Technical questions about mosaicing

[Nao]

So I have a bunch of flower pots, some for indoor and some for outdoor use, some in terracotta, some in light weight concrete and some in the regular ceramic/stoneware flower pots usually are made of. Glazed and unglaced. And I wanted to cover them with mosaic, I mostly have those regular square glass mosaics.

I have glue/mounting paste (or whatever is the right translation) and grout for bathroom tile and two-component epoxy for boat hulls. I also have water based pva wood glue for outdoor use and winter use. Would the mounting paste, grout and epoxy work properly with the materials and conditions listed? What I've read pretty much all pva glues are more or less the same thing even if the label lists different usages, but I don't know if that is true?

I'm thinking the terracotta pots will absorbs water and make the mounting paste and mosaic come loose so I will need some sort of finish or primer or something on the pots first. I don't know if concrete and stoneware absorbs water, I'm assuming they don't?

What would be suitable as primer/sealer? Or is it even needed? I was thinking the epoxy would do but will toxins from it leech out in the indoor air or be absorbed into the edible plants I will plant in the pots? Or is that of no real constern? Of course I could just put plastic bags in the pots but I rather not if it can be avoided.

I'm assuming I would need to sand down the glazed/painted pots but the unpainted/unglazed terracotta/concrete/stoneware pots is fine as they are? Or would the mounting paste/grout stick to the glazed pots too?

I also have a couple of small wooden tables I want to cover with mosaic too.They are mostly going to be used as flower pot stands or side tables and won't need to stand very heavy use. I've read since wood is so movable it nessesary to add a plasterboard on top of the wood and then put the mosaic on the plasterboard. But would that really be necessary or worth the cost if the tables are only going to stand around and look pretty?

I know it's a lot of questions but I really don't know anything about those kind of stuff and when I tried to research it's either mommy bloggers, building sites that's way to technical or they use things that's not sold in my contry.

 

[shunt2011]

I'm not a pro by a long shot. But, I've done pots using silicone to adhere stones, gems etc to the pot then used grout to fill in the spaces. I then used some grout sealer. They lasted quite a few years of use. I planted in mine.

 

[Nao]

Thank you for your reply Shunt, I was thinking of using silicone too since I already had some on hand but consensus seems to be that silicone is way to movable and will cause the grout to crack after not too long.

 

[shunt2011]

I haven't had an issue but I'm sure anything is possible at some point with any process. I used waterproof silicone. I also did bowling balls like gazing balls and used the same. I have a couple that are upwards of 7-8 years.

 

[zanzalawi]

oohhh i really like that idea- the bowling balls. ive been wanting to do something pretty that isnt so fragile

 

[Nao]

Yes, you are probably right, I’m one of those that want to do it once and then have it last the rest of my life and just being overly cautious about everything.

 

[Escott752]

Bowling balls! Excellent idea!

 

[DeeAnna]

Silicone can be squishy and movable in thicker layers, but if applied in a reasonably thin layer -- in other words, use it more like glue and less like caulk -- it can be quite secure and firm.

Also with grout, there are additives that you can stir into the grout that will add a little flexibility -- one example is grouted tile on top of a wood subfloor.

 

[penelopejane]

As DeeAnna said timber is flexible and absorbs water so you really need to think about it as a base.

In the old days they glued the tiles to the surface using just about the same material as they grouted with. You can glue your tiles onto the pot using tile glue. Which is Only as good as the base it is glued to and the surface of the tile. Then grout it. If it’s left in the rain or subject to water from inside the pot the grout will deteriorate over time as the drying out and wetting will effect it.

Tiles, grout, terracotta and cement all take up moisture. Best idea is to have them all take up moisture evenly. Tough to do.

There are ancient mosaics around the world that have lasted Millenia but those subject to weathering have not faired so well.