Acrylic fabrication questions? I can help!
- Thread starter JohnL
- Start date
troylee
In Memoriam
1" acrylic will be fine for a rimless...
henrystyle
Member
How do you calculate what acrylic thickness is needed for acrylic tank building?
Is there a certain formula to figure this out?
Is there a certain formula to figure this out?
Most 'round here would use #4
There isn't "one" good formula - too many variables. For any specific deflection tolerance, size, and bracing scheme, you can derive a formula from Rourke's Formulas for Stress & Strain. But, you will have to know the necessary physical properties, some of which are not published and are kept "secret" by the acrylic mfrs.
James
toddanddaneen
New member
Ok i've got a 110 gallon flat back hex that has 2 cracks roughly 3 inches long at the back center on either side of the overflow. I have already glued the cracks with weld on and it holds water but i'm still a little unsure of using it for an extended peroid of time. Is there a way to brace this up better so that it can be used safely?
henrystyle
Member
ok thanks.
I want to make a slit across the back of my tank to act as the overflow to allow water to fall into an attached external overflow box. I read a several pages back Henrystlye was going to do this.
I was originally going to have a internal overflow box and make holes in the back where the water would flow into the external overflow box but was suggested to remove the internal overflow box and have a slit across the back.
My tank is 48" long 1/4" acrylic. I'm thinking I would like the slit to be 1/4" wide and maybe 24"-30" centered across the back. I would like to make the slit as close to the top as possible to prevent the water line being to low in the display tank. How do I go about making this slit? I would think I would use a router but, I don't have a router table.
I'm attaching a sketchup of my tank. I'm worried about the bracing and if it will weaken the tank.
I was originally going to have a internal overflow box and make holes in the back where the water would flow into the external overflow box but was suggested to remove the internal overflow box and have a slit across the back.
My tank is 48" long 1/4" acrylic. I'm thinking I would like the slit to be 1/4" wide and maybe 24"-30" centered across the back. I would like to make the slit as close to the top as possible to prevent the water line being to low in the display tank. How do I go about making this slit? I would think I would use a router but, I don't have a router table.
I'm attaching a sketchup of my tank. I'm worried about the bracing and if it will weaken the tank.
Attachments
henrystyle
Member
After I thought about it cutting a slot across the back would make the back of the tank bow. The top brace would only be attached to the top portion of the slot. Not good.
The only other option would be to cut teeth into the back panel of acrylic then add an external overflow box to make that plan work.
That should work in theory.
The only other option would be to cut teeth into the back panel of acrylic then add an external overflow box to make that plan work.
That should work in theory.
troylee
In Memoriam
are you slitting the top like the sketch or just the back??? if you slit the back and use a external overflow box you will be fine....i do it almost everyday...
just make sure the overflow box is beefy to take the stress off the back i would suggest 3/8" acrylic and weld it on with weldon 3 or 4....
somethin like this...
chris.francis14
Member
I just filled my new truvu 90 gallon. 48 long 18 wide 24 tall. The center brace seems to bow down a little bit, how normal is this? Do I have anything to worrk about?
The tank is probably underbuilt a little so this would be expected, I'm guessing 3/8" material at most? In time however, it will start to bow up - nothing to worry about, just the material absorbing moisture and growing a little
HTH,
James
troylee
In Memoriam
If ya soak the joint it weakens the material around it... There's a fine line in there for perfect clear joints without excess stress being introduced... I know soaking a little longer allows for cleaner joints on pieces that weren't prepped properly " saw cuts" but it's better to not have all that excess ooze and unnessacary stress IMO. For a short cut... I'm sure James has different thoughts on this but that's mine...
Hi Chris,
Pretty mcuh agree with Troy on this. Unless we're doing thick stuff (1.5"+) I try to keep soak time under a minute. Solvents (and 40) work by means of chemically stressing the material, the shorter duration that is, the better, all other things being equal. One of the reasons I stress a smooth machined edge rather than a saw-cut edge.
Kreisels and similar tanks which are far more complicated and use far thicker materials, are a whole 'nuther creature You are conceivably doing a 50' joint in thick stuff so you have to adjust everything from the gaps you leave to the chemical make-up of the solvent to soak time, clamping, cure time, and so on.
James
Pretty mcuh agree with Troy on this. Unless we're doing thick stuff (1.5"+) I try to keep soak time under a minute. Solvents (and 40) work by means of chemically stressing the material, the shorter duration that is, the better, all other things being equal. One of the reasons I stress a smooth machined edge rather than a saw-cut edge.
Kreisels and similar tanks which are far more complicated and use far thicker materials, are a whole 'nuther creature
You are conceivably doing a 50' joint in thick stuff so you have to adjust everything from the gaps you leave to the chemical make-up of the solvent to soak time, clamping, cure time, and so on.James
