Repairing glass fiber tubes

The glass fiber tube repair kit is available from the mast manufacturer Exel.

The damage can be repaired as long as it is less than half of the circumference of the tube. If the tube is fully broken, contact Vaisala.

Acetone
Brush, width approximately 20 … 50 mm (0.78 … 1.96 in)
Glass fiber mat reel: reel B (35 … 50 mm / 1.38 … 1.97 in). For example, weight 425 g/m², warp 70×320, weft 53×272, thickness 0.32 weave plain
Hardener (Component B), Butanox 50
Mixing pots: PE/PP‑plastic, 1 liter (0.26 gal)
Paper or cloth towel
Pre-accelerated Epoxy Vinyl Ester Resin (Component A), Derakane 411 … 45
Sand paper: fine, grit size 200 … 400
Syringe, 20 ml (0.68 US fl oz)
Tape, polypropylene, PP
Two‑component polyurethane paint, signal red RAL3001 and traffic white RAL9016 (valid only for the coloring that complies with ICAO standards)
Wooden or plastic mixing stick

Wear personal protective equipment (PPE).

Wear safety glasses and rubber gloves all the time.

Wear a dust respirator filter when necessary.

WARNING Read and follow the mast manufacturer safety instructions.

WARNING Acetone is flammable. Make sure that there is good ventilation and avoid skin contact during repair and painting.

Due to the flammability of the components, special packaging is required. Be prepared for higher air freight costs.

Arrange the repair conditions as instructed by the resin or hardener producer.

Prepare the glass fiber tubes.
1. Remove dirt and old paint with acetone and paper.
2. Abrade and clean the surfaces with sand paper.
3. Remove dust with acetone and paper or towel.
Mix the components.

CAUTION Read the manufacturer instructions carefully and follow them.
1. Use a syringe or a scale to measure the quantities of the different components.
2. Do not mix more than 100 g (3.53 oz) at a time, because you have only about 25 minutes to work before the mix hardens.
  
  Normal mixing ratio:
  
  $\frac{C o m p o n e n t A}{C o m p o n e n t B} = \frac{100}{1,5}$
Spread the mixed resin on the damaged area.
Soak the damaged area with the resin.
Wrap the glass fiber mat tightly around the damaged area, and simultaneously spread more resin over the mat.

To obtain as much strength as possible, make sure that the mat is fully soaked.
Wrap at least 2 full layers, 3 or 4 layers where possible. Place the layers in 30 … 45° angles to each other.
To remove air and penetrate the resin into the tube structure, wrap polypropylene tape around the repaired area.
Let the resin cure in the instructed temperature for 24 hours.
Remove the polypropylene tape.
Abrade the surface with sand paper.
Continue to paint the repaired area.

Repairing glass fiber tubes - DKE110F