Page 52 - Australian Paint & Panel March-April 2020

PRODUCT FOCUS
52
PAINT&PANEL MARCH / APRIL 2020
52 RIVETING, WELDING AND BONDING • 64 NEW PRODUCTS
I-CAR'S MARK CZVITKOVITS LOOKS AT THE WHYS OF RIVET BONDING AND WHAT YOU NEED TO KNOW.
RIVET BONDING ON THE RISE
With most repair proce- dures there will be specific rivets and adhesives re-
quired based on the type and location of the join as well as
the materials being joined.
The most common rivet being used for newer vehicles, particularly alu- minium and mixed material structures, is the SPR. SPRs have a coating to prevent galvanic corrosion on dissimilar metals. SPRs come in various sizes of diameter and depth, these are used as specified to ensure the SPR has enough material to pierce without pressing through the base material. A smaller or even larger than specified rivet will compromise the repair
so the correct specifications are critical. Flow Form rivets are a style of rivet that can be used as an alternative to SPRs. Flow Form rivets can be used in the holes left when extracting SPRs from panels. They look very similar except they do not have sharp lower edges as they do not pierce sheet metal, instead they function like sol- id rivets. Solid rivets and Flow Form rivets are inserted into prepared holes and are
pressured to fit into an opening.
Blind rivets such as hemlocks and mon-
obolts are used when access to the back- side is limited. The hemlock is a rivet that pulls two panels together. The hole is a re- quired diameter and is not loose when the rivet is installed. Oversized holes will re- quire the monobolt, which expands radi- ally to fill the hole and seal the panels. Both require a hole through both panels.
STRONG JOINTS
All of these rivets provide strong joints when used as specified and designed. With the ad- dition of adhesive, the joint becomes excep- tionally strong and, in many cases, provide a join that is as strong and even greater in shear strength when used as directed.
The type of adhesives used will depend on the base materials as well as their in- tended location of the component to be joined. In many instances the wrong adhe- sive will not provide the repair character- istics needed with certain materials and the joint can fail. An incorrect choice of adhesive will alter collision energy man- agement of the vehicle, in the same way incorrect repair of steel does. When an area being repaired or a structural join is
A
S WE ROLL INTO 2020 AND
wonder at all the new tech-
nology being introduced and understanding how to repair vehicles safely, sometimes a few
things can become overlooked.
Rivet bonding is one of those things and correct usage of this joining process is critical to perform correctly to ensure
repairs are safe.
Rivet bonding has been introduced to
ensure that not only dissimilar materials, such as aluminium and steel, can be suc- cessfully joined but also similar materials, where heat is a concern, to join metals in
conjunction with a structural adhesive. This process is fast becoming a require- ment for a number of different repairs
At a time when new materials such as aluminium, carbon fibre, magnesium and other composites are becoming more common in new vehicles, there will be a growing demand to use rivet bonding as the joining process. With the introduction of adhesive and rivets be- ing used to join mixed materials, the benefits will include better corrosion protection, a stronger joint, increased structural rigidity and no detrimental heat affect on materials being bonded.