Mike, As Brian stated, try the www.pcbexpress.com site. They have a good explaination of what is needed. I also recall several web sites and perhaps an actual magazine article on the subject. Look at www.seattlerobotics.org search on the keyword "oven" for information. A good google should find ample info on the topic at other sites. A stencil is without doubt the best way to go, however for a "one-of" hobby board, it is probably too expensive. I just use a simple applicator (ok, its the stick cut off from a Q-Tip) and apply the paste across all pads of the device (and on the large heat sink pad of regulators). This will create some solder shorts between pins, however a quick cleanup with soldering braid and a hot iron removes excess solder and makes a beautiful joint. In terms of cooking the board, well, lets just say we are not exactly following the manufacturers "desired thermal profile". Talking with the production engineers where I used to work, it is not an exact science as each part on a cca has a different profile and each reflow oven has its own characteristics. Of course, hobby and production are two different beasts and you have to do what you can. Ken ----- Original Message ----- From: "Mike W" To: Sent: Friday, March 26, 2004 4:36 AM Subject: Re: :[OT] How to solder hidden QPF Ground Pad? > Ken, I've heard of using an oven to solder these parts, do you know of a > URL with definitive info?. > How do you get the heat up and down in a suitably quick way without > cooking the device you are trying to solder?. > tnks, Mike > -- > > On 25 Mar 04, at 21:27, Kenneth Lumia wrote: > > > Brooke, > > > > The best way is to use solder paste and a heat > > source. Some people use a toaster oven (can't use it for food > > anymore) as a heat source and solder a whole board at once. I just use my > > wife's (don't tell her) embossing heat gun (avialable at craft stores for > > around $25) and do one part at a time. Depending on the part, I can solder 32 > > pin QFP's in about 45 seconds by applying heat from the bottom of the board - > > apparently the fiberglass transmits sufficient heat to the top. This also > > works wonders for voltage regulators that have ground pads under the body > > (similar to your case). Heating the board from the top has a tendency to blow > > the the part out of alignment (air velocity is too high). > > > > The down side is that solder paste has a very short shelf life and > > must be kept cold when not in use (not in your fridge with food!). > > > > Ken > > > > ----- Original Message ----- > > From: "Brooke Clarke" > > To: > > Sent: Thursday, March 25, 2004 9:03 PM > > Subject: :[OT] How to solder hidden QPF Ground Pad? > > > > > > > Hi: > > > > > > I would like to use a PIC12F629 to drive the LTC3205. But the LTC3205 > > > only comes in a 24 lead QFP with a ground pad hidden under the package. > > > with a note saying it must besoldered to the PCB. Is there a way for me > > > to solder this part at home? > > > > > > Thanks, > > > > > > Brooke Clarke, N6GCE > > > http://www.PRC68.com > > > > > > -- > > > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > > > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > > > > > > -- > > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu