Design for Safety | GB Galvanizing

Vessels or hollow structures which incorporate enclosed sections must have provision for adequate venting during galvanizing. At galvanizing temperatures any air moisture present in closed sections is rapidly converted to superheated steam, generating explosive forces unless adequately vented to the atmosphere. For the safety of galvanizing personnel, equipment, and the work being galvanized it is essential that venting is provided. Correct venting also ensure that the entire internal surface of work is properly galvanized and fully protected.

Closed vessels which are not to be galvanized inside, such as certain types of heat exchanger, must be provided with snorkel-type vent pipes long enough to project above the level of pickling, fluxing and galvanizing baths when the work is fully immersed. The exact venting requirement should be discussed with the galvanizer.

Hole Designs – click on the appropriate link below to view:

RHS section - straight

Channel frames 2 dimensional

Beam Frames

Beam and universal columns

Channels with end plates

Tubular Frames

Pipe straight lengths

Plates / floor plates

Gates / fence panels

Boat Trailor preparation

Preparing your boat trailer for galvanizing

This information sheet has been prepared by GB Galvanizing to take the guess work out of preparing a boat trailer for Galvanizing. This has been broken down into the following four sections:

Surface Preparation
Venting / Draining Holes
Galvanizing Parts and Accessories
Paperwork Required

Part 1 – SURFACE PREPARATION.

Many boat trailers will require sand blasting before they are ready for galvanizing. Some trailers will not need sand blasting if :

The trailer is made of new material or;
The trailer has already been galvanized and the zinc layer is unbroken.
(.Note: Acid stripping of old galvanized trailers is an extra charge.)

Any trailers that are painted require sand blasting (Blue or Green paint supplied on new tube will not require sand blasting).

Part 2 – VENTING / DRAINING HOLES.

Every tubular section of the boat trailer must have an opening at each end. This allows zinc to enter the tube and air to escape in order to prevent explosions.

Holes must be as close as possible to the ends of the tube. (Hole size should be a minimum of one third of the size of the tube – ie: a 40mm x 40mm tube requires a minimum hole size of 13mm.)

Part 3 – GALVANIZING PARTS AND ACCESSORIES

Leaf Springs
Leaf springs can not be Galvanized due to the fact, that they become very brittle and can fail at any time under load with no warning. There are Galvanized leaf springs available in the market, but these are specially manufactured to avoid embrittlement.

Tow Couplings
Tow couplings must be removed from the trailer or they will seize once Galvanized.

Threaded Items
Any threaded items will need the threads re cut after Galvanizing so that nuts and bolts will fit correctly once they are Galvanized. We do not recommend that U bolts be re galvanized. It is more economical to discard them and purchase pre galvanized U bolts with nuts to suit.

Mud Guards
Trailer mud guards that are separate to the main frame have by far the best Galvanizing finish and can be replaced more easily if you have an accident. Mud guards welded to the main frame could suffer some handling damage when turning the trailer in the Galvanizing process.

Box trailor preparation

Preparing your box trailer for galvanizing

This information sheet has been prepared by GB Galvanizing to take the guess work out of preparing a box trailer for Galvanizing. This has been broken down into the following four sections:

Surface Preparation
Venting / Draining Holes
Galvanizing Parts and Accessories
Minimizing Distortion
Paperwork Required

Part 1 – SURFACE PREPARATION.

Many box trailers will require sand blasting before they are ready for Galvanizing.
Some trailers will not need sand blasting if

The trailer is made of new material or;
The trailer has already been Galvanized and the zinc layer is unbroken.
(Note : Acid stripping of old Galvanized trailers is an extra charge.)

Any trailers that are painted require sand blasting (Blue or Green paint supplied on new tube will not require sand blasting).

Part 2 – VENTING / DRAINING HOLES.

Every tubular section of the trailer must have an opening at each end. This allows zinc to enter the tube and air to escape in order to prevent explosions due to pressure build ups.

Holes must be as close as possible to the ends of the tube. (Hole size should be a minimum of one third the size of the tube – ie: a 4Omm x 4OMM tube requires a minimum hole size of 13mm.)

Part 3 – GALVANIZING PARTS AND ACCESSORIES

Tow Couplings
Tow couplings must be removed from the trailer or they will seize once Galvanized.

Part 4 – MINIMIZING DISTORTION.

Box trailers are very susceptible to distortion usually because they are not designed with Hot Dip Galvanizing in mind, as the name suggests Hot Dip Galvanizing is a hot process , your trailer will be immersed in molten zinc at 450 degrees Celsius. Many box trailers have thin plate welded to a solid frame, tllis can cause problems when it is dipped because the plate builds up and expands faster than the frame does causing the frame to buckle.

So what do I do?
Preferred Method – If possible it is advisable to Galvanize the floor plate separately from the frame and bolt it in after Galvanizing using countersunk head bolts.
Next Preferred Method – Use thicker floor plate (more rigid and less likely to buckle)
Non Preferred Method – Leave trailer with welded floor plate in and accept that it will be more likely to distort.