# Casting resin - is it fish safe?



## RSidetrack

Okay I know this is a very random question - but is casting resin (specifically simlar 41) safe for fish?

I am trying to make a diffuser for my CO2 and everything is just plain ugly (and I hate ugly).  So I figured I could try to make my own - make up a mold, pour it, fill it with the necessary items, put on the connections, etc - and voila - diffuser.

I just don't know if it is fish safe, I believe it isn't food safe so probably not?


----------



## JRay8

Go for it. I keep a reef tank and I would use it.


----------



## RSidetrack

JRay8 said:


> Go for it. I keep a reef tank and I would use it.


So you don't think there are any toxins that would come out of it?  I know drinking glasses (plastic) are polystyrene so I just want to not kill off $100 worth of fish


----------



## PenMan1

If PR resin wasn't fish safe, there would be a heap of dead fish, cause virtually every boat made (except the metal ones, of course) are made from PR resin and fiberglass cloth.

The chemistry for S41 (non-structural PR) and the resin used to make a fiberglass boat are practically identical. The ONLY reason I don't use S401 (boat hull resin) to make pens is that it doesn't dry completely clear and costs a lot more. 

It should be very safe after curing.


----------



## JRay8

They make aquarium decor like castles out of resin.


----------



## 76winger

I would want to make certain before before I put in my Discus tank. But I believe Andy's probably right in that once it's cured there wouldn't be any problems. But just be safe, I would want to start it out in a sparsely populated tank and not a loaded one.


----------



## MesquiteMan

PenMan1 said:


> If PR resin wasn't fish safe, there would be a heap of dead fish, cause virtually every boat made (except the metal ones, of course) are made from PR resin and fiberglass cloth.
> 
> The chemistry for S41 (non-structural PR) and the resin used to make a fiberglass boat are practically identical. The ONLY reason I don't use S401 (boat hull resin) to make pens is that it doesn't dry completely clear and costs a lot more.
> 
> It should be very safe after curing.



I do not know the answer to the question but Andy, your hypothesis is incorrect!  Yes, they make boat hulls out of polyester resin but they also coat those boat hulls, at least in salt water, with copper oxide bottom paints as you know.  Copper oxide, in confined water such as koi ponds or fish tanks, WILL kill fish so it is not safe to assume PR will not kill fish just because boats are made from it!


----------



## MesquiteMan

Rather than just argue with Andy:biggrin:, I decided to do a little Google research.  Here is what I found:



> *Polyester Resin Fish Tank Decorations*
> 
> Over the last few decades polyester resin has dominated as the material of choice for mass produced aquarium ornaments.
> This light versatile material can be molded into any shape imaginable.
> Sand is sometimes used with the resin to bulk out the mixture and this provides some weight to reduce the buoyancy....



More can be found here: http://www.e-aquarium.com.au/polyester-resin-ornaments.htm


On a fish tank forum, they were discussing this very issue and a couple of folks said you can use it IF you allow it to completely cure until there is no smell.


----------



## RSidetrack

Thank you everyone!  Okay - what I plan to do is let it fully cure and I will also run it on an empty tank for a day or two first with the water flowing through it to pick up any toxins that may be around - same process as building a custom 3d background in a tank.

Now - to just figure out how to make the mold :biggrin:


----------



## JRay8

whats in your aquarium?


----------



## DurocShark

I've used it in tanks...

A pleco or other scraping algae eater will not hurt it, nor will the resin hurt the fish. The worst that happens is an aggressive pleco may rough up the surface, but it's invisible when in the water. 

I have a shark I cast way back when that has been in his salt tank for years. No problems.


----------



## workinforwood

we sell lots of stuff made from PR for fish tanks. Long as the resin is fully cured, it's fine. Let it sit a few weeks, wash it and you are good to go.


----------



## wolftat

I just wanted to add that Alumilite is food safe so I would guess that it is fish safe too.


----------



## bitshird

I agree with Jeff, let the object sit for a few weeks to off gas any surface toxin, then  run it in a tank with out fish to clear any remaining toxins


----------



## RSidetrack

JRay8 said:


> whats in your aquarium?


Two bala sharks
Angel Fish
7 cory catfish
2 plecos (1 is almost a foot long now!  another is about 6 inches)
and 3 um shoot I forget what they are called - I have had a couple rolleyes beers, I will probably remember tomorrow lol

I want to get more fish in - bio-filter can more than handle more, but I want more plants, and right now conditions are anything but good for plants, lost $80 worth of plants because of stupidity.

