Acrylic Bonding Techniques & Aquarium Construction

[phixer]

:thinking: Always glad to hear new ideas... Chipmaker, If the bullet resistant plastic you are talking about is what im thinking of then chemically bonding with acrylic cement will cause the laminates to seperate because the two laminates are of different compositions which is what makes it bullet resistant. .. I think... Similar to the plastic laminated into windshields . If they are just two plys of the same material laminated together then I think you might be able to weld this material using a heat gun with the correct tip to melt the two edges and by feeding some of the same material into the weld. The process is similar to ARC welding as you know. This could be tricky if the two laminates are not soluable together.. . If the weld takes and the the two peices are fused you could then run a bead of silicone (or 1750) along the edge to ensure it remains water tight, this might be pretty unsightly though. Or you could build an outside case around it and line it with this stuff, (would be heavy) or a frame around it and seal it with silicone, this too would be tricky with expansion and might cause it to crack or buckle. Have you had any experience working with RAM or flow coat? Im getting close to retirement myself ...32 years on active duty is a long time, geeze man how old are you? ha, ha. They tell me I was a PC on Noahs ARC... Anyhow, will be placing the order tomorrow for the acrylic. Im ordering 1" Polycast but probably wont get around to starting the project until Summer. The place Im ordering the Polycast from dosent do the machining so when I finally get the process down and have a few more tanks built, I'll start this one. Will probably take the material to a local plastics fabricator to have the edges beveled only because the sheets are 10FT long and my table saw cant handle it, I dont trust a jigsaw to make the cuts evenly due to too much blade deflection. The rest I can do myself. Id like to use the two part stuff with an inside bevel of 15 degrees across the face of the edge. This will leave enough of a gap for the cement to fill and to build the fillet against the edge. Will have to build a jig to ensure each side is square before bonding also. The dimensions will be 120 X 24 X 30 or maybe 32" high. I dont want to get too carried away with the depth for safety reasons. Any ideas?
Phixer

 

[chipmaker]

My makrolon acrylic consists of 3 plies....I just need to play around and see what works. The aircraft we maintained did not use the latest and greatest RAM coating, and contained very very little of it, but from talking to a few friends that are still in the military they say its a real pain in the backside doing anything on the acft that has it.(F-22's and F-117's)Each and everytime a screw is removed they need to be recoated, so its a never ending job for sturctural repair......As you know pilots especially military types can be a strange bunch.....Well we had the opportunity to make a unique aquarium for them from the canopy glass of an F-16 for them. We tried to talk them out of it, but they insisted.....If it was not for the overall shape of the thing, it would have been fine, but it had proven to be a real chore to take care of, since there is not the first flat or straight surface anywhere on it. 9 out of 10 folks would wonder why anyone would have such an oddball shaped aquarium, and only pilots or maintenance types would really recognize it as being a canopy glass......Then someone got a hair brained idea and decided to turn it into a container to keep the anticipated mascot in.....but when the Safety Office found out what they intended to keep in it, they put their foot down....they had originally intended to put a cobra in it.....so now it is setting there with a ball python setting in it.......
I can pretty well get a lot of 8802 and 1750 as well as other neat stuff fairly easy. I just have to be carefull and do a test batch before hand. They routinley get rid of this stuff once its reached its shelf life, and the military units are going to always have more of this material on hand just incase, as its easier to throw it than need it and not have it.....so I usually find it at the local DRMO sales yard quite often.....and its rare to find stuff that does still work. It may or may not meet mil spec but for what I use it for it works just fine...
Oh, I joined the military back in 1967 at age 17....stayed for 10 years in the U S Army, got out for a bit and joined the Air National Guard, and then went into the U S Airforce and retired in 2002....I just got too old and tired of being assigned to fighter units. Fighter units are an young persons game. My last duty assignment was assigned to the local Air NAtional Guard unit here in Alabama, which lasted 5 years. I even had an assignment with the U S Navy, out of Pensacola a long while back when they still used the Lexington for naval aviator training..so I got to spend 3 weeks out in the Gulf of Mexico aboard her and participate in the deployment....

