welding of a Hybrid Chassis using Pulsed mig welding
ROO HYBRID CHASSIS
We are proud to announce the release of the all new and updated “Aluminium steel hybrid” chassis; keeping both the strength and losing the all-important weight.
A hybrid chassis built in a lightweight format can mean a weight saving of around 90 – 150 kg on a standard 19 -22ft caravan. Normally 6” drawbar and 6” main rails depending on material thickness and options.
We are constantly working on ways to improve on weight savings as part of our ongoing improvement policy.
The main engineering problems that is/was faced with this style of chassis is (what is known as) galvanic rust. Galvanic rust is an electrical charge created between the steel and aluminium, especially when presented in a salt environment, This forms a white rust build up between the two materials and causes corrosion at an alarming rate.
The solution and challenge, “keep the two materials insulated and away from each other ”
We have overcome this by using a very special high strength bonding agent and by carefully spacing the materials 3mm apart from each other, which separates the aluminium from the steel, in an isolated manner. After months of testing different bonding agents, we have concluded through a series of shear and tensile tests, that the bonding used is more than suitable for the application. It has a lifespan when fully cured of over 100 years, maintaining its strength and flexibility.
The strength of this glue is incredible, it is also shock resistant and flexible enough to move with the steel.
The aluminium frame is then also bolted to the steel frame using zinc plated and galvanised rivet fasteners, and where possible insulators designed to prevent contact between the aluminium and steel base are used.
Each of these bolts grade 8.8 with a tensile strength of 150 000 psi, which we have in addition to the glue 40 of these bolts per frame.
Although the bolts are not required we provide these for extra peace of mind, and they assist in keeping the materials together during the curing time.
We believe the aluminium frame to be the future of caravanning, lighter weight, stronger floor design less rust issues, with countless other advantages and with no aluminium stress usually found on full aluminium chassis in main rail or drawbar areas .
The hybrid chassis uses a complete aluminium top floor / deck and step, aluminium battery boxes, jerry can holders and bumper bar; which all add up to large weight savings.
The grade of aluminium used is an approved grade suitable for use in this application and is manufactured in Australia.
So why not a full aluminium chassis? Because in order to meet the same MPA strength requirement in steel the shear amount of aluminium material used in the drawbar and main frame would equal the weight of the steel counterpart, but not have the longevity or flexibility and strength that steel has.
In a nut shell we have used the steel where it’s strength is required and needed and saved weight using Aluminum where strength is not that critical but weight saving is.
The actual build time of hybrid chassis is approximately 4 days due to manufacturing complexities and processes, and cost can be discussed with your caravan dealer
Specifications / Design changes may occur without prior notice