Hot plate for SMD reflow - Page 1
Forum section: electronics / projects

author: djsb
author_rank: Super Contributor
timestamp: November 29, 2010, 12:23:38 pm
content: I'm thinking about buying or making a hot plate for SMD reflow work. Does anyone know of any plates that are specifically made for the purpose and that are not too expensive? Another possibility is buying a PID controller, a cartridge heater and a thermostat and making a plate out of Aluminium. Like this onehttp://www.neufeld.newton.ks.us/electronics/?p=537Any thoughts?David.

author: GeoffS
author_rank: Unknown
timestamp: November 29, 2010, 01:11:35 pm
content: Have you considered using an electric frypan or skillet?Cut off the raised edge and bolted a piece of 25mm aluminium plate to the base. You could then use a PID controller similar to that in your link for temperature control.

author: not_Dave
author_rank: Newbie
timestamp: November 29, 2010, 01:17:00 pm
content: Have you heard about how they did business at sparkfun? I the beginning they used a hot plate just like you asked. Here is a link to their tutorial..http://www.sparkfun.com/tutorials/59

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: November 29, 2010, 02:31:18 pm
content: Problem with hotplates is heat-up time. Try a toaster oven. I usethis one from CPC. Someone at Adafruitposted about a cheaper one from Argos

author: Hypernova
author_rank: Unknown
timestamp: November 29, 2010, 03:06:24 pm
content: They also sell a kit that let you convert ovens, the same kit should work just as well for hot plates.http://www.sparkfun.com/products/81

author: Time
author_rank: Frequent Contributor
timestamp: November 29, 2010, 04:29:49 pm
content: I agree. Go with a toaster oven.

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: November 29, 2010, 04:51:47 pm
content: I just saw a video somewhere where somebody used an upside-down clothes iron as a hot plate. I was thinking of using the iron as the hot plate as in the example above. Add a base and the PID controller and you'd be all set.

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: November 29, 2010, 07:08:59 pm
content: Quote from: Jon Chandler on November 29, 2010, 04:51:47 pmOops...the post about the ironwas in this forum.

author: TheDirty
author_rank: Frequent Contributor
timestamp: November 29, 2010, 08:08:31 pm
content: I like the refloaster.I keep thinking of making something, but my hot air station works fine and I don't do that many boards.

author: TechGuy
author_rank: Regular Contributor
timestamp: December 02, 2010, 12:36:43 am
content: Quote from: djsb on November 29, 2010, 12:23:38 pmI just purchased a cheap electric hot plate ( for about $20 buck - many years ago). I place my PCB on a flat 20 ga. Aluminum plate (8x10 inch) and place all of the SMD while the PCB is on the alum plate. I prefer to keep the PCB on the alum plate since the loose components can be easily shift out of alignment. Its easier to move the alum plate with the PCB on top than it is to put the PCB on the alum plate without creating a small bump when dropping the PCB the final distance on to the alum plate causing components to shift.When I finish I pick up the alum plate and place it on the hot plate and turn on the hot plate. I wait for the solder to reflow than lift off the alum plate (with oven mitts) on to a hot-pot stand to cool. This helps minimize the duration of the heat on the components. No need for precise temperature regulation since I remove the PCB from the heat source soon after the solder melts. The alum plate also acts like a heat sink after its removed from the hot plate.You could use a alum. frying pan if you wish (but don't use it to cook food after you used it for reflow) but in my opinion a thin flat alum. plate is just easier to work with. You can purchase Alum. plate fromwww.onlinemetals.com) They will cut it to size for you. The problem with a frying pan is placing the PCB in the frying pan without jarring any of the loose components.One recomendation: Avoid using reflow for electrolytic caps, as the high heat will cause some of the electrolyte to evaporate increasing cap ESR and shortenings its life. I prefer to hand solder electrolytic caps by hand after reflow.The only issue with SMD and reflow if you need to rework the PCB. For SMD rework, you'll need a hot air pencil.FYI: Someone asked for a solder paste supplier:http://www.zeph.com/solderpaste.htmFor roll your own PCBs:http://www.parts-express.com/wizards/searchResults.cfm?srchExt=CAT&srchCat=206&CFID=5316298&CFTOKEN=27605062(Boards and Chemicals)http://www.injectorall.com/index.htm(Boards and Chemicals)http://www.dalpro.net/Page.html(Chemicals)http://www.pulsarprofx.com/pcbfx/main_site/pages/products/index.html(Toner transfer mask for better traces and DIY silkscreen) - Toner transfer method not so good with thin traces and small SMD devices. the toner transfer mask helps with thin gauge traces but its not perfer. The preferred method is to use the light senstive artwork transfer.For hotair rework equipment:http://www.assemblyoutfitters.com/shop/category.aspx?catid=23(I have the Xytronics 850D and it works great - worth the money I paid for it).Low cost Stencils:http://www.ohararp.com/Stencils.html($25 - Good customer service too!)For manufactured PCBs I use:http://www.sunstone.com/(ValueProto isn't terribly expensive) if you know of a better/cheaper PCB shop with online ordering in the USA please share it.

author: jamesbowman
author_rank: Newbie
timestamp: December 04, 2010, 09:15:46 pm
content: Yes, I have used hot plate for a 2" x 2" board with fine-pitch SMTs. Works surprisingly well. I used:PCB from batchPCBstencil from ohararppaste from digikeyThrift store provided an old frying pan, and an IR thermometer is good to keep track of the board temperature. As soon as solder melts and components align, remove from heat and allow to cool. It's going to require some rework with flux and wick, but overall much quicker and better-looking result than hand-soldering.