Rack design (first rack build)

[whispersinmyhead]

I am still adjusting the design of my first melamine ball python rack. It will be for 41 qt tubs. Belly heat with 12" THG heat tape. Herpstat 1 for t-stat. It is going to hold six tubs and closed on sides and back.

This is going in my living room with ambient temps of ~70f. My question is: should I design it so a piece of insulation can fit in the bottom? I see some people put some adhered to the bottom of the lowest shelf.

Second question. Is it ok to make a groove in the middle shelf to fit the fat Herpstat probe just beneath the heat tape so I don't have a bulge for the bin to catch on?

[whispersinmyhead]

I forgot to mention it will be on casters as well. I know it will be heavy.

[kitedemon]

Yes you will need to control the ambients it is hard to gain more than a couple of degrees and 70º is an average so that will go up and down now and again.

Yes a channel under the UTh will be fine. Make sure it is shallower than the probe by a touch you need the probe to contact the tape nut sit under it all together. I place a strip of alu. tape on the UTH where the probe is this will help even out the gaps in the tape and gives me more accuracy. Tape or glue the probe wire so that if it gets accidentally pulled it will stay in place. Make sure the bulge of the top is not too high. Most tubs have feet and the bulge should not contact the tub bottom this will prevent wear. Jim I do not know if you wear planning on a fail safe but a second grove on the top shelf maybe a good idea this is where I place my fail safe. The best use of a hydrofarms I don't like the fact the new heat tape gets hotter than flexwatt so I would highly recommend the failsafe. Even if you have a herpstats with relay. Everything can fail.

[interloc]

I've heard actually that you SHOULDN'T use aluminum tape with anything to do with the probe. I'm unsure the accuracy of this but what I've heard is the probe puts out a tiny electrical signal and the aluminum tape conducts the signal and causes weird readings. I personally have experimented with probe attachment options and the one I've come up with is; secure the heat tape to the probe with electrical tape. Then place aluminium tape over the electrical tape. I found the aluminium tape is much stickier so basically it's job is to hold the electrical tape down lol. So it's probe, electrical tale, aluminium tape. This way the electrical tape shields the probe from the metal tape. Just my .02.

[kitedemon]

The interference is because the tape conducts heat. It is not to secure the probe but to conduct heat to the probe. Probes measure a small point and all heat tape varies from edge to edge and inbetween the elements. A strip of tape (2-3 inches) on the under side of the element goes a long way to even out the temp on the element and promote accuracy. If the probe were attached to the element with al. tape on the bottom of say a tank the al. Would conduct the air temps and cause the probe to cool off disproportionally to the element. The way I use evens out the element helping to minimize the variations in the element all are made with strips that get hot and strips that don't. the al tape evens out these variations. In this case the probe is surrounded by wood and only contacting the underside of the element. Heat rises the probe needs some help to prevent it from reading cool.


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[whispersinmyhead]

Thanks guys.

Kitedemon. I realize the ambients are going to be a bit of a struggle. I may have to put a door in the whole rack to keep more heat in. Of course it will be ventilated. I just wonder if I should put and extra shelf at the bottom to sandwich some insulation to keep any cold off the bottom of the rack. It will be constructed from 5/8" melamine. I am told it holds heat pretty good from those into situation. That was a previous thread, before I decided to build the rack.

I like the aluminum tape idea to avoid the hit or cold spot on the tape. Also I think as long as the probe is a constant it will still regulate the same as if it was sitting on top just slightly different temperature setting. I plan on running the rack in the coolest spot in the house for a week ( worst case scenario) and then move it and run it in where it will stay.

One last concern is the soldered ends on the tap. They will stick up a bit too. I am going to place the solder joints at the back. May be I will have to cut grooves for those too. I was going to se rails but I don't wan heat to escape. I want to keep as much heat tape in contact with the tub as possible.

[kitedemon]

Jim depending on the design and cleaning ect. A second thought is to use the wire eyelets like rich does but not use the 'rivet' punch eyes but screws to the shelf. Wire eyelet in the tape on the bus with an insulated screw though the whole works holding both connector and tape to the shelf. It is again just a thought I have not used this tape so it is a theory nothing more.


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[whispersinmyhead]

Well I am looked at the tub a fee minutes ago and there is a ridge on the bottom that will allow some clearance for the soldered joint. The tub will stop at the back wall and because the side angles in and there is the ridge that lifts the tub up about a 1/4" and isn't right at the edge it leaves entry of room. I think this is actually a huge bonus on these tubs vs IRIS flat bottomed tubs. At least for home made racks. Also this little bit of clearance lows a room for heat to escape. The tape may have to work a little harder but I never liked the idea of the heating element sandwiched with no real air circulation. Probably doesn't matter but makes me feel better.

I think I am going to go ahead and add insulation to he very bottom of the rack. It can't hurt and if I can always remove it if need arises.

Thanks again everyone.