Tubs...

Ok, so I've been looking at different tubs for my DIY rack setup and I'm looking for a tub that's a solid color, not clear, and it has to have a lock down lid. Well, I found one at Lowe's that's perfect. Secure lid, solid color and super durable. But there's one flaw that I can't over look...The bottom isn't perfectly flat. Here's a pic.

http://i1141.photobucket.com/albums/...pso3nttclo.jpg

As you can see, there's about a 1/8" raised portion. I'm going to be using Flexwatt, and I think if I use this tub I would only be heating that raised portion, not the entire warm side. I don't know. I know most of the tubs we use aren't perfectly flat unless it's a V-70 or something similar. So, any suggestions? Also, I'm going for a solid color tub so my BP will feel a bit more secure. Basically I'm shooting for a DIY rack that mimics a commercial rack with ARS solid grey tubs. So, any advice would be appreciated. Thanks!

Hope someone answers you, I ran into the same problem. I didn't realize that the bottom wasn't flat till I got home. Waiting for my controller to be delivered so I haven't been able to test it out yet to see if it's going to heat it properly.

I might be over thinking this. I mean, looking at the RBI PVC racks, they're only using 4" heat tape for the CB-70 tubs and those tubs aren't perfectly flat on the bottom, either. Then I looked at the C Serpent rack, and they only use 3" heat tape, and it's actually recessed into the shelf, so the tub isn't actually resting on the heat tape, there's a slight gap. So I think I'll be fine with these tubs. If it doesn't work out, I might try just using a ceramic heat emitter pointed at one side of the tubs instead of using Flexwatt, which would save me some time with wiring. The thing with those though is they tend to kill humidity, so we'll see. I have a UTH laying around, so I'll test the tub tonight and see how much heat actually gets through.

Testing is likely the best way to know for sure. I was using the sterilite tubs which have a similar ridge and they worked but I switched to Vision tubs after buying a rack with them in it and fell in love them so I replaced all my sterilites with Vision tubs. I just felt the ridge was making them less efficient to heat but also a bigger pain to clean too.

Ok I finally got my temp controller in and wired right and it's heating nicely. I set my temp to 91 high 89 low and it cycling just like it should. The probe is on the inside of the tub under the carpet where the hide will be. I'm going to run it a few days just to make sure before I put the snake in.

So it appears the gap between the heat tape and the tub doesn't affect the heating of the tank properly. Sure it not as efficient but I can live with it.

You don't want to place the probe inside the tub you want it sandwiched on the bottom of the tub between the heat tape and the tub. Set your temp at 90 degrees then measure the inside surface temp of the tub with a temp gun and adjust from there.

Ok thanks

No problem, good luck with everything.

I just tested it, as well. There's a 1-2 degree difference between the low spot and the high spot, which isn't bad. These tubs will work fine. Now I can start assembly!

Flex watt needs the air space. It ideally is vented on one or the other surface to prevent thermal blocking. It also drops the runaway stat temp a bit, the problem with flex watt, it runs too hot really.

I am going to add some other suggestions on racks that is not mentioned much, remember for the most part they need a warm room to hold correct ambient/cool temps. If the room is cool (below 74º) the other temps often are off with heroic efforts needed to correct. I would also in the efforts to increase peoples safety suggest using PVCx as a construction material. It will not burn at all or well. It will not spread a fire either it remains localized at the ignition point. It additionally dimensionally stable, highly water and chemical resistant, does not out gas (unless heated to 300ºF+). It also doesn't weigh a ton. The amount of time to construct a rack off sets the cost of materials.

The room the rack will be going in doesn't drop below 78 degrees, so I don't think that's an issue. I'm using a plastic storage shelf from Lowe's, and the shelves are vented, so the heat tape isn't going to be smothered. I'm actually worried about it venting too much. I was thinking about mounting the heat tape onto a reflective foam board panel so more of the heat would be utilized. I'd drill some holes in it so it can still breathe, but deliver heat more efficiently at the same time. Obviously, this setup will be thoroughly tested before any animal gets moved in. And I don't really mind taking my time with this, I enjoy building stuff and making things work more efficiently. In the end, it'll be cheap and it'll work just as well as a manufactured rack.

Also, I've read that heat tape can run a little hot. And I can understand that if it was plugged directly into an uncontrolled power source, but if it's being controlled by a reliable thermostat, how can it run too hot? I'm constantly monitoring my temps and my thermostat is set to 90 degrees, but the surface of the tub barely hits 88 degrees. So I don't understand how it would run too hot if it's hooked up to a thermostat and it's actually losing ~2 degrees during heat transfer. But I guess losing ~2 degrees isn't a big deal, since when the snake lays on it, it essentially insulates it and bumps up the temp a bit. Anyway, I'm rambling. Thanks for your input!

No worries, I was thinking the same thing lol.

Racks are prone to having the probe pull loose and the stat can only work if the probe is in place. Every thermostat can fail. I have owned a number and worked with even more and have seen herpstats, helix, eco zone, ranco, and Johnson give up the ghost. Proportional units tend to fail on. This can be caused by a power spike or 'dirty' power as well. Plan on the worst and hope for the best. Stat failure should not kill the animals a heat source that will hit 130+ degrees if the stat fails will cause havoc. I have seen stats fail and heaters get so hot the tub melted. There is no need to have a heat source get over 100ºF ever. If you need that kind of heat and are losing 10ºF the system design is at fault.

Def agree on using PVC board, its well worth it. I can understand though if its not a option due to $ or availability constraints. I dont use Flexwatt, I use THG instead so I can't compare the one to the other. I also agree with the point on the probe issue, you will often have to try it in different locations on the rack to get the more consistent temps throughout the rack. I have had mine near the begining of the heat tape and found this to be one of the worst spots as the rest of the rack runs too hot. I find in about the middle works best.