RocketScience
Member
- Joined
- Aug 27, 2017
- Messages
- 16
- Reaction score
- 2
The proper way to prep aluminum for adhesive bonding is to phosphoric acid anodize (no-seal) and use a thin (almost see-through) primer designed for bonding and bond to that. An alternative is to use an adhesive promoting alodine. Another lesser alternative is to sulfuric acid anodize without a seal and the same primer. Adhesive bonding to raw aluminum doesn't work that well as you found out.
Additionally, the design of the fins at the base should have been tapered as high a ratio (shallow) to a knife edge. The stress is all built up at the edges and the weak bond made it unzip.
So for rocketeers, taper from about .020" to desired thickness at fin, say .12", while conforming to shape of rocket, and alodine and bond. Anodize is better but cannot do in garage.
Additionally, the design of the fins at the base should have been tapered as high a ratio (shallow) to a knife edge. The stress is all built up at the edges and the weak bond made it unzip.
So for rocketeers, taper from about .020" to desired thickness at fin, say .12", while conforming to shape of rocket, and alodine and bond. Anodize is better but cannot do in garage.
Last edited: