I was thinking about making a simple tool to make flat plate that uses some sort of electric heating element.
I’ve seen heating strips like on mc master, but not sure if these would be the best for the job? Either that or the elements from a stove or something similar?
I have the PID controller and though if I had a flat tool that clamped together using heating elements I might be able to make some panels without creating a full fledged oven.
Does anyone possibly have some insight?
Many ways to do this, but one easy way is if your tool surface is pretty flat, you can buy a custom heating pad and place this on the bottom side. This works very well. Other ways would be to use heating wires, liquid heating, or other types of heating elements imbedded in to the tool. Also, there is a carbon nano coating that can also be applied and heated. Carbon fiber can also work if you isolate it well.
ive used underfloor heating wires , i had a spare kit so it came with the thermostat.
i used a large slab of granite from a kitchen sink (washbowl) cutout … i use it for doing flat laminates and as a heat source for my oven 
I have used Nickel Chromium wire to make a blade for cutting foam. Just use a switch from an old train set for power. Wire gets hot as Hell! You can get wire or ribbon. It’s pretty cheap too.
Please see - http://compositescentral.net/showthread.php?t=5872
for my solution to heated Aluminium Moulds, I have been using many configurations of this method for over 15yrs. with 100’s of successfull outcomes.
Happy to share any info with you.
Regards
John Hayes
www.bladerunneroutriggers.com
That’s pretty much what I need to do right there…
I’m just panning on making a flat plate mold so I can make some honeycomb panels.
What heating elements do you use? Where do you source them?
So from looking at your pictures of the molds you created, maybe something like this is similiar?
Yes, those elements can be cold formed by yourself around a suitable mandrel, keeping in mind the minimum rad. quoted for the dia. chosen, you can crack these elements if you push that min. Rad. once you have matched the routered recess to take the element you can simply centre punch the side of the recess to contain the element or make flat plates to do the same job, say every ft. is ample, I have plenty of pics. if req.?
Regards
Hello,
In injection plastic industrie they use some cartridge heater, I suppose is what Bladerunner use for his mold.
http://www.amazon.fr/Amico-%C3%A9l%C3%A9ment-chauffant-cartouche-chauffante/dp/B00GASO30Y
http://www.schiltz.be/images/Products/pdf/F0740_cartouche_chauffante.pdf
You can also use wire with a pid and isolate it inside a composite tool. I made a couple molds and plugged them into a heatcon to precisely control the heat, vacuum and have cure data. Works ok…I was curing conventional prepreg and forming core. I think ooa may work much better but have no experience with it in a heated tool.
Yah, i’m thinking that using the cartridge heaters is probably the way to go. I’ve got one at work that was for another use that I"m going to do some tests with. Seems like the cartridge elements are easy to work with and fairly inexpensive. Not sure how even the heating will be but, I’m thinking that they should be good enough.
I have a block of alumnimum that i’m going to fit one of the cartridges into first to see how it works. For a final flat mold I’d drill some holes to drop them in.
There’s probably a variety of methods that would do the same job. It’s a matter of finding the easiest and most efficient i guess.
I have the PID controller, So I’ll see what I can come up with. I guess one try at a time.
Not sure how big you job is , but I use a hot box everyday to heat tools. 25mm cheap foam , PU glued together with a ceramic heater brought from hardware store or bathroom heat lamp’s work every well also.
I could think of a quicker easier way 
and cost less than $100 and very efficient.
Tim
There is nothing simpler than normal oven type elements, set into your aluminium tool,
the heat control is immediate, no need for long term heat lamps etc. to raise the temp of your aluminium tool, with a thermostat you have infinite control to suit your resin system, which allows you to control all aspects of the cure, my resin system and Expancel, (which eliminates the use of unreliable bladders) requires 110-120 deg. C. ramp or down as per specs.
Been using this system for over 15yrs. to date I have not had 1 failure - “Touch Wood”!
A hot box is easy but, do you have ramp/soak controller and get to 200-300F? I"m really talking about an oven not a hot box. I bought foam, not PU. I think it’s polyiso. It can withstand higher temps than PU or EPS but not super high. The other pain with an oven is that you need to have a fan or fans in order to get even heat distribution.
I"ll eventually build an oven but wanted to make some flat panels right now and not have to deal with an building an oven.
I think I"m on board with John about building aluminum tools and using bendable or cartridge heating elements. I have a test plate that I’m gonna try to get to work.
I did look at Alan Harper’s page and I have to say I love the idea of a silicone RVB that has the element built in. I think I’d go that direction once I have molds that justify it.
It’s an amazing setup just from the repeatability standpoint for open molding IMHO.
I agree… seems like a good way to go. I’m curious as to the pricing for the heating part. The RVB bags can be a little spendy but, for production they’re hard to beat
Yep I use this temp controller http://www.ebay.com.au/itm/D-STC-1000-Digital-Temperature-Thermostat-Controller-220V-/281206350864
And I use this ceramic heater fan.
http://www.ebay.com.au/itm/MORETTI-CERAMIC-FAN-HEATER-INDOOR-WORKSHOP-GARAGE-240V-2000W-THERMOSTAT-MPTC20-/281427090781
I have a mate how does pre-preg motor bike parts with similar set up ( 65’c stuff) it’s good to use some heat reflective insulation material on the inside also. Cheap set up cost with great repeatable results. One advantage of a small oven/hot box is , if doing multiple sets of flat plate moulds ? You could have 5 or 10 sets of moulds in the at a time , which also makes it very energy efficient as once hot it only cycles every now and then
Many ways to skin a cat , just giving you idea’s
Tim
This is true about doing multiple tools this way. I also have a similiar controller i got from ebay. ANd by fan, I mean a constant run fan that’s independent from the heat to provide good circulation. Maybe it’s not necessary in a smallish oven? The big ovens usually have a constant run fan to circulate the air.
That sort of oven is probably cheaper ultimately, than an individual heated plate. However with the metal heated tool, I can cycle it up to 300F and then the parts cure in 1 hour vs like 5 or 6 at 180F
As usual each method has it’s advantages.
I appreciate the ideas, this is a good place to discuss possibilities. Many of y’all have some great ideas and have some useful experiences.
I do think that in the end, I’ll need to have both an oven and heated tools. As well as that heated rvb. Like anything, it’s partially economically driven choices. I’m just trying to do things as cheaply as possible right now.
So I was messing with a cartridge heater, seems like it’d be a good choice but… I’ll have to get a plate of alumnium and then drill out some holes. Probably not a bad choice.
I did also find thesething: https://www.watlow.com/products/heaters/flexible-silicone-heaters.cfm
a guy on ebay has some for pretty cheap, like $30… says it’s good to 500F
I think this might be an easier solution. I’ll have to get one to do some testing but, sounds like it’d work great and I should be able to sandwich it between two sheets of aluminum to cure two panels simultaneously.