PVA as vaguely waterproof varnish ? :hmm:

[gentlegreen]

I have been making a plywood "hydroponic planter" - mostly to house drainpipes with sealed ends and planting holes, but I am building in polythene-lined compost compartments too..
The thing only has to last a couple of years ...

I have various kinds of paint lying around, but randomly I "varnished" it with PVA.

Is it going to turn into a gloopy mess ?
Should I rub it down and use the ancient smooth masonry paint I have ?

I suppose if I was really serious about waterproofing plywood, I would have bought a load of epoxy ...

 

[danski]

Yacht varnish or similar maybe?

 

[Nigel]

It may be a bit late now but have you tried using OSB board instead of ply!
Built a shed ages ago with help from Lithuanian builder, he advised me to use OSB board!
Not a shed of rot on it and appears to be waterproof!

Is OSB Waterproof?

Building or renovating a home, shed, cabin, or another structure is a challenge when it comes to weather delays. Rain can soak and damage building materials, and further delay construction timelines as materials dry out.

plasticinehouse.com

 

[jontz01]

The reason I use sbr instead of pva as a paving primer is; or so I have been told is that, pva is water soluble once cured, whereas sbr is not.

Was it exterior pva? I don't fancy your chances but no harm in trying..

 

[Nigel]

One advantage of using PVA is its apparent; according to this article non toxicity for human, animal and not too bad for plant life!

Is Polyvinyl Alcohol Bad for the Environment?

Paper is a product we use almost daily at offices, schools, or at home. But do you know that papermaking uses polyvinyl alcohol? What is this? Is polyvinyl alcohol bad for the environment? Let's evaluate

www.ourendangeredworld.com

 

[two sheds]

I've got shitloads of pva which I don't really know what to do with. I've been told you can dilute it to make it into an adhesive but I don't believe that either. I see some pvas are waterproof but I used sba? to grit my slate path to make it unslippy. Did last a couple of years of walking on it.

 

[Supine]

to grit my slate path to make it unslippy. Did last a couple of years of walking on it.

Can you give us some details on this please? The slate tiles outside my front door are super smooth and lethal in the rain!

 

[two sheds]

Can you give us some details on this please? The slate tiles outside my front door are super smooth and lethal in the rain!

It was SBR not SBA sorry. Mind out when you get it home if you buy some. I discovered the pot it was sold in was flimsy by dropping it on the floor of my local doctor's surgery (large) carpet and it split. I spent a good half hour mopping it up alternately thinking 'please don't set hard please don't fucking set hard' and 'I really can't tell my neighbour cos I'll never hear the last of it'.

SBR, or Styrene Butadiene Rubber, is a water resistant bonding and sealing agent, and shares many similar characteristics with PVA. One key difference is that, whereas PVA remains water soluble after drying, once dry SBR is not.

I mixed it in with sand and painted it on. As I say it lasted a couple of years. I did check if there was a more permanent method. Someone recommended using a wire brush which didn't seem to work very well, and I've just seen someone say sand blasting.

Other recommendations are to kill moss if that's causing it, but I'm starting to think gravel or chippings might be the way for mine because it's lower than the surrounding garden. At the moment I'm just letting dead leaves build up because that seems to make it better.

In summary, please let me know anything you do that works

 

[gentlegreen]

Oh well, I guess I'm going to be sanding off the parts that my salad might touch.
Maybe I'll cut up some spare PVC square guttering to trim the top edges ...
I kind of knew it was a mistake because PVA is used as a fishing bait delivery technique ...
I do have some Sterling OSB board, but I've made the thing now and I need to get it in service...

Next step is to use my heatgun to fold the ends of my downpipe growing containers ... perhaps I'll see how amenable my PVC gutters are to being neatly folded ...

 

[two sheds]

would wood treating it with a treatment that sank in and then lining it with plastic work?

 

[gentlegreen]

would wood treating it with a treatment that sank in and then lining it with plastic work?

Probably too late now that I've stuffed the pores with PVA
I bet I now find I have a vaguely viable can of silicone-based weatherseal now in my stash of ancient shed contents

 

[two sheds]

could always wash the pva off


sorry

 

[gentlegreen]

could always wash the pva off


sorry

I may do that as well

 

[IC3D]

You should have diluted it and made a wash. Couple of coats to seal the pores then paint over.

 

[two sheds]

that might still work?

 

[IC3D]

that might still work?

Don't see why not perhaps thin out those gloopy bits that will otherwise take days to dry

 

[gentlegreen]

Don't see why not perhaps thin out those gloopy bits that will otherwise take days to dry

I did dilute it a bit.
It's all lovely and clear now and deceptively varnished

 

[DownwardDog]

I have been making a plywood "hydroponic planter" - mostly to house drainpipes with sealed ends and planting holes, but I am building in polythene-lined compost compartments too..
The thing only has to last a couple of years ...

I have various kinds of paint lying around, but randomly I "varnished" it with PVA.

Is it going to turn into a gloopy mess ?
Should I rub it down and use the ancient smooth masonry paint I have ?

I suppose if I was really serious about waterproofing plywood, I would have bought a load of epoxy ...



View attachment 321215

Unless it's "outdoor/exterior" PVA it's not going to be water resistant for very long. Also the bonds will pull apart in any application where the timber gets wet and dry cycles repeatedly.

Did you apply it with a paintball gun?

 

[gentlegreen]

Unless it's "outdoor/exterior" PVA it's not going to be water resistant for very long. Also the bonds will pull apart in any application where the timber gets wet and dry cycles repeatedly.

Did you apply it with a paintball gun?

It's held together with screws though I sloshed extra PVA in the gaps.
It literally only needs to hold together reasonably well for a couple of years - and I've had plywood do that when not protected at all.
I'm almost certainly going to see if I can flatten my square guttering and cover the critical parts.
I had it in my head from decades ago someone saying that I had PVA-lined vertical channels under my render ducting water into the sills and causing cracks (I dealt with that decades ago)- though I realise now it was almost more of a "lost wax" thing ...

 

[Epona]

When we were making swift boxes from plywood recently we used some Ronseal paint that was waterproof and safe for wildlife once dry - the main purpose of painting was to protect the plywood and prevent it from taking on moisture and laminating/rotting - so I'd suggest something similar for a project like this.