Need help with 390 build

[warsaw132]

So here's the deal. Yesterday I got the urge to build a tank and started looking into it and saw it was doable. However I have a few questions. The dimensions im looking at is 70x36x36 so im curious as to what the thickness of the acrylic will have to be to support the pressure of the tank. I looked up the dimensions and it will be about 390 gallons. Also I figured I could use a 55 gallon tank for a sump. Also how much sand should I put in my tank to have a decent sandbed? Thanks guys

 

[acrylic51]

It's very doable.....There are some important factors you might want to consider......How much acrylic experience do you have.......Taking on something of this magnitude (trust me) isn't a first time project.....The videos make it appear super, super easy, but it's a lot of practice and confidence when you have $$$$ that you could ruin in a second.......
Next big question is what are you planning on keeping......36" depth might appear awesome, but it will be a hindrance at some point either through the lighting aspect or maintenance on the tank......My next question is do you want cross bracing, or an open top.....These things factor heavily into material thickness. I might add that your height of 36" plays a large part in material thickness as well......

 

[acrylic51]

Quote:
Originally Posted by Warsaw132 http:///t/390524/need-help-with-390-build#post_3459070
So here's the deal. Yesterday I got the urge to build a tank and started looking into it and saw it was doable. However I have a few questions. The dimensions im looking at is 70x36x36 so im curious as to what the thickness of the acrylic will have to be to support the pressure of the tank. I looked up the dimensions and it will be about 390 gallons. Also I figured I could use a 55 gallon tank for a sump. Also how much sand should I put in my tank to have a decent sand bed? Thanks guys
If your going to build your own tank....Why skimp....

Build a "big" sump...........

Personal preference on a sand bed, and there is no right or wrong answer, it comes down to what appeals to you.....What are you after....A DSB, SSB........

 

[warsaw132]

I have never built with acrylic before, however I have a few buddies that have built their own tanks before and they are going to lend me a hand. As far as bracing I am looking at doing s 4" lip all around the tank and havening 2 5" braces going across a third of the way down the tank. I am wanting a sand bed probably around 3-4 inches so I can have fish that burrow if I want.

 

[warsaw132]

Also as far as the height goes that was just a basis. If it would be easier and cheaper to make it 30" tall I would.

 

[acrylic51]

Really it depends on the initial size of your sheets to actually figure cost.....Bottom line you need to look at your yield per sheet at some points....Could save or cost you a lot of cash.......
Again I give a bit of caution.....If your friends and such haven't worked with 1" I advise to get plenty of scraps and practice....1" is a different animal when it comes to bonding/welding....The things you can get away with as far as 1/2", 3/8" and 1/4" you won't with 1" thick.....You need to be well versed in the "pin method". That will get you; your cleanest seams. DO NOT attempt to butt the pieces flush to each other and try to force solvent into the joint. It will not "wet" or "penetrate" the entire joint, and a dry joint is doomed for disaster........Also don't let anyone tell you that WeldOn 40 or 42 is what you should be using....WeldOn 4 will get you a super strong joint, and WeldOn 40 or 42 isn't quite as strong unless it's annealed which most of us can't do at home.....
As far as your euro bracing....I would probably on safety side go wider than 4"....Seems pretty wide, but you have to remember your length and your height you want to use.....Also advising against squared corners on your euro bracing.....Layout your euro bracing and use "radius" cuts.....Radius cuts carry the stress a lot better than square cuts......Your cross bracing looks fine, but I would still widen the euro bracing.....I went with no cross bracing, so euro bracing is a lot wider.....

 

[2quills]

Agree with all of what Shawn said.
Have you put any consideration towards what brand of material you'd be using? There's really only 2 maybe 3 brands of acrylic that any self respecting tank manufacture would ever recommend using to build aquariums out of. I'm pretty sure that anything less than one of those and you're taking a gamble. Cheaper acrylics are usually manufactured elsewhere outside of the united states where standards and quality control aren't held up to exacting standards.
With that being said, if you went with a 24" tall tank you could yield your front and back panels out of one full sheet of acrylic. And if you went 24" wide then you could get your bottom panel and top euro brace out of another full sheet. Just need another piece that would give you your side pieces. You're looking at 2 1/2 sheets for the build.
With your current measurements you'd need to purchase a full sheet for the top, bottom, front, back and another 1/2 sheet for the sides.
You could probably save yourself $1500 dollars right there.
Anyone know what a sheet of 1" polycast or plexi-G goes for these days?

 

[acrylic51]

Last time I checked Plexi-G was roughly $700 per sheet, but they were oversized sheets......Polycast black 1" was close to a $1000 when I purchased mine, and the clear Polycast was between $800-$900 again over sized sheets. That's why I recommend laying your cut pattern out and seeing what yields you get and adjust from there if need be.....I was a little over $3000 for materials and then you have to figure in shipping charges.....
Corey is correct on quality.....Maybe not in a sense as trying to compare a BMW to a Yugo, but where the quality is noted substantially is in thickness tolerances. There could be a lot of thickness variations on a single sheet, and some acrylic just doesn't bond as well as others. As Corey mentioned a few brands, and probably the "best" IMHO in the business won't use anything but Polycast, and his work speaks for itself. Not saying there isn't other options, just when dealing with the cost, and possibly the cost of clean up and destruction of your home, why gamble to save a few dollars......
Edge prep is key......Make yourself some good jigs and plenty of pins and keep the pliers handy........

Corey could attest to my panic when the head of pin pulled off in the middle of gluing up a panel......

 

[2quills]

Quote:
Originally Posted by acrylic51 http:///t/390524/need-help-with-390-build#post_3459382
Last time I checked Plexi-G was roughly $700 per sheet, but they were oversized sheets......Polycast black 1" was close to a $1000 when I purchased mine, and the clear Polycast was between $800-$900 again over sized sheets. That's why I recommend laying your cut pattern out and seeing what yields you get and adjust from there if need be.....I was a little over $3000 for materials and then you have to figure in shipping charges.....
Corey is correct on quality.....Maybe not in a sense as trying to compare a BMW to a Yugo, but where the quality is noted substantially is in thickness tolerances. There could be a lot of thickness variations on a single sheet, and some acrylic just doesn't bond as well as others. As Corey mentioned a few brands, and probably the "best" IMHO in the business won't use anything but Polycast, and his work speaks for itself. Not saying there isn't other options, just when dealing with the cost, and possibly the cost of clean up and destruction of your home, why gamble to save a few dollars......
Edge prep is key......Make yourself some good jigs and plenty of pins and keep the pliers handy........

Corey could attest to my panic when the head of pin pulled off in the middle of gluing up a panel......

I'm sure it's pretty nerve wracking knowing that one wrong move or screw up can mess up all your work. I'm rolling the dice on the cheap stuff for my sump but that's only because of the extra support from all of the bracing and baffles. I'll risk it for a $400 sump. A $1500-$2000 tank I'm not so sure. But it's definitely being done by some.
Would whole heatedly recommend practicing on something small for yourself first. But if you do decide to build it make sure you come back with pics.
Hey Warsaw, I just realized you're from Port, A. I'm pretty much right down the road from ya.

 

[acrylic51]

The build is definitely do able.......Corey hit it on the head practice.....I can't tell you how much scrap I practiced with; different techniques, different prep procedures.....I think the worst is "man handling" the pieces.....Even with a lot of practice the nerves get to you when you have the piece in place and start running the seam....
Go for it!!!!! But practice on smaller builds and stuff, just to get the hang of the solvent flow.

 

[warsaw132]

This is also going to be a summer project. Im just getting my ideas and plans together right now so nothing is set in stone. How wide should I make the bracing?
And corey its a small world. Lol. I didn't know there was anyone on here in my neck of the woods

 

[2quills]

Quote:
Originally Posted by Warsaw132 http:///t/390524/need-help-with-390-build#post_3459512
This is also going to be a summer project. Im just getting my ideas and plans together right now so nothing is set in stone. How wide should I make the bracing?
And corey its a small world. Lol. I didn't know there was anyone on here in my neck of the woods
Yeah it's pretty much just me and one other guy from Corpus (if you can ever get him out of the aquarium forum). And one more who's from Ingleside area (I think).
It's probably going to depend on what type of acrylic that you chose to go with. I can tell you that there are only 2 shops in the area that you can get it from, one's on the west side and the other guy is here in the Bluff. Neither one of them carry the top 2 choices in their shops. The one guy on the west side of town said he could probably get me Plexi G. But both of them carry the import stuff. If you go with the import stuff then you can probably get you're pieces cut to size. If they have to special order something for you then it's going to cost you quite a bit extra and they'll make you take the whole sheets.
Seeing as how you plan to use 1" for a 70x36x36 then that's probably already over the recommend thickness for that size tank. Shawn (Acrylic51) just built a 415g out of 1" polycast and even a master builder told him it 1" was probably over kill . But one thing to consider is that the thicker you can go, the less deflection you will have.
If you go with 1" material. You can probably get away with a smaller brace maybe 4"-6"???
If you wen't with 3/4" material you'd probably want to go with a much wider brace to help minimize deflection like 8"-10", perhaps?
Ohhhhhhhhh, Shawn???

 

[warsaw132]

Thank you for all the info. The tank is going to be a fish only tank. Any idea how much rock I should use and how much live sand I will need?

 

[acrylic51]

Corey you know the secrets.....Again I picked the "masters" brain for close to 6 months.....And honestly if anyone were to build a tank for me it would be James.....Material thickness dictates so much, as well as dimensions.......Using 3/4" material will dictate wider bracing and more of it....The bottom line comes down to deflection in your panels......Without them "under load" they will appear perfect.......With 3/4" material and thin bracing overtime usually upon filling or a day or 2, you'll see "by measuring" deflection.....That does happen, but the key is keeping it to a minimum, and how much can you live with.......

Me......personally "0".
Again when I built my tank I picked James brain to death.....1" all the way around was over kill...... My ultimate goal though was no cross bracing, and no deflection......To get what I wanted meant thicker material......Is there deflection.....Probably so, but to be honest measuring it, I can't find it; now if we mic'd it we'd probably see a bit, but noting noticeable using a tape measure......You can always use thinner material on the bottom to save a little cash if you want and that is done all the time......With 3/4" material my euro bracing would definitely be 6"..........Again I over build, but I like safety, and "thickness" is "sexy"..........
As far as sand and live rock......Bottom line it's personal preference. There isn't a right or wrong way about that area......You don't have to have either if you choose not to.....Personal preference....