Building an oven >>>for post cure

General Composites Discussions Equipment Talk
#1

I realize that post cure is required of many epoxy systems and is quite beneficial for ehancing the properties, but buying a real oven is out of the question.

What I have been thinking about is building an oven using the same principles as learned in grade 9 science class…or what ever grade that was. Where you made an enclosure that was lined with aluminum foil or something reflective and a clear top so that sunlight could come in and heat it all up.

I wonder if this could be used indoors with a similar setup but using a IR lamp to provide the heat and energy?

Would it allow for relatively uniform heating through out the box?

Any ideas?

#2

I started building a 4’ x 6’ and 3’ foot tall post curing / sheet blow molding oven a while back and never finished it…:o

Here’s a link to the basic plans…

http://www.wisil.recumbents.com/wisil/bubbles/hpvbubbles.htm

#3

ideas:
temp controlled heating elements. won’t have to worry about what temp it is wavering around!

uniform heating have be done by high-temp blowers/fans in the enclosure, making the hot air the same all over the oven.

box sides. that blue foam sheeting that they use on new houses. Easy to work with! CHECK the high-temp rating though! :slight_smile:

heatlamps will work too, again, find a way to monitor temps.

solar: large frenel lens heating a blackbody (black iron/rocks/etc) and have fans blowing past the blackbodys! maybe black anodized heatsinks even!

#4

Heating elements would be the best way to go as far as modulating the heat/temp, but I think that a heat lamp would be the easiest and least expensive, which is a big limitting factor in everything I do…

would it be better to have all sides enclosed by Al or steel or would my idea of having a clear top be ok? maybe 2 way mirror on top?

#5

I’m currently building an RC hydroplane using a Divinycell and carbon fiber sandwich construction. I’d also like to build a oven. I’m considering using preinsulated panels in the link below. Has anyone had any experience with this?

http://www.satinsulation.com/sat-insulation/?page=Features-Advantages

#6

i use an electric heated home oven like for cooking, put the bottom rack all the way down and takeout the other rack, put it on 150 degrees, put the part in, crack the door a bit…1 hour and DING! the parts are done

#7

Just NEVER use that oven again for food! :eek:

#8

doesn’t that stink up the house?

#9

I have no experience to speak of but it doesn’t say that if can handle any temps that would be used for post cure in my opinion…

#10

I built an oven a few years ago. It had a recirculating fan arrangement to blow air over the heating elements then into the oven where the parts were.
The controls were way expensive, over $6K ! Way too much for the home builder.
If I had to build another one I’d use the guts from a domestic oven and build an insulated cabinet for them. For post curing the domestic oven controls should be fine.
This is the one I built;

#11

Here’s another one I used to use for larger parts where I use very slow resins. With only two small electric fan heaters about 12" diameter (the kind you use in the living room to supplement your regular heat) it goes up to 120-130 degreesF !

It’s 2x4’s covered with foil covered bubble-wrap from Lowes Hardware Store. 8 feet long, 6feet wide. 6 feet high. Basically what you call a hot box.
Remember, wood catches fire at Fahrenheit 451, I think. (I read a book called that once).

#12

451 is the burning temp of paper – I suppose paper is made of wood. Farenheit 451 is about the burning of books, hence the title.

#13

Al would be fine for low temp (less than 450f), but it all depends on the insulation you use. Foam sheets might not handle it, but standard insulation would work fine. Maybe use those steel studs used in construction, andmake a mini-house!! Wrap fiberglass insulation around, and there ya go.
If you use heat lamps, then yeah clear tops would be ok, as long as it’s tempered glass.

#14

Unless you are trying to start a fire,and you have crappy cold and wet wood, and it takes almost a half of a phonebook to start the lots.

But yeah, wood and plastic bubble wrap isn’t good for mid-high temp stuff

#15

Quote;“Maybe use those steel studs used in construction,”
Yes, that’s exactly what’s inside that first gavanised steel oven.

#16

I’m most likeely going to pick up some galvanized sheet or stainless and make it a collapsable unit with the aide of some bolts and stuff. I’m not looking to make it too big, the largest thing I am ever planning on doing is a set of motorbike fairings, so it will need to accomodate that, but that is still a ways inthe future. Most things I make are small.

#17

Instead of bolt together, get a long piano hinge for each corner, pull the rod out and shorteh up the hinge. Then add a grip to the rod so you can slip it in and out easily.

#18

i read about constructing an oven in the “competition car composites” book… looks easy, using parts from an old home oven… thing is, its gotta be big enough to fit a hood in my case :rolleyes:

#19

This stuff is easy to work with and would make a great frame.

http://www.8020.net/

#20

You can buy 80/20 extrusions and parts on ebay under their seller name there. Cheaper probably.

I was looking for some aluminum plate the other day and found them on ebay.
http://stores.ebay.com/8020-Inc-Garage-Sale I’ll probably end up buying/cutting some mild steel at work and then having it all welded together.

20_RC51_00, keep us updated… I am in need of building a post cure oven myself. Also i may do some high temp parts in the future… 350F at the hottest.

That 80-20 looks like the stuff to use for a frame, but those plastic connectors they have won’t cut the mustard.

Some may laugh but i do the same stuff as RC51 does, i’m thinking a small oven 1ft tall x 3ft deep x 3ft wide. Put her on legs and wheels so i am able to roll it around.

Caswell plating forum has an oven building forum… thing i noticed with most of the guys there they’re building ovens that will do 1000F + so their elements and controllers are overkill for what we need. I’m thinking of buying two toaster ovens and tearing them down for their parts for use in my homemade oven. The only other thing i can think that i may need is a fan to circulate the hot air. The toaster ovens are 1500 watts each.