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Nylon 66, glass filled - etching the surface in preparation for adhesive bonding

We need a soluion based etch for an injection molded nylon part on the inside to prepare the surface for the application of bonding cement. Most recommendations up to now have been to mechanically abrade the surface but it is impractical on ther inside of a small part that has geometry.

Bill Jaques
elastomers - Perry, Ohio
2006

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2006

Bill,

For a number of years we have used the following formulation for etching nylon (all grades) prior to adhesive bonding:

75 parts Potassium dichromate
120 parts Water
1750 parts sulfuric acid

Add the water to the Potassum dichromate and dissolve as much of the dichromate as you can (it won't be a lot). Add a small amount of the sulfuric acid with lots of stirring. This should dissolve the potassium dichromate. Add the rest of the sulfuric acid very slowly with lots of stirring to avoid local heating. Cool the solution to room temperature before use.

As for the etching the part should be immersed for 5-15 seconds and then rinses with distilled or demineralised water. Once etched the part should be bonded within 3 days, but can be extended to 14 days if bagged and kept clean.

Brian Terry
Aerospace - Yeovil, Somerset, UK

I don't know about nylon. Maybe it requires a chemical treatment such as the one already recommended. But if the only characteristic that you need is roughness, you may explore the possibility of imparting some roughness to the injection tool. This is frequently done to other plastics that will be bonded or ultrasound welded.

Guillermo Marrufo
Monterrey, NL, Mexico
2006