8 ms·

A possible (probable?) issue is your oven. In my experience, they heat in cycles: if you set one to 180 it will heat to 240, then cool to 150, then .... Etc. Ev

A possible (probable?) issue is your oven. In my experience, they heat in cycles: if you set one to 180 it will heat to 240, then cool to 150, then .... Etc. Even a large electric range will cycle with a range of temperatures. In other words they are designed to maintain an average temperature rather than constant. In addition there issue of calibration. Even expensive full size ovens can be significantly off. How do I know this? I worked with Japanese laquer (Urushi) which was baked onto metal for bonding. But Urushi is the sap of a tree related to poison oak and over-heating leads to fumes that are not great. Experiments with small (toaster) ovens and large electric ranges produced bad results. Most electric kilns for ceramics, especially those that are computer controlled, are highly recommended for sensitive work where temperature control is important.

dontknowme 8y ago
Likely. Kitchen ovens and small ovens in general do not have the accuracy required to reflow. As you say, they will cycle between full power and no power and rely on the large oven hysteresis to get an average temperature which is OK for cooking, but can be easily off by 10+C at times, even if ventilated. One solution is to wrap the item in something which acts as a dampener. A couple of layers of crumpled tinfoil will help. Note that you definitely can reflow in a low-end kitchen oven with the appropriate changes ;). I built two small ovens for reflowing. Search for "arduino reflow" for some pointers.
yummybear 8y ago
Would a heat gun and an infrared thermometer perhaps be better - don't know if you risk blowing the components off the board though. Maybe on a lower setting.
- himynameistimli 8y ago
  I think a heat gun would + tweezers would probably be sufficient enough, however, he'll probably need to reference ifixit images to figure out where things need to go. I think it's a bit too difficult to hold a heat gun, an infrared thermometer, a set of tweezers and flux, so I would just get a feel by testing it out with some other busted PCB.
code_duck 8y ago
I’m familiar with this from a couple of interests, too. One is trying to decarboxylate cannabis to prepare it to make edible goods. You want to hold it under 250° for a period of time, and the quality of the temperature controller and other factors about your oven or toaster oven do make a big difference. Overheating can ruin it fairly easily, and underheating fails to produce full potency. Also we run into this in a glassblowing. One wants borosilicate items to rest in the kiln somewhere between 1040 and 1100 F (~600C). The simplest kilns have a infinite switch, same as an electric range. With attention and experience, it’s possible to make it steadily hold a temperature. More common these days is a digital controller. The simplest is something like a Fuji PXR3. However, just having a digital controller does not ensure that your kiln stays at the target temperature. The controller must be calibrated properly for the oven size, elements and insulation. In most kilns elements are either on all the way or off, so controllers use a relay to control power. The more sophisticated ones do this very quickly, like flickering. Typical controllers do cycles of a few seconds. If the controller is not calibrated properly, which is common in glass studios, the kiln will overshoot or undershoot the target temperature repeatedly by up to 50°. It’s complicated by the fact that these kilns sometimes have doors that remain partially open, and the amount of mass of glass inside affects the thermal characteristics, too. For a very precise small oven, the ones that they make for enamel or firing dental porcelain are pretty good.
- code_duck 8y ago
  ^RIP my intended formatting, sorry
ambicapter 8y ago
As anyone who has tried to bake in an oven in a rental has found out...I finally bought an oven thermometer and my oven will easily go 100ºF over the indicated temperature. I literally either cut baking time in half or lower the oven dial by ~100º.
- SlowRobotAhead 8y ago
  Rental or not, the difference between almost any low end to high end cooking item is the temperature control. Sous vide, big green egg grills, induction ranges, some of the air fryers, etc. It’s all about precision temperature.
- dpark 8y ago
  If you’re lowering the temperature by 100 degrees, your problem isn’t the temperature swing. It’s that your oven’s internal thermistor needs replacement.
bluedino 8y ago
>> Even expensive full size ovens can be >> significantly off. It's funny how often the cooks complain about the ovens not being accurate on the Bon Appetit YouTube channel. There are 3rd party thermometers installed in each one. The ovens are Viking or Fisher and Pytel or something, high-cost ovens that the average home chef would dream of. And they stink!
- bookofjoe 8y ago
  In praise of American build quality (at least back in the 1960s): My GE electric oven, installed when my house was built in 1967 — 52 years ago — is dead-on accurate when tested with a third-party Taylor oven thermometer. Full disclosure: one of the four burners on top is non-functional.
- cr0sh 8y ago
  > It's funny how often the cooks complain about the ovens not being accurate on the Bon Appetit YouTube channel. I wonder if it's more the cooks than it is the oven. My wife once worked at a shop where she had to prepare fresh-baked cookies from scratch, and their oven was often "on the glitch". The owner of the shop also owned a pizza place next door. So when the oven went on the fritz, she'd do what any self-sufficient cook would do, and borrow the commercial gas pizza oven next door. Now mind you - this was a commercial full-sized pizza oven, running at an insane temperature - well over 700 degrees. But it was a consistent temperature... ...so my wife would pop 'em in, wait an appropriate amount of time while also watching the cookies closely, then pull them out when they were properly cooked. They'd turn out perfectly every time. That isn't to say you could cook anything at that increased temperature - you can't. But there are many things you can do, if you know what the heck you're doing. Sometimes you gotta make due with the tools at your disposal, because you may not have a choice otherwise. Or at least try to do it. If things hadn't gone right with the cookies, in the trash they would've went - but it went so well, my wife started to learn how to use that pizza oven for all it was worth, because it was usually always at temperature and consistent.
  - wrdqex 8y ago
    So let me get this straight: - The chefs on said youtube channel complain about the temperature being non-consistent on their ovens. - Your wife also ran into this problem with her oven. - Your wife was able to cook using a pizza oven, which did NOT display this problem. - Therefore, the chefs from the channel are bad chefs, worse than your wife. I have not watched this youtube channel and cannot comment on the skill of the chefs, but your comment's conclusion does not logically follow.
iClaudiusX 8y ago
I found this to be the case for mid-level espresso machines as well. Luckily it is fairly simple to add a PID controller and a more accurate platinum temperature sensor to hold the brew temp to within a few degrees Celsius for a much more consistent extraction.
dpark 8y ago
> In my experience, they heat in cycles: if you set one to 180 it will heat to 240, then cool to 150 Get a better oven. A 90 degree Celsius swing is insane. Ovens do generally have some amount of swing but it should’t be anything close to that.
michaelcampbell 8y ago
Not to mention the picture appears to be a toaster oven; not paragons of heat stability.

