How long does it really take?
The big appeal of Plastic Pools is that they are ready to go- held at a constant Temp level, so that whenever the fancy strikes you, you can slide into the chemical bath and 'relax.'
i've never actually seen a Snorkle equiped rig, let alone lived with one, but the appeal is undeniable. So i'm curious to hear from those who have: How long from the time your strike the first match to the relaxing dip? Also, how about some of your best fire lighting tips.
It depends a lot on the time of the year. In early spring or late fall the water in my tub may only be 40 degrees. Then it will take me four or five hours to heat the tub up to soaking temperature. During the summer it usually only takes me about two hours.
There are so many factors that can affect the heating rate that there is no easy single answer. First question is what size of tub and stove are you thinking of? The heating rate chart that we have on the page Designing Your Tub, http://snorkel.com/how-to-buy/design...ur-hot-tub.php gives accurate heat rates based on our experience here in Seattle with an ambient temperature in the high 50's and a floating foam cover on the tub.
Other than size, ambient temperature and presence/absence of cover, the next consideration is fuel and fire tending. We use a combination of scrap cedar for kindling and fuel to the extent we have it, but usually the principal fuel wood is split alder, a medium BTU content wood. For best results we use cordwood split once again. The smaller the pieces, the faster and hotter the burn and the quicker the tub heats. The trade-off is more heat is going up the chimney.
Tending and feeding the fire is critical. If you want it to heat really quickly, you probably want to be tending the fire every 15 minutes or so, poking the fire to rearrange the logs and maximize air flow and feeding it to keep the firebox full. A small, infrequently tended fire will not produce the results in our charts.
We had a customer in Fairbanks, AK who claimed he could fill the tub (6 x 3 with Snorkel Stove) with well water at about 36 degrees and have it to tubbing (we assume that meant 102-104) temperature in two hours. Seemed a bit of a reach to us, but who knows. On the other end of the spectrum are customers in the Rockies with a tub at 7-9000 feet elevation using wood like aspen, an extremely low BTU content wood. The combination of low oxygen and poor fuel means their heating rates will be measurably less than our experience at sea level with reasonably good fuel.
This doesn't give you the precise answer you are looking for, but gives you an idea of the major variables involved and you should take these into consideration in evaluating posts that others might make.
Last edited by Tom H; 07-19-2006 at 06:32 AM.
Thanks for the feed back.
Prairie- how big is your tub? i'm sure that a lot of us would like to see your design.
Tom- Thanks a lot for the help. i arrive home from work around dawn in the winter, and a nice toasty soak before bed sounds delicious. i May be better off with a LP system and a timer, but wood fired really appeals to my "Inner Cheapskate!"
i understand that the secret to a quick warmup is to generate as many btu's as you can. Which i'm sure is a matter of proper wood selection, preperation and seasoning, and draft control.
Do folks have much luck "banking" slow burn over night? i never really have with indoor stoves- i can't seem to slow the air flow without putting the fire out. But the draft system on the snorkle seem simple enough that even an idiot like me could work it.
Mine is a 5x3 round tub, very much like the ones you can buy. It works well but the wood I used did have some knots which leaked for a couple of years. The tubs you buy from Snorkel are made from heart wood, so knots are not an issue. Cutting a proper bevel on the staves is critical. If everything does not fit perfectly the tub will leak.
It took me a while to learn how to get the stove to draft properly because it does seem to act a little differently than a conventional stove. It works well, just different. I now start the fire with something that will burn very hot and fast. That gets the air moving through the stove in the right direction and I can then start adding more wood. I have also found that wind makes a difference. A breeze seems to help keep the stove drafting well, but on calm days it is a bit more difficult to keep slower burning wood going. Fortunately out here on the North Dakota prairie a lack of wind is seldom an issue.
With a good piece of ash or boxelder I can keep a slow fire burning over night. I am sure other hard woods will work too. This fall I plan to try using coal. I'd give it a try now but no one in the area is selling coal this time of year and I don't feel like making a trip to the mine. I have a wood stove in the house (an older Buck Stove) and I have been using coal in that for years. It works very well for a slow overnight fire.
Quick start up next day
I took a piece of foam insulation, I think that it was 1/2 inch thick, and cut it to fit in the tub, forward of the fence, in two pieces. I sealed the edges with a clear tape like shipping tape.
