HDPE in tanks

[JPKeenan]

I was just wondering if anyone knew if this type of plastic would be safe in a FW tank?

A company I know makes some stuff made of of that type of plastic, I might be getting some stuff from them if it is safe for aquarium use.

 

[meegosh]

Looks like the San Francisco aquarium uses HDPE pipes for a majority of their plumbing (everything underground is HDPE). It seems like it is safe but as far as pipes go, they are harder to do repairs on than regular PVC.

I would also be concerned with any coatings they may use after they mold whatever they are making you.

http://lmgtfy.com/?q=HDPE+in+aquariums

 

[JPKeenan]

hmmm, would figure that most places are use an oil or silicone. Wonder if boiling would get that mess off.

What I wouldn't give to have access to someone with a GCS (gas chromatic spectrograph).

 

[newfound77951]

FWIW I use HDPE bottles at work to store nutrient samples and I can tell you they don't leach any nitrates, silica or phosphate. If you're concerned give them a soak in some vinegar for a day or two....we clean our bottles using 10% HCl but that stuff's a little nasty.

 

[JPKeenan]

cool!

Most anything going in my tanks get at the minimum a boil or a rinse.... or both.

Crazy.... I just heard two contradictory opinions about using super glue and krazy glue in tanks.

 

[yetee]

I dont think you should have any problems with HDPE that stuff is tough. The only problem I see is if you are trying to bond it to anything... the only way I know of is to physically weld it together with a plastic welder. Chemical adhesives will not work.

 

[JPKeenan]

you'd think roughing it up and a drop of super glue would do the trick... I will have to see.

One of the things I think I might like to go is just coat it with sand to see how it would look. The piece I have is sort of sand castle looking.

 

[yetee]

it might work but in my experience super glue just peels right off of it. even when it is roughed up. thats one of the reasons hdpe is used for so many things because nothing sticks to it, or penetrates it.

 

[JPKeenan]

Poo! Like I said I was thinking of maybe trying to make a cool-ish looking sandcastle out of it. I got the hdpe stuff for free so worth a shot at least.

 

[yetee]

well if nothing you try works you could try hot glue(needs to be pretty hot 500-600 deg), I think it is made of a type of polyethaline but I cant remember if you can bond hdpe to ldpe using ldpe as your fill. I think you have to use your higher density PE as the fill. and if hot glue doesnt work you can try using a torch to melt where you want to bond and just stick it together (kind of like a tack weld).

 

[Kurt_Nelson]

Several adhesives can be used to bond it...

bonding uhmw - Google Search

The question though is whether those adhesives are aquarium-safe. My guess is "no".

 

[JPKeenan]

true about them being aquarium safe. If I could just scuff it all up, "paint brush" on some silicone and roll it in sand it would be good enough to start with.

 

[yetee]

uhmw and hdpe are two different materials.

 

[Kurt_Nelson]

True... but they're both in the same family. With regards to bonding, what works for one should work for the other.

 

[JPKeenan]

LOL maybe I should just stick with low tech and do the caveman thing... rocks and sticks .

I did come up with an idea for a bell jar, if that is what you call them.... The stuff you place above your CO2 line to collect it and have it dissolve into the water..... The little plastic thing that you get from gum ball machines. That might work to place the line under it so there is gas and water exchange.