Building my own hot tub (part 6)

April 29, 2010 at 08:39 (DIY - hot tub, Hot tub (part 6))

Some time has past since my last post about hot tub.

Must admit that you have to have + degrees outside before you try filling hot tub.  I was lazy enough to play up to 3 days trying to get hot tub planks to suck the water in and those 30 min. leak seams to be lie anyway. I used silicone where side planks meet the floor panel and (not in side of  side plank cuts but just inner corner of hot tub). This was done because of crappy pump i mentioned (btw: pump seams to be dead for now) so I could fill the hot tub quicker and planks would “auto” expand. As you can see we made some benches as well.

After 3 day play (refilling, refilling) the hot tub has been holding water for more than 2 weeks and water level has dropped only for about 5cm (mostly because evaporation).  I had only one test run and I got water temperature from +7’C to 25’C   in about 7-8 hours. Not enough and I think I know the reason as well. Stove needs to be lower, so that the cold water (lower pipe) would be on same level on both sides. Also if possible you and I should use bricks to cover stove so that the heat and energy would not scatter so quickly.

And the ladder made from left overs.

A tip:  When firing the stove you should cover hot tub from top and keep mixing the water. It heats up quicker this way.

Interesting note: On first test round I did not add any more wood after 22:00 and water at that time was 25’C. Next day around 11:00 water had still +22’C (air temperature at that night was aprox. 4-6’C only.


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Building my own hot tub (part 5)

February 8, 2010 at 15:04 (DIY - hot tub, Hot tub (part 5))

I got old wood fired sauna stove for free.  It has some holes so that its not usable indoors or sauna anymore, but is good enough for hot tub. That old stove needed some things: water pipe and  more than 1m long chimney so that stove has thrust when wood is burning.
How does the stove work and how it heats the water. I hope you have seen stoves in sauna which have water pipes in side and behind which to lead into big water tank.  Simplest way to describe it is so that cold water enters from water tank to stove where hot pipe inside of stove will heat the water up and lead it back to water tank from another tube which is placed higher than entrance pipe for cold water. This will make water circulate and heat the water in the water tank. For test run i did buy crappy hose (more plastic than rubber) we had to cool it down with snow so that it would not melt as there was air in the pipes which gives possibility for water to start boiling (means higher temperature and circulation is disturbed). Good hose is bit expensive, but seams that I need to buy good one anyway.

I got old water pump from my neighbor (thank you!) which did not had much power (400L in hour). With such climate  here in Estonia (-13 degree) this pump was definitely not powerful enough, but was worth of trying. Friend came to help me again. On first testing day after stove was setup we managed to get water into hot tub only for about 20cm. Because of 2 things…

1- Crappy pump: Because water did froze before it infiltrated/leached into wood leaving holes or tracks so that it started to leak and did not stop. When we did cast the water on side planks id froze immediately. Whole hot tub has been outdoors for couple of weeks and temperature of wood was certainly lower than -10’C. (if we only could get water faster inside)
2- Side planks which were cut and measured too precisely: When you put hot tub together attaching side planks you must be sure that last plank is wider than it seams to fit place (4-6cm). At that moment we realized that side planks tenon bottom was touching floor panel and we did not had possibility to pull side planks together enough at the bottom.  This resulted water to froze between side planks and tenon leaving tracks for water to leak and you are unable to pull it together enough any more (bottom).

Second day (after everything did froze during night) we filled hot tub partially, added bit snow (because it was the quicker way leveling the water line than waiting for that pump to fill the tub) and fired up the stove.  It did work for 2 hours before it started to leak again! Why? ice ice ice from first testing day… we did took all the side planks off and moved them into sauna to dry out the wood. Also we did made more side planks for upcoming test run (i hope for no more).

Today I will not write about how to make holes for water pipes but I will post more detail pictures sooner or later  so you all can figure it out your self.  If you are in hurry – then leave comment here!
Meanwhile i need to smoke some.

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Building my own hot tub (part 4)

January 18, 2010 at 09:05 (DIY - hot tub, Hot tub (part 4))

About the floor. Important  was to use load strips to pull floor planks tightly next to each other before screwing crossbars to their place. As figure in “part 3” shows that there are 3 crossbars under the floor.  Two different wood drills have been used for drilling holes in floor holders. According to screws that were bought,  drill were 12mm (for making draft) and 6mm (long one – drilling trough crossbar) . When you drill trough crossbar you should drill it some where else not on top of floor planks.