After I soak, I'll cover the water by floating the foam on it. The two pieces make it easy to put them in and take them out. Then I may also add a log or two to the fire box. The wooden cover on top of that, and that water will almost be soaking temperature the next day too. That wooden tub is a good insulator, and that foam does a good job on top.
A few new logs in the firebox and I'm ready to hottub. That foam helps the tub heat faster initually too.
Heat up time
In Seattle where I live, in the summertime, I use my tub alot, and heating day to day is maybe 20/30 minutes. I have a 5x 3.5 (custom depth) with a Scuba. In the winter, when we heat up the tub it may take 3 hours, but then we generally use it every day for 4-5 days, reheating takes 45 minutes or so. I'm probably on the edge of Scuba heating effeciency. This is our 2nd snorkel tub with our original Scuba stove. I've had a tub for over 20 years. It's also worthwhile to keep a timer on the stove going and load your firebox every 20 minutes to keep the hottest burn going.
how long does it take
I use a couple of "tricks" to speed things up. I start small kindling with a hand-held propane torch. Gets the fire going quickly without using paper, which tends to cause flying ash that clogs the exhaust screen. I also put a small submersible pump in the tub while the water is heating up. It circulates the water to extract the heat from the stove. I get a >20 degree rise in water temp/hour. I remove the pump before getting in. Keep the tub covered during the heating phase so you don't lose much heat to the air. Hope this helps you. Guy
I usually get between 15 and 20 degrees (Fahrenheit) per hour with junk wood and stoking every 20 minutes.
I also run the pump (I have the filter kit) the whole time in order to circulate the water.
The top keeps the heat in, that's for sure! Good tips!
I've found heating my 3x5 tub and keeping it hot pretty easy to do, considering it's a five-ten minute walk from my house. The reason for the long walk is its location adjacent to a beautiful thirty foot waterfall in the middle of my acreage. (see pic) I've rigged a hose from the spring that seeps out under the waterfall to the tub for filling, cleaning, and temperature maintenance. The hose is attached to the opposite end of the string to my drain plug, so I can pull in cool water if needed without ever leaving the tub. Because I have a smaller tub and wanted to keep seating options flexible, rather than put in permanent seats I filled a couple of milk crates with enough rocks to sink them and attached wood tops to those. That works out very well to make maximum use of limited space. The seats can be moved or removed at will.
I keep a box of fire-starters up at the tub - those blocks of compressed sawdust impregnated with parafin or some other flamable material available at the local grocery stores here.
Depending on how wet it's been lately, I may carry dry kindling up to the tub. I have a pile of cordwood already stacked up there that I replenish from trees that fall somewhere close to tub, and stash kindling behind the tub, but in this wet, humid environment sometimes the kindling isn't as dry as it could be.
I set a piece of wood inside the firebox, then lay the lit firestarter on top of that, and arrange kindling in a teepee fashion over the firestarter. In no time I'll have a small blaze going. If I'm in a hurry to heat the tub, I'll stand over it and add small pieces of wood constantly. That will get me 40 degrees of heat gain per hour.
More often, once a good blaze is started, I stuff the firebox full with cordwood, leaving the damper open and the lid slid back to allow maximum air intake. During Summer months, in a couple of hours the tub will be hot. In colder months I reload the firebox after a couple of hours and the second stuffing usually does the trick.
Once the tub reaches temperature, even without a fire, I find it only loses about ten degrees per day, so a short kindling fire brings it quickly back to comfy temps. I have the wood top, but no other insulation. I usually try to get in the tub with the fire still going, and keep a couple of pieces of wood within reach so I can add to the fire if need be.
If I plan to return the next day, I'll add wood to the firebox when I leave. It's easy enough to start a new fire if need be that I don't worry about whether a banked fire will keep overnight, but with a good bed of ashes and a damped down stove that isn't hard to do.
I use locally gathered firewood, which around here is a variety of hardwoods. Currently I'm burning a mix of maple and sycamore, and about to add some basswood to the pile.
I have an old kayak paddle handy for stirring the water, but when I've wanted to get a soak in a hurry, I've been known to climb in when only the top layer is warm enough and keep my body horizontal near the top as the fire does its thing, grabbing handfuls of cooler water from the bottom to equalize as the tub heats. At the level my thermometer hangs, I generally find it to read about ten degrees warmer in an un-mixed tub than the temperature a fully mixed tub would provide.
Hope that helps!
Last edited by wvwaterfall; 07-09-2008 at 10:31 AM.
Reason: just a little fine tuning...