Leaded solder paste recommendations - Page 1
Forum section: electronics / general

author: deanclaxton
author_rank: Regular Contributor
timestamp: July 04, 2025, 10:05:14 am
content: Hi all,Outside of my regular day job I build products for vintage computers (Apple II mostly). I have a manual stencil printer (Neoden frameless), pick and place (Autotronik BS-281), and small batch IR reflow oven (Charmhigh BRTRO-420) at home that I use to put the boards together. I had been using GC10 solder paste until it became difficult to source, then I switched to another temperature stable paste Chip Quik TS391SNL250.My current project requires a 40 piin DIP socket and 40 pin box header on the PCB, and I selected some surface mount products to reduce manufacturing time (versus hand soldering 80 joints per assembly).I'm space constrained on this board, and the box header and DIP socket are pretty close to one another. I'm having a couple of issues assembling them - I think due to shadowing effects I'm having trouble getting the paste to flow on the box header as the leads go back under the body. I can't increase soak time without the 40 pin DIP socket melting during reflow (it seems to be made from a different material to the box header - I'm in contact with the supplier about this). I really need to spend some time tweaking the reflow profile, but then I thought perhaps a switch to leaded solder might help?I'm very interested in recommendations for a leaded solder paste - preferably one that doesn't require refrigeration as I often build boards in the evening or weekend and don't want to have to wait hours for the paste to warm up.I imagine a better reflow oven might help, but I dont have a lot of space left in my work area.Interested in your thoughts and suggestions.

author: loki42
author_rank: Frequent Contributor
timestamp: July 04, 2025, 10:30:18 am
content: There is a lot of lead free low temp options. Some don't mix well if parts have lead though. Check out the options from indium. They are very good and very easy to use.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: July 04, 2025, 10:35:21 am
content: I've used various random leaded paste from Aliexpress over the years, and all of them have been fine with no refrigeration - I get through a 500g pot in a year or so, occasionally I stir in a little liquid flux if it gets dry.It's getting harder to source (see other thread below), so it's becoming pretty much "whatever you can get" these days.https://www.eevblog.com/forum/chat/solder-paste-uk/msg5965847/#msg5965847

author: tooki
author_rank: Super Contributor
timestamp: July 04, 2025, 10:39:39 am
content: Quote from: mikeselectricstuff on July 04, 2025, 10:35:21 amDigikey will happily ship leaded solder. I’ve ordered various ones over the last 2 years. I believe Mouser will, too. Why not just order from them?? You’ll know what you’re getting, and a reasonable guarantee of freshness. I also know for a fact that they will ship it properly, including an insulated bag with cold pack if needed.

author: neillnz
author_rank: Contributor
timestamp: July 04, 2025, 11:43:57 am
content: I do small runs in my home workshop, manual stencil, hand placed parts and fimware only modified T-962A. I use Chip Quick SMD291AX50T3 from Digikey. They send it to New Zealand in a freezer bag with with an ice pack which is very optimistic of them, but I still am able to use it past it's expiry date.I do referigirate it. I take it out of the fridge and warm it gently, either in direct sunlight in the Summer time or in the air flow of the heat pump(air conditioner in reverse cycle) in Winter. It takes perhaps 15 minutes to soften then I give it a good stir.I have been using it for 3 years now(not the same tub). I have never had any issues with it. Always nice shiny joints that flow beautifully.Also it truely is a no-clean paste.

author: Rat_Patrol
author_rank: Frequent Contributor
timestamp: July 08, 2025, 03:16:57 am
content: I use a lot of Chip Quick no-clean leaded solder paste, it is good to go. I get it from DigiKey or Mouser most of the time.

author: deanclaxton
author_rank: Regular Contributor
timestamp: July 08, 2025, 11:09:55 am
content: Thanks everyone - I ordered some SMD291AX250T3 from Mouser so will give it a go

author: tooki
author_rank: Super Contributor
timestamp: July 08, 2025, 03:58:16 pm
content: Quote from: deanclaxton on July 08, 2025, 11:09:55 amI’ve used that paste for many, many boards. No complaints.

author: Rat_Patrol
author_rank: Frequent Contributor
timestamp: July 09, 2025, 12:17:00 am
content: Quote from: tooki on July 08, 2025, 03:58:16 pmSame