for a microscope yet as I try not to go below 0402 passives (prefer larger), but haven't had issues with paste flux or solder paste (I lay it in a line, not dots per pad).Quote from: FrankE on April 03, 2016, 05:54:41 pmI hear you. Good consumables add up quick.

author: FrankE
author_rank: Regular Contributor
timestamp: April 07, 2016, 11:21:43 am
content: I gave up trying to standardise bottle sizes in 50mL, 100mL and 200mL with interchangeable caps as I couldn't find anywhere with the full range of screw cap, Luer lok cap, wash spout cap and push spray cap. Well, not strictly true, I found companies that stocked everything but either horrendously expensive, without e-commerce or large minimum quantities of each item. I recall this over 10 years ago the last time I tried to sort my consumables out.The 60mL flux bottle from RS £2.46 ended up as good value as anything I found.It has a Luer taper cap rather than a Luer Lok. You push on the tip rather than screw on. Harder to find push on tips that Luer Lok ones, i'll tell ya.The syringes arrived today from Acuflow (ebay) BD 3mL and 5mL with luer Lok screw fitting. Same length, different bore. I'll order 10mL ones as well and since I'll wait an age for the blunt tips from China, maybe .

author: FrankE
author_rank: Regular Contributor
timestamp: April 08, 2016, 02:58:52 pm
content: I received the Luer Lok blunt needle tips today. They don't appear to be the standard colours and sizes defined on dispensing sites. The colours I have and their OD in mm (which is all I'm tooled up to measure) are:Colour................OD mmOrange Dk.........1.74Olive.................1.74Slate.................1.55Green Bright......1.21Brown...............0.96Pink..................0.84Purple...............0.74Blue..................0.64Orange Lt..........0.57Red 0.45White 0.44The product description states11 different diameters:1.55 / 1.37 / 1.16 / 0.84 / 0.7 / 0.60 / 0.51 / 0.41 / 0.34 / 0.26 / 0.21 mm.It's not important, it's for rough manual dispensing of "what looks about right" which is quite a broad goldilocks band. I'm not running continuous process plant calibrated to dispense a known bolus volume or mass through a defined tube diameters in a specified shot time.I'm currently using the pink (OD 0.84mm) for 0403 SMD rework electronics and bright green (OD 1.21mm) for through hole flux dispensing. I haven't set up a syringe for heatsink compound yet butI'll experiment and find a sizeIndustry standard correct colours, gauges and dimensions:Colour.....Gauge....ID in..... ID mm...OD in.....OD mmOlive........14.......0.069..... 1.753.....0.083.....2.108Orange.....15.......0.059..... 1.449.....0.072.....1.829Purple......16.......0.053..... 1.346.....0.065.....1.651White.......17.......0.048..... 1.219.....0.058.....1.473Pink.........18.......0.038..... 0.965.....0.049.....1.245Brown......19.......0.033..... 0.835.....0.043.....1.092Yellow......20.......0.025..... 0.635.....0.036.....0.914Green......21.......0.022..... 0.559.....0.033.....0.838Black.......22.......0.020..... 0.508.....0.028.....0.711Sky Blue..23.......0.016..... 0.406.....0.025.....0.635 About right amazon one 0.64Red.........24..... 0.015..... 0.381.....0.022.....0.559Blue........25..... 0.012..... 0.305.....0.020.....0.508Cream.....26..... 0.011..... 0.279.....0.019.....0.483Grey........27..... 0.009..... 0.229.....0.016.....0.406Lavender..30..... 0.006..... 0.152.....0.012.....0.305