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Dienstag, 3. Dezember 2013

Broken Aluminum Frame repair with fiberglass and resin.

I bought a used bike to repair and resell and noticed, that the frame had a crack. I decided to build up a rigid mountain bike for myself and repair the frame. 

The bike was a Pinarello Treviso Mountainbike, a very rare bike from 1990 or 1991. Aluminium frames were pretty rare at that time, however the weight of the frame is only 1.6 kg.  Quite obvious that it broke.

If you look at the dropout, you notice, that it is welded the rear tube, which got squashed. An obvious design flaw. Since I can't weld aluminum, and always wanted to repair a cracked frame with fiberglass and resin, I repaired the frame this way:
 At first, I brazed a steel base layer, which distributes the force from the dropout better to the brittle aluminum frame.

 With a lot of good glue and some fibres, I glued the steelframe to the aluminium frame.
 I covered everything with resin and added fiberglass. I used an old bicycle tube to apply pressure to the fiberglass. With this technique you can use a lot more fibers and less resin which makes the frame stronger.
 After a few layers, I finished it.

 As a test ride, I took the bike to the most difficult trail in my area and rode it hard. It is interesting what you can do with a rigid bike, if you have tires with a lot of grip. I always thought before, that I would need my Enduro to ride that trail.

 I know I mixed up the components from two decades. I can already feel the retro bike enthusiasts cringing.
 The repaired part of the frame:


  1. A customer sent us there very expensive Prada bag for a repair to a spot of colour loss. The colour loss was originally a pen mark which the owner cleaned with an abrasive cleaner which not only took the pen mark out but removed the dye as well. The bag was sent back to Italy Prada who said they was not able to repair/recolour.

  2. Well, I would say it's really a great idea to repair broken aluminum frame with fiberglass and resin as it will make it harder and it will be more durable and run for longer.

    Fibreglass repairs

  3. It looks good as new after that solid repair work, man. Bicycles are hinged on a really good frame. So, you have to make sure its metals are dense and strong. Thanks for sharing these repair tricks!

    Bernice Parsons @ Badger Anodising

  4. I really like your idea of repairing a broken aluminum frame. Thanks for sharing this idea with us.

    welding aluminum