Pluton

It would be much appreciated if any of the kiln experts in this forum could help identify the type of refractory brick used in this 1972 vintage Thermo-Lite cone 10 rated updraught gas kiln, as seen in the advertisement below in Ceramics Monhly, Jan 1971 issue. The refractory is in the form of standard 9 x 4.5 x 2.5 inch bricks mortared together and is therefore presumably not a castable material. It is cream colored, very soft, much more so than today's IFB, and does not contain sand. When rubbed it powders, much like a soft blackboard chalk or soft plaster, and it appears to have been both foamed and filled with some organic material that has been burnt out leaving elongated voids with striations on their surface (not obvious in the image below, but clearly seen with a hand lens). The kiln was purchased used and appears never to have been fired (the dark lower right corner is shadow, not soot). It has four rather nice burners jetted for natural gas and is similar in concept to today's Olympic brand Torchbearer kilns (and in case you were wondering, it did not come with the penny of same vintage). Reasons for asking are twofold: - The refractory is somewhat friable and comes from a time when asbestos was commonly used. Although it does not appear to contain fiber (unlike say asbestos cement), I guess that is always a possibility and will handle it accordingly, but would appreciate knowing if that was common practice back then. - Curiosity; is this simply fireclay whipped up with some organic burnout material? Why would this gas kiln use a different type of refractory than is used in electric kilns of the same vintage (and current manufacture)?

1972 Brent Model C belt part numbers: This model of wheel uses two separate ribbed, polyester reinforced polyurethane 60 degree v-belts, type 5M1090, i.e. 5mm width, 1090mm "length" (outside circumference), or if you prefer 0.16 inch width, and roughly 42.8 inches circumference. Amaco Brent sells a pair of these belts as Part # 22037T (but their web sales are currently suspended so you have to go through one of their distributors, and then it's drop-shipped by Brent). The manufacturer of the ones sold by Brent is Bando , part # BANFLEX 5M1090 (made in Japan, available through industrial distributors) An equivalent product from Gates Rubber is: GATES Polyflex 5M1090 (Made in USA, widely available from many distributors) Price is pretty much the same wherever you buy.

RV4NAYSD503A ALLEN BRADLEY potentiometer 50 kOhm, 2W RV4 RV4NAYSD Series Part Number: RV4NAYSD503A Mfr: ALLEN BRADLEY RV4NAYSD503A ALLEN BRADLEY RV4 series potentiometer. 50000.0 ohms. 2 watt. 500 volt. This appears to have a shorter shaft than the original, but manufacturer, wattage (2W), resistance (50k-ohm) and linear taper (i.e. type J) are corrrect. If you can't source a long shaft version, just glue the pinion to the shorter shaft if it's too short for the grub screw to grip.

For anyone needing to replace this 50k ohm rotary potentiometer it's a 1/4" diameter long shaft linear taper type for which a Google search finds many sources and different qualities ranging from $0.90 to $20, the former being a generic unsealed type (hence the big gob of silicone RTV in the image in earlier post) and the latter being a precision instrument type. Certainly more common than the 'slider' type used on later models. Wheel was a freebie thrown in with some other Craigslist purchases, so if it gives 10 years of incidental use for the price of belts, switch, fuse holder, and paint I'll be more than happy. Although it's 52 years old, it appears to be a low mileage specimen that took a long barn vacation with rodents. If the drive train dies it will revert to a banding wheel, the wheel head bearings are very smooth running.

Mark, you are right, it's a model C. And I just noticed when photographing the inside of the foot pedal that it's date stamped JAN 1972. And the good news is the foot pedal, motor controller, and motor all seem to be working fine now with new fuse holder and toggle switch installed. Just waiting for the belts to arrive. The three trim pots are on the controller board shown in the Feb 17 post above, but they aren't that obvious because they are seen edge on in the photo. I've added arrows to the image below to point them out. Two are brownish plastic, and the third is a lighter colored plastic. I didn't turn any of them because everything seems to be running fine as it is, and may never need to be adjusted. Nevertheless, I'm intrigued to know why there are three not just two. The foot pedal contains only a single 50k-ohm rotary potentiometer and the plastic rack and pinion to drive it as seen in the image below. (And a huge gob of RTV silicone over the terminals.) The good information and helpful people on this forum are much appreciated. This is my first experience with an electric wheel as up to now I've been throwing on a hand-powered Japanese style (home-built) wheel and a 1971 kick wheel like the one in this ad. Steel flywheel, but 12" wheel head. Just need a period boom-box and some 70s mix tapes for the studio....

