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janardian
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Group: Forum Members
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Hey everyone, Our college student club participates in the SAMPE Beam competition every year ( http://www.nasampe.org/page/bridgecontest). We've been using donated (and usually expired) CF/GF prepreg to make 24" long I beams for the competition. This year however we don't have access to an industrial oven/autoclave, and we are (desperately) thinking of making our own. We have a fairly decent budget (not enough to buy an industrial oven ourselves tho). However we don't have a lot of hands on experience in oven making. Are there any good resources/DIY guides on that, especially one that caters to beginners? Any help will be greatly appreciated. For reference the material we have has a cure temp of 250-300F. Since we'd cure our beams with tooling material (usually aluminum bars), we'd probably need inner dimensions to be at least 14" x 26" x 10". Power bills are not an issue since we use university resources anyway. An idea that was floated around was to simply modify and extend a regular kitchen oven and add heat guns for even heat distribution. Thoughts? Ideas? Thank you!
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Hanaldo
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Group: Forum Members
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Super easy to build an MDF/Fibreboard oven that easily handles 400F. This is the build thread I posted for mine: http://www.talkcomposites.com/21047/MDF-Curing-OvenIve been using it virtually every day for the last 2 years, so it is very reliable. Easy to adjust the dimensions to suit whatever you need. Not so easy if you need the pressure of an autoclave though. This would of course need to be a much stronger build, and for obvious reasons you need to be careful with the combination of compressed oxygen and heat.
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janardian
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Group: Forum Members
Posts: 15,
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+xSuper easy to build an MDF/Fibreboard oven that easily handles 400F. This is the build thread I posted for mine: http://www.talkcomposites.com/21047/MDF-Curing-OvenIve been using it virtually every day for the last 2 years, so it is very reliable. Easy to adjust the dimensions to suit whatever you need. Not so easy if you need the pressure of an autoclave though. This would of course need to be a much stronger build, and for obvious reasons you need to be careful with the combination of compressed oxygen and heat. Thank you so much!! looks really cool, and 2 years is amazing durability-wise! Would you have more details on the build/schematic? I'm asking since we're pretty much going to build this from scratch and lack any experience doing this.
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Hanaldo
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Group: Forum Members
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It's pretty straight forward really, just 16mm thick MDF supported with 45mm pine on the insides and 45mm aluminium rectangular bar on the front. The support is important as the mdf will sag without it. I then sandwiched fibreglass insulation in between the pine supports, and the inside skin is 6mm fibreboard for even better heat insulation.
Other than that, it's simply a 2kw heating element, an oven fan and motor (both purchased off ebay), and a shroud to force the air to circulate around the oven. You also need to mount the fan so that the fan is inside the oven, and the motor is outside. If you buy an oven fan rather than any other sort of fan then they are made for this and have an extended shaft to go through the wall.
Its really very easy, don't over think it. It's just basic woodworking to build a box, and you just mount a heating element and fan on the back. It's a glorified hot box. The hardest part is working out the doors and a way to secure them closed, even the wiring is easy.
Hapoy to answer any specific questions you've got!
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janardian
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Group: Forum Members
Posts: 15,
Visits: 105
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+xIt's pretty straight forward really, just 16mm thick MDF supported with 45mm pine on the insides and 45mm aluminium rectangular bar on the front. The support is important as the mdf will sag without it. I then sandwiched fibreglass insulation in between the pine supports, and the inside skin is 6mm fibreboard for even better heat insulation. Other than that, it's simply a 2kw heating element, an oven fan and motor (both purchased off ebay), and a shroud to force the air to circulate around the oven. You also need to mount the fan so that the fan is inside the oven, and the motor is outside. If you buy an oven fan rather than any other sort of fan then they are made for this and have an extended shaft to go through the wall. Its really very easy, don't over think it. It's just basic woodworking to build a box, and you just mount a heating element and fan on the back. It's a glorified hot box. The hardest part is working out the doors and a way to secure them closed, even the wiring is easy. Hapoy to answer any specific questions you've got! Awesome, Thanks!!!
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Michael Guilford
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bit of a late reply.
But my curing oven is made from 100mm foil backed insulation board. with a piece of tilebacker on the base for durability and heat distribution
I have wired two 2000w heating elements in series to bring power down to 500w and use a thermostat to regulate temperature. You could also use a PWM controller to regulate power.
The fan motor is on the outside (would overheat inside). I use a tiny 12v van with a RC plane prop as a fan, connected through the walls.
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janardian
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Group: Forum Members
Posts: 15,
Visits: 105
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+xbit of a late reply. But my curing oven is made from 100mm foil backed insulation board. with a piece of tilebacker on the base for durability and heat distribution I have wired two 2000w heating elements in series to bring power down to 500w and use a thermostat to regulate temperature. You could also use a PWM controller to regulate power. The fan motor is on the outside (would overheat inside). I use a tiny 12v van with a RC plane prop as a fan, connected through the walls. Thank you for your answer! every bit helps!
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Steve Broad
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+x+xbit of a late reply. But my curing oven is made from 100mm foil backed insulation board. with a piece of tilebacker on the base for durability and heat distribution I have wired two 2000w heating elements in series to bring power down to 500w and use a thermostat to regulate temperature. You could also use a PWM controller to regulate power. The fan motor is on the outside (would overheat inside). I use a tiny 12v van with a RC plane prop as a fan, connected through the walls. Thank you for your answer! every bit helps! Mine is made from ply sheet and 50mm insulation and silver foil. Heat is supplied by 4 separate circuits powering 150w bulbs. one of these circuits is connected to an adjustable thermostat, allowing me to control oven temps. Used an old metal desk fan with the motor in the wall :-) 
Old microwave glass for viewing progress. Controls and wiring is a little bit Heath Robinson, but it works and I might tidy it up some day (probably not :-) ) If you look between the rows of switches you can see some of the remote temp sensors that allow me to check that I am getting an even cook.
Oven built to take front clip of my car. It fits, just . Photo has loaded sideways for some reason :-(
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janardian
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Group: Forum Members
Posts: 15,
Visits: 105
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Hey everyone, thanks for your tips and suggestions! We are making some progress with the oven, but are stuck at the oven fan part. What model/ fan would you recommend, and what wiring/connections should we use for that (we're looking at a 250-275F cure)?
Once again, thanks for all the help!
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janardian
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Group: Forum Members
Posts: 15,
Visits: 105
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+x+x+xbit of a late reply. But my curing oven is made from 100mm foil backed insulation board. with a piece of tilebacker on the base for durability and heat distribution I have wired two 2000w heating elements in series to bring power down to 500w and use a thermostat to regulate temperature. You could also use a PWM controller to regulate power. The fan motor is on the outside (would overheat inside). I use a tiny 12v van with a RC plane prop as a fan, connected through the walls. Thank you for your answer! every bit helps! Mine is made from ply sheet and 50mm insulation and silver foil. Heat is supplied by 4 separate circuits powering 150w bulbs. one of these circuits is connected to an adjustable thermostat, allowing me to control oven temps. Used an old metal desk fan with the motor in the wall :-)
Old microwave glass for viewing progress. Controls and wiring is a little bit Heath Robinson, but it works and I might tidy it up some day (probably not :-) ) If you look between the rows of switches you can see some of the remote temp sensors that allow me to check that I am getting an even cook.
Oven built to take front clip of my car. It fits, just . Photo has loaded sideways for some reason :-(
That is a really cool and interesting way to do it!
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