 

[nytrillium]

I saw someone saying that 100% silicone doesnt bond to Plexi very well... Is that true? I never knew that. i used it to put a baffle in my girlfriends turtle tank and it held fine.
I ask only because im about to make my algae scrubber nad i have no good place to get weldon or similar products. Would PVC cement work as a solvent glue instead? Someone told me to try that.

 

[chipmaker]

NYTrillium.......what you were told is correct to a certain point. SIlicone does not hold all that well on acrylics. That is not to say it will not work for sticking some things in place like a baffle etc, but its not a good diea to use it if there is any chance if it lets loose it could cause a flood, such as in the overall construction of a acrylic tank or sump. Its fine to use it to stick a baffle etc in a acrylic sump or glass tank install a plexi baffle etc...thats about it.
PVC cement only works with PVC materials....does nothing to hold acrylic. Super glue would be a better choice than pvc cement.

 

[nytrillium]

Hmmm alright ill see if i can find some acrylic glue like weld-on online. I dont think the glass places by me have anythign like that. Ill check though because i have to get a tank drilled.

 

[nytrillium]

hah... nice. i just called the 2 glass places here. One wouldnt even do it and the other couldnt pin down a price for me. He said it depended on how long it took and it could be up to $40.00 sh*t for that price per hole i could go get a dremel tool and a set of bits and do myself.

 

[chipmaker]

It certainly should not take a genuine glass shop long to drill a tank by any means, when it usually seems to take most DIYers about 10 mintes or so....around here the LFS charges much more, but they charge for their time to take tank to glass shop.
Just what are you trying to stick together?....the algae scrubber thingine or ? Do you have any sign companaies in the area that makes platic signs? They may be able to sell you some weldon...or look for a crafts store. Our local crafts store even sells it. Its made by Craftics, ad simply called Plastik Acrylic Solvent Cement....same as Weldon #3 and its about $5 for an 8 ounce bottle.

 

[dennycrane]

I've been following this thread a little. I'm cuious - How much pressure can these bonds withstand? I'm going to go big in our new house with an aquarium (3-5k) and I am trying to work out which methedology to use - I'm pretty much set on wood, but if this bond could withhold the pressures...

 

[nytrillium]

i just bought some weldon 16 on ebizzle. And no.... we dont have much up here in the boonies.
Denny: Just my thoughts but if your doing a big tank and want to save on material costs i would do something like a plywood tank instead of bothering with super thick acrylics (very expensive). There are a few threads on here for plywood tanks. One guy used a rhyno lining type product from Autozone i think to seal the inside of the tank. He used silicone i think as a gasket to seal the front acrylic to the plywood. And yes the joints are just about as strong as the acrylic itself since it basically IS acrylic. Its similar to welding in that the material used to join the two pieces is the same material...

 

[phixer]

Chipmaker, thats a cool project, Ive been in fighters my whole life practically and RAM is a pain in the A**. Lots of Technical Directives and inspections. Can relate to what your saying. RAM is basically fancy Bondo, the flo-coat stuff is what the canopies are coated with, its a risilent rubberized material.
Denny, the height of your tank is the biggest factor in determining what the internal pressure will be. Generally speaking tall tanks generate more pressure and require thicker material. An acrylic bond is very similar to a weld and if done properly is equally as strong as the base material.
I ordered the Polycast the other day. The 1" acrylic deviated too much in thickness and actually could even go below 1", so I went with the 1.25 to be absoloutely sure it remains thicker than 1" and wont bow as much. I called Spartec and they said Cell Cast is all they carry. Should be able to build safely to 32" tall now. Will have to run the numbers again though. Best regards.
Phixer

 

[phixer]

Bump

 

[acrylic51]

Quote:
Originally Posted by Phixer http:///t/196219/acrylic-bonding-techniques-aquarium-construction/20#post_1484754
Chipmaker, thats a cool project, Ive been in fighters my whole life practically and RAM is a pain in the A**. Lots of Technical Directives and inspections. Can relate to what your saying. RAM is basically fancy Bondo, the flo-coat stuff is what the canopies are coated with, its a risilent rubberized material.
Denny, the height of your tank is the biggest factor in determining what the internal pressure will be. Generally speaking tall tanks generate more pressure and require thicker material. An acrylic bond is very similar to a weld and if done properly is equally as strong as the base material.
I ordered the Polycast the other day. The 1" acrylic deviated too much in thickness and actually could even go below 1", so I went with the 1.25 to be absoloutely sure it remains thicker than 1" and wont bow as much. I called Spartec and they said Cell Cast is all they carry. Should be able to build safely to 32" tall now. Will have to run the numbers again though. Best regards.
Phixer
Spartec specs are probably some of the tightest in the industry.....The top material to use for construction.....I doubt very seriously it dips below 1". Polycast is made by Spartec.........

 

[phixer.]

Has anyone used weld on #42 without annealing? Im tackling another large build soon and this time Im going to try #42. Mainly because of the thickness and size of these for this build. Material on this tank is 1.5" thick. I have the dispenser and despite the high cost it's Swiss made and appears to be high quality. Would be interested in hearing your experiences with #40, 42, PS30 or any other 2 part polymerizable cement. The last build was 1.25" thick and despite perfect machining was very hard to get bubble free joints using pins with solvent.
My experience has been that solvent works best for material 1" or thinner with panels under 8ft long.

 

[acrylic51]

I've used 40 which isn't bad IMO other than the smell gets to you a bit.....42 I've played with, but the strength increase is minimal unless it's annealed, and that's 1 reason I opted not to use the 42 on my build.....
As far as the 2 part I'd contact James @ Envision and get his take on mixing a 2 part for your material choice......Actually I don't think there is any strength difference between the 40 & 42 other 1 is applied with the gun; and yes an expensive tool.....40 isn't bad at all getting clear clean joints. I played around quite a bit with smaller pieces before tackling my build. Again without it being annealed no real strength increase, but finding a big enough oven.....
Then pin/shim method wasn't to bad IMO.....Took some practice and getting use to....My issue was that I used pins, and to my surprise and it didn't happen during practice for whatever reason, when I went to pull the pins, a couple of them the heads came off and dang you talk about a bit of panic setting in.......

 

[phixer.]

The heads came off the pins! Did you get them out with pliers? I used a bunch of stainless steel wire from a medical supply place .010 I think it was and MC Bond solvent but had to buy a lot of it because they wont sell small qtys.
#42 should be the same as 40 just uses an applicator gun which mixes it 10:1 for you. Both should be annealed, here whats interesting...When I was researching this I traveled around and examined many really big public tanks, Scripps, Seaworld and recently the one in the Dubai mall. I was surprised to learn just how many of them are not annealed. On the Dubai tank, you can see the seams from the second story, there is just no way panels that big would fit into an oven. Many of these tanks are assembled on site using beveled butt joints with the cement poured into them and then buffed to finish. Some of the panels for the Dubai tank are 12 feet x 12 feet and appeared to be about 10" thick.
Have had to learn this by bit by bit over the years because so much of this is industry is closely guarded trade secrets.

 

[acrylic51]

