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Steve Broad
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Group: Forum Members
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+xYeh, night shift brain. Mine works the same. No idea what I was thinking when I wrote that haha. Although what I said is true if you are using On/Off mode rather than Program mode. So sometimes, like when I'm doing roll wrapped tube, I don't need a ramp and just go straight to final cure temp. And in this case, the element gets full power with no ramp. So it is still important that the area around the element can handle radiant temps of 300°+, in case you mess up and forget to put it in Prog, etc. Glad that it isn't just me with one of those brains :-) Haven't tried On/Off mode yet. I have surrounded the rear and sides of the heating element with and old car exhaust shield designed to survive 900 deg C plus so it should be OK.
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Hanaldo
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Group: Forum Members
Posts: 2.5K,
Visits: 28K
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Yeh, night shift brain. Mine works the same. No idea what I was thinking when I wrote that haha.
Although what I said is true if you are using On/Off mode rather than Program mode. So sometimes, like when I'm doing roll wrapped tube, I don't need a ramp and just go straight to final cure temp. And in this case, the element gets full power with no ramp. So it is still important that the area around the element can handle radiant temps of 300°+, in case you mess up and forget to put it in Prog, etc.
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Steve Broad
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Group: Forum Members
Posts: 408,
Visits: 4.1K
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+x+x+x+x+x+xA few members on here have made their own ovens so it is doable DIY. There are a few threads on members own oven projects. However we always tend to advise you take the safety side of it very seriously. If you get it wrong you could burn your shed down! Hence why we are always a bit hesitant in suggesting making your own unless you have the correct electrical knowledge and general knowledge on making an oven safely. Warren, thanks, yep, I completely agree. Kevin Agreed, safety is always important when dealing with electricity. If you are not confident there are plenty of electricians that will do the work for you. If you are concerned about using heating elements you can use light bulbs as the heat source. They will be surrounded by heat resistant materials and the max temperature will be around 120 deg C for basic curing (you can cure most prepregs below 100 deg) or 160 deg C if post curing, all of which are not even hot enough to ignite paper. So the chances of setting your garage alight, as long as you don't have an electrical issue (but that is the same for any appliance/lighting/heating circuit) are virtually nil. However, I accept that EC staff members have to be very careful with what they recommend. And, likewise, these comments are my own personal opinions based on a fair few years of experience in building curing ovens. You will have to make your own judgement on your skills and capabilities when it comes to building anything involving electricity. The biggest danger, aside from a wiring issue, is the heating element. Sure 120° is quite low temperature and not going to ignite anything, but it's the element - these are just on and off full power and get extremely hot. Especially if you are ramping straight up to 120, thats going to be a solid 20-30 minutes in a mid sized oven where a 2kw element is at full power and very very hot. So everything right next to the element is what you have to be worried about, you don't want anything there that could be flammable, and you have to make sure that nothing can shift or fall on the element. Anyway, I think it is quite a low risk sort of project, you just have to think about it a bit. It's really dead easy to do. That's why I suggested light bulbs. However it is interesting what you say about the element being on full power. I use the PID to raise the temperature from ambient (15-20 deg C) to an initial 80 over 30 minutes , hold for 30 minutes then continue to 120 over 20 minutes and hold for an hour. The controller is constantly turning the element on and off and it never gets red hot and therefore doesn't emit any light, so I am going to have to install a low wattage lamp so I can monitor what is going on :-) If the PID is ramping the heat up, then it shouldn't be switching the element off. It will constantly switch as it approaches target temp and maintains target temp, but if your thermocouple is reading 80 degrees and your target temp is 120 degrees, then it should just switch the element on until it gets to about 110-115 or so. And it should only take @ 20 seconds for the element to get red hot. Ah, no, it is cleverer than that :-) You set the desired temp and the time you want it to take to get there. So, working on 3 degC/min ramp (recommended max temp ramp for the prepreg I use), 20degC ambient and 80degC initial target, I would set the time at 20 minutes. This PID then calculates how often to switch the element on and off to maintain this temp ramp rate (using the thermocouple data to monitor and moderate). The PID has a light that indicates when the element is on and it is off and on like a slow car indicator :-) And this is in an oven 1.7m x 1.7m x 0.8m. The element gets very hot but not hot enough to glow.
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Hanaldo
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Group: Forum Members
Posts: 2.5K,
Visits: 28K
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+x+x+x+x+xA few members on here have made their own ovens so it is doable DIY. There are a few threads on members own oven projects. However we always tend to advise you take the safety side of it very seriously. If you get it wrong you could burn your shed down! Hence why we are always a bit hesitant in suggesting making your own unless you have the correct electrical knowledge and general knowledge on making an oven safely. Warren, thanks, yep, I completely agree. Kevin Agreed, safety is always important when dealing with electricity. If you are not confident there are plenty of electricians that will do the work for you. If you are concerned about using heating elements you can use light bulbs as the heat source. They will be surrounded by heat resistant materials and the max temperature will be around 120 deg C for basic curing (you can cure most prepregs below 100 deg) or 160 deg C if post curing, all of which are not even hot enough to ignite paper. So the chances of setting your garage alight, as long as you don't have an electrical issue (but that is the same for any appliance/lighting/heating circuit) are virtually nil. However, I accept that EC staff members have to be very careful with what they recommend. And, likewise, these comments are my own personal opinions based on a fair few years of experience in building curing ovens. You will have to make your own judgement on your skills and capabilities when it comes to building anything involving electricity. The biggest danger, aside from a wiring issue, is the heating element. Sure 120° is quite low temperature and not going to ignite anything, but it's the element - these are just on and off full power and get extremely hot. Especially if you are ramping straight up to 120, thats going to be a solid 20-30 minutes in a mid sized oven where a 2kw element is at full power and very very hot. So everything right next to the element is what you have to be worried about, you don't want anything there that could be flammable, and you have to make sure that nothing can shift or fall on the element. Anyway, I think it is quite a low risk sort of project, you just have to think about it a bit. It's really dead easy to do. That's why I suggested light bulbs. However it is interesting what you say about the element being on full power. I use the PID to raise the temperature from ambient (15-20 deg C) to an initial 80 over 30 minutes , hold for 30 minutes then continue to 120 over 20 minutes and hold for an hour. The controller is constantly turning the element on and off and it never gets red hot and therefore doesn't emit any light, so I am going to have to install a low wattage lamp so I can monitor what is going on :-) If the PID is ramping the heat up, then it shouldn't be switching the element off. It will constantly switch as it approaches target temp and maintains target temp, but if your thermocouple is reading 80 degrees and your target temp is 120 degrees, then it should just switch the element on until it gets to about 110-115 or so. And it should only take @ 20 seconds for the element to get red hot.
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Steve Broad
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Group: Forum Members
Posts: 408,
Visits: 4.1K
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+x+x+x+xA few members on here have made their own ovens so it is doable DIY. There are a few threads on members own oven projects. However we always tend to advise you take the safety side of it very seriously. If you get it wrong you could burn your shed down! Hence why we are always a bit hesitant in suggesting making your own unless you have the correct electrical knowledge and general knowledge on making an oven safely. Warren, thanks, yep, I completely agree. Kevin Agreed, safety is always important when dealing with electricity. If you are not confident there are plenty of electricians that will do the work for you. If you are concerned about using heating elements you can use light bulbs as the heat source. They will be surrounded by heat resistant materials and the max temperature will be around 120 deg C for basic curing (you can cure most prepregs below 100 deg) or 160 deg C if post curing, all of which are not even hot enough to ignite paper. So the chances of setting your garage alight, as long as you don't have an electrical issue (but that is the same for any appliance/lighting/heating circuit) are virtually nil. However, I accept that EC staff members have to be very careful with what they recommend. And, likewise, these comments are my own personal opinions based on a fair few years of experience in building curing ovens. You will have to make your own judgement on your skills and capabilities when it comes to building anything involving electricity. The biggest danger, aside from a wiring issue, is the heating element. Sure 120° is quite low temperature and not going to ignite anything, but it's the element - these are just on and off full power and get extremely hot. Especially if you are ramping straight up to 120, thats going to be a solid 20-30 minutes in a mid sized oven where a 2kw element is at full power and very very hot. So everything right next to the element is what you have to be worried about, you don't want anything there that could be flammable, and you have to make sure that nothing can shift or fall on the element. Anyway, I think it is quite a low risk sort of project, you just have to think about it a bit. It's really dead easy to do. That's why I suggested light bulbs. However it is interesting what you say about the element being on full power. I use the PID to raise the temperature from ambient (15-20 deg C) to an initial 80 over 30 minutes , hold for 30 minutes then continue to 120 over 20 minutes and hold for an hour. The controller is constantly turning the element on and off and it never gets red hot and therefore doesn't emit any light, so I am going to have to install a low wattage lamp so I can monitor what is going on :-)
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Hanaldo
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Group: Forum Members
Posts: 2.5K,
Visits: 28K
