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Old Nov 12, 2005, 09:46 AM
Knowledge increases life's FOV
Sled Driver's Avatar
Third Stone from the Sun
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How did you build your hot box?

Got an industrial heater system with temperature control assembled and working yesterday. Now I need to build a new hot box to put it in and I am looking for more ideas...

How did you build your hot box?
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Old Nov 12, 2005, 09:56 AM
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Batmanwpg's Avatar
Winnipeg, Canada
Joined Aug 2004
914 Posts
hot box

I need ideas also. The one I have to build needs to get up to 250° F. Is this possible using 100 w light bulbs?

Bear
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Old Nov 12, 2005, 11:17 AM
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San Diego, CA, USA
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My box is just made from plastic-coated expanded-bead polystyrene foam. If you need more than say 120°F, it would be better to use wood or metal for the box and insulate with fiberglass.

Sure, 250°F is possible with 100W bulbs, depending on the size of the box and the number of bulbs.

-David
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Old Nov 12, 2005, 01:19 PM
Or am I...
Bournemouth, Dorset, UK
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Sorry but whats a Hot box?? A box to dry paint in??
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Old Nov 12, 2005, 04:13 PM
built flown + crashed it
Pewsey, Great Britain (UK)
Joined Oct 2004
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i bought a small oil filled radiator with a thermostat for the heat source. My room is limited so i build up a box after bagging, 3 sheets of 8ft x 2ft foam and two end bits 2 x 2ft held on with a bit of tape and leave it all alone for 24 hrs. I experimented with the tempature setting until it stabalized where i wanted it, and put a sharpe pen mark on the dial. Works great for me, bag the wing, go to bed, go to work, wing is done. Workbench is free again. Keep the foam on a high shelf out of the way.
Just thinking about it a little, you could make it much more durable by linning the sheets with hardboard or thin ply, and then screw on some catches so it all clips together, hmmm i better get some ply.
Basically the same concept as phil barnes uses on his dvd.
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Old Nov 12, 2005, 05:17 PM
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Quote:
Originally Posted by im-sad
Sorry but whats a Hot box?? A box to dry paint in??
Paint, yes... but more typically to speed up the cure of epoxy. If you make it hot enough, you can also post-cure your parts.
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Old Nov 12, 2005, 06:24 PM
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Congress, AZ
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Mine is 1" foam, aluminum faced, from Home Depot. I use a 2" piece of Foamular 250 for a removeable lid (heat goes up, right?)

A indoor/outdoor thermometer is used to monitor temperature. The original plan was to use a 110v dimmer to control temp, but hasn't proved to be necessary.

Heat is with either 1 or 2 light bulbs, wattage varied as needed. One 100 watt bulb will get to 90 to 100 degrees, depending on outside temp. Two 100 watt bulbs raise it another 20 to 30 degrees.

A piece of aluminum foil is on the underside of the lid to protect the foam. Two layers of 1" alum backed foam could be used, and this wouldn't be needed.

Gary
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Old Nov 14, 2005, 04:39 PM
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St Augustine, FL
Joined Jan 2005
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Hotbox

Just about to finish mine. Has 0.5 inch MDF with 3/4 inch foam insulation with aluminum on both sides. Putting a high temp duct fan in it for heat circulation and using up to 6 100 watt lamps (not in photo but you can see the channel it will be put in) in it controlled with a automatic temperature controller. Put the fan in there so that I can stack a couple of wings on top of each other at the same time and hopefully get the same temp everywhere in the oven.
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Old Nov 15, 2005, 09:17 AM
DLD
David Layne
Tracy, Ca
Joined Jun 2004
665 Posts
Hot box

Hollow doors make a good hot box. The air inside makes a good insulator. I used three doors with mdf floor and ceiling, then hinged the fourth door. Two heat lamps were attached to the floor of the box, and I hung fuselage molds from hooks, nose down. The heat lamps will get the box to 120-130 degrees. It's cheap, easy and effective.

David Layne
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Old Nov 15, 2005, 02:23 PM
Nucking Futs
I'm Rick James's Avatar
Southern Killafornia
Joined Jan 2005
1,626 Posts
Quote:
How did you build your hot box?
I rolled up the windows in my car and lit up!!!!

Just kidding man, good luck with your project.

IRJ
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Old Nov 15, 2005, 03:04 PM
Knowledge increases life's FOV
Sled Driver's Avatar
Third Stone from the Sun
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Quote:
Originally Posted by I'm Rick James
I rolled up the windows in my car and lit up!!!!

Just kidding man, good luck with your project.

IRJ

Was wondering whether someone with a misspent youth, or adulthood, would offer that solution...
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Old Nov 15, 2005, 07:45 PM
The End
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AREA-52, Oceanside Southern Killafornia
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Seriously, is a hot box a requirement? I plan on making fuselages, so if I need one, I'll build one. Were do you get the specs to know how hot and for how long?

Hate to be dumb, but what are the benefits?
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Old Nov 15, 2005, 08:33 PM
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St Augustine, FL
Joined Jan 2005
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curing temp

Speeds up the curing time.
Raises Tg of the epoxy.
Tg, or the “glass transition temperature,” is the temperature “range” at which the cured epoxy will begin to significantly compromise its physical properties of consistency, hardness, shear strength, tension strength, compression strength, flexural strength, etc. Epoxies cured at room temperature have a maximum Tg of 60-65oC regardless of their hardener ratios, or up to 90oC with a post-cure at 60oC heat for 2 hours. To get an epoxy to develop a Tg over 90oC it needs to be cured for hours in a specially built high-heat oven. This will increase the Tg when cured, and make the resin structure stronger.
Benefits for polyester resin are not that big (if your are planning on using that for your fuse).
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Old Nov 15, 2005, 11:32 PM
Nucking Futs
I'm Rick James's Avatar
Southern Killafornia
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for what you want to do Terry, you don't need it IMHO.

IRJ
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Old Nov 16, 2005, 02:57 PM
Knowledge increases life's FOV
Sled Driver's Avatar
Third Stone from the Sun
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Two questions...

Quote:
Originally Posted by DLD
Hollow doors make a good hot box. The air inside makes a good insulator. I used three doors with mdf floor and ceiling, then hinged the fourth door. Two heat lamps were attached to the floor of the box, and I hung fuselage molds from hooks, nose down. The heat lamps will get the box to 120-130 degrees. It's cheap, easy and effective.

David Layne


Will a wood box work for 150-160 degrees F cure temperatures?

Would you recommend that major axis (longest lenth) be vertical or horizontal for curring bagged wings?
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Last edited by Sled Driver; Nov 14, 2006 at 10:59 PM.
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