dontknowme 8y ago

Likely. Kitchen ovens and small ovens in general do not have the accuracy required to reflow. As you say, they will cycle between full power and no power and rely on the large oven hysteresis to get an average temperature which is OK for cooking, but can be easily off by 10+C at times, even if ventilated. One solution is to wrap the item in something which acts as a dampener. A couple of layers of crumpled tinfoil will help. Note that you definitely can reflow in a low-end kitchen oven with the appropriate changes ;). I built two small ovens for reflowing. Search for "arduino reflow" for some pointers.

yummybear 8y ago

Would a heat gun and an infrared thermometer perhaps be better - don't know if you risk blowing the components off the board though. Maybe on a lower setting.

himynameistimli 8y ago
I think a heat gun would + tweezers would probably be sufficient enough, however, he'll probably need to reference ifixit images to figure out where things need to go. I think it's a bit too difficult to hold a heat gun, an infrared thermometer, a set of tweezers and flux, so I would just get a feel by testing it out with some other busted PCB.

code_duck 8y ago

I’m familiar with this from a couple of interests, too. One is trying to decarboxylate cannabis to prepare it to make edible goods. You want to hold it under 250° for a period of time, and the quality of the temperature controller and other factors about your oven or toaster oven do make a big difference. Overheating can ruin it fairly easily, and underheating fails to produce full potency. Also we run into this in a glassblowing. One wants borosilicate items to rest in the kiln somewhere between 1040 and 1100 F (~600C). The simplest kilns have a infinite switch, same as an electric range. With attention and experience, it’s possible to make it steadily hold a temperature. More common these days is a digital controller. The simplest is something like a Fuji PXR3. However, just having a digital controller does not ensure that your kiln stays at the target temperature. The controller must be calibrated properly for the oven size, elements and insulation. In most kilns elements are either on all the way or off, so controllers use a relay to control power. The more sophisticated ones do this very quickly, like flickering. Typical controllers do cycles of a few seconds. If the controller is not calibrated properly, which is common in glass studios, the kiln will overshoot or undershoot the target temperature repeatedly by up to 50°. It’s complicated by the fact that these kilns sometimes have doors that remain partially open, and the amount of mass of glass inside affects the thermal characteristics, too. For a very precise small oven, the ones that they make for enamel or firing dental porcelain are pretty good.

code_duck 8y ago
^RIP my intended formatting, sorry

ambicapter 8y ago

As anyone who has tried to bake in an oven in a rental has found out...I finally bought an oven thermometer and my oven will easily go 100ºF over the indicated temperature. I literally either cut baking time in half or lower the oven dial by ~100º.

SlowRobotAhead 8y ago
Rental or not, the difference between almost any low end to high end cooking item is the temperature control. Sous vide, big green egg grills, induction ranges, some of the air fryers, etc. It’s all about precision temperature.
dpark 8y ago
If you’re lowering the temperature by 100 degrees, your problem isn’t the temperature swing. It’s that your oven’s internal thermistor needs replacement.

bluedino 8y ago

>> Even expensive full size ovens can be >> significantly off. It's funny how often the cooks complain about the ovens not being accurate on the Bon Appetit YouTube channel. There are 3rd party thermometers installed in each one. The ovens are Viking or Fisher and Pytel or something, high-cost ovens that the average home chef would dream of. And they stink!

bookofjoe 8y ago
In praise of American build quality (at least back in the 1960s): My GE electric oven, installed when my house was built in 1967 — 52 years ago — is dead-on accurate when tested with a third-party Taylor oven thermometer. Full disclosure: one of the four burners on top is non-functional.
cr0sh 8y ago
> It's funny how often the cooks complain about the ovens not being accurate on the Bon Appetit YouTube channel. I wonder if it's more the cooks than it is the oven. My wife once worked at a shop where she had to prepare fresh-baked cookies from scratch, and their oven was often "on the glitch". The owner of the shop also owned a pizza place next door. So when the oven went on the fritz, she'd do what any self-sufficient cook would do, and borrow the commercial gas pizza oven next door. Now mind you - this was a commercial full-sized pizza oven, running at an insane temperature - well over 700 degrees. But it was a consistent temperature... ...so my wife would pop 'em in, wait an appropriate amount of time while also watching the cookies closely, then pull them out when they were properly cooked. They'd turn out perfectly every time. That isn't to say you could cook anything at that increased temperature - you can't. But there are many things you can do, if you know what the heck you're doing. Sometimes you gotta make due with the tools at your disposal, because you may not have a choice otherwise. Or at least try to do it. If things hadn't gone right with the cookies, in the trash they would've went - but it went so well, my wife started to learn how to use that pizza oven for all it was worth, because it was usually always at temperature and consistent.
- wrdqex 8y ago
  So let me get this straight: - The chefs on said youtube channel complain about the temperature being non-consistent on their ovens. - Your wife also ran into this problem with her oven. - Your wife was able to cook using a pizza oven, which did NOT display this problem. - Therefore, the chefs from the channel are bad chefs, worse than your wife. I have not watched this youtube channel and cannot comment on the skill of the chefs, but your comment's conclusion does not logically follow.

iClaudiusX 8y ago

I found this to be the case for mid-level espresso machines as well. Luckily it is fairly simple to add a PID controller and a more accurate platinum temperature sensor to hold the brew temp to within a few degrees Celsius for a much more consistent extraction.

dpark 8y ago

> In my experience, they heat in cycles: if you set one to 180 it will heat to 240, then cool to 150 Get a better oven. A 90 degree Celsius swing is insane. Ovens do generally have some amount of swing but it should’t be anything close to that.

michaelcampbell 8y ago

Not to mention the picture appears to be a toaster oven; not paragons of heat stability.