I am always looking for a cheaper alternative than what is sold for aquarium use. I know that can result in unwanted results. I am wanting to glue some rocks together and was wondering if people have any experience with polymorph plastic or what hot glue sticks are made from. I know both are just plastic, but I also know some are processed and made of toxic chemicals. Thoughts backed up with experience or factual knowledge appreciated.
Polymorph plastics or glue sticks
- Thread starter MuralReef
- Start date
When I set up my tank I used live rock that had been shipped. I glued in place and filled with water. My structure is most solid I have ever had in a tank. So I would think the rock would dry a little but what I did was use spray bottle to keep rock moist while I built the structure. Not sure if this helps but trying lol.
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I was just looking this up today as well. I came across several sites that suggested Hydraulic Cement from Quikrete at Home Depot or Lowes. Says it dries firm in 5 minutes and fully cured in 2-4 hours. Something like that might be doable with the spray bottle that Andrew mentioned. And combined with drilling in an acrylic rod or something would make a pretty strong structure.
A 10# bucket is only $7.75 at Lowes
A 10# bucket is only $7.75 at Lowes
That's what I used. If you also get the acrylic fortifier it's nearly identical to Marco rock. Only difference is large amounts can cause tank pH to be buffered higher particularly while it cures. If you run a calcium reactor, this can be beneficial, but it can hurt you if you use kalk and use quite a bit.
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Did you use acrylic fortifier or aggregate? If not that may have been why it started to crumble. Mixes advertised as hydraulic cement (technically all cement is hydraulic cement) are very weak because they dont have much aggregate to give it strength. Adding sand, acrylic, or combination of the two fixes that issue. Straight "hydraulic cement" is just Portland cement with additives to make it cure faster.
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I have read hours worth of discussions on the subject and talked to several civil engineers I work with when I was deciding which method I wanted to use and haven't personally found any cases of correct mixing crumbling after years of use (though most forums on the subject die off after a couple years tops). It's not that hard to answer "Yes, I did and it still crumbled", or "No, I didn't and it's possible that played a role". Particularly since Marco rock, which you recommended, is hydraulic cement plus aggregate and acrylic fortifier.
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I've used "InstaMorph" brand moldable plastic that I bought on Amazon, it's not horribly expensive when you buy in larger sizes and it goes a fairly long way. It works fine on wet rocks as long as the surface has lots of nooks and crannies for it to grab into and hold when it sets. For the times it didn't grab as solidly as I liked I just separated the rocks and globbed a bunch of superglue on it and stuck the rocks back together. The trick is getting it at the right temp so it's pliable enough to squish into the gaps, without burning yourself. There are a number of other brands available that also say "non-toxic" but I guess you have to take them at their word.
^this. The plastic or fiberglass rod is the key to a solid structure. What actually binds the two rocks together is of much less importance. Driveway markers at home depot are a very inexpensive way to add some rigidity.
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