Rectangular Box Welded Pond Liner Insert (Flexible)
FREE SHIPPING!
Line your rectangular tanks/containers quick and easy with this high-quality drop-in flexible liner.
Perfect for creating beautiful koi ponds.
This is a FLEXIBLE liner and is not free-standing.
Est Ship Date: 5 Business Days after Order Date
Features
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High quality, flexible liner, heat welded into 3D shaped boxes
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Comes standard with 12" flaps to easily secure the liner in place
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Fish, plant and human safe - NSF-61 Certified
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Very puncture and tear resistant while still remaining flexible
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Two liner materials available - EIA liner is twice as puncture resistant and is more bendable to work with
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Includes 12" x 4" of liner patch tape - extra patch tape can be purchased
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Order a sample of this liner here
This product has not been tested for indoor applications, and is recommended for outdoor use only.
Product Description
Our rectangular box-welded liners are strong, light and UV resistant. They are designed as flexible preformed liners that can be unpacked and installed quickly. The main advantage of a box-welded liner is that once it's installed, it's the exact shape you need, with no bulky folding of the liner required. In addition, the liner is light and flexible, making it much easier to ship compared with other preformed solutions such as rigid plastic or fiberglass. For formal shaped ponds, such as some Japanese style ponds, our box-welded liners are the perfect option.
Something to keep in mind when ordering this liner that might not be immediately apparent from the photo, is that the liner is flexible. It is not rigid, and as such the liner cannot be filled with water while freestanding - it must be supported in some way. It can be supported above or in-ground by being placed in some kind of a frame (a plywood frame works well). The circular shapes take a little more work to create a frame since the frame must be curved, but by building a frame out of 2 x 4 and then bending plywood or another material into an arc and then attaching to the 2 x 4 frame, it is possible to create a curved shape to hold the liner.
Each liner is welded at our facility into the desired shape before shipping.
Liner Material Options
This product is available in two different liner materials. Both are fish, plant and human safe, with the upgraded EIA liner even being NSF certified as safe for holding human drinking water. Both liner materials are guaranteed not to leach any harmful chemicals into the water, which makes them excellent for use in fish farming, horticulture, koi ponds, or water filtration applications.
Reinforced Polypropylene
Reinforced 45mil polypropylene is strong, light, flexible and UV resistant. Please note that reinforced polypropylene is different than reinforced polyethylene, which we also sell as a flat liner. The polypropylene is a premium product that is stronger, more UV resistant and has the quality that we can heat-weld it into the 3D shaped boxes. As a comparison, our reinforced polypropylene is around 4 times more puncture resistant than a standard EPDM rubber pond liner.
EIA Liner - (Ethylene Interpolymer Alloy)
EIA Liner is a premium product in both quality and price to the polypropylene liner option above. It is around twice as strong and twice as puncture resistant as polypropylene mentioned above (which itself is already a strong liner). It is also NSF certified for holding drinking water meant for human consumption (potable water). However, the main advantage from our point of view is the ability for us to use a slightly different welding method which takes the reliability up another notch. While the polypropylene liners mentioned above can be hand or extrusion welded, EIA Liner lends itself to Radio /High-Frequency welding (also called microwave welding). This is done with a different piece of equipment which drastically lowers the likelihood of human error while welding the liner together.
Which liner should you choose? That's easy - the EIA liner if you can afford it but if you can't, or are looking to save a little money, go for the polypropylene liner which is also a very reliable product.
How to Secure a Box Welded Liner
There are multiple ways to secure a box welded liner depending on your design.
Listed below are the most common methods.
How to Intall a Termination Bar
Frequently Asked Questions
Warranty Information
Our box-welded liners are warranted to be free from defects in material and workmanship for 25 years from the day of purchase. This includes the ability of the liner to withstand normal weathering and environmental degradation when used as a primary containment membrane holding water. There are a few limitations however for the warranty to be valid: The liner must be covered at all times by soil or water, the warranty is not covered against damage resulting from acts of god, or catastrophic events such as earthquakes, tornadoes, or hurricanes. The liner is also not covered against punctures or damage resulting from improper installation, or use. Examples of improper installation or use include damage by machinery or other equipment, people, animals, ice, or sharp/rough objects in the soil or substrate.