Belt issue now resolved. Called Brent again and spoke to different person who clarified that Amaco Brent part number 22037T describes a pair of separate v-belts, (not a single twin-groove belt in the style of the 4 and 6-groove belts on modern wheels as I was told previously). This part number is not available directly from Brent Amaco, only through distributors, and is currently in stock at The Ceramic Shop whose website describes it as a pair of 42-1/2" x 3/16" belts for a model CX wheel. Expect to receive the belts shortly and have this wheel back up and running. Much appreciate the help on this forum.

I now have a new fuse holder and appropriate fuses purchased online. Rust has been blasted off and steelwork painted - looks smart! The additional images below may help identify the model and vintage. The foot pedal is the more rounded style and contains a single rotary potentiometer driven by a plastic rack and pinion arrangement (don't have an image handy). The table top and deck have two matching holes left and right, approximately midway between front and back. Not obvious what these are for (belt guard perhaps?) and unfortunately they allowed water to leak underneath the table top causing rusting of the steel deck, but nothing serious, everything is structurlly sound. The wheel head is 12" diameter and has a nice touch indicated by arrows in the image below - the two bosses for optional bat pins are pre-spot-drilled on hopefully exact 10" centers so all one has to do is drill through from the back in a drill press and obtain perfect hole spacing first time. THANK YOU Robert Brent! Some additional background: wheel came as a freebie with a Craigslist purchase of a 1971 vintage THERMO-LITE updraft gas kiln (another story for another day), missing belts and belt guard. It did not run when plugged in, which I traced to one of the solder tabs on the fuse holder having broken off the internal contact with the fuse. Fuse is good and motor turns freely on 24v so I'm hoping that's all that is wrong with it and it will run fine when I've replaced the fuse holder (tomorrow). It came with some personal papers of the original owner (deceased) from which I'm guessing they were not very technically inclined, so perhaps they removed the belts and guard in an attempted repair and then gave up. Both wheel and kiln were in a barn of 'treasures' for many years. Motor controller face plate has a toggle, not rocker, switch on the left and the fuse holder on the right. The face plate does not match any of the ones on the Brent website now or 4 years ago. Four years ago I called Brent and gave a description (no photos) to a technical person who concluded it was a model B, not C, which is probably correct since it appears to have a 1/2 HP motor. He gave me a part number for the modern belt guard which he thought would fit (incorrect) and described the belt as a two-groove item, not two separate belts (which I believe now is also incorrect), and he suggested getting a new style foot pedal/speed controller which would be a direct replacement (which again I suspect is incorrect). When I described the motor controller face plate he said it might be a very early model which they did not support at all. I'm well set up with tools and materials so fabricating a belt guard will not be a problem. However, the belt length and hence distance between the motor and wheel head axes needs to be determined first. Thanks to Mark and others on this forum I now know I'm looking for a pair of polyurethane 1/4" wide belts, presumably classic not wedge profile, but I don't know what length. If anyone can provide a manufacturer and part number for the pair of belts, their length (inner and outer), or the spacing between motor and wheel head axes it would be very much appreciated. Also, does anyone know the functions of the three trim-pots on the motor controller board (image in post above)? I'm guessing one is lo-speed, one is hi-speed, but what's the third one for? Acceleration/braking, i.e. overshoot avoidance/damping? Many thans to all!

Thank you Mark and Hulk. Digging through the archives I've found great information from you and others and am making good progress. First, fusing. The correct fuse is 6mm x 30mm ceramic body sand filled 10 amp slow blow. I hadn't noticed that this is actually indicated on a sticker on the controller itself, see photo below. This is also the type specified for current model Brent wheels. The 20A fuse that came with the wheel made no sense since its purpose is to protect the appliance itself, not the building wiring which is protected by its own breaker in the building's load center. Next, belt guards. The wheel had neither belt nor guard when I acquired it and I assumed the guard had been separated and lost and I was planning on replacing it with a modern one from Brent. However, there is a steel rib welded across the underside of the deck which looks as if it would prevent a new style guard being fitted, image below. There are two holes drilled in the deck close to this rib, and corresponding holes in the mustard yellow molded plastic (not Formica) table top. Did these early wheels use a different guard attached by two countersunk machine screws through the table top and deck, or is mine one of those sold without a guard? Don't worry, I'll fabricate something if there isn't a commercial option - wouldn't want the cat to lose its tail. (As an aside, Hulk posted a news article about the Brent sale to Amaco which quotes Robert Brent saying he wanted to pursue a business without liability concerns (making calendars), and I wonder if he was reflecting on the wisdom of having sold wheels without guards.) Now belts. Did this model use two separate 1/4 inch wide belts side-by-side, or did it use a single belt with two grooves similar to the current 4 and 6 groove belts? I believe this latter would be called a banded twin groove belt. Does anyone have a specification for the belt (or belts) and a manufacturer's part number (not a Brent part number as they don't sell them any longer)? Images below show the profile of the grooves. The required belt length won't be known until the wheel is reassembled and the guard situation is resolved. I'll post additional images that may help identify the model of wheel in due course, but in the meantime, many thanks to anyone who can answer the questions above.

I have a 70's Brent Model C "blue motor" wheel that I'm restoring to operating condition. Not sure of the exact vintage, but the motor control circuitry is in a standard rectangular electrical box, so I'm guessing pretty early in the history of Brent wheels. The fuse holder is broken and takes rather (very?) uncommon 6mm x 30mm fuses so I would like to replace it with a more modern standard. The rating of the fuse that came with it is 20A which seems excessively high considering this model was intended to run on a standard 115V/20A circuit. Normally I would expect an appliance to be fused at a lower current value than the circuit supplying it. The fuse that came with it is not surprisingly still intact. Does any of the above experts (to whom I'm immensely grateful for what has already been posted) know what fuse was originally specified, - amperage, and whether slow or fast blow? Failing that, what fuse does the modern equivalent wheel take? I did talk to Brent folks several years ago when I first acquired this wheel and a helpful gentleman told me the DC motor should spin at moderate speed on 24 V, which it does. Beyond that, they could provide no information, such as how to service the motor, circuit diagrams etc., so the information posted in this thread has been invaluable. Has anyone found a way to lubricate the bearings of the "blue motor"? Does anyone know the manufacturer of it and model, specifications etc. (in case it needs to be replaced/repaired)? Thanks to all!

Somewhat south of your location in Strongsville, OH, between Peninsula and Streetsboro, our surface clay goes down 80 to100 feet, and is I believe part of the Hiram Till deposit from the last glacial retreat. It looks to be same as what you have in your yard. I have been using this successfully for several years, mostly wood-fired to cone 10, but read on... Un-amended, and fired in oxidation to bisque temperature it gives an attractive orange terracotta and a deep brick red at cone 6, which is probably its sweet spot. Like most 'found' secondary clays it has a rather narrow window for vitrification but works quite nicely wood-fired to cone 10 in a 'neutral' (i.e. alternating oxidation and mild reduction) when blended with 25% fireclay (Hawthorne Bond) to provide additional alumina. Color is an attractive (to me) dark red/brown with a purple tinge, and it gives nice effects with ash. In heavy reduction at cone 10 it needs considerbly more fireclay to keep it 'open' and avoid bloating, that is, to counteract the fluxing effect of the high iron content in reduction. I dig it wet, dry it, slake it and blend to the consistency of half-and-half, strain through window screen to remove large stuff, sediment briefly , then allow to settle in buckets for several months followed by air drying to throwing consistency. This retains all the fine silt and the finer fraction of sand which moderates the shrinkage. It throws nicely with and wthout the fireclay addition (blended as slip), much like a grogged body. It gives a nice range of colors in ash glaze, depending on firing conditions, but has rather high shrinkage which could be reduced by calcining a fraction, which I have not done since I have other simpler options.