I started using twisty tie wraps, but couldn't get a good clean joint, and I'm pretty anal........I had James coaching me as well, so had to be good.....Pins I found in my oldest daughter sewing kit were laying around and I thought what the heck......They actually worked very well....Corey (2Quills) and I had talked earlier about such a thing happening, and I left the needle nose pliers laying on the opposite side of the room, and I had already done 3 other panels.....I just needed to lay the front panel in place.....Everything was shimmed and looking good.....Even pull on the pins all the way around, I shoot the solvent into the joint, start pulling and the first 2 were good, and then all hell broke loose....Heads started coming off and I thought no biggie keep moving and just go back and pull the other....Worse case it'll pull material out of the joint.....I went and tried to pull with my bare fingers, and we know what happens as those pins sit in solvent and the weight of the panels.....Fear set in a bit, I look across the room and there lays my pliers....I scrambled to get to them and luckily was able to wiggle it out, without affecting the seam......
My front seems had to be totally perfect and using the black acrylic on the 1 end will really magnify any bubbles in a joint.....I did find the black a lot more challenging to work with.....At least with clear acrylic you can actually see your joint.....My best advise is keep pliers handy, but using 42 you shouldn't have an issue....because your filling the joint and then setting the panel in place.....
Have you thought about and I don't know if this is a good idea or sound idea, but beveling your corners at 45's and then making a jig/clamp to hold panels in place (vertical) panel and then shooting the solvent and then slowly lowering the panel into place not allowing the seam to be pushed out and dry......You would be forcing any bubbles out of the seam, but at the same time keeping your seams consistently spaced.....Worse part is the clean up and polishing the seams.....Honestly polishing the seams aren't bad.....I actually enjoyed and wish I had taken pics of some scrap I purposely destroyed through the table saw and then beat it to death with the sander, but just to show how it can be sanded out and filled with 40 and then sanded and buffed and unless you look at a goofy angle you wouldn't know unless you seen the before and after.....

 

[phixer.]

Im surprised you were able to get those pins out in time. At that point I probably would have resorted to using my teeth and a combination of choice words spoken at a high volume. It would suck to have a metal pin stuck in a seam, but Im sure this has happened before to someone. Thats a tricky situation...
Yes. The edges will be beveled using a CNC router. The jig fixtures and process for casting these joints is much different than what I used for solvent cementing before. The thickness of the material also determines the angle of the bevel as you know. For 1.5" it should be about 1/8 gap on one side with the panel in the vertical position. I asked Cryo for confimation on this and am waiting to hear back from them...
The jigs are interesting. For the sides it will consist of two threaded 1/2 rods. One running horizontally on each side of the panel with plates on the ends that the threaded rods go thru. These plates/rods are faced with a rubber pad and are slightly tightened down with washers and nuts clamping the acrylic side panel. They sit on two 2x4s stood vertically rising from the floor that support the weight. The 2x4s are clamped to the stand to keep them upright. The panel is kept in 90 degree alignment with the base using aluminum quick squares with the inside corners cut off to allow clearance for the dam. The panel is cast in place with the cement poured into a mold created with tape around the outside perimeter of the base. The inside of the joint is made with double sided tape on the bottom and a square block of acrylic acting as a dam that runs front to back. This acrylic block is 32" long and 1/2 tall. It is lined with nonstick 3m 685 riveters tape and keeps the cement from adhering to it. The dam and tape are peeled off after the joint is dry. Although the joint will look more like a block masonry type I'll probably cover the edge seams hardwood trim anyhow. Im mostly concerned with strength since I cannot anneal it.
The larger panels are bonded a little different. To allow the cement to flow under the panel and create a uniform joint along the edge Im going to suspend the tank using twelve 10" diameter vacuum lifting suction cups with nylon straps. I could support the weight of the tank on shims but this would not allow the cement to flow under these areas and would create localized point loading stress zones from the weight of the panel, this could result in crazing of these areas later on, which I dont want. Need to spread the weight out. The ways I came up with would be to either suspend the tank with suction cups on the vertical surfaces then cast the joint the same way as the sides... or glue the top on first with solvent, let it dry, flip it in the rotisserie jig (using car rotisserie jig to rotate tank) and support the tank from the inside with blocks enough to form a very small gap while I cast the bottom. Im not down with using two types of bonding for the same tank though.
Would really like to hear some other ideas of how to cast cement for the top and bottom without using shims,this has been a challenge for me to figure out. I want to cement with a continuous pour rather than in sections.

