What plexiglass thickness for this tank?

alazo1

Premium Member
Hello,
I'm planning a diy tank made of plexiglass (27" long, 21" front to back, 18" high). 44 gallons. I plan on having brace from front to back in the middle and both sides.

According to Tap plastics 1/4" thickness is for aquariums up to 41 gallons so the guy said to be safe and go 3/8". They however don't say the length tolerances.

thanks,
Albert
 

Acrylics

Active member
Forget Tap altogether and DO NOT use their material for a tank. Polycast or Plexi-Glas G only...
As Peppie stated, 3/8" all around with 3" eurobrace and you're good to go, no crossbracing needed.

James
 

alazo1

Premium Member
Thanks for the heads up.

What's wrong with Tap Plastic's plexiglass (acrylic)?. Is it the clarity?. Does anyone know an online store that you can buy this cut?.

thanks,
Albert
 

peppie

New member
You want to use one of two types of Cell Cast Acrylic for a tank, Plexiglas-G , or Polycast.
Tapps sells neither.
 

Acrylics

Active member
Thanks for the heads up.

What's wrong with Tap Plastic's plexiglass (acrylic)?. Is it the clarity?. Does anyone know an online store that you can buy this cut?.
Their cast acrylic is called Chemcast. I've replace *a lot* of tanks built with this material. The joints will hold fine for a little while, then for some reason - the joints/material fails - usually catastrophically. The best materials on the market are Plex G and Polycast. It's what *all* of the better builders use, and for good reason.. IMO you should too :)

Look in your local yellow pages under "Plastics, sheet, rod, and film" or something to this effect. Look for names like Piedmont Plastics, Lard Plastics, these guys will cut to size for you. You will still have to route the edges and do your own prep work though.

If you don't mind me asking - where are you? I might be able to point you in a good direction :)

James
 

Acrylics

Active member
There's quite a few in your area. Port is one I'd try. They stock Polycast up here but usually don't stock Plexi-Glas G. Do a little looking in your yellow pages under "Plastic: sheet, rod, film" or something to this effect.

550 E. Trimble Road #A
San Jose, CA 95131
Ph # 408-571-2231
Fax # 408-571-2279
800-800-2478

Polycast will be more expensive than Plex G but both are good. If you ask for Plex G, make absolutely certain the material has "Plexi-Glas G" written all over one side of the masking paper in blue ink. If it doesn't have this - it ain't Plex G.

If you run into issues finding decent material, lemme know. I know a few people down there and we'll get you taken care of :)

Plus.. Tap charges $8/sq ft for their 1/4" material, not sure what they charge for 3/8" but I'd guess $12/ft or so.. you can do better than that :)

HTH,
James
 

fng_71

New member
look around for some good calculators. maybe someone out there has one handy. from what i've read acrylic thickness is affected more by the height of the tank than the length.
 

Acrylics

Active member
look around for some good calculators. maybe someone out there has one handy. from what i've read acrylic thickness is affected more by the height of the tank than the length.
no good calculators that I know of. None of them tank bracing into account.

*generally* speaking.. up to 18" height use 3/8", 24" height use 1/2", 30" height use 3/4"
^^ assumes 3" eurobrace and a 5-6" crossbace every ~24" in span..
so a 48 x 24 x 24" tank will use 1/2" with 3" eurobrace and a single crossbrace. Extend it out to 72" and we just add another crossbrace. If we don't add the crossbrace, we have to go up in thickness or increase the width of the eurobrace. None of the calculators take this stuff into account.

Hope this makes sense :)
James
 

alazo1

Premium Member
I will call Port tomorrow James, thanks.

I did find a calculator yesterday that takes the brace or no brace into account. The info that James is giving is spot on.

Here's the link. It does talk about using a certain type of acrylic (acrylite gp) so I don't know what the difference with others are.
http://www.sdplastics.com/customacrylicaquariums.html Go to the middle of the page for the link.

I was thinking about using 1/2" to make it rimless but unless I can find some used plexi it's not going to happen. As it is the price of 3/8" may be out of budget and I may have to rethink things.

This tank build is due to planning to move my biocube 29 into a larger stand so that I can have a sump. The plan originally was to take out the back filter wall off the bc and essentially making it an upgrade. After making the stand I am now thinking to make the bigger tank and sell the bc.

Albert
 

Acrylics

Active member
I will call Port tomorrow James, thanks.

I did find a calculator yesterday that takes the brace or no brace into account. The info that James is giving is spot on.

Here's the link. It does talk about using a certain type of acrylic (acrylite gp) so I don't know what the difference with others are.
http://www.sdplastics.com/customacrylicaquariums.html Go to the middle of the page for the link.

I was thinking about using 1/2" to make it rimless but unless I can find some used plexi it's not going to happen. As it is the price of 3/8" may be out of budget and I may have to rethink things.

This tank build is due to planning to move my biocube 29 into a larger stand so that I can have a sump. The plan originally was to take out the back filter wall off the bc and essentially making it an upgrade. After making the stand I am now thinking to make the bigger tank and sell the bc.

Albert
The Cyro calculator is *severely* flawed. Use it as a guide but I wouldn't build anything by it. 1/2" will not make a good rimless tank, I promise you it will bow badly.
The Cyro formula only states closed tank or open tank, but doesn't define what "closed" means. Doesn't account for width of eurobracing nor does it account for crossbracing. And it doesn't define what deflection levels are. The input factors are incorrect (750psi) and there are one or two others that are not valid..

For closed tanks, the material thicknesses are too thick while far too thin for open tanks..

Cyro knows it's flawed, but will not change it. I actually built the example tanks several years ago and had Cyro's chief technical engineer at my shop to see for himself - they will not change anything, so they continue to give out bad info.. Bad Cyro, bad.. :hmm4:

James
 

CMcNeil

New member
acrylics is right on about rimless and braced tanks.i made 2 rimless tanks for myself out of acrylic.one was 24x24x16 and it was made from 3/4" and it had a slight bow.the second was 30x30x16 made from 1" and it had a slight bow as well.the bow was minimal and IMO no big deal.id say the max bow at the center was just under 1/8"
 
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