Caryl Posted December 6, 2005 Report Share Posted December 6, 2005 DISCLAIMER!!! We (that being my husband Grant, myself, or the FNZAS) TAKE ABSOLUTELY NO RESPONSIBILITY for any problems arising from anyone making their own heatpads using these instructions. Grant has many years electronic and electrical experience and has a number of electrical qualifications. We suggest you get your finished pad checked and signed off by a registered electrician. Failure to do so will result in your insurance company refusing to pay out in event of fire or damaged caused by the heatpad malfunctioning. That said, our own heatpad has been running about 10 years with no problems so far. Materials: Pinex the same size as the tank base Silicone covered resistance cable Thermostat Map pins or drawing pins Parcel tape We originally bought the silicone cable from Argus Heating in Christchurch. The company no longer appears at that address or phone number but there is an Argus Heating at 445 St Asaph St, ph 03 379 5100 so I would assume it is the same company as the man who helped us, Brian Shaw, is still listed as the after hours contact. He was very helpful and helped us work out what we wanted. He will need to know the length of the cable and the power (in watts) you need. I’m sure there are other places selling this cable but this is the one we know. First thing to decide is the power required to heat the tank. This will be determined by the size of the tank and the lowest room temperature where the tank is situated. In a warm room where the temperature is unlikely to fall below 15˚C, 150 watts for a 60cm tank holding about 100 litres should be adequate. This also depends on whether the tank is insulated. If it is open on all sides then more heating may be required. Our lounge tank, holding approx. 250 litres, is heated by 300 watts and maintains its temperature well. It is only open to the front. The length of cable must then be calculated. As the tank is going to sit on the cable, there must be enough cable to support the tank with very little stress. Calculate the area of the tank by multiplying the length (in cm) by the breadth. Divide the result by 200 and this will give the cable length in metres. None of these measurements is critical. As there is a large range of cable resistances available (2 – 3000 ohms) there will be a cable suitable for the power and length combination required. A length of mains flex will be needed to connect to the thermostat. This will be attached by the cable supplier as it needs to be crimped and sealed using heatshrink and glued sleeves for safety. This method ensures the joint will also be waterproof to guard against water splashes. They will make the flex whatever length you require. The heater is assembled on the Pinex base by arranging it to cover the whole base as evenly as possible to minimise stress on the base of the tank. The joint where the flex is attached will be larger than the cable so cut a depression in the Pinex to lower the joint into. The top of the joint will need to be even with the top of the cable. Diagram shows one suggested pattern to evenly distribute cable. Use the pins to hold the cable in place on the Pinex while laying it out, ensuring there are no sharp corners in the cable. The parcel tape is then used to keep the cable in place when the pins are removed. Check that the top of the cable is level so there are no high points to stress the bottom of the tank. The tank can then be placed on the cable. Do not slide the tank when it is placed on the cable as this will roll the cable, possibly stressing it, and cause breaks in the wire. A separate thermostat is needed to control the heater. Make sure you wire the two together correctly or get a qualified electrician to do it. After this article appeared in the Aquarium World magazine, we received a letter of complaint from a man who was building his own heatpads and insisting the cable had to be placed in grooves so it was flush with the base as he claimed there would be too much stress on the glass. The tank has been sitting on the pad for about 10 years now and no leaks so far. We have 2 other tanks on similarly built pads with no problems either. We will add the following though… 1. No DIY is foolproof. Never attempt to make you own electrical equipment unless you have electrical training or experience. 2. As the tank rests directly on the cable in this design ensure the cable is evenly distributed under the tank so there is no part of the tank with a large unsupported area of glass. 3. When placing the tank on the cable be careful not to drag the tank across the cable as this could drag the cable out of position. 4. The thermostat must be rated to handle the load of the heatpad. Commonly available thermostats (not so commonly available these days I don’t think) are rated to a mazimum of 300 watts. Too high a load could cause the thermostat to fail, overheating (or not heating) the water. 5. Always double check your calculations and perhaps get someone else to confirm your answers. Remember even the ‘experts’ can get it wrong. 6. Have you checked your contents or house insurance policy to see if you are covered for damage done by leaking tanks? Quote Link to comment Share on other sites More sharing options...
Caryl Posted December 6, 2005 Author Report Share Posted December 6, 2005 AMAZONIAN makes his own heatpads and does a beautiful job. Don't know if he is willing to do them for anyone else though as he is a very busy man. He might have other sources for cable or alternative suggestions re construction though. Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted December 6, 2005 Report Share Posted December 6, 2005 I was going to have a go at making one but found their price was that good at Argus Heating it was as well to get them to make it. The design I am getting is 31 metres of element (8 watts/metre) placed between two layers of aluminium foil and installed between the polystyrene and tank. It is earthed and for another $15 you can add another safety cutout to the cicuit. Mine is 48 inches x 18 inches and I thought it was a good deal at that price. It is apparently not easy to get the thermostats so that is my next mission. Local pet shop said they had tried but could not get them from Brooklands. I have got one jacked up from a friend but need one more, as I have ordered two elements. Quote Link to comment Share on other sites More sharing options...
Alan Posted December 6, 2005 Report Share Posted December 6, 2005 What was the price of it Alan?? Watch out for the heat sensor, if it is copper you will have to have it inside some sort of protection from the main tank water. Otherwise youll give the fish a dose of copper poisoning. Possibly a sleeve built into the tank?? Alan NZKA 104 Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted December 6, 2005 Report Share Posted December 6, 2005 Cost was $67 without the overheating cutout (it goes in the middle of the heatpad and is a small make and break---you can choose what temperature it will operate at---I was advised not to bother with it}. It will be a straight heater wired through a standard aquarium thermostat placed in one of the tanks. I am planning a 48inch tank in 6 compartments with another 48inch tank underneath and all in the same stand. Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted December 6, 2005 Report Share Posted December 6, 2005 The pad sits on top of polystyrene so any protrusions will sink back into the poly and take any pressure off the tank bottom. The tanks at Critter Kingdom in Stanmore Road are heated this way with pads made by Argus. Quote Link to comment Share on other sites More sharing options...
Caryl Posted December 6, 2005 Author Report Share Posted December 6, 2005 My pad sits the wire on the poly but even after all these years it hasn't sunk into the poly much. Quote Link to comment Share on other sites More sharing options...
DiverJohn Posted December 7, 2005 Report Share Posted December 7, 2005 . It is apparently not easy to get the thermostats so that is my next mission. I would be interested in some details on the thermometers/ controllers you are using Alan. DJ Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted December 7, 2005 Report Share Posted December 7, 2005 I have an electronic themometer with a probe. records temp. plus max/min. I have yet to get there yet but Homershams say they have an electronic thermostat with a digital readout and remote probe for about $140 plus gst. I am getting the car fixed at the moment and when I get it back I will be out there for a look at what is available. I am getting a big fat zero from all the pet shops. Quote Link to comment Share on other sites More sharing options...
Alan Posted December 8, 2005 Report Share Posted December 8, 2005 I have just located some thermostats . NB Thermostats only. No heater. These are what are required for doing the undertank heatpads. I know this could be under the for sale, but they'd cost you $21 plus pp. Only a few are available. Alan NZKA 104 Quote Link to comment Share on other sites More sharing options...
Caryl Posted December 8, 2005 Author Report Share Posted December 8, 2005 Anyone needing one I suggest you contact Alan ASAP as they are very hard to get these days. Not much demand for them. Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted December 8, 2005 Report Share Posted December 8, 2005 I have just gone mad and bought two electronic thermostats. They should make the fish breed as they are labeled "love controls" model TS 13021 a division of Dwyer instruments---$130 + gst. They have a digital readout and remote probe, encased in silicone. More than I had planned but should be good. Alan-- are your $21 ones the bimetelic strip ones everyone has been telling me has not been imported for years and I was originally planning on using? Quote Link to comment Share on other sites More sharing options...
Alan Posted December 8, 2005 Report Share Posted December 8, 2005 Yes Alan they are. They are exactly the same as the ones in a heaterstat without the heater coil of course They are the Reliant brand. I have suggested to ppl that have a tank full of expensive fish, that would break a bank account to replace them (if you could) to put one into line with their heater in the tank, so that if the heater jambs on the tank isn't boiled, the thermostat comes on and alerts YOU that the heater isn't cutting out. CHEAP insurance. Alan NZKA 104 Quote Link to comment Share on other sites More sharing options...
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