Tung oil to waterproof hot tub

Ben Hammerton

New member
Messages
3
Location
England
Hi everyone,

Total newbie to the forum, nice to meet you all. I am from Suffolk, England, and was recommended to join here by a lady called Cynthia who has written an article on Tung Oil, and I emailed for some advice and she said to ask you guys and gals also!

I have created a wooden hot tub, out of very hard brazilian wood... and used pretty tight canoe joints.... so that side of things is pretty good, however of course there will always be gaps, and therefore leaks. Leaks are totally normal on a wooden hot tub, and in fact soft woods such as larch and cedar are the norm, and swelling is preferable to seal the joints... but I wanted to be different and use a prettier hardwood.

I knew I would likely need to do a bit of sealing and wanted it to be as close to natural as I could.... and have decided that Tung Oil looks like the best bet.

So far I have given one coat to the outside of the tub, and at the moment that is all I have done, and that was a few days ago..... I am planning on doing a few more.

My question for you guys and gals is in relation to using Tung oil on the inner surface of the tub, because I can seal the outside again and again, but in reality the inside is probably more effective..... what are your thoughts on just using one or two coats? That way I get to protect the wood, give it a nice sheen, and add more of a seal at the same time.

Can anyone see any problems here? Or would you suggest another route?

Thanks in advance for any help!

Regards,

Ben
 
Hi everyone,

Total newbie to the forum, nice to meet you all. I am from Suffolk, England, and was recommended to join here by a lady called Cynthia who has written an article on Tung Oil, and I emailed for some advice and she said to ask you guys and gals also!

I have created a wooden hot tub, out of very hard brazilian wood... and used pretty tight canoe joints.... so that side of things is pretty good, however of course there will always be gaps, and therefore leaks. Leaks are totally normal on a wooden hot tub, and in fact soft woods such as larch and cedar are the norm, and swelling is preferable to seal the joints... but I wanted to be different and use a prettier hardwood.

I knew I would likely need to do a bit of sealing and wanted it to be as close to natural as I could.... and have decided that Tung Oil looks like the best bet.

So far I have given one coat to the outside of the tub, and at the moment that is all I have done, and that was a few days ago..... I am planning on doing a few more.

My question for you guys and gals is in relation to using Tung oil on the inner surface of the tub, because I can seal the outside again and again, but in reality the inside is probably more effective..... what are your thoughts on just using one or two coats? That way I get to protect the wood, give it a nice sheen, and add more of a seal at the same time.

Can anyone see any problems here? Or would you suggest another route?

Thanks in advance for any help!

Regards,

Ben
You want to use paraffin a flammable, whitish, translucent, waxy solid consisting of a mixture of saturated hydrocarbons, obtained by distillation from petroleum or shale and used in candles, cosmetics, polishes, and sealing and waterproofing compounds.
 
Ok thanks....... What suggestions are there on the use of Tung Oil on the inner surface please.

What do people think about using Tung Oil layers on the inside to form the waterproof seal, or should some form of wax be applied over the top?
 
Ok thanks....... What suggestions are there on the use of Tung Oil on the inner surface please.

What do people think about using Tung Oil layers on the inside to form the waterproof seal, or should some form of wax be applied over the top?
Tung oil will seal the wood, but will likely leave an oily film on the water surface when you fill the tub. Also sealing the wood will prevent/inhibit it from expanding
Leakage on a wooden tub is generally through the seams, not the wood itself. Once the wood absorbs water and expands, the seams will pretty much seal themselves. Works the same way in a wooden boat.
I wouldn't do anything to the inside - just leave it bare and let the water do its thing.
 
Hi Ben, and welcome to the family. I'm with Jim on this. Leave the inside natural. You didn't mention the specific wood you are using, but a few of the exotics contain oils that can cause contact dermatitis in some people and I wonder if the heat of the tub would release those oils? If your wood won't expand enough when wet to seal the joints you may have to think about some form of caulking between each board.
 
My only experience with tung oil is with a muzzle loading firearm I built in 1976. The gun is a repro Brown Bess. Lots of wood. It was intended to be used outdoors, of course, under any type of weather conditions. I liberally coated the wood inside and out with PURE tung oil. Over these many years, lots of rain and snow and other high humidity environments, I would say all is as good as the day I applied it. It's my opinion your choice of tung for your project is a good one. But, do use only pure, no additives. Good luck, let us know how it works out for you.
 
My only experience with tung oil is with a muzzle loading firearm I built in 1976. The gun is a repro Brown Bess. Lots of wood. It was intended to be used outdoors, of course, under any type of weather conditions. I liberally coated the wood inside and out with PURE tung oil. Over these many years, lots of rain and snow and other high humidity environments, I would say all is as good as the day I applied it. It's my opinion your choice of tung for your project is a good one. But, do use only pure, no additives. Good luck, let us know how it works out for you.
Frank I built my 1st Ky long rifle in 82 and all I used was 100% tung oil. The finish still looks awesome after all the years out door competitions. It's great finish.
 
Thanks all, much appreciated.

I have used Muiracatiara (Tiger Wood), which is super hard (with very very little expansion), so am going to keep thinking of some ways to do this.... otherwise might have to seal the inner join between the uprights and the base, and try that.... with the aim that the water will hopefully cause some expansion if I can get it to fill high enough...... unless anyone can think of anything else?
 
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