Trying out Sculpey caves - The Planted Tank Forum
LinkBack Thread Tools Display Modes
post #1 of 16 (permalink) Old 02-12-2009, 10:49 PM Thread Starter
Algae Grower
PTrader: (0/0%)
Join Date: Jan 2009
Location: Southwestern CO
Posts: 118
Trying out Sculpey caves

In two and a half weeks, I'm going to be setting up a 34-gallon corner tank. It will eventually house 2 dojo loaches, 3 peppered loaches, and a school of white cloud mountain minnows.
Right now, it has one golden dojo and 2 cories of uncertain species who came with the tank. It's a touch understocked.

With all these bottom-dwelling critters, I'm going to need an awful lot of bottom territory - the dojo and peppered loaches should share, but have not been introduced yet (peppers are in quarantine 2 weeks today!). So, how do I accomplish this without losing too much planting space, resorting to terra-cotta pots, or buying an ugly and overpriced commercial reptile product? I make caves. After a bunch of research, the most common method of cave-making (styrofoam and concrete) is not something I want to try; it's very very cold outside, I lack a garage, and I'm concerned about my ability to shape styrofoam into what I want. What I want is a cave with a profile like this:


where the bottom line is the substrate, the verticals are walls with cutouts for easy access by fish and easy viewing by humans, and the top has a tray. That way, I don't lose too much of the planting area, the caves look more natural once they're grown in (especially if I can coax a plant to drape down over the edges) and the weight of the extra dirt holds the caves down better... the peppers can be a little spazzy at times, and I could see them knocking furnishings around.

After a little research, it seems that polymer clay is safe for aquarium use after curing. I did several hours of internet searching for this, and came to the following conclusion:

1. The manufacturer of Sculpey states that polymer clay is non-toxic, but not food safe. I'm using this brand since I've used it before and like it, and it's available and fairly inexpensive here.

2. The final product is not food safe not because of any leaching problem, but because it's porous and might harbor bacteria. This is not a problem in the aquarium, where every surface harbors bacteria anyway, and where we typically encourage beneficial bacteria to grow.

3. Fired polymer clay is essentially fancy PVC and should have zero effect on water chemistry; it should not cause any more problems than a terra-cotta pot or one of those resin ornaments. Being PVC, it also should not decay and release anything nasty over the long term.

4. Many people, on many forums, have gotten scared off and have not tried this (or have not posted results). A very few have. Those few say it works. My source is mostly, with a very few other, unrelated blogs.

With a little creativity, polymer clay can mimic natural stone in looks and texture. Unfortunately, I couldn't find any of the type that already mimics stone (it's called Granitex, and isn't available here. I will be going to a large city this weekend and may get lucky.)

I cooked up two caves over the last weekend. One mimics a plain grey river stone. The other was an attempt at mimicing black marble. They still look like fake rocks; at least they look like fake rocks that have half a chance of looking good if they're discreetly placed. Since these were tests, I did not include the substrate tray, and they're significantly smaller than the ones I want for the corner tank. First I want to see if the material works at all.

I fired them, let them sit for a full day, and then placed them both in about a pint of water, figuring that if they do not affect a small volume, they won't affect a large one. I'm well aware that they may leach something outside the range of my test kits, since I don't have fancy ones (API master kit, plus some cheapo 5-in-1 strips), but this is not the only test I'll be doing. Since my chemical testing ability is pretty pathetic, I'll be checking out how some of my pest Physa sp. pond snails like it; if they're fine, it'll get introduced to a small, established tank with fish.

The water parameters started at:
NH3 0
NO2- 0
NO3- 0
GH 180
KH 180
pH 7.8

In three days, they have not budged at all. If that's still the case tonight, I will remove them from the little cup, place them in a larger bowl, and add some pond snails. Hopefully they won't die.

My favorite article on bio-assay gives the (rather arbitrary) values of one day for acute poisoning, and a month for chronic poisoning. Since I have less time than a month to get this aquarium up and running, I will be shortening the bio-assay to about two weeks. I am fairly confident that this material is in fact not toxic; I just want to make sure of it before subjecting my favorite loaches to something unknown!

There will be no alteration of the pond snails' behavior (gasping at the surface, crawling out of the water, refusing to eat, or death) in one week of exposure to the caves. They will continue to eat, move around, and lay eggs.

The snails will be checked at least twice daily, twelve hours apart. I will record how many are live or dead, how many are on or in the caves, and how many are at the surface. If I get really excited, I may even bring them and their bowl to work for closer monitoring.

So... anyone done this? Thoughts? Glaring holes in my logic?

Sixwing is offline  
Sponsored Links
post #2 of 16 (permalink) Old 02-13-2009, 12:25 AM
Planted Tank Obsessed
brion0's Avatar
PTrader: (3/100%)
Join Date: Sep 2008
Location: Idaho Falls,ID
Posts: 422
Ive put some large caves made of Fimo an Sculpy in tanks. The only thing I noticed, my pleco would rasp on it,an pry ate a little. Though it didnt seem to hurt his health.

29 gal journal

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

55 gal low tech

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
brion0 is offline  
post #3 of 16 (permalink) Old 02-13-2009, 02:28 AM
Algae Grower
PTrader: (3/100%)
Join Date: Oct 2008
Location: Sarasota, Florida
Posts: 82
Sculpy/Fimo and the rest are PVC. They pose no threat to your tanks, water or flora/fauna as long as they have been cured. The only two possible points of worry are not curing, some feel the suspension liquid used in these polyclays may be harmful, or mixing in a harmful material during the creation process.

