Small Quantity of Loctite GC 10 - Page 1
Forum section: electronics / general

author: elau
author_rank: Newbie
timestamp: March 05, 2021, 04:36:29 am
content: Loctite GC 10 seems to be well regarded here and I’d like to try it out but I’m not sure I’m ready to spend over $100 on a tub from Digi-Key. Are there any options for smaller quantities or samples that anyone has come across?

author: jmelson
author_rank: Super Contributor
timestamp: March 05, 2021, 05:25:21 pm
content: Quote from: elau on March 05, 2021, 04:36:29 amIt is worth the expense to get it, it is better than a BUNCH of other pastes I have tried. It has a long shelf life, check on eBay, you can find people who will sell you some GC10 that is a little older but still perfectly OK. Also, just do a web search, there are a bunch of specialty vendors that sell it online, and some of their prices are much better. Also, don't buy 500 g unless you really do a lot of reflow soldering. 500 g will do many hundreds of boards. There are smaller containers available.Jon

author: elau
author_rank: Newbie
timestamp: March 06, 2021, 03:12:33 am
content: Quote from: jmelson on March 05, 2021, 05:25:21 pmEBay has a couple that are well past their expiration date but even so prices are pretty high. I might give one of them a shot if the seller will accept a lowball offer.Do you have any links for the specialty sellers online that have good pricing? In my standard googling I’m not seeing much better than the 500g tubs at over $100.

author: jmelson
author_rank: Super Contributor
timestamp: March 06, 2021, 04:16:23 pm
content: This is the best one I've found so far, under $100 in single quantity. This is new, from the manufacturer. It seems smaller jars, etc. are not available from Loctite?https://www.eis-inc.com/lead-free-solder-paste/p-hen1993881Newark has it for $102/jar.Jon

author: Kean
author_rank: Unknown
timestamp: March 06, 2021, 05:08:02 pm
content: Quote from: blueskull on March 05, 2021, 04:40:01 amThere are several formulations in the TS391 series - including leaded (AX), lead free (SNL), and low temperature (LT) variants.And they come packaged as 15g, 35g, 50g, 250g, or 500g.You probably want the cheapest (lead free) options which are TS391SNL (15g syringe) or TS391SNL50 (50g tub).

author: Reckless
author_rank: Frequent Contributor
timestamp: March 07, 2021, 01:40:51 am
content: We don't like GC-10 paste. It gets runny way too fast for us within 30 mins. We prefer AIM solder paste over loctite. We get tombstoning and other issues more with other pastes. So far tried 5 other brands of solder paste and AIM lead free paste has been the best for us including Indium which is supposed to be the best in the business used by apple/etc.

author: jmelson
author_rank: Super Contributor
timestamp: March 07, 2021, 02:41:44 am
content: Quote from: Reckless on March 07, 2021, 01:40:51 amVERY VERY strange! Are you refrigerating the paste? You are not supposed to. I've been using GC10, and have on occasion left boards out overnight and the printed paste looked JUST like it did the day before. I HAVE had the runny paste issue with, I think, some Indium paste. I got nice square bricks when printed, but an hour later they had all sagged and the flux had run out over the board.Are you sure this isn't counterfeit paste? Do you mix the paste before putting on the stencil? The GC10 usually doesn't separate, but it is a good idea to mix it anyway.I have also gone through a number of different paste manufacturers, but found the GC10 to work REALLY well for me!Jon

author: Mangozac
author_rank: Frequent Contributor
timestamp: March 07, 2021, 10:30:36 am
content: Quote from: Reckless on March 07, 2021, 01:40:51 amI second the use of AIM pastes. NC257-2 gives us textbook solder joints even after leaving it on the stencil for far longer than recommended!

author: Reckless
author_rank: Frequent Contributor
timestamp: March 08, 2021, 01:46:09 am
content: Quote from: jmelson on March 07, 2021, 02:41:44 amIt is kept long term in warehouse which has been cooler during cold weather. We notice the runniness when it warms up in 20-30 mins. We take printed pcbs and place in cooler warehouse to stop the runniness but its a hassle. I'm not the operator but we do mix the paste. I bought from two different suppliers and would be hard to counterfeit. We originally used 6 mil stencils which was a disaster with gc-10 and 0402 not for all the other pastes. We are using 4-5 mil stencils now and it works but we need to move fast with it. I think its because we started with aim paste that we had good experience with that that we saw a better solder paste. I got 40 jars of gc-10 near expiration off ebay for $7/ea thats the only reason im using it. My new problem is once you get used to $7 solder paste its no fun going back to $70. I've been trying to find a decent chinese solder paste but even china is a bit pricey.

author: Reckless
author_rank: Frequent Contributor
timestamp: March 08, 2021, 01:51:13 am
content: Quote from: Mangozac on March 07, 2021, 10:30:36 amWe use Aim M8

author: SMTech
author_rank: Frequent Contributor
timestamp: March 08, 2021, 10:05:40 am
content: In the UK I can name 3 solder brands that manufacture (or at least blend) their own pastes in the UK and sell very good product at good prices [Solderking, Warton, BLT]. This has to mean there are others on other continents, that aren't one of the massive brands. Every paste we have trialed has boasted "low slump" and slump is the issue Reckless is describing. I've never seen a paste with bad slump in any of those, I haven't tried GC10 because I use a very similar BLT paste that costs around 1/2 the price, excellent stencil and shelf life, good data sheets, minimal to no flux separation visible when you open a new tub compared to quite a lot when we used to use a Multicore/Henkel/Loctite one.

author: Mangozac
author_rank: Frequent Contributor
timestamp: March 08, 2021, 10:14:30 pm
content: Having the paste at least blended locally is the most important factor. Even room temperature stable pastes get destroyed if you ship them internationally and after trying a few times we gave up. AIM pastes are blended locally here in Australia and they ship overnight in a cold box. We then store in a wine fridge set to 18°C. The result is paste that behaves perfectly for ages, even after being scooped back up off the stencil and stored overnight a few times.

author: jmelson
author_rank: Super Contributor
timestamp: March 13, 2021, 06:06:21 pm
content: Quote from: Reckless on March 08, 2021, 01:46:09 amOK, I bought a 500 g jar of GC10 from a distributor at full price. It is now several years past the expiration date, and has never been refrigerated. It has also never experienced large temperature swings, I just keep it in the shop. When it gets too dried-out I add a few drops of butanol, which seems to be the ideal solvent for solder paste.I have used about 5-6 different solder pastes before GC-10, and only one of them was good. I suspect the one other good one, (from Warton Metals in the UK) may have just been relabeled GC-10. If not, it was sure a similar formula. All the others were somewhere between horrible and completely unusable, even when new. I had LOTS of rework in the past. Using either the Warton or GC-10, I rarely have any bad solder joints, even on my most demanding stuff (0.5mm lead pitch TQFPs.)I did have one brand that did the separating out and "melting" thing, the nice square bricks when printed turned to broad heaps with a pool of clear liquid surrounding them. And, that happened in some 10 - 15 minutes, I think.Anyway, I'm just mystified, as GC-10 has worked so remarkably well for me! I do use thin stencils (0.003" 0.8mm) so as to not get too much paste on the pads.Jon

author: jmelson
author_rank: Super Contributor
timestamp: March 13, 2021, 06:10:38 pm
content: Quote from: SMTech on March 08, 2021, 10:05:40 amI imported a jar of Warton lead-free paste some years ago and can vouch for that! It worked amazingly well for us, but now that GC-10 is available easily in the US, I don't want to go to the expense of importing the Warton stuff. As far as I can tell, the Warton Metals paste worked exactly like the GC-10.Jon

author: wraper
author_rank: Unknown
timestamp: March 13, 2021, 06:18:29 pm
content: GC 10 is now available in 250G jars. I think I've seen even smaller packaging somewhere EDIT: I think it was GC 50. Also Loctite recently released GC-18 (low voiding and cheaper) and GC-50 (good for syringe) which are also temperature stable but have shorter shelf life.https://www2.mouser.com/ProductDetail/298-2446444

author: Reckless
author_rank: Frequent Contributor
timestamp: March 14, 2021, 03:32:58 am
content: Quote from: jmelson on March 13, 2021, 06:06:21 pmYou are using 3mil stencils thats why. We have used 4-6mil and AIM worked GC-10 had issues. Going down to 3mil most likely would have solved our issues with gc-10 may have caused issues with others. Our loctite rep recommended 4mil so we went from 6mil down to 4mil. I have to order 2 stencils tomorrow, may try 3mil.

author: jmelson
author_rank: Super Contributor
timestamp: March 14, 2021, 04:18:04 am
content: Fascinating! I've been using 3 mil stencils (I make them myself) for so long that I don't know how any of these pastes will do with a thicker stencil. I do still have one stencil that I think is 5 mil thick. That board has only SOIC parts and passives, so that worked just fine.Jon

author: Harjit
author_rank: Regular Contributor
timestamp: March 14, 2021, 10:30:56 pm
content: Quote from: jmelson on March 14, 2021, 04:18:04 amHow are you making your own stencils? Laser cutter? Metal or film?Glad to see that there is a 50gm GC-10 tub.

