Screws and fasteners other than rivets

[cameront120]

Has anyone here bothered to swap out all of the screws for fastening marker lights, etc. with stainless fasteners? I'm thinking of switching them all out to stainless steel and am wondering if anyone has discovered if there is a common screw size, or do they vary from application to application? Thanks in advance for any thoughts.

Cheers!

[Tim A.]

I suspect that the screws for similar looking marker lights are the same, but might be different from other lights, etc. To make such replacements, I have removed a sample screw and gone to my local hardware or marine supply store in order to buy equivalent stainless steel screws.

You should be aware that using all stainless screws is not a guaranty against corrosion. Galvanic (or electrolytic) corrosion is possible any place where water can collect for a period of time at the contact between aluminum and the stainless screws. This is not the same as rust and may attack the aluminum without affecting the stainless. Because it requires the presence of water, it is much more common in boats than in trailers. Some forms of hardened aluminum are particularly sensitive to galvanic corrosion. I mention this type of corrosion only because it is possible, not because it is likely with your trailer. Galvanic corrosion is more likely to occur for aluminum trailers in locations with aerosol salt, such as along a marine coast with surf.

[cameront120]

That's interesting Tim. I never thought of that type of corrosion. I wonder if this would be much of a concern if the lights were given a bead of sikaflex around their perimeter and into the screw hole before fastening?

[nickcrowhurst]

Cameron, half inch #8 stainless steel self-tapping screws from the local hardware store work for me. You will need hundreds if, like me, you replace them inside as well as outside. I've found it more economical to buy complete boxes, rather than loose. I have not found galvanic corrosion to be a problem, but, if you are near the ocean, a little zinc chromate paste or Sikaflex on the threads would do no harm.
Nick.

[Tim A.]

The reason I brought up galvanic corrosion is because so many seem to expect "perfect" solutions, whether it is stainless steel, UV-proof plastic, paint and clearcoating, or plywood. Unfortunately, nothing is perfect!

I have replaced many screws on our Bambi with stainless steel ones and have been very happy with doing so. For any exterior application, that has meant a little blob of sealant because I want those screw holes to be watertight. I happen to use mostly 3M marine sealant (urethane type) because that is easy for me to get when I find that the old tube has turned into a rock.

[cameront120]

Thank you both for your tips and input!