We have many polyclay decorations in our theme tanks. A trick I use to help make things look a little more natural is to mix sand with the clay and form from there. Experiment with dark and light sand in the same color clay to get a great marble effect.
RandomKayos is offline  
post #4 of 16 (permalink) Old 02-13-2009, 03:28 PM Thread Starter
Algae Grower
PTrader: (0/0%)
Join Date: Jan 2009
Location: Southwestern CO
Posts: 118
Thanks a bundle, brion0 and RandomKayos! That's what I want to know!

While I'll continue to watch those pond snails, I will certainly make the new decorations. Will have to try that sand trick. Which means I'll have to find some black sand. *s*

Oh.. the snails were cruising around happily this morning, too.
4 on caves, 1 on glass, 1 on Java fernlet.
Sixwing is offline  
post #5 of 16 (permalink) Old 02-13-2009, 04:25 PM
PTrader: (0/0%)
Join Date: Dec 2007
Posts: 167
you can also mold nice structure with cement.

by purchasing straight Portland cement you can experiment with many different aggregate materials and also tints. with some practice you can make pieces that look just like real rocks.

reef aquarists have done quite a bit with this idea to make artifical live rock.

try a search for "hypertufa".

concrete aggregate rocks need to be fully cured in a water bath before introduction to aquarium.
crabcake is offline  
post #6 of 16 (permalink) Old 02-13-2009, 05:34 PM Thread Starter
Algae Grower
PTrader: (0/0%)
Join Date: Jan 2009
Location: Southwestern CO
Posts: 118

There's some neat hypertufa projects out there. It seems to be used for very large, thick-walled projects, and also be very messy, so I won't be able to do that this time... the aforementioned very cold weather and lack of garage mean that anything I do, I do inside.

When I've got my own garden again, look out, containers. Could make some truly cool custom pieces that way.
Sixwing is offline  
post #7 of 16 (permalink) Old 02-18-2009, 03:01 PM Thread Starter
Algae Grower
PTrader: (0/0%)
Join Date: Jan 2009
Location: Southwestern CO
Posts: 118
I'm calling this a success. On advice that these are safe, I put one of my test caves in the quarantine with the loaches. Two days later, one of them (and maybe two) are using it regularly - though the third one does not seem to fit. The final product will be larger, though, so they can all get in at once.

Sixwing is offline  
post #8 of 16 (permalink) Old 12-12-2010, 07:25 PM
Planted Tank Guru
Hilde's Avatar
PTrader: (1/100%)
Join Date: May 2008
Location: Mableton, GA
Posts: 6,257
So what happened? Pics?
Hilde is offline  
post #9 of 16 (permalink) Old 12-15-2010, 01:37 AM
Posts: n/a
I would love to see them as well.
post #10 of 16 (permalink) Old 12-15-2010, 02:40 AM
Planted Tank Enthusiast
bigboij's Avatar
PTrader: (1/100%)
Join Date: Jul 2009
Location: Denver, CO
Posts: 885

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

SunSun Pimp #2
Fluval Ebi Pimp #4
bigboij is offline  
post #11 of 16 (permalink) Old 11-15-2014, 12:44 PM
PTrader: (0/0%)
Join Date: Nov 2014
Location: Alabama
Posts: 1
Thumbs up Thank you!!!

I have tried a few DIY options. Namely, the PVC pipe cave - this is where you heat one end of a PVC pipe by putting it in boiling water, put it in a clamping device to crimp the end and this creates a pleco cave. I made two of them and both are untouched by my longfins in my current setup setup. They could care less about the other DIY options I threw in there too - coffee cups, slate/tile caves and such. Whether these options are too smooth - even though I did scrape the inside of the PVC cave to give some texture - or perhaps too light in color I don't know. My longfins only seem to like one pottery type pleco cave I picked up off Kensfish a few years back. They fight over it ferociously. Ken's fish has been sold out for a little while so I was looking for something that I could use to create one of the same looking/feeling type of caves that they current squabble over. There was so little literature on the web That I am glad someone posted this. Thank you for your research and the time you took in reporting your water chemistry testing results. Thanks to everyone else who added their experience with using this product as well. =)
Cuka is offline  
post #12 of 16 (permalink) Old 08-31-2015, 06:06 PM
PTrader: (0/0%)
Join Date: Aug 2015
Location: collinsville ms
Posts: 2
I'm about to start construction on a sculpey clay castle
Do i need to put the glaze on it or leave it unglazed for a fish tank (freshwater - plecos, gupppies, glofish & pictus cats & plants)
lunatikchik is offline  
post #13 of 16 (permalink) Old 08-31-2015, 07:13 PM
Planted Tank Enthusiast
Mikeygmzmg's Avatar
PTrader: (3/80%)
Join Date: Mar 2015
Location: Socal
Posts: 871
Originally Posted by bigboij View Post

-Mikey G
Mikeygmzmg is offline  
post #14 of 16 (permalink) Old 08-31-2015, 07:21 PM
Children Boogie
mistergreen's Avatar
PTrader: (13/100%)
Join Date: Dec 2006
Location: Cincinnati
Posts: 16,743
Originally Posted by lunatikchik View Post
I'm about to start construction on a sculpey clay castle
Do i need to put the glaze on it or leave it unglazed for a fish tank (freshwater - plecos, gupppies, glofish & pictus cats & plants)
You can't glaze it like real pottery.
It should be fine unglazed. It's the same material as pvc. Oven bake gets rid of the chemical that keeps it soft.
mistergreen is offline  
post #15 of 16 (permalink) Old 07-20-2017, 12:15 PM
PTrader: (0/0%)
Join Date: Jul 2017
Posts: 1
Hi, i have a questio, did you happen to use colored polymer clay? i was wondering if i were to paint (using acrylic) the polymer clay and seal it with sculpey sealer of some sort, if that would be okay for the turtles?
Jenyffer is offline  

caves, polymer clay

Quick Reply

Register Now

In order to be able to post messages on the The Planted Tank Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome