Acrylic fabrication questions? I can help!

[Acrylics]

Wow James... haven't seen that thread in a while. Brings back lots of memories of when you had to hold my hand thru my tank build. :wavehand: BTW, it's still holding water after 6 years of use, all due to your expert tutelage.

I've been away from the forums for a bit, but it's great to see how active you still are with helping everyone here.

Hope everything is well with you.

Chris

Hiya Chris, nice to see one of the nicest guys ever 'round here :wavehand: good to hear your tank is still holding up well, and indeed - hope all is well with you

Lots of great info here James, been through a bunch of the thread...

I am just finishing up plumbing and did a test run in the garage with this older tank. My question is about structural integrity after the previous owner cut back the bracing. I added the external box and full of water I notice there is a pretty good jog in the brace where the external box is glued on. The brace is only about 1" across the back. So the back is bowing out and the box is holding it in, so there is more bowing in the tank back at the ends of the tank. Do you think I have an issue here or will I get advance notice of impending disaster if what is left of the bracing starts to crack? I cut the drain slots in the tank back to flow to the overflow box.

Personally, I wouldn't want to see this tank in use but I'm picky that way. With the back bracing essentially gone, there's not much holding the front to the back which is the purpose of the cross-brace.

As for if it will give fair warning or not.. I can't really say with any degree of certainty, but if you are to keep this in service - keep a close eye on it.

James

 

[CJBROWN]

Personally, I wouldn't want to see this tank in use but I'm picky that way. With the back bracing essentially gone, there's not much holding the front to the back which is the purpose of the cross-brace.

As for if it will give fair warning or not.. I can't really say with any degree of certainty, but if you are to keep this in service - keep a close eye on it.

James

Frankly I got to thinking about this same thing and it was making me real nervous. I have since remedied the issue by welding on a top plate of 1/4" X 3" acrylic all the way across the back on top. It ties in the center brace and what was left of the euro-bracing across the two openings.

Thank you for the reply though.

 

[CJBROWN]

Here's a pic of the top plate mod to beef everything up back there.

Did the water fill tonight to test everything again. New glass sump with acrylic dividers glued in with GE sillie cone. Works like a champ.

Rocks and sand are on their way. :bounce3:

 

[SuperNemo]

James,

I would like to make a long tank, just like the one Calvin did (12ft). I know that he used the weldon 42 gun. Is that the only way to do it? Do you know of another way to join two pieces of acrylic side by side without the applicator gun. Would regular weldon 4 work?

Thanks.

Jimmy

 

[madmike]

I would like to make a long tank, just like the one Calvin did (12ft). I know that he used the weldon 42 gun. Is that the only way to do it? Do you know of another way to join two pieces of acrylic side by side without the applicator gun. Would regular weldon 4 work?

Jimmy, I built a 12 footer about a year ago. Luckily James only lives about 1/2 hour from my place so I was able to learn a great deal from him about how to go about this. I think for the average acrylic hobbyist, 42 would be the only real option. Plenty of room for small error in tooling the acrylic that can be sanded down once finished. I think that james is about the only person in the world that could glue two pieces side by side and make them look flawless with a water thin solvent (I have seen some pieces he has done )

 

[Acrylics]

James,

I would like to make a long tank, just like the one Calvin did (12ft). I know that he used the weldon 42 gun. Is that the only way to do it? Do you know of another way to join two pieces of acrylic side by side without the applicator gun. Would regular weldon 4 work?

You can use WO 40 if you have either a centrifuge or a vacuum pump to get rid of the bubbles in the 40 mix.

You *could* use WO 4 but really can't advise it; you're machining would have to be *absolutely* perfect, there can be no difference in material thickness, material has be perfectly flat, solvent has to match material's mole wt and environmental conditions, and technique has to be flawless - so yes, it *can* be done, but again - can't advise it.

Even with the applicator gun, there are a bunch of hours in finish work, so be aware of this going into it

James

 

[SuperNemo]

James, I'm well aware of the hours of sanding required after the bonding process.

there was a question that tonylee (i think) proposed on calvin's thread. He stated that it would be better to cut a 45 degree angle on both sheets and glue that way instead of the 90 degree straight cut. what method do you think if better for clarity (i.e more of a seamless look).

 

[Acrylics]

James, I'm well aware of the hours of sanding required after the bonding process.

there was a question that tonylee (i think) proposed on calvin's thread. He stated that it would be better to cut a 45 degree angle on both sheets and glue that way instead of the 90 degree straight cut. what method do you think if better for clarity (i.e more of a seamless look).

that's the way to do it, and that's the way I showed Mike (^above^) how to do it. And if I remember correctly - we did the 45 cuts here at the shop, but I may be mistaken on that part

Doing it this way provides more tensile strength to the joint as well as making it more "seamless" in appearance. It does stress the material a little more but that's the trade-off we're willing to accept

James

 

[SuperNemo]

sounds good. i thought about this process a lot over the planning stage. this might be a dumb question, but how do you guarantee that the 45 degree cuts are flush with the material. i mean when you push two 45 together, they have a tendancy to **** up/down versus a 90 degree which just pushes against each other when forces together. i know that if you clamp it closer to the edges, the shifting would be minimal and line up nicely, but would like your opinion.

 

[Acrylics]

sounds good. i thought about this process a lot over the planning stage. this might be a dumb question, but how do you guarantee that the 45 degree cuts are flush with the material. i mean when you push two 45 together, they have a tendancy to **** up/down versus a 90 degree which just pushes against each other when forces together. i know that if you clamp it closer to the edges, the shifting would be minimal and line up nicely, but would like your opinion.

You don't force them together at all. You leave a small gap between them, and then gently squeeze them together - just enough to get some of the 40/42 to squeeze out.. and leave it for the day. Forcing it too hard will squeeze all of the glue out, which we don't want. In this case, the pieces should never touch each other at all, the 40/42 is there to stick to both pieces and fill that minor gap

James

 

[SuperNemo]

so, it would be best to leave like a 1/16 thin space between the two sheet and then let the glue seep in. you do push the piece closer together right?

what thickness do you suggest for the long side? i would like anywhere from 24-29 high depending on cost of acrylic thickness. but the depth max out at about 32 inches.

i'm thinking the tank should be 12ft long, but might go a little longer if the cost of acrylic is not so much more.

thanks, jimmy

 

[madmike]

Depending upon how think your material is going to be (mine ended up at 3/4" for a 19.5" tall tank because I wanted as few cross braces as possible, my tank only has 2) you need a helluva good 45 degree bit (whiteside carbide $$$$) and a really powerfull router. I am a copycat and purchased the same router james uses the 3.25hp porter cable that spins at 21,000 rpm. I ended up doing ALL 4 seams twice in order to get a *nearly* bubble free joint. The REAL hard part of the entire build was routing a 12 foot long piece of acrylic accross a router table and keeping it *absolutly* perfect.

This is definitly a do-able project but I would greatly recommend getting a couple of pieces of material you are planning to use and make a practice joint prior to attempting the tank. I learned a TON of little things during my first joints that made my subsequent trials much better. This and having one of the best tank builders in the world locally to bounce ideas off of made my tank a great success. Now that I know I can build these seams successfully my next tank will be much longer and wider

 

[SuperNemo]

mike, how did you do the routering of the 12ft long piece.

 

[rkaires]

Hi James,

I have some minor crazing on the top panel of one of my tanks. It's on the front edge and not in the seam. Can this be polished out with micomesh or Novis or is it best to leave it alone?

Thanks,

 

[madmike]

mike, how did you do the routering of the 12ft long piece.

As the song says "with a little help from my friends!" lol... but seriously I built a 4x8 router table and ran it across just like any other piece... except i had to run it out 12 feet! That meant building supports for it to run out to and having alot of friends make absolutely sure it stayed against the fence

 

[SuperNemo]

mike, when you glue the two pieces together, did you line up one side during gluing or did you just glue it together. i would assume that it you aligned one side during gluing that you would only have to router one side versus both sides.

 

[Acrylics]

You align it to one side, but still want to route both sides after they are glued together. This will give a good gluable edge to both sides and make them dimensionally consistent.

James

 

[SuperNemo]

james, what thickness should the acrylic be if i want to make the tank 24" high? what about 30" high?

 

[SeanT]

My acrylic tank cracked in the top corner.
It is 60"x48'x24'.

I am shopping for a new tank currently.
My question is, can this tank be repaired so that I can use it as a big ol' refugium?

Here are some pics of the damage.

 

[Acrylics]

Hi James,

I have some minor crazing on the top panel of one of my tanks. It's on the front edge and not in the seam. Can this be polished out with micomesh or Novis or is it best to leave it alone?

Sorry I missed this... it's usually best if left alone. The friction induced heat from trying to repair can often stress the material making it even worse.

james, what thickness should the acrylic be if i want to make the tank 24" high? what about 30" high?

At 12' in span, 3/4" at a bare minimum for 24" high, and 1" acrylic at a bare minimum for 30" high. Thickness above based on using 3" eurobrace and 6" crossbrace every 24" on center - yielding 18" wide openings. If you want less crossbracing, you need to increase the width of the eurobrace or increase thickness, preferably both

My acrylic tank cracked in the top corner.
It is 60"x48'x24'.

I am shopping for a new tank currently.
My question is, can this tank be repaired so that I can use it as a big ol' refugium?

Since the crack is starting to go down the vertical panel, the top should be cut off down past the crack and a new top glued on.
You *could* try to fill it, glue something on, etc., but these would not be reliable so wouldn't advise it.

HTH,
James