looking for some oven advice please

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looking for some oven advice please

Author	Message
Pugsport	Pugsport posted 9 Years Ago HOT Topic Details
Group: Forum Members Posts: 14, Visits: 167	hello im just after some advice as im looking to start building an oven fairly soon. i have this design so far although i might make it a little larger so i could get a bonnet in there. this oven is 1000mm square and 500mm high front view side veiw frame will be made from: - 20x20x1.5mm box section oven walls/skin will be made from: - 1.5mm thick mild steel sheet insulation will be: - 100mm celotex right the things im not to sure about at the moment are seal for the door, how best to hold the door in place and where inside the heating element should go. my plans for the above were door seal: - use a silicone RTV sealant from a 310ml tube and make my own gasket as i can not seem to find a silicone thats not made for a domestic oven and then think of a way of fixing it to the door http://www.ebay.co.uk/itm/3-x-BLACK-RTV-SILICONE-INSTANT-GASKET-WATERPROOF-ADHESIVE-SEALANT-310ml-/231315155288?hash=item35db752958:g:w2gAAOSwnDZT-cOF door mounting: - i was thinking of M12 threaded bar welded to the box section so i could fix the door in place with nuts but i can also see a disadvantage to this as well as advantage, on the plus side you would be able to make sure all the door was in contact with the seal and adjust pressure around the door for best fit. negative would be quite a few bolts to do up and undo when putting the door on or taking it off and due to extra bracing the door might be fairly heavy heating element mounting: - im in thinking it would be best to use the element in the standard domestic oven place on the back wall of the oven but im not sure how well this would for wider overs of say 1500mm wide 1000mm deep and 500mm high any advice on the above three things would be great and also any advice on the overall design would be great if you can spot any problems i have missed out or over looked
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morepower	morepower posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 242, Visits: 1.2K	Ducting and forced air circulation? You need to get air flowing through the oven quickly and in a way that makes the oven an even temperature all over the oven. Hot and cold spots will affect the cure. Mine recirculates the air once every 6 seconds (IIRC) with the air being pulled into the fan and over the heating element across the floor and is pushed up vertically in an opposite corner so the duct does run along one side but pulls air in at 90 degrees to the direction the air is blown out. This means the air also gets pulled from the corner at the furthest point from where the air is blown.
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andygtt	andygtt posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 157, Visits: 1.2K	my oven (that i build a month or so ago) is very similar dimensions internally to yours and I used 100mm celutex... i used a single 2000w oven element and an oven fan (a must IMO), I built a unit to house them both and i have mounted it on the front of my oven. It holds 120 deg c very well and is a breeze at 80deg c or lower. Cant help much on the door, mine is a very simple affair and the front is just a large bit of celutex that i push in place (I threaded a large bolt through it to hold onto).
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Pugsport	Pugsport posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 14, Visits: 167	yes sorry guys i will be using a heating element and fan setup from a domestic cooker which i can see working quite well on a smaller oven but one thats quite long i think if the heating element is placed in the middle you might end up with cold spots on the outer sides but thats just my thinking i think i may have managed to work out away that i can hinge the door and still manage to get a good seal all around the door. my thinking is to use two continuous hinges, one down ether side to hinge a 50/50 split door. my thinking is to elongate the holes that will mount the hinge to the oven body meaning the hinge can slide backwards and forwards a little, then with the part loaded in the oven and doors shut use some thread bar or bolts along with a length of box section (box section to spread the force applied to the door) to hold the door in place when the oven is in use. front view of door design door hinges in blue, orange box section is to spread the force across the door seal applied by the nuts/bolts, grey is the metal door itself, yellow is a plate that covers the gap where the doors meet (may not use this part as the celotex will cover the gap once placed over the top) side view of door design door hinge in light blue, thread bar in grey along with the 1.5mm side panel
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Hanaldo	Hanaldo posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	You need to use a shroud as well, otherwise you will end up with uneven heating. This is simply a sheet of metal that sits just in front of the fan and heater, and extends almost all the way to the edges of the oven but stops an inch or so short. It should have a cut out in front of the fan to allow the fan to pull air in, and then it pushed it past the heater element and forces it to circulate to the edges of the oven. This keeps the temperature of the oven remarkably even, I've got a 0.4 degree difference between the middle and the edges of my oven. As for the door, I quite slowly discovered that simple is always better. I spent months trying to come up with a solution for keeping the doors closed, and tried 4 different methods. In the end, I showed it to the fabricator I work with and it took him 2 minutes to weld up a piece of square tube with flat bar on each end that measures perfectly across the top and just wedges the doors completely shut. It takes 2 seconds to open and close the doors, there's no wear and tear, and it's just so simple and easy.
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Pugsport	Pugsport posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 14, Visits: 167	Hanaldo (31/05/2016) You need to use a shroud as well, otherwise you will end up with uneven heating. This is simply a sheet of metal that sits just in front of the fan and heater, and extends almost all the way to the edges of the oven but stops an inch or so short. It should have a cut out in front of the fan to allow the fan to pull air in, and then it pushed it past the heater element and forces it to circulate to the edges of the oven. This keeps the temperature of the oven remarkably even, I've got a 0.4 degree difference between the middle and the edges of my oven. As for the door, I quite slowly discovered that simple is always better. I spent months trying to come up with a solution for keeping the doors closed, and tried 4 different methods. In the end, I showed it to the fabricator I work with and it took him 2 minutes to weld up a piece of square tube with flat bar on each end that measures perfectly across the top and just wedges the doors completely shut. It takes 2 seconds to open and close the doors, there's no wear and tear, and it's just so simple and easy. ahh yes i had seen that done and was thinking about maybe making a aluminium or steel box/shroud to put round it but i never knew about leaving 1 inch from the edges so thanks for that. yes you could be right on the door front, i might make it like the one above and see how i get on with it (im thinking impact driver and 12mm socket will help reduce time ) im not sure how much ill be using the oven right now as im only planning to make my own stuff and maybe a few other bits for people if they so wish. another quick question is do you draw air in from outside the oven or just keep it sealed tight or as tight as you can
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