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Q&As since 1989


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Grade 5 bolt question

I am installing e-track in my motorcycle trailer and have a question regarding the proper bolt to use, material wise. I prefer to use a Grade 5 bolt, but I am concerned about corrosion. Stainless steel would be preferred but I am concerned about strength. I will be strapping two large dresser style motorcycles in the trailer. If I use a Grade 5 steel bolt is there a problem with corrosion. I can only find these in Zinc? Confused. Help.

Joe Baker
- Edgewater, Maryland, USA
2003

One approach would be to cover the threads with bearing grease (a thin film) and then paint the bolt head and nut after installation. Inspect monthly and replace when it starts to rust more than you can live with. Plan B is to oversize the bolt diameter.

James Watts
- Navarre, Florida
2003

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2003

Plastics are metallised for thousands of reasons, but in general it is to make the plastic look like a metal component. Plastic parts are cheaper and easier to fabricate than their metal counterpart, but only certain ones can be successfully plated.

These include ABS, PP, HIPS, MIPS, SAN, acrylics, etc. The generic way of doing it is to etch their surface and then activate with a suitable noble metal system. Once activated the plastic can be coated with an electroless metal deposit and then thickened by an electrochemically deposited metal.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK