Galvanized screws represent the fasteners of choice for numerous sections marine crafts of equipment parts, thanks to their high resilience to corrosion in this challenging environment. However, this does not go to say that the process of galvanization confers the screws complete immunity.
Depending on how frequently they are subjected to saltwater as well as the salinity levels, the fasteners will eventually develop rust layers and salt buildups, which have the potential to lock them in place. Therefore, in order to replace the rusted screws, the first order of business consists of dislodging them from their location. Best case scenario, you’ll have to dissolve the layer of corrosion. Well, worst case scenario is that you’ll have to put the screw out of its misery. Let’s elaborate.
- The chemical approach – applying solvent solutions to liquefy the rust
First things first, let’s see if we can’t avoid the less gentle screw unhinging techniques. The principle here is that certain solutions such as Coca Cola (yes, it’s also good for that), freshly squeezed lemon juice or, if you prefer a more technical style, freshly synthesized hydrogen peroxide have the ability to remove corrosion buildups. Pour little bit into the screw’s head and let it soak it in. You can also tap the fastener gently to improve absorption. Even if this trick fails to loosen the screw, it will improve the rate of success for the next one.
- The mechanical approach – subjecting the screw to light impacts or twisting it
You first need to ensure that the dimensions of the screwdriver’s head match the ones of the screw, as otherwise you risk stripping it or damaging the utensil. Instead of turning it counterclockwise to loosen it, turn it clockwise as you would if you were tightening it; this may actually fragment the corrosion buildup, causing it to release its grip on the screw. A screw with a raised head can also be manipulated by locking the vice grips onto and twisting. Alternatively, lock the screwdriver onto the head and gently tap on its end with a hammer a few times.
- The temperature alteration approach – hot & cold screw ‘therapy’
With the mechanical approach providing close to no results, it’s time to test the effects of temperature changes on our stubborn galvanized screw. Using a propane torch or a soldering iron, proceed to heating up the screw, causing the metal to expand, but only if the materials in the proximity are not vulnerable to extreme heat. If they are, applying dry ice onto the screw constitutes a better solution, as the screw will contract and become easier to extract.
- The more drastic mechanical approach – smash and grab
If you’re still reading this, then none of these options worked and you’re dealing with a really stubborn fastener. Well then, nothing to do but say a prayer for it and bust it open. To do that, you’ll need a hammer and a chisel/punch. Place the chisel’s pointy end on the screws head and, with precise motions, hit the other end with the hammer. Be careful, as you don’t want to damage the hole, complicating repairs even further. The screw will eventually crack into 2 sections which you can remove with a pair of pliers.
Started my career in the fastener world in 1969 at, Parker Kalon Corp. a NJ based screw manufacturer located in Clifton, NJ working in inventory control, scheduling secondary production and concluding there in purchasing. In 1971 I accepted a sales position at Star Stainless Screw Co., Totowa, NJ working in inside sales and later as an outside salesman, having a successful career at Star I had the desire with a friend to start our own fastener distribution company in 1980 named: Divspec, Kenilworth, NJ. This was a successful adventure but ended in 1985 with me starting Melfast in August 1985 and have stayed competitive and successful to date. Melfast serves the OEM market with approximately 400 accounts nationally.