As seen on picture, after middle crossbar is attached and the screws are screwed you can release load strips. I highly recommend you to build the floor on flat surface.

That day one friend came to help me (Thank you Raimo!),  so it supposed to be quick and easy – hell no! We started with the work bit late, around 14:00 clock.  As it was getting dark already at 17:00 and it was also cold out side (-15’C) we had to use some motive fluid to continue.  You should not attempt this at home for your own safety.

After all crossbars attached, we turned floor over and marked circle with home made caliper of 0,95m from center. We broke my cheap jigsaw but we still had 3 more planks to cut from circle, work was finished with normal wood saw. Some corrections were made with disc cuter.  We finished around 00:00 (midnight) barrel ready and went to sauna for getting cold out of bones.  Off course there is need for finishing touches like grinding top edges and drilling holes for drainage and pipes. Meanwhile I plan to make furniture in side.

Some morning pictures of barrel / hot tub:

If you find something helpful from this site please leave comment or share your work.

bye for now!
(smoke break)

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Building my own hot tub (part 3)

January 12, 2010 at 13:28 (DIY - hot tub, Hot tub (part 3))

Now its time for some blueprints. First I want to point out about hot tub diameter that was 1,95m and not 2m. Also why the first cut in side plank was exactly 9,5 cm from one end. Idea is that building process should be easy and not to run into stupid things like complicated floor parts, cutting planks lengthwise or what ever. Everything is based on planks I have bought which are standard at least in Europe. Not sure about USA or UK as there is common to use Imperial units instead of metric.  Metric system for your better understanding: 1m = 100cm = 1000mm and if you feel or did not understand some issues I have written here, send e-mail or post comment here, I will try to help you out!

you can also try unit conversion like “9,5cm in inch” hit the search and you should have result like 3,740…

Just to remind that planks I got have dimensions:

  • height 45mm (4,5cm)
  • width 95mm (9,5cm)
  • length was various for me , some were 5,4m some 3,6m

MS Paint is not the best program for blueprints but does the trick.  Note that the crossbars are sideways attached to floor panel, together with side planks they form stand by supporting each other on the same level. So that your hot tub floor would not fell in part. I have cut almost suitable planks for floor panel already.Important is that you can pull together floor planks tightly. If possible you should use load straps (trucks), just in case on any side you should but some planks so that you would not harm floor planks when you use load straps.

When floor panel planks are but together, last thing is to make caliper with what you can mark nice circle with diameter of 95cm. After that you should cut edges and follow the line you have drawn . Jigsaw should be enough but be prepared to make some corrections with sandpaper or disc cuter with  polishing disc attached. (remember to measure 9 times before you cut)
Now about pullers, as i could not find suitable metal sheets (aprox. 3mm thick) yet. I intend to use load straps for test run. According to “manual” they should be able to hold the load about 8 tons or in straight 4 tons. I got them quite cheep.

Note that when barrel (hot tub) with such diameter can expand up do 2cm  in outer circumference when getting wet.  If you intend to use metal pullers you should be prepared to loose it up a bit. Otherwise you can brake strips and end up with injury.  On first 20-30min you can experience that hot tube does not hold water. This is normal for first 30 min, let the wood expand.

As you have most parts but together DO NOT paint or use any chemicals/clues on wood. You can turn your relaxing hot tub into chemical waste barrel where no one wants to be or nether its healthy for your self. Its allowed only to use natural wood oil to be used on outer side of hot tube to prolong hot tube life, in this case I do not have any recommendations.

Damn smoke break.
More pictures next time.

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Building my own hot tub (part 2)

January 12, 2010 at 11:39 (DIY - hot tub, Hot tub (part 2))

Let’s continue with the journey! Important thing is to remember that you must measure 9 times and cut only once.  As wood planks that i have bought were in 3 different lengths I wanted to make maximum out of them, so I drew all the planks on paper (1/10) so that there wouldn’t be any non useful remains left. I calculated all the sizes and tried various possibilities. I used this paper also as a plan when I started to cut the wood. Smallest remains had 30cms of length, which can be still used for hot tub furniture, like chairs.

It took about 8 hours to cut the wood (including lunch and smoke brakes) and prepare side planks. As the standard height of a hot tub is 1,1m, I decided to do it the same way.  After I have cut edges in the correct angle for 66 side planks  (and a couple of spare ones), I made 3 cuts to every side plank, which is important.  I bet you are wondering why an earth there are cuttings in side planks seen in the picture, well they are for the bottom floor planks.  First cut is exactly 9,5cm from one end, second cut is 11,5cm and third cut is  14cm. Very crucial is to understand that the length between the first cut and the third cut is exactly 4,5cm as floor thickness is 4,5cm or planks I am using.  If this will be more than 4,5cm you will struggle later on when you put the hot tub together. Side planks should be able to hold themselves on  floor panel when you put it all together. Note that these three cuts should be 2cms into planks and from one side only, not from the wider side of planks (inner side). Otherwise you would screw up everything.

It was time for me to find the chisel, which I did found but for some reason it was broken, ok, I found a big screwdriver which was for some reason sharpened to one side as it would be chisel. I really do not remember if I did that and for what reason. I would really suggest you to find proper firmer chisel and hammer.  You need to remove the wood between first and third cut. Cleaner and nicer you will do the better quality you will have; I might need to use some sand paper for fixing my dirty work with that screwdriver I made in the dark. I hope you got the idea.

Smoke break again!

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Building my own hot tub (part 1)

January 11, 2010 at 14:53 (DIY - hot tub, Hot tub (part 1))

A hot tub or as we call it in Estonia “kümblustünn” is a thing I have been missing from my yard. Specially when it is -15 degrees out side and it is snowing.
Half a year ago I planed to build one my self, searched for some blueprints and ended up with nothing. Found only some crappy ideas how to build one from 1000l plastic canister, whose ugly looks and small dimensions would scare birds away.
Around 6 months have passed by since I got the idea for getting a hot tub. Now I wanted to build a motor boat, but hey! My wife said I should keep my promises better, she was pointing out the idea of a hot tub in the yard (she wanted to have a nice time in the hot tub with friends and I don’t mind to see bunch of women running in bikinis during wintertime). So I decided to build one and from wood as its done in Northern countries.
Short notice: If you plan to build one yourself following the steps I described or blueprints, please read all the posts about building a hot tube that I will have posted here in this blog before you start.
Ok, First thing is to build a huge barrel from wood. Why wood and which wood? Wood is good thermal isolator and easy to work with. For a hot tub it has other good qualities such as: dry wood expands when getting wet, fir and pine have resin inside which will prolong the life of the hot tub compared to oak or birch, to be mentioned wood is also more natural than than any damned plastic canister. In my opinion, pine would be better for hot tub building than fir, as fir planks usually have more branches, which affects the quality of a hot tub being water tight later on.
After a couple of days of planning and drawing some blueprints it was about time to buy the material (wood).
I have decided to make a hot tub with diameter of 2m and height of 1,1m. It should be enough up to 6 people as I do not intend to install stove inside of hot tub. After some calculations, I ended up with an aprox. need of 130m wood (45×95mm) so there can be remaining pieces. Some remaining pieces of wood can be used for building hot tub furniture (beer can holders and chairs). I got my hands on fir planks with good price and 4 sides sliced (machined) and they were 45mm x 95mm, which comes from standard unsliced 50mm x 100mm wood planks.
So how wood planks should look like? Because machined wood (modern style) was too expensive to buy and pointless to buy equipment to make some for yourself.
I decided to go a bit old school and make it as predecessors use to make wooden barrels.

Modern Style of wood plank allows you to build easily various shapes of hot tubs, for example oval shape or different sizes with out re calculating edge angle for side planks again.
As the outer diameter is 1,95m (why 1,95? you will figure it out later), I had to calculate the length “circle” (6.123m). Now divide outer length with the width of wood plank (its 95mm) 6.123m/0,095m= 0,0645 pcs.
which means that you need almost 65 side panels (wood planks). The count of side planks also gives us possibility to calculate what the angle for side plank edges should be. Circle inner angle amount is 360 degrees so as we have 65 side planks it means we have 65 corners, every corner has angle 5,54 degrees, we need to know the correct angle of one side plank both edges, lets divide 5,54 with 2 and we get= 2,77 . This is the correct angle that every side plank edge should have. When you put two side planks together you should have an angle of 5,54 degrees

The easiest way for cutting the edge of planks is using a panel saw which blade angle is adjustable. I bet you have better conditions than I have, but if you keep working, then -15 does not feel cold at all.
That’s it for now.
Need to have a smoke break.

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