PDA

View Full Version : Heated Steps



garagemark
12-05-2010, 09:39 AM
You guys were so much help on making my old hot tub repairs, I need to tap your expertise again. This time I want to build/fabricate three steps up to the tub; and I want them heated.

I have access to 6 watt self regulating heat trace in bulk lengths (Raychem). My inquiry centers around the best materials to imbed this heat trace in. I have considered casting it into concrete treads, but that is quite time and effort consuming; not to mention a hellofa mess.

Any other ideas of materials or techniques to make these three treads from? I have a complete wood shop if needed, as well as metal working capabilities.

Oh, and these steps will be 120 volt ground fault protected.

Thanks,
Mark

firbikrhd1
12-05-2010, 10:37 AM
This isn't directly related to your question as it doesn't address the heat trace. That said, since the water in the hot tub will be heated anyway, why not plumb to circulate it under the steps? No additional wiring, or energy use. The water is already warm.

MotorradMike
12-05-2010, 10:40 AM
What about circulating hot tub water through tubing in the steps.
You already have hot water and circulating pumps.

MotorradMike
12-05-2010, 10:42 AM
Great minds think alike.
I could totally work with you firbikrhd1.

garagemark
12-05-2010, 11:14 AM
Dog-gone fellas, I never thought about that. You guys may be on to something.

OK, lets assume circulated water. So what material would disperse the heat transfer well enough to cover the entire tread; and still remain non slip? I really don't want to cast concrete, but if the consensus is that wood would work, I could route channels in the underside of the steps (and then sandwich the tubing).

Keep on guys. This is a super think tank.

Mark

Dang! On edit: The heater/pump doesn't run all the time. I would have to install a dedicated circulating pump in the system. Crap, that idea just got more complex... though I'm still pondering.

Duffy
12-05-2010, 11:57 AM
That MAY be a good idea, EXCEPT you will have the area of three treads outside the insulated box of the hot tub. Be aware that the heat loss from those treads could be expensive, unless you build in some controls. NOW the problem is degenerating into a complex one.
A hydronic circulating pump draws very little power and will move all the water you want. The tubing more or less HAS to be plastic, since the water is both treated and highly aerated, so not the best stuff to introduce into metal tubing. What plastic tubing can bend tightly to form the 3 or 4-pass snake on each tread?
Do you series-feed the treads or parallel-feed them?
If you take out a mortgage and buy a couple of lengths of 3/8" hard copper tube, a bunch of fittings, and some flashing copper, you could solder up a set of tread plates. Three passes soldered to the flashing, and routed in a wooden tread, covered with a thin rubber tread cover from Home Depot.
Once these are plumbed into a set, the only control you will need is one to turn the tread pump on with the circulating pump. By the time you get to the tub, the treads will be warm. I think that parallel feed would work best and easiest.
Maybe electric trace cable WOULD be easier!

Carld
12-05-2010, 12:01 PM
If your using wood for the steps you could rout a groove in the step, insert the heat strip and cover it with a sheet of wood and put the step on the risers with the heat strip on the bottom side.

winchman
12-05-2010, 12:10 PM
Wood that's heated above ambient temperature is going to dry out very quickly, and it's likely to crack as a result.

How about these electrically heated aluminum stair treads?

http://www.morelectricheating.com/Customer/moelhe/images/items/heattrak%20aluminum%20top%20stair%20treads%20snow% 20melting%20mats_l.jpg

from:
http://www.morelectricheating.com/Default.aspx?page=category%20search%20results&CatList=576&Parent=1062&tree=79*Manufacturers*0@@1056*Heat+Trak+Snow+Melti ng+Mats*0@@1061*Heat+Trak+Aluminum+Stair+Tread+Sno w+Mats*0@@1062*Heat+Trak+120V+Aluminum+Stair+Tread +Mats*576@@

You could use recycled-plastic deck lumber with grooves milled in the underside for the hot water tubing as a lower-cost alternative.

garagemark
12-05-2010, 12:16 PM
You may be right Duffy. Electric heat trace can make the turns easily; and it's just shy of free for me. I can fabricate each tread with a tail sticking out into a plastic junction box on the end, and then parallel feed all three. Since the stuff is self regulating, a thermostat is not even needed.

These steps will be little longer than 30" with a handrail on one end. I like the idea of a rubber mat of some type, but will need a little better heat transfer so the entire step melts off. Maybe a sheet of aluminum under the mat to dissipate the heat would do it.

So, assuming 4 runs of about 26 or so inches (+ bends), it would require about 10 ft of trace per tread. At full bore, each tread would draw about 60 watts,= 180 watts, or 1.5 amps. However, once warm, the trace would self regulate to a little less amperage yet.

The main thing here is to melt snow off the treads, not to make big heat for the feet. Going in your feet warm quite quickly; and coming out you could care less how cold anything is. I am just concerned about slipping in each direction. It HAS happened.

Hmm. I'll keep pondering.

Edit: NICE looking steps winchman. I could go for something like that... except the $400+ price per step. But you gave me another idea. How about a sandwich of metal, heat tape, and metal, with insulation under the stack (or simply mounted right onto the existing wooden step)?