 

[acrylic51]

The pins (2) weren't the easiest to pull trust me.....It did take a little effort....I was more concerned about "jacking" up the look of the seam.....
I'm not sure why the cast joint wouldn't be clear.......What solvent are you using again.....Doesn't take much effort to buff them out completely.....The jigs sound something similar to how I kept mine square....I didn't need straps though of course....I did use the plastic squares vs the aluminum.....Double sided tape works nicely for holding them into place.....I'm anxious to see this put together to say the least....Sounds like my kind of excitement......
I don't see why you could cast a continuous bead of 42 and slightly lower the 4 sides into place, or possibly easier would be to raise the bottom panel into place applying pressure that would form the joint....It would also allow any air to be pushed out, but the pressure would need to be controlled at all times.....A tranny jack comes into mind as far as lifting the panel into place.....

 

[phixer.]

The cast joint should be clear. Sorry for any confusion. If I lay a bead of 42 down and set the tank into it the weight of the tank (678 lbs) would displace the cement and focus the weight on the thin edge. The joint would then esssentially be two sections. An inside one and an outside one. I need to have a small gap between the edge of the vertical panel and the horizontal one of about .060 for the cement to flow under to create one solid casting. The largest gap will come from the outside bevel edge about 1/8 to 1/4 gap.
The tank will be assembled on site on the stand. After each assembly step it will be slid onto the rotatry jig to be flipped and then slid back onto the stand to be cemented. Using melamine to provide a slippery surface. The rotisserie jig will have a little vertical flex to it so I dont want to glue up on the jig. It wont have any torsional flex to it though because of the jigs square tubing cage around the tank. I wont have a crew available to help me flip this thing all the time which is another reason I came up with the rotisserie jig.
I'll take pictures and document the assembly process in a thread after I get the details for this build worked out. The stand will be an H beam/cinderblock construction with a wood outer shell. Four W6 x 25 H beams bolted to the blocks.

 

[acrylic51]

Quote:
Originally Posted by phixer. http:///t/196219/acrylic-bonding-techniques-aquarium-construction/20#post_3509368
The cast joint should be clear. Sorry for any confusion. If I lay a bead of 42 down and set the tank into it the weight of the tank (678 lbs) would displace the cement and focus the weight on the thin edge. The joint would then esssentially be two sections. An inside one and an outside one. I need to have a small gap between the edge of the vertical panel and the horizontal one of about .060 for the cement to flow under to create one solid casting. The largest gap will come from the outside bevel edge about 1/8 to 1/4 gap.
The tank will be assembled on site on the stand. After each assembly step it will be slid onto the rotatry jig to be flipped and then slid back onto the stand to be cemented. Using melamine to provide a slippery surface. The rotisserie jig will have a little vertical flex to it so I dont want to glue up on the jig. It wont have any torsional flex to it though because of the jigs square tubing cage around the tank. I wont have a crew available to help me flip this thing all the time which is another reason I came up with the rotisserie jig.
I'll take pictures and document the assembly process in a thread after I get the details for this build worked out. The stand will be an H beam/cinderblock construction with a wood outer shell. Four W6 x 25 H beams bolted to the blocks.
That's where I'm referring to being able to manipulate the downward force of the panel......If you lay a bead and your only lowering the other panel just enough to squeeze the bead of solvent....Your not letting the entire weight of the panel rest on the bottom panel.....You just want enough pressure to force any air out of the joint, and with the correct size bead of solvent that downward pressure should actually then press or squeeze to fill your beveled cut in the panels.....So in my mind the joint or seam would be seamless or invisible depending how much time you actually spent dressing it up.....
There was a build thread over on RC where a guy seamed panels in the center of a 10' long tank, and it looked rough somewhat at the beginning, but after going through the sanding process you couldn't tell the panels were ever joined......
I had thought about your exact stand build when I first started into the new build, but somewhere along the line, and I can't remember who or what, but was advised against that type stand build.....Theoretically in my mind I saw no issue with doing it and I've seen it done, but I remember James cautioning me about it though.......There were others that chimed in against that method......Honestly a steel stand would be more than adequate to handle the load as well.....