Wagner,=20 I will look up some insulation data for you tomorrow. If you are serious, = there are better ways to get a radiant heater, such as Watlow company that = makes electric heating elements. They are also from my home town, so=20 maybe you will keep one of my neighbors working.=20 There are fiberglass insulation materials rated for these temperatures=20 (don't use building insulation it will stink) and this would probably not = be a bad way to go.=20 THe thermal lag is basically due to thermal mass of the oven. Also, there = is overshoot, basically due to thermal mass of the sensor. In a=20 production oven, the temperature sensor is riveted to the oven wall, a=20 massive piece of poor heat conducting steel, terrible place to put a=20 sensor but plenty cheap. Your lightwieght sensor adjacent to the board is = a much better idea.=20 Another great way to make a heater is to buy a bunch of nichrome wire and=20 wind it onto a high temperature insulator such as mica or ceramics. I=20 just happen to have several rolls of nichrome..... -- Lawrence Lile Senior Project Engineer Toastmaster, Inc.=20 Division of Salton, Inc.=20 573-446-5661 voice 573-446-5676 fax Wagner Lipnharski Sent by: pic microcontroller discussion list 02/06/2003 03:44 PM Please respond to pic microcontroller discussion list =20 To: PICLIST@MITVMA.MIT.EDU cc:=20 Subject: Re: [EE]: SMT soldering PicDude wrote: > Like one of one of those toasters in restaurants/buffets/etc > that is open on 2 ends, and the toast darkness controlled by > varying the speed of the conveyer? Similar to what Quizno's > uses to toast their subs. Perhaps you should get a part-time > job there to test the SMT idea? > > Cheers, > -Neil. Not really, :) The idea in a conveyor belt, is not changing the belt speed, since the=20 belt should be the same from the entry to exit. The idea is to have 3 or 4 chambers over the belt, each one with a profile step temperature, and the size (longer or short) is based on the time the board should be exposed to that temperature, so, a 4 minutes initial profile step (160=B0F) should be 2 times longer than the second profile step at 325=B0F, and this, 150% longer than the final step (450=B0F). The transportation belt could be done in several ways, it could be also steel wires or metallic nets. Today I went to Lowes and saw the coiled range top heaters, 6 and 8=20 inches, cost $18 and $28. There is not a single technical information at all in the packages. They real don't invest in people's expertise in technology, the manufacturers assume all consumers are dumb idiots that would be confused if they print 500W - 110VAC unit. The problem, probably is that the person who makes the revision of the package printing, is also someone that doesn't have a minimum clue what means 500W, so how it would revise the text? It only says about what range it fits, not even the Voltage, it is a shame. In some European countries you can find products like this when they print; size, gross and net weight, power consume, power productivity (consume vs thermal), resistance of the contacts and some=20 even express expected life of the product in hours of use. I really don't understand then why there are laws that force food and drink products to express how many milligrams of Sodium Benzoate or Phosphoric Acid is present into the drink. We should assume that a regular Coca-Cola addict has any idea what Sodium or Potassium Benzoate means? I doubt what percent of the population really knows what "mg" means. Well, the top and bottom heater could be done with two of those coiled elements, and it would be a very nice finish unit, clean and resilient. Observing the actual toaster oven working, I realize the thermal lag, is mostly caused by thermal losses, from the metal walls and leakage in the assembly. Anyone around can recommend some thermal insulation material that can=20 stand easily 550 to 600=B0F? It would be great if this material could be solid, so, cut and adapt would be a real way to go. This would be used to create the inner chamber walls. Wagner. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics