WarmGlass.com - Search

Search found 35 matches

Go to advanced search

by tob
Tue Mar 15, 2016 3:56 pm
Forum: Techniques and Tools
Topic: DTC 800
Replies: 7
Views: 5437

Re: DTC 800

Why would I want to consider changing? Does the rtc 1000 offer any advantages? Jim If your DTC 800 can't be repaired for a reasonable price, the RTC-1000 offers the advantage of being currently in production, which the DTC 800 is not. There are probably some other advantages too, but I would consid...
by tob
Thu Feb 25, 2016 9:10 pm
Forum: Techniques and Tools
Topic: Boiling Glass?
Replies: 9
Views: 11225

Re: Boiling Glass?

I think it's important to note that the instructions posted above say to anneal Bullseye at 950°, which at that thickness (four layers) is incorrect. Bullseye lowered their annealing recommendation to 900° for thicker pieces. The one-hour anneal is also far too short for a four layer piece. Anneali...
by tob
Wed Dec 30, 2015 8:41 pm
Forum: Jewelry Making
Topic: Lamp worked rondels and other 2D forms
Replies: 25
Views: 27734

Re: Lamp worked rondels and other 2D forms

I do stained glass. I wonder whether shapes like stained glass rondels be made by the lampworking process? I remember from magnet exchanges that I occasionally saw cool lampworked forms that were mostly flat and could be easily encorporated into stained glass window matrices. I think it would be co...
by tob
Wed Dec 30, 2015 7:11 am
Forum: Techniques and Tools
Topic: relays for kilns
Replies: 28
Views: 28276

Re: relays for kilns

Ironically, I had essentially this same conversation yesterday with someone who just bought a new SCR from me and wondered why, after receiving it, it didn't have connections for both lines of a 240Vac circuit. Since I knew this had been discussed at length several times before, I hunted down one of...
by tob
Fri Dec 25, 2015 4:32 pm
Forum: Techniques and Tools
Topic: relays for kilns
Replies: 28
Views: 28276

Re: relays for kilns

Yes, as I said, I figured it was just a typo. But I thought I would point it out so anyone else who might be unfamiliar with relay/contactor terminology and reading the thread wouldn't get more confused than they probably already are. Then, while pointing it out I got a little carried away with the ...
by tob
Fri Dec 25, 2015 9:08 am
Forum: Techniques and Tools
Topic: relays for kilns
Replies: 28
Views: 28276

Re: relays for kilns

There appears to be a typo in your post, Bert. There's no such thing as a DPDT normally open relay. The terminals on one side are normally open, but those on the other side are normally closed. So the user can choose between them for normally open or normally closed operation. Only a single throw re...
by tob
Fri Dec 25, 2015 6:03 am
Forum: Techniques and Tools
Topic: Boiling Glass?
Replies: 9
Views: 11225

Re: Boiling Glass?

When trapped between fused layers of glass the powder releases gas which creates the bubbles. In the case of baking soda - sodium bicarbonate - the bubbles would contain CO2. Baking soda will also change (raise) the COE of the glass immediately in contact with it, by adding sodium. So it would be wi...
by tob
Mon Dec 21, 2015 4:25 pm
Forum: Techniques and Tools
Topic: relays for kilns
Replies: 28
Views: 28276

Re: relays for kilns

The only two things I can think of that might be necessary between the alarm output and contactor are: 1) A transformer, if your output voltage is different than the coil voltage of the contactor. (Although I find this scenario very unlikely because there are better ways to deal with it.) 2) Far mor...
by tob
Fri Dec 18, 2015 12:30 am
Forum: Techniques and Tools
Topic: relays for kilns
Replies: 28
Views: 28276

Re: relays for kilns

I agree with Brad here, but I do it only slightly differently. I use a mechanical DPDT contactor attached to a hitemp limit circuit with a light switch, and a SPST SSR controlling the kiln. This setup allows you to remove all power to the elements when you want safety, and control the elements the ...
by tob
Thu Dec 17, 2015 7:24 pm
Forum: Techniques and Tools
Topic: relays for kilns
Replies: 28
Views: 28276

Re: relays for kilns

Correct me if I am wrong but it looks like the Chromalox 4115-40900 you have are SPST, not DPST that I need. Mark You are correct that like nearly all SSRs, these are SPST. But you are incorrect in believing you need DPST SSRs to control your kiln. (And good luck finding one, they are pretty rare.)...
by tob
Thu Dec 17, 2015 7:14 pm
Forum: Techniques and Tools
Topic: relays for kilns
Replies: 28
Views: 28276

Re: relays for kilns

Removed my accidental double post...
by tob
Wed Dec 16, 2015 6:53 pm
Forum: Techniques and Tools
Topic: relays for kilns
Replies: 28
Views: 28276

Re: relays for kilns

That’s nothing new or unusual, Bert. Manufacturers and equipment builders have been offering that option for many, many years. In fact, the Watlow Din-A-Mite SCRs that you bought from me a very long time ago have always offered the option of what Watlow calls a “through-wall” heatsink. The SCR works...
by tob
Wed Dec 16, 2015 12:51 am
Forum: Newcomer Forum
Topic: Help with devitrification
Replies: 9
Views: 9352

Re: Help with devitrification

Completely OT, but saw you and thought I would stop in and say hi, Chris. I'm sure you miss the lovely nine month long Alfred winters. (Now that I've relocated to Georgia, I know I don't.) Living in Hawaii must really suck...
by tob
Tue Dec 15, 2015 4:22 pm
Forum: Techniques and Tools
Topic: relays for kilns
Replies: 28
Views: 28276

Re: relays for kilns

Bert already alluded to this, but I will also mention that if your controller allows it, you should set the power on/off cycle time to the shortest possible setting when using SSRs. (Assuming the controller itself isn't using an internal relay for output.) Unlike electro-mechanical relays, shorter c...
by tob
Tue Dec 15, 2015 3:56 pm
Forum: Techniques and Tools
Topic: relays for kilns
Replies: 28
Views: 28276

Re: relays for kilns

Can anyone suggest who might sell a SSR for this kiln (Skutt GM-22-CS). I contacted Skutt and here is the answer I got: "Unfortunately, we don't offer solid state relays for this kiln and don't have a design to put solid state relays on it." Also tried Allied Electronics. No luck. Here ar...
by tob
Thu Dec 10, 2015 12:00 am
Forum: Techniques and Tools
Topic: relays for kilns
Replies: 28
Views: 28276

Re: relays for kilns

A bit late to this, but the thread caught my eye while I was perusing the board, and since I have some experience with these things I thought I would comment. There’s a good reason why electro-mechanical relays should be considered a “wear item” and not expected to last forever. The electrical conta...
by tob
Mon Mar 30, 2015 5:55 pm
Forum: Techniques and Tools
Topic: Watlow controller
Replies: 21
Views: 12259

Re: Watlow controller

...snip... not consistent with other charts I have seen. ... On one website they have 2 grades of this available, Class K and ClassM, the differences being the number of strands. They rate 6 awg class k at 75 amps and class M at 105 amps. Another website rates their 6 awg cable at 115 amps max. ......
by tob
Sat Mar 28, 2015 2:35 pm
Forum: Techniques and Tools
Topic: Watlow controller
Replies: 21
Views: 12259

Re: Watlow controller

The ampacity chart on this page - http://www.powerstream.com/Wire_Size.htm - should help explain the difference you found between the load carrying ratings of regular copper and TGGT wire Bert. The higher temperature rating of the fiberglass insulation on TGGT wire, and the nickel (not tin) coating ...
by tob
Sat Mar 28, 2015 2:42 am
Forum: Techniques and Tools
Topic: Watlow controller
Replies: 21
Views: 12259

Re: Watlow controller

If you don't need to control the 3 elements independently, then that's the way to go. Two 3 pole relays will do the job for you pretty inexpensively. Zoro is a great place to buy stuff like this. They have a good selection, great prices, and in my experience, ship very quickly. My only criticism is ...
by tob
Fri Mar 27, 2015 2:21 am
Forum: Techniques and Tools
Topic: Watlow controller
Replies: 21
Views: 12259

Re: Watlow controller

Are you sure you need a double throw contactor Bert? Unless you're doing something fairly unusual, it seems like a 2 pole, single throw should be sufficient. If you don't need the double throw, here's a Square D contactor rated at 50A resistive, for $34. It's three pole instead of two, but you don't...

Go to advanced search

Warm Glass

2575 Old Glory Road, Suite 700
Suite 700
Clemmons, NC 27012
Phone: (336) 712 8003
Email: wg@warmglass.com

cron