What's the best glue to stick large rocks together?
June 15, 2020 12:16 PM Subscribe
Here's a picture of rocks around my pond. You can see that I have planted some small plants in pots. I hate them. i would like to glue 5 rocks together to make a planter (one for the bottom, four for the sides). What is the best adhesive to do that? I'd like to try to make it water-tight because these are water-friendly plants. thanks.
If you don't mind using a fair amount of material, marine epoxy putty is my favorite do-all ofr these sorts of situations. You can paint it to make it match (grey could sort of blend in) but I would think you could do that with 3-4 sticks of marine weld.
Here's an example, I just buy the putty sold at my local hardware store. Wear gloves when you're mixing it and apply it rapidly.
posted by arnicae at 12:27 PM on June 15, 2020 [2 favorites]
Here's an example, I just buy the putty sold at my local hardware store. Wear gloves when you're mixing it and apply it rapidly.
posted by arnicae at 12:27 PM on June 15, 2020 [2 favorites]
Use grout or mortar; it's meant to join ceramic to whatever that tile substrate is, and you're meant to use big globs of it to fill in voids. It's similar to cement, so you can make shapes with molds. People use vermiculite in cement as filler to make hypertufa pots, there's a rich search vein awaiting. Also, you can get spray paint that will make things look like granite or other rock, and that would be good camo for any pot.
posted by theora55 at 12:32 PM on June 15, 2020 [6 favorites]
posted by theora55 at 12:32 PM on June 15, 2020 [6 favorites]
Water-weld, who knew? I have no current use, but I love knowing about stuff like that.
posted by theora55 at 12:33 PM on June 15, 2020 [2 favorites]
posted by theora55 at 12:33 PM on June 15, 2020 [2 favorites]
I would just make a rock-look hypertufa trough of the shape you want. You can embed real rocks in the surface etc as you cast it. It will be much better than gluing rocks together, which is not really a way people make planters, for several reasons.
posted by SaltySalticid at 12:36 PM on June 15, 2020 [3 favorites]
posted by SaltySalticid at 12:36 PM on June 15, 2020 [3 favorites]
I have seen a planter done with Flex Seal Paste.. I have also seen a stone wall have two rocks replaced and secured using the stuff. (Same person did both.) I am biased as it being crappy as a As Seen on TV product, but it works.
posted by AugustWest at 12:45 PM on June 15, 2020 [1 favorite]
posted by AugustWest at 12:45 PM on June 15, 2020 [1 favorite]
Response by poster: funnily, I just used marine epoxy to join a plastic shelf to another plastic pot and let it dry for day and when I pick up the thing, the shelf came RIGHT off what I had epoxied it to. Isn't that weird? it doesn't work on plastic??
I don't want to make those hypertufa things. I think they look weird and will not really look good next to my real, weathered rocks. I might try the As Seen On TV stuff and also maybe I'll try mortar on some.
And no, I'm not capable of sanding or changing the rocks in any way, if that changes anything about any of the suggestions.
posted by DMelanogaster at 1:02 PM on June 15, 2020
I don't want to make those hypertufa things. I think they look weird and will not really look good next to my real, weathered rocks. I might try the As Seen On TV stuff and also maybe I'll try mortar on some.
And no, I'm not capable of sanding or changing the rocks in any way, if that changes anything about any of the suggestions.
posted by DMelanogaster at 1:02 PM on June 15, 2020
DMelanogaster - most plastics are molded and usually the mold leaves a coating of wax/silicone/oil on the product. This is main reason adhesives fail with plastics. Solution is to clean object but method depends on plastic type.
posted by unearthed at 1:18 PM on June 15, 2020 [1 favorite]
posted by unearthed at 1:18 PM on June 15, 2020 [1 favorite]
Best answer: I am positive your planters are going to leak if you try to make them by gluing rocks together. Can you use a low-profile pot or planter as a liner or frame, and glue the rocks to it?
posted by agentofselection at 1:46 PM on June 15, 2020 [4 favorites]
posted by agentofselection at 1:46 PM on June 15, 2020 [4 favorites]
I'm not sure where you're located (i.e., gardening zone). Plant looks like a hosta? They are very hardy here in the Midwest US. Is there any way you can just plant it in the ground between rocks for a natural look, and I think the plant would be happier.
posted by j810c at 1:56 PM on June 15, 2020 [2 favorites]
posted by j810c at 1:56 PM on June 15, 2020 [2 favorites]
I think leakage might be a feature instead of a bug. Plants need drainage.
posted by ananci at 2:08 PM on June 15, 2020 [2 favorites]
posted by ananci at 2:08 PM on June 15, 2020 [2 favorites]
I'd think about a construction adhesive that mentions concrete. A caulk tube can give you some control over where you want a lot of adhesive vs. a little. To prep I'd use a wire brush followed by soap + water + sponge followed by water rinse and dry.
posted by Dmenet at 2:21 PM on June 15, 2020 [1 favorite]
posted by Dmenet at 2:21 PM on June 15, 2020 [1 favorite]
Nope. Nothin' here. I would get nice neutral colored planters that complement (but not match) the existing rock waterfall (which is pretty as it is) or find some planters with a faux pebble surface.
Here is one DIY example using river rock mesh tile.
posted by TrishaU at 4:06 PM on June 15, 2020
Here is one DIY example using river rock mesh tile.
posted by TrishaU at 4:06 PM on June 15, 2020
Response by poster: j819C --- I am in planting zone 7b. The plant in the gray pot is, in fact, a hosta. What you can't see is another pot like that that holds my favorite water plant, a papyrus. I also have a water-friendly iris to pot. Here's the issue: The reason I can't plant in soil in between the rocks is because there is pond liner under the rocks and, under that, a layer of brick (it's complicated! many layers! ). So there really is no soil there around the pond, yet I LOVE having plants in the rocks around the pond. It gives a certain texture. Without plants in there around the pond just looks like a rock pile.
It just would really add to the aesthetic of the pond area to have this variety of plants planted right IN the rocks.
So, I guess this is a hard project but it won't be that expensive to buy a few adhesives, like "one that says concrete," and that As Seen On TV rubber stuff, and maybe one other. It'll be a fun project to try, I think, although how I'm going to hold the rocks together into the right shape as the adhesive dries is going to be a challenge!
TrishU's rier rock mesh tile and other similar planters look too "home decor" for my area, which I've worked hard to look pretty damned natural. I had hoped that that rectangular gray metal planter in my photo would fit nicely into the landscape but it doesn't.
So thanks!
posted by DMelanogaster at 4:49 PM on June 15, 2020
It just would really add to the aesthetic of the pond area to have this variety of plants planted right IN the rocks.
So, I guess this is a hard project but it won't be that expensive to buy a few adhesives, like "one that says concrete," and that As Seen On TV rubber stuff, and maybe one other. It'll be a fun project to try, I think, although how I'm going to hold the rocks together into the right shape as the adhesive dries is going to be a challenge!
TrishU's rier rock mesh tile and other similar planters look too "home decor" for my area, which I've worked hard to look pretty damned natural. I had hoped that that rectangular gray metal planter in my photo would fit nicely into the landscape but it doesn't.
So thanks!
posted by DMelanogaster at 4:49 PM on June 15, 2020
Best answer: Your pond looks great! How about a flexible planting container like a rubber tote that is trimmed to height with rocks positioned around it. Might need sphagnum moss or something else as a filler to disguise the transitions. Or even a double or triple layer of thick plastic bags could be the planting container. Something flexible and watertight that could hold the plants and be squishable enough to be squeezed in between rocks.
Just this weekend I saw some plants hanging on a metal signpost. They were planted in some fabric saddlebags and doing well. Best of luck!
posted by goodsearch at 6:04 PM on June 15, 2020 [1 favorite]
Just this weekend I saw some plants hanging on a metal signpost. They were planted in some fabric saddlebags and doing well. Best of luck!
posted by goodsearch at 6:04 PM on June 15, 2020 [1 favorite]
Best answer: Speaking from zone 7, I would not focus much on watertight - drainage is good.
For keeping the shape while you cement the rocks, just assemble them in a larger plastic pot or bucket for a mold (you have to be a little careful with the cement, but as you discovered, many of these adhesives won't stick to plastic).
posted by aspersioncast at 9:25 AM on June 16, 2020 [1 favorite]
For keeping the shape while you cement the rocks, just assemble them in a larger plastic pot or bucket for a mold (you have to be a little careful with the cement, but as you discovered, many of these adhesives won't stick to plastic).
posted by aspersioncast at 9:25 AM on June 16, 2020 [1 favorite]
Response by poster: aspersioncast, are you suggesting any particular type of cement?
posted by DMelanogaster at 4:42 PM on June 16, 2020
posted by DMelanogaster at 4:42 PM on June 16, 2020
Best answer: So, I would also say you don't want 'watertight' but something that you can put dirt in/around in a way that all of the soil will not wash away, given a hard soaking rain.
I have a pond, as well, though not as 'formal' as yours - no paving nearby, so it just goes into the grass, and plants tend to just grow.
But, what I am picturing is you arrange the rocks as you wish, and so they are stable. Then you can use either pond liner, or the expanding black foam to 'fill in' the large gaps. Then you can put first and your plants in the resulting void. I am assuming you are not going to want to move the rocks or the plantings in the future (something like a hosta should be able to survive the frost with the rock and soil insulation).
You'll want *some* drainage, but not a river.. but you don't want it to not drain at all, or else it'll just be a pool of standing water over time.
posted by rich at 5:52 AM on June 17, 2020 [1 favorite]
I have a pond, as well, though not as 'formal' as yours - no paving nearby, so it just goes into the grass, and plants tend to just grow.
But, what I am picturing is you arrange the rocks as you wish, and so they are stable. Then you can use either pond liner, or the expanding black foam to 'fill in' the large gaps. Then you can put first and your plants in the resulting void. I am assuming you are not going to want to move the rocks or the plantings in the future (something like a hosta should be able to survive the frost with the rock and soil insulation).
You'll want *some* drainage, but not a river.. but you don't want it to not drain at all, or else it'll just be a pool of standing water over time.
posted by rich at 5:52 AM on June 17, 2020 [1 favorite]
No particular cement recommendations - I have used stone mortar and chicken wire for this sort of thing, but looking back at your use-case, any pot cast this way will be totally unwieldy.
In your shoes I'd be stacking rocks the way I want them and using the mortar to hold them together.
posted by aspersioncast at 7:03 AM on June 17, 2020 [1 favorite]
In your shoes I'd be stacking rocks the way I want them and using the mortar to hold them together.
posted by aspersioncast at 7:03 AM on June 17, 2020 [1 favorite]
Response by poster: My solution: stack the rocks the way I want them and stick a plant in a bag with soil and stick the bag in "the resulting void" (nice phrase) and throw some sphagnum moss (which I just ordered) around. If rocks are not stable enough, fill in with pond expanding foam (which I own to excess). THANK YOU ALL!
posted by DMelanogaster at 10:07 AM on June 17, 2020
posted by DMelanogaster at 10:07 AM on June 17, 2020
This thread is closed to new comments.
posted by klausman at 12:23 PM on June 15, 2020