MG Chemicals - 4860P-35G 4860P 63/37 No Clean, Leaded Solder Paste, 35 g (1.2 oz) Pneumatic Dispenser (Complete with Plunger & Dispensing Tip)

You will read a lot on the internet about how this stuff must be refrigerated, only has a limited shelf life, etc. This has not been my experience at all. I have left this out on my desk for weeks, using it intermittently, and never had any problems. Based on this, and also my lack of a proper reflow oven, I have concluded that solder paste is much more forgiving than many would have you believe.When I first bought this I had a lot of trouble applying it to the very small circuits I was designing. Apparently you are supposed to buy special applicators, but it was my first time using solder paste and I had no idea. This led me to invent a very unconventional but surprisingly effective solution: fastening a spare 3D printing nozzle with tape to the end of the syringe and using it to apply tiny dots of paste just where I needed. Using this method I have soldered components as small as 0402 with ease.As for baking the circuits, you really don't need to worry about temperature profiles and precision if you are just doing this as a hobby. I simply put solder where I need it, place the parts making sure they are well aligned, and throw it in the toaster oven on the "Broil" setting until all the solder has melted and is shiny. I have made several circuits this way and never had any problems.To summarize, if you are thinking about getting in to reflow soldering, GO FOR IT! It's hard to get it wrong, and it's so much faster/funner/easier than doing everything by hand. I can't even imagine going back to through hole at this point.

I reflow around 50 PCBs each week and have tried lots of of different pastes, ranging from the variety of Chinese pastes, to Kester's excellent EP256. This is my favorite so far, here's why:-Plunger pressure is minimal, and it is easy to reseal the container. You can tell that MG Chemicals put some thought into the syringe design, eliminating the rubber seal and significantly reducing the pressure required to dispense the paste. My thumb gets very sore after pasting a lot of boards with EP256, but with this paste it is a breeze.-The paste flows easily onto the board while maintaining a good tack to hold your parts in place during reflow. A lot of the Chinese pastes are easy to dispense, but they aren't tacky enough to hold the smaller parts in place during reflow. Kester EP256 is tacky enough, but is difficult to place on the boards when the temperature dips down below 70F. Once you warm up the boards and the paste a bit, the EP256 isn't too bad, but this paste is much easier to place.The only downside is the smell. The solvent used is quite pungent, so if you're sensitive to strong chemical smells, I would stay away from this paste and instead go with the Kester EP256, which does not have a strong chemical smell and actually smells quite sweet when reflowing; however, I suspect that it is this pungent cocktail that makes this paste easier to use under non-ideal conditions.BOTTOM LINE:If you work in non-ideal conditions (temperature, fresh tube of solder paste, etc.), and can handle the strong smell, this is the best paste out there.

It melts somewhere around 220C, but I'm estimating that with a contact-free thermometer. That's a temperature that's not hard to hit with a hot plate, frying pan with a glass cover and a thin layer of sand under the board.I tried to use this on solder pads for a 5050 chip by hand. I could not get it to stay where I wanted to and I was unable to dispense it evenly. It's very stiff and comes out in globs. I'm new at SMD soldering and the resulting board was useless - there were shorts under some components.So I wised up and started ordering stencils with my boards. Pros: every board I've done that way worked first time, even when mounting arrays of 24 5050 chips. Cons: unless there's a better technique than laying down a bunch of paste over the stencil holes and using a scrap board to spackle it into the holes, you waste a fair bit of the paste in this process. And this stuff is not cheap. And the waste contains lead, giving you a disposal problem.But it gets it done. I find that if I point my thermometer at the board, the stuff melts between 220 and 230C, and it visibly changes from dull gray to a shiny silver and wicks into place predictably. The stencil approach means pads get only a very thin coating of paste, but it's sufficient, and parts can be adjusted with tweezers and then generally stay where you put them.Since I'm going to be spreading it, not daubing it, next time I'll look for a small can of it and skip the needle. Just too hard to control the flow with that thing.First time users should be told: keep it in the fridge until an hour before you need it. This stuff doesn't have a long shelf life. Also, there's a smell of ammonia or something like it when you use it, especially when it cooks. Ventilation is a good idea.