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+x+x+xA few members on here have made their own ovens so it is doable DIY. There are a few threads on members own oven projects. However we always tend to advise you take the safety side of it very seriously. If you get it wrong you could burn your shed down! Hence why we are always a bit hesitant in suggesting making your own unless you have the correct electrical knowledge and general knowledge on making an oven safely. Warren, thanks, yep, I completely agree. Kevin Agreed, safety is always important when dealing with electricity. If you are not confident there are plenty of electricians that will do the work for you. If you are concerned about using heating elements you can use light bulbs as the heat source. They will be surrounded by heat resistant materials and the max temperature will be around 120 deg C for basic curing (you can cure most prepregs below 100 deg) or 160 deg C if post curing, all of which are not even hot enough to ignite paper. So the chances of setting your garage alight, as long as you don't have an electrical issue (but that is the same for any appliance/lighting/heating circuit) are virtually nil. However, I accept that EC staff members have to be very careful with what they recommend. And, likewise, these comments are my own personal opinions based on a fair few years of experience in building curing ovens. You will have to make your own judgement on your skills and capabilities when it comes to building anything involving electricity. The biggest danger, aside from a wiring issue, is the heating element. Sure 120° is quite low temperature and not going to ignite anything, but it's the element - these are just on and off full power and get extremely hot. Especially if you are ramping straight up to 120, thats going to be a solid 20-30 minutes in a mid sized oven where a 2kw element is at full power and very very hot. So everything right next to the element is what you have to be worried about, you don't want anything there that could be flammable, and you have to make sure that nothing can shift or fall on the element. Anyway, I think it is quite a low risk sort of project, you just have to think about it a bit. It's really dead easy to do.
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Steve Broad
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Group: Forum Members
Posts: 408,
Visits: 4.1K
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+x+xA few members on here have made their own ovens so it is doable DIY. There are a few threads on members own oven projects. However we always tend to advise you take the safety side of it very seriously. If you get it wrong you could burn your shed down! Hence why we are always a bit hesitant in suggesting making your own unless you have the correct electrical knowledge and general knowledge on making an oven safely. Warren, thanks, yep, I completely agree. Kevin Agreed, safety is always important when dealing with electricity. If you are not confident there are plenty of electricians that will do the work for you. If you are concerned about using heating elements you can use light bulbs as the heat source. They will be surrounded by heat resistant materials and the max temperature will be around 120 deg C for basic curing (you can cure most prepregs below 100 deg) or 160 deg C if post curing, all of which are not even hot enough to ignite paper. So the chances of setting your garage alight, as long as you don't have an electrical issue (but that is the same for any appliance/lighting/heating circuit) are virtually nil. However, I accept that EC staff members have to be very careful with what they recommend. And, likewise, these comments are my own personal opinions based on a fair few years of experience in building curing ovens. You will have to make your own judgement on your skills and capabilities when it comes to building anything involving electricity.
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Castle Works Motorsports
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Group: Forum Members
Posts: 4,
Visits: 11
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+xA few members on here have made their own ovens so it is doable DIY. There are a few threads on members own oven projects. However we always tend to advise you take the safety side of it very seriously. If you get it wrong you could burn your shed down! Hence why we are always a bit hesitant in suggesting making your own unless you have the correct electrical knowledge and general knowledge on making an oven safely. Warren, thanks, yep, I completely agree. Kevin
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Warren (Staff)
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Group: Administrators
Posts: 2.5K,
Visits: 8K
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A few members on here have made their own ovens so it is doable DIY. There are a few threads on members own oven projects. However we always tend to advise you take the safety side of it very seriously. If you get it wrong you could burn your shed down! Hence why we are always a bit hesitant in suggesting making your own unless you have the correct electrical knowledge and general knowledge on making an oven safely.
Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
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Castle Works Motorsports
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Group: Forum Members
Posts: 4,
Visits: 11
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+x+xIf you're looking at trying prepregs you might find some of the stuff in my post useful: https://explorecomposites.com/articles/lamination/basics-laminating-with-pre-pregs/There's a link in there to another post about building ovens (cheap). A used electric oven should work fine if you can handle the fact that it doesn't mix the air so the temperatures can be very uneven. Should be able to supplement with a few thermocouples to give some visibility on whats going on with the actual part temperature. From a heating perspective it is way overkill - but nice and safe to operate compared to home-made stuff. If you get a fan assisted oven, which I forgot to mention, then the air is circulated and, as it is also a small volume, the temperature will be pretty even. Hi Chris, Thanks for the reply, that is all very helpful. Kevin
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