Hi, I have a 700 gallon tank with a leak at bottom of the tank. It appears to be at in middle of the back of the tank at the seam. Which Weld-on product do you suggest I use and how do you suggest I apply it to the my tank. My tank is 10'x3'x3' and weighs a ton. I don't think I can get it lifted to be able to pour a bead down a seam. I appreciate your suggestion and time!
Weld-on #40 and #42
- Thread starter wednesday13
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This could be the single most useful thread that I've found on here. Thank you Wednesday. Wish I would have found it sooner.
Glad to see this thread grow. For those unfamiliar with 40/42 it's the standard adhesive for bonding material over 1" thick. Somewhat of a trade secret amongst acrylic aquarium MFGs and custom fabricators as most will not reveal their methods. Another reason it's good to have a thread such as this. It's not as well known because most hobbyists dont fabricate with material thicker than 1".
Annealing of the material is done by some by not all prior to bonding and really depends upon the amount of stress imparted into the acrylic during machining. 40/42 works best when applied to acrylic that is not under stress as the acrylic will tend to relax over time causing crazing.
An example of this would be to bend a piece of acrylic and then glue it while under stress, ideally you want the material to be relaxed prior to bonding with any 2 part polymerizable cement such as 40/42.
Annealing of the material is done by some by not all prior to bonding and really depends upon the amount of stress imparted into the acrylic during machining. 40/42 works best when applied to acrylic that is not under stress as the acrylic will tend to relax over time causing crazing.
An example of this would be to bend a piece of acrylic and then glue it while under stress, ideally you want the material to be relaxed prior to bonding with any 2 part polymerizable cement such as 40/42.
Thank you Phixer. Not giving up on my crazing seam monster tank just yet
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I wouldn't give up on it either. Id build a 45 degree jig for the tank and pour an internal fillet along the seam like Wednesday does.
There's another site out there where guys document the builds of huge plywood tanks and use this method to create internal 45 degree fillets of epoxy along the seams of fiberglass laminated plywood.
The tanks are rock solid.
There's another site out there where guys document the builds of huge plywood tanks and use this method to create internal 45 degree fillets of epoxy along the seams of fiberglass laminated plywood.
The tanks are rock solid.
Phixer what do you mean by jig? Would leaning the tank against a wall work? Or would the pressure distort the joint angles as it sets? I plan on doing this with an 8x3x2.5 acrylic with 3/4 thickness.
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The jig will give you a true 45 and the best looking results...Ive never used one, but consistency is not 100% and theres not much pot life of the product so you have to be kinda quick about it. Its also fairly hard to tilt the tank enough for a true 45, especially on end for the sides.
I've got a crew of guys. We can tilt against a wall and approximate the 45 degree angle, pour, let set, rotate, and repeat for all joints.
Sound like a good plan? How long does the product take to set enough that I can rotate and do another side without it dripping?
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Sound like a good plan? How long does the product take to set enough that I can rotate and do another side without it dripping?
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Uniformity is what your looking for. A 45 degree angle jig is easy to make with some plywood and a carpenters square. Ideally you want each fillet to be uniform and at the same angles in order to provide the same strength since they will be subjected to the same pressure.
If one seam has a good 45 degree fillet and the other a 10 degree fillet, the two sides will not have the same strength when the tank is filled. This is due to the ammount of surface area the cement is in contact with. In other words how much area it bites into. More surface area = greater strength. With equal 45 deg angles you get the same strength all around providing the initial base joint is good.
Cure time depends on temp and humidity, normally less than 30 minutes here in Denver between 70-80F.
If one seam has a good 45 degree fillet and the other a 10 degree fillet, the two sides will not have the same strength when the tank is filled. This is due to the ammount of surface area the cement is in contact with. In other words how much area it bites into. More surface area = greater strength. With equal 45 deg angles you get the same strength all around providing the initial base joint is good.
Cure time depends on temp and humidity, normally less than 30 minutes here in Denver between 70-80F.
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Working as quickly as you can even with help i'd wager around 1-5 pours a day and thats really stretching it if ur good lol. I usually cant stand breathing fumes more than 8-12 hrs at a time lol...if you live in a drier location the glue will set up quicker. Here in ohio, small batches of #40 have taken up to 3hrs for me to cure due to humidity in summers and cold in winters. Large batches of glue also set up as quick as 15 min. Theres no possible way to do the entire tank in a day imo. It usually takes me atleast a week of glueing every day if not 2 weeks to complete any tank ive done 55-450gal. I like alot of glue and usually use 1/2-1 gallon or more of #40 per tank, no way to speed up drying times. The acrylic also gets very hot and if you keep pouring batches without letting it cool you'll craze the sh** outta ur acrylic and its not pleasant, ruins clarity, and can only be fixed in a giant oven at that point so ur stuck with it. Take ur time and be patient. Not a bad idea to pour one seam a day so u can figure out what happens whe it heats up and get used to working with the product it can be very messy.
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