I have the stock lighting (2 15w T12 bulbs) on a 50 gal - no CO2, etc etc.

My plan is by the end of the week:
Build a new custom canopy
4 36w (again, beer, might be off on that 32W, 39W, can't remember) T8s
Pressurized CO2 injection with pH controller
move some plants from my 30g (has 96W VHO flourescent) and DIY CO2 reactor (plants are overflowing the tank, literally, they are coming out of the top lid.


No fish in the 30g lost them all when on vacation one time, the automatic feeder got water in and clogged up :frown:  Lost guppies, mollys, and several other fish.  I haven't restocked because I am still dealing with a huge, and no exaggeration, I mean HUGE snail infestation.  Problem is the only ways to kill the snails... kills the plants.

My plan.... is once I get some of the plants out, get the tank cycled right (clean water, reasonable levels, and put the two bala sharks in.  They will take care of the snails within the tank no problem.  Then I will do what I did on my 50g for all the snails in the filter.  Clean - boil in salt water, soak in salt water, rinse and replace.  I have a Rena Filstar XP3 for the 50 gal (I know - little overkill) and Rena Filstar XP2 (again overkill) for 30 gal.  Hopefully that will solve the snail problem because.....

I have 6, planning on 4 more, 10gal tanks and I am going to start breeding again.  Angels, Guppies and Tetras.  That is what I bred before I moved.  (Lost the 4 other tanks in the move :frown.  I used to primarily focus on Guppies, I was after a perfect strain - Blue/Bluish Green with Leopard spot pattern.  Was almost there before moving.

Anyway, babbling at this point, feel free to hit me up on PM if you want to do more fish talk or, well this is the casual conversation forum so here is good too :biggrin:


----------



## MesquiteMan

Here's a pleco for you aquarium guys!  I got this pleco bowfishing in a local river.  It is the bowfishing world record at 25+" and a little over 8#!

Some of the rivers around here are FULL of plecos from folks that turned them loose after they got too big.  PLEASE don't do that with yours!  They are EXTREMELY destructive to the environment since they don't have any enemies and they burrow into the bank to create "dens" where they lay their eggs.  This causes serious bank erosion.


----------



## leestoresund

Did it taste good?

Lee


----------



## DurocShark

I'd like to second Curtis' plea: Don't dump your aquarium fish in natural water!!!! Aquarium plants either!


----------



## RSidetrack

Nope never dump your fish anywhere - if they get too big or if you have to get rid of any find a LFS and give them away there.

The bala sharks can get rather large too.  Most of the time fish grow to a size to fit the aquarium - other just go crazy.  Hopefully mine will stay within a nominal size for my aquarium - but if not I will just take them to a LFS - or use it as an excuse to get a bigger tank


----------



## RSidetrack

MesquiteMan said:


> Here's a pleco for you aquarium guys!  I got this pleco bowfishing in a local river.  It is the bowfishing world record at 25+" and a little over 8#!
> 
> Some of the rivers around here are FULL of plecos from folks that turned them loose after they got too big.  PLEASE don't do that with yours!  They are EXTREMELY destructive to the environment since they don't have any enemies and they burrow into the bank to create "dens" where they lay their eggs.  This causes serious bank erosion.


Definitely much more attractive when they are smaller   That is huge - never seen one that big.


----------



## Parson

I just sold my 150. Kinda sad because I had at least $5k in it and sold it for a tenth of that price... MH lighting, ugly rusty chiller, and ecosystem sump plus a nice solid oak stand.

Post some pix of your tank!


----------



## MesquiteMan

leestoresund said:


> Did it taste good?
> 
> Lee



I have no idea.  I donated it to the biology department at Texas State University.  One of their professors has done a lot of research on Plecos in the local ecosystem and he was interested in it.

However, the 100's of other, smaller ones I have shot were enjoyed by the buzzards and coyotes.  I did try cleaning one once since I don't like to just toss but my results were less than satisfactory.  The main part of the body is a hard shell and not possible to skin.  They are not much fun to shoot since they just sit there but they sure to need to be removed from the ecosystem.


----------



## MesquiteMan

RSidetrack said:


> Definitely much more attractive when they are smaller   That is huge - never seen one that big.



Here are some smaller ones for you!


----------

