Home made curing oven heat source

General Composites Discussions Equipment Talk
#1

Hi everyone

Im going to be making a home made curing oven so to speak. Initially i was going to use those infrared heat lights as the heat source, however after reading a few posts on the forum i read that they can provide inconsistent heat across the part.

So i was wondering, what about this as a heat source and a fan blowing inside to circulate the air…
http://www.chicken-house.co.uk/cgi-bin/sh000001.pl?REFPAGE=http%3a%2f%2fwww%2echicken-house%2eco%2euk%2facatalog%2fHeat_Lamp_Components%2ehtml&WD=ceramic&PN=60w_Dull_Emitter__Ceramic_Heat_Lamp_Bulb%2ehtml%23a19#a19

How many do people think are needed to reach 80 degrees C? Also what would be a good distance away from the mould?

Thanks

#2

If you want really controled temperature, use temperature controller like Fuji PXR4 (PXR3 is bit cheaper but with far less functions).

Then buy SSR(solid state relay) driver:

and heating element with fins. Something like that:

Fan is blowing air thru heating element. You also need thermocoupe or RTD (resistance thermometer).

Required heating element power depends on many factors. Mostly from size of oven, insulation quality, rate of heating…

#3

You could always salvage some of the parts from a hair dryer

#4

some fantastic advice thanks guys! using those parts or similar seems like a much better idea :slight_smile:

#5

I use them for heating. With that Fuji controller you are able to program up to 8 ramps/soaks. It can control temperature very accuratly. There are several different configurations for Fuji PXR4, be carefull what you select (controller souce voltage, etc.). You can also buy it with optional data link to PC.

#6

How far away from your mould do you have the heating element? do you have anything between the element & the mould or is it completely exposed? The inside dimensions of my oven are goung to be around 100cm x 100cm x 40cm tall, do you think this 350w heating element would be powerfull enough?: https://www.easupplies.com/TEMPCO-CSF00520-SS-Heater-p/hv2ei8.htm
Thanks

#7

We made an oven 1m x 1m x 1m back in the summer. it consisted of 6 1mm thick stainless steel sheets 1m x 1m with 2 edges folded 90 degrees to form a 20mm rebate. We bought a second hand fan oven and used elements and fan and controller as well as the heat resistant wire. In the bottom we spread bricks from a night storage heater with the grill element laid on top. The fan and oven element are mounted in the back steel panel.The whole thing was surrounded with 50mm kingspan insulation. it is fully collapsible for storage and worked very well but could be improved by more insulation. I will see if we have any photos.

#8

That sounds pretty much what im trying to accomplish, i was even planning on using 50mm kingspan :). What insulation would you use instead to improve it as id like to keep as much heat in as possible to save it using too much power. Do you happen to know what wattage the heating element it? If you have any pics id really appreciate them.

#9

sorry cant find any photos I will ask my son later if he has any. I dont know the wattage of the main element but it came from a standard fan oven. it was very apparent that the greatest heat loss was from the joins in the insulation so next time i set it up I will use another thickness of insulation and stagger the joints. In our workshop space is at a premium so equipment not used every day tends to be packed away. The oven did maintain 200 degrees C so we counted it as a success but would cost less in electric if we paid more attention to detail!

#10

perky416: I have it in autoclave, 500mm diameter and 1000mm long. I used 50mm rock wool insulation there. I have 1000W heating element. I didnt test it but I think it will be enough for heating to 100-150degC. But its different on my project because autoclave is something like 230lb of steel (not counting internal insulation covers and other parts). I hope 50mm insulation will be enough to keep clave surface cool enough.

#11

Im not sure how it differs with an autoclave but at work we have massive temperature chambers, I managed to get a panel off the inside of the door today, all they use is fibreglass insulation surrounded by a couple mm thick powder coated mild steel, and at 95 degrees you cant tell at all, the outside is room temperature. The insulation is 100mm thick. I was speaking to one of the lads that does the maintenance on them a couple of hours ago, he said that 50mm at 100 degrees should be fine.
Paul33 on our chambers at work I noticed that around the door there are 2 rubber seals running parallel around the whole edge with sticky back foam stuck between them and you cant feel any heat loss, again the same lad said you can get the seal from Radio Spares. I might buy some and try it to avoid the heat loss around the edges.

#12

How bug are your parts your making, i use a heating pad its 1m x 1.5 m it works great. No need fir enclosure.

#13

What temperature does the heating pad reach?
I was going to do a few parts at a time, total not reaching more than 1m x 1m.

#14

Youre right. It should be same. I was just thinking that in my project there will be bigger heat losses because of metal fittings, internal shell connected to outer body, unisolated space around flanges etc. It will sink some heat. Also because I have several kg of metal parts/shell inside, I need higher Watt heating elements to be able to follow recommended temperature ramp. But this shouldnt be a problem.