Official Luthiers Forum!
http://www.luthiersforum.com/forum/

heating blanket temp control ?
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=39704		 Page 1 of 3
Author:  ernie [ Wed Mar 13, 2013 11:43 am ]
Post subject:  heating blanket temp control ?
I have an older (17yr old) hvy duty temp control used for flourescent lighting that I use with my 6by 36 in watlow heating blanket. Measuring with a pacific transducer temp gauge it heats up to 260 deg F in 3minutes , at the lowest setting.Is there a way to slow down the temp control so that it heats to 260 in 6 minutes instead of 3 . I am using it to bend pineapple uke sides .060 by 60mm wide or 2 3/8in ind, rosewood, I would like it to get to 260f in 6 minutes rather than 3 . as I have to bend the side 2 times to get the correct set without springback. What type of temp control do you use ?. I also have a router speed controller 15 amp that I use with an omega 1.5in by 18in omega blanket that I use for bending rosette stock , it heats slowly to 250 deg F.Are some of you using the router speed controller ?? Earlier on I tried to bend the sides at .080 and they would not budge as the heating blanket heats up to 375 in abt 5min. too fast IMHO. Thanks
Author:  LarryH [ Wed Mar 13, 2013 12:23 pm ]
Post subject:  Re: heating blanket temp control ?
ernie wrote:
What type of temp control do you use ?


Very interested as well, sorry I can't help Ernie as I just got my heating blanket and am setting it up now.
Author:  Heath Blair [ Wed Mar 13, 2013 1:04 pm ]
Post subject:  Re: heating blanket temp control ?
I believe my temp controller came with the blanket, from John Hall. However, I'm pretty sure it's exactly the same as the router speed controller from Harbor Freight. Don't know how fast it gets to 260. You might just try cycling yours on and off to keep it where you like.
Author:  Jeffrey L. Suits [ Wed Mar 13, 2013 1:23 pm ]
Post subject:  Re: heating blanket temp control ?
I have this, from LMI, works a charm: http://www.lmii.com/CartTwo/thirdproduc ... s#MoreInfo
Author:  klooker [ Wed Mar 13, 2013 1:45 pm ]
Post subject:  Re: heating blanket temp control ?
I was lucky, my buddy gave me a variac.

It works great, unfortunately they're not cheap.

Kevin Looker
Author:  nyazzip [ Wed Mar 13, 2013 1:51 pm ]
Post subject:  Re: heating blanket temp control ?
in addition to voltage-dropping devices such as variacs, there are also conrollers that flip a power switch on and off X times per minute(rate is variable by turning a dial), which has the same effect. i actually have one that i got for free. the important thing is that whatever device you use, the current rating has to be sufficient. i have a 10 amp variac i have used with a heating blanket(but not for side bending yet; rather, sprouting seeds indoors).
Author:  Trevor Gore [ Wed Mar 13, 2013 6:17 pm ]
Post subject:  Re: heating blanket temp control ?
Depends what you mean by control...

If you just want to limit power, all you need is thyristor circuit of the correct rating. Essentially a high wattage dimmer for incandescent lights. Check with your local electrical supplier/big box store.

If you want control to a temperature set point, you need a controller, like, for example, one of these. Just make sure it can handle the switching power (or buffer it via a relay that will).
Author:  ernie [ Wed Mar 13, 2013 8:38 pm ]
Post subject:  Re: heating blanket temp control ?
Thanks trev , yes I want to control the temp , and have it stay there for a few minutes e.g. 300eg F for 6or 7 minutes until the rosewood starts to bend .I have the hvy duty light dimmer for flourescents, but even at the lowest setting it gets too hot too quickly. Never knew this stuff existed. Which model ?? would you recommend for the watlow, it can heat to almost 500deG F but I prefer to keep it between 300-350. It draws I/m guessing abt 10-13 amps at 110-120 volts ac Thank you very much cheers ernie
Author:  gozierdt [ Wed Mar 13, 2013 9:02 pm ]
Post subject:  Re: heating blanket temp control ?
As Trevor said, a PID controller will give you whatever level of control you want. If you
search on PID controllers, you'll get a lot of hits- it can seem sort of daunting to set up
an automatic control like this, but there are several threads that give
very detailed instructions on how to set one of these up. If you don't want that level
of complication (but believe me, it's so nice to set one of these up and let it run the
temps, while you control the physical bending process), some of the other answers
give you intermediate levels- and generally less expensive- levels of control. You can
also find the PID controllers on Ebay for very good prices.
Author:  Imbler [ Wed Mar 13, 2013 9:38 pm ]
Post subject:  Re: heating blanket temp control ?
Jeffrey L. Suits wrote:
I have this, from LMI, works a charm: http://www.lmii.com/CartTwo/thirdproduc ... s#MoreInfo


I have that as well - really makes bending less nerve wracking!
Mike
Author:  ernie [ Thu Mar 14, 2013 7:04 am ]
Post subject:  Re: heating blanket temp control ?
Thanks to all for the helpful advice. I looked at the LMI vid pid controller with the thermocouple.there area number of inexpensive ones on e- bay. But which one to buy, and how and where would you get the thermocouple and wire it into the PID controller ?.Suggestions ??
Author:  Fred Tellier [ Thu Mar 14, 2013 9:05 am ]
Post subject:  Re: heating blanket temp control ?
Any PID controller will work but you need around 10 amps to power the blanket, most controllers only put out 4 or 5 amps so you need a relay that will be switched by the PID controller. As for programming it is quite simple as what I use is just the switching mode, as the PID control is overkill for what we are doing. I spent many years dealing with temperature control of paint ovens, and air supply equipment as an Industrial controls electrician in a auto factory paint shop so converting to a PID controller for my bender seemed the right thing to do. I have talked a few of our members through the process by PM's so feel free to contact me.

These controllers are the safest way to do bending, I am even contemplating converting my stewmac style bending iron to a thermocouple so I can use my controller on it also. I also have started using it to control my hide glue pot by putting a thermocouple in the water.

Fred
Author:  Fred Tellier [ Thu Mar 14, 2013 9:15 am ]
Post subject:  Re: heating blanket temp control ?
I just did a quick search on ebay and found this unit http://www.ebay.ca/itm/AC-110-240V-Digital-PID-Temperature-controller-25A-SSR-K-thermocouple-Sensor-/140924009810?pt=LH_DefaultDomain_0&hash=item20cfb9bd52
includes relay and has on/off switching mode control.

Here is my unit built into a box that I made in a very short time out of scrap wood I had laying around my shop. I was able to find a 10 amp unit so did not need the relay. With controller, timer, and outlet I probably have less than $50 in it and have used it for 5 years without problems.

Image

Image

Fred
Author:  ernie [ Thu Mar 14, 2013 9:35 am ]
Post subject:  Re: heating blanket temp control ?
Thanks for the link Fred I appreciate your help vy much, and the photos. I e- mailed the ebay seller to make sure that it can work on the 10 amps that the watlow takes or abt 1100 watts.I/m still not sure of how to wire the whole configuration up.I looked at your wiring in the back, was still puzzled .I would need to have all the pid parts /accessories with me in order to make sense of the photo you sent me. I will copy your photo. Do I need to do the exact same wiring as you have in the photo, if I ordered the parts from this fellow?? or would I need to make some modifications. From viewing the o/brien vid, I only need 1 wire from the thermocouple slipped under the heating blanket? is that correct?. Once again thanks for all your help ernie
Author:  WaddyThomson [ Thu Mar 14, 2013 9:56 am ]
Post subject:  Re: heating blanket temp control ?
I have one of those controller thingys, but don't have a clue how to program it. Where is that info available?
Author:  Fred Tellier [ Thu Mar 14, 2013 10:04 am ]
Post subject:  Re: heating blanket temp control ?
Quote:
Do I need to do the exact same wiring as you have in the photo, if I ordered the parts from this fellow?? or would I need to make some modifications.


When you get the controller and other parts email me a scan of the info provided and I can help. My wiring is specific to the terminal connections of my unit. The timer is not necessary but being easily distracted it is a great safety addition for me. I plan on rewiring with a timer bypass switch for when I use it for the glue pot. As for the thermocouple you can create one from the wire provided as usually it is too large to use. The actual wire is a thermocouple when the bare ends are twisted together, the dissimilar alloy of the two wires creates a thermocouple when they touch.

I did this for several years before I came across a different style of thermocouple on ebay while helping another list member put together a controller. See this link
http://www.ebay.ca/itm/K-Type-Thermocouple-Probe-f-Digital-Thermometer-Stainless-Steel-Sensor-TC2-2pcs-/221176084069?pt=LH_DefaultDomain_0&hash=item337f1f3665

Fred
Author:  Fred Tellier [ Thu Mar 14, 2013 10:06 am ]
Post subject:  Re: heating blanket temp control ?
Waddy PM me we can figure it out. Do you have the documentation that came with it?

Fred
Author:  LarryH [ Thu Mar 14, 2013 11:01 am ]
Post subject:  Re: heating blanket temp control ?
That's very nice Fred. Thanks for posting the links, pics and help. BTW did you notice the price of the E-Bay unit? $32.99 plus $38 for shipping. Doesn't lessen your helpful post in any way but that shipping cost is surprising.

EDIT: There's a $13 dollar shipping option if look at the er...shipping options. Also the seller's in San Diego which won't most but I'll contact locally if I decide to buy.
Author:  ernie [ Thu Mar 14, 2013 11:32 am ]
Post subject:  Re: heating blanket temp control ?
Thanks Fred, waiting to hear a response from the seller?? and thanks for the offer tohelp , mucho appreciation. Larry yup , that must be a long trip to the PostOffice?.
Author:  WaddyThomson [ Thu Mar 14, 2013 1:25 pm ]
Post subject:  Re: heating blanket temp control ?
Thanks, Fred. I'll pull it out and see what I can find about model # etc. I bought a box with it built in, but uised, with no documentation. I have no idea what all those FE's and stuff that pop up in the window mean. It may take some serious splanin!
Author:  Fred Tellier [ Thu Mar 14, 2013 1:39 pm ]
Post subject:  Re: heating blanket temp control ?
I see free shipping unless you want the fast delivery options

Fred
Author:  ernie [ Thu Mar 14, 2013 5:01 pm ]
Post subject:  Re: heating blanket temp control ?
It/s much $$$$ for express.shipping.Still waiting to hear from the seller. Does this unit come with it/s own 10 amp power supply ?? or do you purchase one seperately Fred ?? thanks.
Author:  Trevor Gore [ Thu Mar 14, 2013 5:38 pm ]
Post subject:  Re: heating blanket temp control ?
For those of you not familiar with tuning PID controllers, the best and easiest bet is to get one of the self-tuning ones, as per the style shown in my earlier link.
Author:  Fred Tellier [ Thu Mar 14, 2013 7:23 pm ]
Post subject:  Re: heating blanket temp control ?
For our usage the PID even self tuned will never work any better than the same unit set to on/off control, it will track at about 3 or 4 deg F around the set point.

Fred
Author:  Brad Way [ Thu Mar 14, 2013 9:27 pm ]
Post subject:  Re: heating blanket temp control ?
I have a few PID controller from Auber Instruments. Their prices are pretty good. Probably my only issues with this type of control is finding a good play for the thermocouple.

Good luck!

Attachment:
photo (4).JPG
Page 1 of 3 All times are UTC - 5 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/