DIY Silicone Heat Blanket

[bhenry]

[bhenry]

[troublemaker]

gozaimaas, what is your total ohm? Also what oz. fiberglass did you use?

[gozaimaas]

I think its 6oz cloth. Mats are measuring 328 ohms with multimeter set to 20.
I will do a dummy run in the press today and see how long it takes to get up to temp.

[troublemaker]

I changed my mats to 10oz due to what stated above about feeling the wires through the mat. 328 ohms isn't correct, if those are 240VAC mats you should be around 26-36 ohms, and 10-13 ohms for 120VAC.

[bhenry]

[quote="troublemaker"]I changed my mats to 10oz due to what stated above about feeling the wires through the mat.
is this a problem? Should I add another layer?

[gozaimaas]

I changed my mats to 10oz due to what stated above about feeling the wires through the mat. 328 ohms isn't correct, if those are 240VAC mats you should be around 26-36 ohms, and 10-13 ohms for 120VAC.

Must be 32.8 ohms. I am an electrical retard lol.

[gozaimaas]

I changed my mats to 10oz due to what stated above about feeling the wires through the mat.
is this a problem? Should I add another layer?

I seriously doubt it will be a problem. When everything is under compression the mats will be flat and your cassette will even out any difference.

[bhenry]

I'll give it a try.
Thanks to all who have offered their advice and experiences.

[gozaimaas]

Ok here are some results from my heat mats
33 ohms @240v



I ramped the heat up as per the data sheet that came with my epoxy. 10 mins at 60 degrees c and then ramp to 100 degrees and sit there for 15 mins.
It took 10 mins to ramp from 60 to 100, the top and bottom temps never moved more than 1 degree away from each other. It started to slow as it hit 95 and worked its way up to 100.
Absolutely flawless results from both the mats and the sestos pid.



The only deviation from the factory settings was calibration of the thermocouples which I performed in a jug of boiling water to 100 degrees.
They match perfectly at 100 degrees and are 0.3 different at 17 degrees


Note. The thermocouples that come with the ebay sestos pid units are fine. Cut the end fitting off with pliers and use a battery charger to weld them back together (see thread by troublemaker).
DO NOT TWIST THE WIRES, they must be seperate all the way to the weld.

Bad


Good

[falls]

now you're cooking....

[gozaimaas]

now you're cooking....

Hai!

[troublemaker]

33 ohms is more like it! 7.2 amps, 1745watts, that's a great mat.

[gozaimaas]

Yeah they work great. I just cooked my first board at 100 degrees. No problems.

[falls]

What resin are you using?
100C for rapid cure or just the recommendation?

If you have a few spare TC's it would be a good experiment to put one in the tip and tail to see what happens throughout the layup when controlling temp in the middle (I assume).