author: jmelson
author_rank: Super Contributor
timestamp: March 14, 2021, 11:19:37 pm
content: Quote from: Harjit on March 14, 2021, 10:30:56 pmI built a laser photoplotter in 1996 to make high-quality artwork for PC boards. Since boards are so cheap now, I rarely use it for that. But, when I first got into P&P and reflow soldering in 2007, it ocurred to me that a stencil was just like a PC board except there's no fiberglass. So, I tried it out with 5 mil brass shim stock, laminated both sides of the brass and made mirror-image artwork just like for a double-sided PC board. It worked quite well. Later I moved to 3 mil shim stock to reduce the amount of solder.So, the stencils are made on 0.003" brass sheet and etched in warm ferric chloride spray. You have to keep the etching step very fast to prevent etching under the resist, that would make the apertures too big.Here's the photoplotter :http://pico-systems.com/photoplot.htmlIt has a 5 mW 670 nm laser that is focused to a tiny spot, and writes pixels 0.001" long, advancing the carriage 0.001" each raster stripe. The stencils need to line up with commercially fabricated boards, and it does quite well, possiibly a mil of error over 10 inches or so. The recording drum turns at 600 RPM, exposing 10 raster lines/second, or 0.6 inch/minute.

author: Harjit
author_rank: Regular Contributor
timestamp: March 20, 2021, 03:56:25 pm
content: Sorry to be off topic - Really, really cool! Thank you for sharing.

author: ThomasRR
author_rank: Newbie
timestamp: March 25, 2021, 09:14:56 am
content: Do not refrigerate the GC-10 paste. GC-18 and GC-50 will not last as much as the GC-10.We get the paste from here:https://www.newark.com/es/loctite/gc-10-type-4-jar/solder-paste-sac-200deg-c-jar/dp/53Y2106Good price and fast delivery

author: wraper
author_rank: Unknown
timestamp: March 25, 2021, 10:10:28 am
content: Quote from: ThomasRR on March 25, 2021, 09:14:56 amDon't know about Newark US but I was burned with Farnell UK part of their business. Last time I received GC-10 with only 5 months left till expiry date. And for Europeans it's cheaper at Digikey and Mouser.

author: SMTech
author_rank: Frequent Contributor
timestamp: March 25, 2021, 10:38:51 am
content: Quote from: wraper on March 25, 2021, 10:10:28 amOnly 5 months! I mean come on, get a grip what do you expect them to do with perfectly good paste with a perfectly workable shelf life that if you obey the pastes own rules, has to be used in way less than its shelf life once you break the seal?

author: wraper
author_rank: Unknown
timestamp: March 25, 2021, 10:52:25 am
content: Quote from: SMTech on March 25, 2021, 10:38:51 amWhen you buy something with 12 months shelf life, IMHO you should expect at least more than half of it left. What's the point in buying paste with 12 month shelf life paste when it has less shelf life left than 6 month shelf life paste? What it means, they did not manage their stock properly. And it becomes a significant issue when you do things in relatively small amounts as many people here, and do not spend 500g of paste in one day.

author: SMTech
author_rank: Frequent Contributor
timestamp: March 25, 2021, 11:50:15 am
content: Well unfortunately for you, they don't make GC10 (or many others frankly) for low volume users, you get the nasty overpriced chipquik stuff in a syringe. Open the pot- your extended shelf life is over, done, dusted - mix the stuff you have used back in and its worse still. The fact that anecdotally people use the same pot for months and get "good" results is not something any paste manufacturer would recommend or support in a production environment because it is no longer performing to their metrics. We used to use a Loctite paste years ago, didn't buy it from Farnell, its not the place you'll get the best pricing and that might even hold true if you have an account with a discount structure applied. We would have gone herehttps://grosvenor-group.com/product/loctite-gc10-solder-paste-sac305t4-885v-52k/although we would have been buying other things too...

author: jc101
author_rank: Frequent Contributor
timestamp: March 25, 2021, 08:16:14 pm
content: Quote from: wraper on March 25, 2021, 10:52:25 amI bought a tub from Farnell in early 2020, arrived with a few days remaining on the date. I've been working through it since then without issue. Not had any issues so far, might need another one in a couple of months. I open it, take some out, put the lid back on and then keep it in a ziplock bag.

author: wraper
author_rank: Unknown
timestamp: March 25, 2021, 08:29:53 pm
content: Quote from: jc101 on March 25, 2021, 08:16:14 pmIt's completely unacceptable. Expired GC 10 causes issues with vapor phase soldering. It's usually noticeable only under microscope but PCB here and there becomes covered with small particles. Looks like small amount of solder alloy particles is washed away by Galden and then sticks on PCB in various places. My observation is that it lasts maximum 4-6 months after expiry date before starts causing noticeable problems.

author: jc101
author_rank: Frequent Contributor
timestamp: March 25, 2021, 08:33:52 pm
content: Quote from: wraper on March 25, 2021, 08:29:53 pmNot a problem for me, I just use a small batch reflow oven for prototypes. Good to know about the vapour phase issue though.