Thursday, April 15, 2010

Etching Acetal (Delrin) plastic in preparation for painting, gluing, etc

It looks like it might be possible to glue delrin with 3M DP-8005 after this chromic acid etching process. I'll do some more testing later.

I mixed:
40g water
25g potassium dichromate
500g concentrated sulfuric acid
I guess this mixture is commonly called chromic acid.

Things that I should have done:
Use a Pyrex beaker

Don't use the magnetic stirrer, just use a teflon stir stick

Use an ice bath at the beginning of the procedure


  1. Also don't expose your skin... and use nitrile gloves.

  2. Thanks for the information on etching Delrin. I am a model railroader who paints diesel engines, and have had trouble with paint adhesion on the Delrin handrails and other small details. I'm going to try your idea. I'll let you know what happens.
    Thanks again.
    Alan in Maine.

  3. I just tried flaming the Delrin surface and it is quite effective. Just used a standard propane torch flamed the surface briefly. See for more information about surface preparation.
    I used Loctite U-05FL.

  4. Idea is not bad but must be careful and use nitrile gloves to avoid any trouble with skin.

  5. Thanks for sharing. I hope it will be helpful to many people that are searching for this topic. Keep posting guys and keep this forum a great place to learn things.

  6. Well its too dangerous to expose your skin. proper glove should be use to produce such exercise.

  7. Thanks for the video. Do you know if it is safe to store the mixture for later use? If so, do you know what the approximate shelf life is? Thanks.