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Temperature Timer
Posted: Thu Dec 03, 2015 4:14 am
by Akiwi
Not sure if this should be a new topic, but I googled for a while and didn't find anything.
Does anyone have a good solution for a Temperature Timer?
I have found digital temperature controllers prettty cheap, like this here.
http://www.ebay.de/itm/Digital-PID-Temp ... 1297681965
But I want to do something like cook my board at different temperatures for different time periods.
E.g. my current epoxy recommends Optimal Temperature cycle: 24h/23°C + 5h bei 60°C + 6h bei 80°C.
Or for example chrislandy wrote:
chrislandy wrote:Nice, but with regard to the cure time: Do your own testing on the resin you use but I tested mine (lab tested) with different cure cycles and there is essentially no difference (or slightly better properties) from cooking straight away rather than waiting the 24hrs then cooking.
I found a dwell at 40deg for an hour or so then raising to 80deg for 8hrs got me a good void free laminate plus the strengths I wanted - but obviously thats my resin that I use. It allows the resin to reduce viscosity and flow before going off, that way you get better consolidation from the vacuum.
So I want to be able to do this without having to constantly be present to change temperatures.
Currently my Ghetto HotBox is a few sheets of styropour held together using some wire pins and a cheap fan heater blowing into it.
Posted: Thu Dec 03, 2015 4:21 am
by mammuth
Omega has cheap ones with (multi) ramp profile .. 7500 or 7800 series afair
Posted: Thu Dec 03, 2015 4:56 am
by chrislandy
Try and find a used Eurotherm or CAL controller that is SSR compatible
Two well established companies that are used in industry.
I got a really good deal on ebay for mine
Posted: Sat Dec 05, 2015 8:06 am
by motoman
We add this function to our controller on programming level.
Posted: Sat Dec 05, 2015 2:29 pm
by Akiwi
This was one of those things I didn't know existed.
I was looking at doing it with an Arduino module..
I guess I like making things complicated for myself sometimes.
Sorry for the stupid question.
Posted: Sat Dec 05, 2015 3:31 pm
by MadRussian
if you into electronics and programming or like to play with that kind of stuff SSR and programmable controller is the only way to go. However several threads here about SSR overheat and crops out in worst possible time.
If you don't... use paper and pen and timer every time you making skis/board and of course reliable control or thermostat no SSR and no problems
KISS method always work when in doubt.
Posted: Sat Dec 05, 2015 10:26 pm
by OAC
This was one of my best addition to my setup. One PID and two SSR's. One on/off switch. Works with both one-phase and three-phase(sublimation mat). Couldn't resist to put the vacuum meter thru it. The "OAC control-master 3000"!
https://goo.gl/photos/eB2ZmYSE4KAn733v7
Posted: Sun Dec 06, 2015 12:51 pm
by Akiwi
OAC wrote:This was one of my best addition to my setup. One PID and two SSR's. One on/off switch. Works with both one-phase and three-phase(sublimation mat). Couldn't resist to put the vacuum meter thru it. The "OAC control-master 3000"!
https://goo.gl/photos/eB2ZmYSE4KAn733v7
Looks pretty tidy.
Hpw does it control your vacuum?
Posted: Mon Dec 07, 2015 1:46 am
by chrislandy
MR you are quite right and I also subscribe to KISS and have about read a bucket load of issues with overheating SSR's on this and other forums. Given all that through I am still an advocate for them with the correct application.
With my setup, insulated box oven with a SSR compatible CAL controller, the SSR flashes for approximately 5 second every minute once up to temp. Even getting up to temperature it pulses 15-20s on 30s off and barely gets above ambient temperature.
After reading about the overheating issues I thought about a heatsink on it but then measured it and it was well within the operating temperature on the datasheet for the SSR so didn't bother!
The most important thing I've also learnt in the past is to buy well established brand components rather than random ebay HK imports.[/quote]
Posted: Mon Dec 07, 2015 2:09 am
by falls
I use these ramp/soak programmable PIDs from Auber Instruments
http://www.auberins.com/index.php?main_ ... ducts_id=4
They have been effective for me.
My control box has 2 SSRs mounted on a large heat sink.
Posted: Mon Dec 07, 2015 7:13 pm
by OAC
Akiwi wrote:
Hpw does it control your vacuum?
It doesn't, the hose just go thru it, it's more off keeping all the control functions in one place.
Posted: Mon Dec 07, 2015 11:38 pm
by Akiwi
There appear to be quite a few used Eurotherm PID devices on e-bay starting at €50.00 So I will probably pick up one of those with a SSR. the 2208e 2204e and 2216e appear to be programmible with ramp and soak functions.
Looks like the way to go.
Posted: Tue Dec 08, 2015 12:37 pm
by OAC
Posted: Tue Dec 08, 2015 2:15 pm
by Akiwi
Yes, But can you program it to do different temperatures for different periods of time?
Posted: Tue Dec 08, 2015 10:22 pm
by OAC
I don't think so, but there is some typ of manual interface on the PID. Haven't used it.
My cycle:
I put the skis in the press. PID set to 80°C, turn on, Takes around 5min to reach 80°C.
Set a manual timer to 2h. Take out the skis. Let them cool off. Put them in the "Heat-Box 3000"(not "PID'ed" yet)for 24h at 50 - 55°C. Out comes a perfect pair of skis!