Paint to make a Cardboardbox a Watertight Trough as seen on programme

I remember an episode of Gardeners World, which was probably a couple of years ago now, which I was impressed with becasue they showed you a paint that you could put on the inside of a cardboard box and it would seal it so well it could be used as a water trough.  I want to make some of my own planters and troughs and appear to be unable to find information on what this paint was.  Can anyone in the forum please tell me?  Thanks in advance

Not sure about that but do remember Geoff Hamilton making troughs and so on from hypertufa and used carboads boxed as the frame-is this it?

http://www.finegardening.com/how-to/articles/make-hypertufa-trough.aspx

A painted cardboard box just wouldn't be strong enough surely?-no matter what paint you used.

I remember something similar to the hypertufa ones above, not a painted box one. 

Has anyone tried the hypertufa/concrete ones? I'm just imagining how much mess I might end up getting in if I tried it & how many stages it could go wrong at! 

Great idea to make your own however though, large planters can be quite expensive.

Yes, we have some hypertufa ones still going strong after a good few years.  We also coated some old sinks with it, that is now coming off and needs replacing, but has lasted at least 10 years if not longer.

They are a bit of a fiidle to make, but not that much, two supported boxes, one inside the other and the cement peat mix between the two - if making a big one some chicken wire in the mixture helps to hold it in place.  Good, effective, inexpensive way of making expensive looking troughs.

There are almost certainly some websites available with the proper way of doing it, and equally probably some charity shops have dear Geoff's books in stock - I would not be without mine, my gardening hero was Geoff, still is I suppose

That's good, sounds like it's worth doing then.

The method in the link Sotongeoff posted doesn't use wire or boxes, just some reinforcing fibres & anything as a mould.  I wonder which is easier. 

Lokelani wrote (see)

That's good, sounds like it's worth doing then.

The method in the link Sotongeoff posted doesn't use wire or boxes, just some reinforcing fibres & anything as a mould.  I wonder which is easier. 

-bit confused -on page 2 of that link it shows one box inside another as a mould

Oh so it does now I look again! Silly me.

I went as far as a link halfway down the page called:

Further reading, create a hypertufa container in five easy stages.

Which shows how to use old pots as moulds. I don't know why I followed that link before scrolling all the way down the first page. I seemed logical at the time! 

Now I won't know which method to try first!

Well whatever you do is sounds a bit icky-I shall expect a photo of the results

Whoops I should clarify - it was far more recent than Geoff Hamilton, I'm thinking in the last 2-5yrs.  It was a paint which meant the box could hold water - so it was a water trough as opposed to a planter.

What I actually want to do is to make my own outer pots for my orchids to stand in that will cope with moisture.  I have so many orchids and keep needing bigger and bigger pots, its hard to keep up! 

This might be the answer-it involves coating the box with the stuff for waterproofing flat roofs etc

http://www.ehow.com/how_7805328_make-cardboard-weatherproof.html

Yes, there was something on Ideal World or similar commercial TV channel recently which showed a waterproofing paint used to make a cardboard box hold water.  I don't think they were proposing you use it to make planting boxes though - it was just a demonstration of the paint.

No Melody T, I had assumed it was a more recent programme, my point was more that they had been going strong since then!  Still, no harm in looking out for the old books, can't beat an old 'un you know.

Im new to this but my advice is start small. I started with using one plastic pot inside another to make a mould. Make up more of the mix than you think you need as it has to be packed in, as the walls need to be at least a inch thick, and be patient with the drying process. Dont be tempted to remove from the mould in under about three days, make sure the mould surfaces are lubricated or you wont get it out, and rough the pot up with a stiff brush to shape it and remove rough edges and so on. I am gradually moving up to making pots from larger bowl-shaped pots. This weekend I plan to add some cement dye but you should probably not use standard grey cement with this  - best get the white cement which I think they call snocrete. The colour will be much better. 

Good fun but fairly messy.   Have a look at Video