Reflow Solder Station Recommendations - Page 1
Forum section: electronics / general

author: jpanhalt
author_rank: Super Contributor
timestamp: February 29, 2020, 10:33:10 pm
content: My current project has convinced me to look at a reflow solder station. I've got an old Corning, stirred hotplate that I could probably use while manually adjusting the temp, but with purpose-designed stuff going for <$300 and some <$100 on Amazon, it hardly seems worth it.Any recommendations?Conditions:Double-sided board; all components on topLeaded solderPCB Size < 10 cm x 11 cm

author: fourfathom
author_rank: Super Contributor
timestamp: March 01, 2020, 01:46:53 am
content: I recently switched from an electric skillet (which had very uneven heating) to a small toaster-oven (probably this one:https://www.amazon.com/BLACK-DECKER-Controls-Stainless-TO1705SB/dp/B071K1KM3Z). It has upper and lower heating elements, and does not have a fan.I've seen toaster-oven conversion projects where there was added thermal insulation and sealing, the oven controller guts were removed and replaced, and other optimizations, but I just use it as-is, with an external arduino-style controller, a thermocouple + interface, and an 20A solid-state relay. I have the oven temperature controlled dialed to max, with both elements on, and let the Arduino control the on-off cycle (it also beeps an speaker to tell me when to open the oven door for the cool-down cycle). I can share the details if you are interested, but I'm getting a pretty decent reflow profile for leaded solder. The cool-down ramp is slower than I would like, but since my components are rated for the higher-temperature lead-free solder, I figure it's pretty safe and I've seen no problems. A fan blowing into the open oven would probably accelerate the cool-down.The oven comes with a steel grill (which I don't use) and a thin Aluminum tray which is good for holding my boards. I have the thermocouple secured to a small perf-proto board and I place that next to the board being soldered. You will discover that the temperature continues to rise substantially after you shut off the heat elements. My controller program learns this and compensates for it. It's really quite simple and I've seen no need to make it more complicated.

author: jpanhalt
author_rank: Super Contributor
timestamp: March 01, 2020, 03:51:52 am
content: Thank you for the complete description. I have been hand soldering for a long time and have used hot air for desoldering. This is my first foray into reflow.I wanted something that was pretty much off the shelf as it is for a current project, but from reviews on Amazon (price ranges $85 to $280), the low-end units may require almost as much fixing as your whole build required. It will be a few days before I make any decision.John

author: fourfathom
author_rank: Super Contributor
timestamp: March 01, 2020, 05:46:28 am
content: FYI, here is an infrared view of the electric skillet. Unfortunately, I had my Android phone FLIR adaptor set to the lower temperature range, but you can still see how uneven the heating is. I tried to even things out by putting a piece of steel plate over the skillet surface, but that dramatically slowed the cool-down rate -- much worse than in the toaster oven.

author: Rat_Patrol
author_rank: Frequent Contributor
timestamp: March 05, 2020, 09:31:37 pm
content: I went with a Controleo modded toaster oven. Total cost was around $350 for the project IIRC.While its my first jump into reflow ovens, so I don't have a lot of experiene, after seeing the horror stories of burnt boards and all the mods needed from the cheap Chinese units, I think its the best bang-for-buck option if you are willing to take a day and build the unit. Its not technically hard, just slightly tedious. Not bad though, the directions are good. I am very happy with the repeat ability of the reflow. I can even run double sided boards with the same solder paste by using a carbon fiber fireproof "blanket" to insulate and hold the bottom components (just 1206 passives and SOT23 stuff) when I run the top reflow, which is slightly different to make up for the thermal mass of the carbon fiber blanket. This lets me get away with lower temp solder on both reflows, and not have to push to the extreme limits of some of my parts with LF solder paste on the first reflow.It also has a built-in bake function, which I use constantly. I'm actually going to setup another toaster oven (w/o all the insulation and extras) just for curing and baking PCBs, since I waterproof them with a thermal set conformal coating.

author: asmi
author_rank: Super Contributor
timestamp: March 05, 2020, 09:57:48 pm
content: Quote from: Rat_Patrol on March 05, 2020, 09:31:37 pmThose burned boards stories were caused by idiots, not by units. I have never burned a single board in my oven.Quote from: Rat_Patrol on March 05, 2020, 09:31:37 pmNo need for any of that. Solder will hold these parts in place upside down with no problems. I've done hundreds of double-sided boards, and never did I have a single component fall out from the bottom side.