I am looking for a way to make heat shrink tube mastic adhere to urathane tubing.
I am building a sensor that is to be used for winter maintenance vehicles (plow trucks). The sensor element is potted in a 3/4 inch steel tube with a 24 inch wire extending to a connector. The wire is protected by flexible tubing covering the wire from the sensor to a connector. A piece of shrink tube connects the tubing to the connector. The tubing needs to have good adhesion in the potting material and to the mastic liner of the shrink tube.
The problem I am finding is that it is hard to find a compatible tube that will adhere well to the potting material (Locktite urathane has been selected at this time) and the mastic liner of the shrink tube. I see poor "wetting" and adhesive strength of the surface of several types of tubing to either the potting or the mastic.
I tried urathane and various rubber tubing (1/4 ID, 3/8 OD). Rubber seems to adhere best to the mastic. I'd like to use a urathane tubing material, but I can't get the mastic to give good peel strength.
Are there materials I should try that "prepare" the surface of the urathane to allow good adhesion of a urethane material to the heat activated mastic of shrink tube?