Hybrid Low-Iron & Acrylic Tank?

[GuySmilie]

<a href=showthread.php?s=&postid=11490882#post11490882 target=_blank>Originally posted</a> by jnarowe
....Maybe I am making it more complicated by adding the block behind the glass to form a "slot", but it seems to me that would be significantly more stable, particularly if the tank had to be shipped.....

A block behind the glass may or may not help for shipping, but if done the way shown in Spazz's drawing above, that front glass ain't going anywhere, once there is water pressure against it.

Of course the bottom edge would need the same treatment as the sides. Upper cross bracing (for the glass) would depend on the engineering limitations of its expanse and thickness vs load.

 

[spazz]

<a href=showthread.php?s=&postid=11490942#post11490942 target=_blank>Originally posted</a> by H20ENG
I would glue 2 edges together, stick one in a vise, then clamp a bucket to the other piece, with a fish scale between them. Slowly fill it with sand or water to add weight and see what the shear strength is.

Crude but will demonstrate the effect.

Try several samples with different prep styles too. Sand 2 pieces with 120Grit, and leave 2 with saw cut edges, clean it with alcohol so it will stick well.

this is pretty much waht my thoughts were. if you apply a steady pressure to the seam to see what its long term strength is you can really tell if it will hold or not. you can calculate the psi that will be applied to the seam. then you should just double that number, and then apply it to the square surface area that will be bonded. if you make 2 test pieces that are 1 sq inch and then 2 square inches to see what he difference is in bond strength. it will be more with the 2 sq.in. of surface area but it might not be double. you will need a scale that is bigger than a fish scale but not much bigger. you can always use a digital scale to measure the weight inthe pail and the hook it on the edge of the acrylic .then leave it there for a week and see how far it streched out. if there is too much strech its not going to work. you cant have alot of strech or it will cause the acrylic to bow out on the sides.


if you have the single block like i have in the picture it will be alot easier to install. it will also be alot easier to clean up once the glass is set. the nice thing about this design is the glass will float some what in the frame becasue of the elasticity of the 795 or 5200 the glass will be protected from major shock. its like a rubber cusion in there. also the pressure of the water against the glass will increase the pressure on the seal so it wont leak.

 

[jnarowe]

OK guys. I am going to try this in January. I am not sure of the properties of starfire are different from regular glass, so I guess I would have to get a couple pieces of it to try.

 

[Macimage]

My 225 gallon in wall is acrylic with a starfire front. I'll take some photos of the metal strapping that was used on it this weekend. I don't know what type of sealant they used between the acrylic and starfire though.

Joyce

 

[jnarowe]

Sweet Joyce! Can you post who made it as well? I am extremely interested in seeing what you have. Thanks!

 

[Macimage]

I had the tank custom built, however, overall I was unhappy with the build quality of the tank itself and wouldn't recommend them. I would only recommend the way they did it to be done better.

The actual acrylic to starfire part was fine (which should have been the hard part!). However, on my blue background they put such a skinny sheet of blue acrylic over the clear acrylic that after I filled it up, it peeled up. They had to pick up the tank and replace it with a thicker sheet. You can see tons of glue bubbles on the backside where they glued the blue background to the clear.

Then after a few years, the actual top of the acrylic part of the tank started to separate from the acrylic back of the tank. Of course, I had to empty it and have the acrylic repaired. I lost most of my fish and corals in that fiasco.

Of course, from the viewing side it looks great. I had an external overflow put on one side so you don't see the overflow in the tank.

But the upside is that the actual acrylic to starfire part worked out great!!

Joyce

 

[jnarowe]

sounds very promising. I wonder what they used to bond the glass to acrylic?

So do you have any pics of it?

 

[Macimage]

I'll find some of the ones from the delivery several years ago on my other computer. I think there were some good shots of it that may show the way it's put together.

I haven't taken any new ones recently. I'll do that tomorrow after work too.

Joyce

 

[jnarowe]

thank you so much.

 

[purebullet417]

bump interested in this

 

[spazz]

i found a company that makes a glue for acrylic to glass applications. im talking to them to see if this would work for an aquarium application where pressure is a factor.

 

[jnarowe]

That is great news Scott. Please keep us informed. Is it OK to do the strength testing on 3M 5200 with just acrylic pieces, or do I have to use one piece of glass?

 

[H20ENG]

Jon,
I would test both acrylic to acrylic, and acrylic to glass.

I know when they set the 2.5" acrylic tunnels at my old job, they used a very wicked Sika primer to etch the acrylic first.

Now theres another name that I've used alot of - Sikaflex. Gooey, sticky, great stuff Being around boats, you probably have used it too.

 

[jnarowe]

yeah, I sell a lot of Sika stuff. I haven't used any Sika primers though.

 

[spazz]

<a href=showthread.php?s=&postid=11561302#post11561302 target=_blank>Originally posted</a> by H20ENG
Jon,
I would test both acrylic to acrylic, and acrylic to glass.

I know when they set the 2.5" acrylic tunnels at my old job, they used a very wicked Sika primer to etch the acrylic first.

Now theres another name that I've used alot of - Sikaflex. Gooey, sticky, great stuff Being around boats, you probably have used it too.

yep this is exactly what i would do.. test acrylic to acrylic and acrylic to glass.
there is a primer they have for the dow corning 795 that you might want to look into. also the promer that H20ENG recomends would be good to try that way to get different primers with different strenghts. you cna find out which one is the best for that application.

 

[jnarowe]

Thanks guys. I'll try to get to the testing part in the next 2 - 3 weeks.

 

[Icefire]

Why not just do a frame in angled iron, all welded up, than use GE industrial silicone that is reef safe and cure fast, you just put 1/8" thick of silicone all inside the angled iron and than press all glass in them. Then you seal up the inside edge at the same time.

Cost effective, would be strong enought and it would be glass only. Once the tank is finish, you could just weld some cross brace over the top and maybe under the tank.

 

[spazz]

<a href=showthread.php?s=&postid=11572801#post11572801 target=_blank>Originally posted</a> by Icefire
Why not just do a frame in angled iron, all welded up, than use GE industrial silicone that is reef safe and cure fast, you just put 1/8" thick of silicone all inside the angled iron and than press all glass in them. Then you seal up the inside edge at the same time.

Cost effective, would be strong enought and it would be glass only. Once the tank is finish, you could just weld some cross brace over the top and maybe under the tank.

i see 2 problems with that. first he wants to have it earth quake proof so he wants to limit the amount of glass in the tank structure. next it is really hard to drill all the holes and make the overflows for a tank that big using glass.

 

[Icefire]

Looking at WA earthquake activity, most are under 2 of magnetude with some going up to 4. with silicone between the glass and iron, I wouldn't worry for the earthquake. In a tank, I'm sure a wavemaker make more pressure than a 4 M earthquake.

As far as drilling the glass, it's not that hard. He could have all the plane tempered if it make it more secure.

Basicly, he want to do what I suggest but Acrylic instead of Iron.

 

[spazz]

he wants to have the best of both worlds. the ease of working with acrylic (drilling holes and makeing the overflow external) and the scratch restance of glass for the front panel. i see what he wants and understand the reasons for it. now its just to find the right solutions to make it work. and not burst 3 years down the road.