Toolguy
12-05-2010, 03:10 PM
If you box it in and insulate the inside except for the bottom of the steps (I'd make them aluminum extrusion or maybe diamond tread plate) you would simply put a cheap electric heater in the box, set the thermostat on low and easily and cheaply keep them warm. Unplug or turn off when not in use.

datsun280zxt
12-05-2010, 03:47 PM
If you box it in and insulate the inside except for the bottom of the steps (I'd make them aluminum extrusion) you would simply put a cheap electric heater in the box, set the thermostat on low and easily and cheaply keep them warm. Unplug or turn off when not in use.

Then that would almost be too easy!

rock_breaker
12-05-2010, 04:08 PM
Look for a company (Kroy in 2002) that makes vynl planks -- 2" x 8" x 20 feet. I bought our decking materials from one of their dealers "Western Mfg. Supply Inc. Farmington NM. (now out of business) anyway the planks are hollow with a web stucture inside to develope strength. They are pricey but require no maintenance.

I have to pay dearly for the heat trace you describe but am considering it for our walkway & porch.

The planks may also be available at Home Depot or LoweS.

Rich Carlstedt
12-05-2010, 04:29 PM
How about some heat lamps focused on the steps.
No electrical danger
Use any surface on the steps
Cheap
Add a lite step (s) as well for safety

garagemark
12-05-2010, 04:31 PM
The box idea is a sound one and it would certainly be the easiest, but any little box heater would draw much more power than thirty feet of heat trace. I want this thing to run 24-7... cause you just never know when we might have a Cialis moment!

I (actually my crews) change out and throw away hundreds of feet of perfectly good trace around this time of year. I can't get it all but can get a decent amount of it. I'd really like to find a way to utilize it if I can.

Mark

Still a lot of good ideas coming out of this. Thanks.

darryl
12-05-2010, 06:18 PM
Just for experimental sake I bought a few stove-top heating elements to play with. Buck or two for three I think- but that's not relevant. You can unwind the coils and bend this stuff to a radius- about as tight as the inner coil before it heads off to a connection, about 3 inches diameter circle-

Anyway, nobody says you have to run them from 110 or 220. You can just as easily power them from say 30 volts- whatever. The option is to embed one of these into a routed groove in each tread, or by any other method you would fasten it to the underside of the tread. I'd almost be tempted to use checkerplate for the tread, even if you cover it with a no-slip compound like hypalon or whatever. The elements could be wired in series, say three treads, and each would get 40 volts from a 110v supply. Might still be way too much heat though, so the option is to use a transformer with a suitable secondary voltage to power it. The transformer gives isolation as well, so it would actually be a safer way to go.

Out of incessant curiosity, I've just cut into a section of this and removed about one foot so I can take a measurement. One end has a solid center conductor coming out, the other end has the element wire coming out. Evidently, the ends of the element wire are fastened to a solid wire to facilitate making a connection at each end. Also, I think the solid inner conductor wire probably goes into the sheath to the point where the heat begins- where the coil itself becomes flat. No need to heat right to the actual ends of the sheath- keep the heat only where the pots and pans would touch it. If you cut a complete element into lengths, you would have to make the electrical connection to the element wire itself. Not a big deal, just a detail during construction.

I've just made a rough measurement- it takes 6 volts to put 1 amp through 1 foot. 12 volts would put 2 amps through 1 ft, etc.

This was the smaller of the two stove-top elements, and it turns out there's 6 ft of length to it. More simple math- it would take 36 volts to put 1 amp through 6 ft (36 watts) or if run from 110, that would mean 3 amps flowing, for about 350 watts. If run from 220, that translates to a 1400 watt element. It's probably rated at 1500 watts then, but as I've suggested you can set whatever power output from it that you want, by feeding it the suitable voltage.

I'm going to suggest a step that's 36 inches wide, which would take the full length of the element in one loop, making it easy to work with.

Now the problem is to determine how much power it takes to keep the treads warm to the degree you want, or at least within a comfortable range. It might not be out of line to suggest 50 watts per tread. That being the case, you would feed each element about 40 volts. This works out well since 3 treads can be directly driven from 110 if they are wired in series.

Hmm. There you go- three small stove-top elements, unwound and shaped into a loop for each tread, wired in series, drawing about 1.6 amps or so, for a total of about 175 watts- roughly figuring. No need to cut the ends off the element at all. Checkerplate treads, sandwiched to a plastic plank, encapsulating the heating element in silicon rubber, coated in anti-skid compound. You could probably even inset the tread into the plastic plank, that might give a nice finished look to it.

RussZHC
12-05-2010, 09:34 PM
Because of cost to you, the trace should be the least expensive.

I would still go to the 'hassle' of boxing in and insulating the steps (not the least of which the extra warmth when done may draw little critters or some not so little).

Not affiliated, ya dah, ya dah:

http://www.infloor.com/

but has a lot of useful information about various infloor (and in ground, as in heated parking pad) options, all of which are variations on a theme and quite similar to what you maybe after.