Portable greenhouses, backyard greenhouses and polytunnel greenhouses are all made of a steel frame. Because steel rusts, it must be protected, or the service life of the greenhouse will be very short. Protecting steel to help prevent or stop rust is called “coating”. Currently, there are 2 main steel coating methods: powder coating and galvanizing.
Did you know? that the discovery of galvanizing somewhat involved experiments on frogs? Followed decades later by a paper written by a French chemist wearing a wig! Cherry on the cake, the term “galvanizing” comes from Luigi GALVANI, a 18th century Italian scientist (the one teasing dead frogs)
Powder Coating technology allows us to drive cars or ride bikes that don’t rust, install wire mesh fences of various colors, etc… The coating process was developed in Europe in the 40’s. Powder coating maximum service life is around 15 to 20 years. It is widely used because it is a cheaper alternative to galvanization coating.
Galvanizing technology is widely used in greenhouse manufacturing. It was developed as early as the 17th century. Hot dip galvanization basics were discovered first in 1742 by a French chemist. Today, we know that hot dip galvanizing can provide 34 to 170 years of protection for steel. Galvanizing process is now commonly used for a large array of applications, including greenhouse tubing.
For example, Delite Garden polytunnel greenhouse frames are made of hot-dip galvanized tubes and hardware. Because they have been immersed in a bath of molten zinc, the tubes, bolts and nuts service life is increased greatly.
On the other hand, cheaper models such as walk-in greenhouses and mini greenhouses are made of powder coated steel tubes. Steel will not decay for a long time, but will not perform as good as hot dip galvanized steel tubing on the long run.
The difference in coating methods between greenhouse ranges is purely a ratio between product service expectancy and economic efficiency. Low-priced items will tend to utilize cost reduced manufacturing techniques while pricier items will focus on meeting higher expectations by end users.
While Covid has had a positive impact on sales of indoor and outdoor greenhouses, we strongly believe in a more durable growth in galvanized greenhouses, poly tunnels and hobby greenhouses over the coming years. Here are a few reasons why greenhouse galvanized pipes will outperform coated tubes.
1 – Hot dip galvanizing increases greatly service life
Hot dip galva coating is the best, and thickest galvanizing coating. It is also affordable enough to make profit off hot dipped polytunnel frames.
Usually, a hot dipped greenhouse galvanized pipe does not need to be coated afterward. Usually large span greenhouses, used for intensive farming and hydroponics, are made of these tubes, not coated tubes. Why? Simply because coating lasts only 20 years max while hot dipping can offer 35 to 50 years of service.
2 – Hot dip galvanizing implies heavy duty tubes
The truth is, hot dip galvanizing is most commonly done on min. 1.2mm (18 gauge steel) wall tubes. Whether you see “heavy duty” used to qualify walk-in greenhouses, or backyard greenhouse steel frames, just know that there is actually nothing “heavy duty” about it compared to hot dip greenhouse galvanized pipe.
A concrete example : walk-in greenhouse are mostly made of 25mm, 0.7mm coated steel tube. Delite Garden Supplies polytunnel is made with 32mm 1.2mm tubing. That’s a 28% increase in diameter and 70% increase in thickness!!
3 – Greenhouse galvanized pipe just looks better
Everyone knows that coating can be damaged with scratches and dents. But with galvanizing, the tube is uniformly shiny and grey. Additionally, our polytunnel tubes all feature galvanizing flakes.
See for yourself :
4 – Not just galvanized coating, but organic coating too
All our greenhouse steel tubes are galvanized and protected with an organic coating. Not only the zinc layer protects the steel, but the organic coating protects the zinc layer.
You may have plenty of other questions, whether it is about the galvanizing process, materials and compounds used. Feel free to contact us if you have specific requirements. We welcome any inquiry for custom greenhouse steel tube frames!
When he's not working late, he is out hunting for beautiful landscapes. Strong believer in self-made entrepreneurship, Yan enjoys China, its delicacies and pushing the boundaries of his Chinese colleagues.