Innovation Tailored To You

plastic hdpe boxes tanks are versitile unique custom one of a kind and made to order. goof for marine enviroments, aquaculture,  and food grade. for Rv tanks boat tanks for cape dory and bayliner antique boats for referbishment

      Benifits of HDPE

(High-Density Polyethylene)


           - Corrosion Resistant 

           - Seamless Joints

           - Water Tight

           - Light Weight

           - Long Lasting

we fabricate HDPE holding grey black water tanks for Boats and RVs Campers and for brands such as cape dory and bayliner





  • Corrosion-Resistant Tanks

  • Commercial Fishing Equipment

  • Food Grade Plastic Products

  • Kayak and Small Boat Repair

  • Custom Projects

  • RV Tanks

  • Waste Water Tanks

  • Gray and Black Water Tanks

  • Freshwater Tanks

  • Cape Dory Custom Tanks

  • Bayliner Custom Tanks

  • HDPE Parts and Equipment



Our experience for helping you choose the right material for your unique project is just a phone call or click away.


      Sullivan Plastic Products is a custom plastics company that uses High-Density Polyethylene (HDPE) with heat extrusion welding to fabricate custom products for your business, boat, RV, or camper. Our experience and capabilities focus on custom fabrication, and prototype development of products consisting of plastic materials. We have the knowledge and experience to partner with your innovation to turn your ideas into a tangible plastic product.


      We enjoy developing new products for our customers- it's part of the excitement of a custom fabricating business. In the past, we have created custom tanks for the aquaculture industry, snowboard and skateboard pipe rails. We have worked in a partnership with the University of Maine and had the privilege of being part of VolturnUS, the first North America offshore turbine connected to the grid.  We are known for our well-built commercial fishing equipment and have built a reputation of being a quality custom manufacturer for marine gear.  We will work hard to create rugged, long-lasting products to hold up against the elements. You will definitely benefit from your investment!



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We Use The Best Materials

       Our High-Density Polyethylene (HDPE) is a versatile plastic, making it the perfect choice for a variety of purposes. HDPE is strong, durable, and lightweight when compared to alternatives like fiberglass or aluminum. When fused together, HDPE offers a zero-leak rate due to the seamless nature of the material. HDPE can be heat fused together to form a joint that is as strong as, or stronger than the material itself.  Heat extrusion welding is the most common and reliable welding techniques used to weld virtually seamless HDPE connections. HDPE products offer an alternative to other tradition materials because it is corrosion and chemical resistant, long lasting, non-toxic, and it is a food grade plastic.


       Corrosion and Chemical Resistance – HDPE materials will not rust, corrode,or support biological scale or growth. It has superb chemical resistance compared to traditional materials. HDPE performs exceptionally well in marine applications, including commercial fishing, agriculture, and aquaculture, outwearing more costly material alternatives. All while offering excellent corrosion resistance to acids, bases, and salts. HDPE is unaffected by bacteria and fungi, offering resistance to many organic substances. These types of materials are allow us to create hard to find tanks for Cape Dory, Bayliner, O'Day and other older boats because we can custom fabricate a new holding tank to fit the existing system.

Latest Projects

We are an innovative extrusion welding and custom plastic manufacturer! Sullivan Plastic Products offers several advantages:


• Our commitment to finding workable, cost-effective solutions for every customer

• Knowledgeable design & innovation to help satisfy your unique requirements

• Complete conception-to-delivery production capabilities

• Completely customizable solutions, including dimensions and designs

• Rugged, durable products that are exceptionally cost-effective in any environment

• Our dedication to customer service is unmatched