“A quick note to let you know that I am very happy with the drop in liner that you made for me in August 2019. Been a fun addition to a balcony garden lifestyle in a high density urban townhouse setting. Used classic Japanese burnt cedar siding (‘yakisugi’) for facing on the pool sides. Think it came out quite well for a small, low budget project”
“Your pond liner is great should have water in the next few days and turtles to follow up thank you for your help and amazing product It was well worth it!
"The two most spoiled turtles in America. Basically, a big box made of redwood. Common out here in California. Poured a concrete pad underneath. Wire enclosure due to raccoons is important. Water hyacinth grows like mad. Overall very happy with the liner. No leaks, seams all good. Size was as requested. Will buy again when needed." - W.Fletcher, California, PolyPro
“Box liner was great thanks." - R.Fall Also purchased underlayment and a fully welded flange.
Technical Information | |||
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Description | 45 mil Polypropylene | EIA Liner | Test Method |
Fabrication & Warehouse | Oregon | Oregon | |
Weight | .21lb / sq ft | .21lb / sq ft | |
Thickness | 45 MILS | 30 MILS min | |
Plies Reinforcing | 1 | 1 | |
Breaking Strength - Fabric, min (lbs) | 300 lbs | 550 lbs min | ASTM D 751 |
LOW TEMPERATURE FLEXIBILITY 1/8" MANDREL (°F) | -50 F | Pass at -30 F | ASTM D2136 |
Puncture Resistance | 110 | 275 | ASTM D 4833 |
Hydrostatic Resistance min (psi) | 450 psi | 800 psi | ASTM D 751 |
Ply Adhesion minimum (lbs/in) | 20 | 15 | ASTM D413 |
Water Absorption (% wt. change, max) | 0.5% | 0.025 kg/m2 max. @ 70º F/21º C | ASTM D 471 |
UV Resistance | >12,000 hours | 8000 hours min. with no appreciable change | ASTM G155 Xenon Arc |
Chlorine Resistance | up to 3ppm (< 100 deg F) | up to 3ppm (< 100 deg F) *for long term chlorination we would recommend the EIA liner. | |
Max Sustained Temp | 180° F |
Technical Information | ||
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Description | 45 mil Polypropylene | Test Method |
Fabrication & Warehouse | Oregon | |
Weight | .21lb / sq ft | |
Thickness | 45 MILS | |
Plies Reinforcing | 1 | |
Breaking Strength - Fabric, min (lbs) | 300 lbs | ASTM D 751 |
LOW TEMPERATURE FLEXIBILITY 1/8" MANDREL (°F) | -50 F | ASTM D2136 |
Puncture Resistance | 110 | ASTM D 4833 |
Hydrostatic Resistance min (psi) | 450 psi | ASTM D 751 |
Ply Adhesion minimum (lbs/in) | 20 | ASTM D413 |
Water Absorption (% wt. change, max) | 0.5% | ASTM D 471 |
UV Resistance | >12,000 hours | ASTM G155 Xenon Arc |
Chlorine Resistance | up to 3ppm (< 100 deg F) | |
Max Sustained Temp |
Technical Information | ||
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Description | EIA Liner | Test Method |
Fabrication & Warehouse | Oregon | |
Weight | .21lb / sq ft | |
Thickness | 30 MILS min | |
Plies Reinforcing | 1 | |
Breaking Strength - Fabric, min (lbs) | 550 lbs min | ASTM D 751 |
LOW TEMPERATURE FLEXIBILITY 1/8" MANDREL (°F) | Pass at -30 F | ASTM D2136 |
Puncture Resistance | 275 | ASTM D 4833 |
Hydrostatic Resistance min (psi) | 800 psi | ASTM D 751 |
Ply Adhesion minimum (lbs/in) | 15 | ASTM D413 |
Water Absorption (% wt. change, max) | 0.025 kg/m2 max. @ 70º F/21º C | ASTM D 471 |
UV Resistance | 8000 hours min. with no appreciable change | ASTM G155 Xenon Arc |
Chlorine Resistance | up to 3ppm (< 100 deg F) *for long term chlorination we would recommend the EIA liner. | |
Max Sustained Temp | 180° F |
SKU | BW-PPRO |
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Testimonials | Rect Box Liner |