Installing Formers in a Fiberglass Fuse

This article is based on epoxy fiberglass fuse and this method works equally well to polyester resin fuses, the only difference is using polyester laminating resin instead of an epoxy resin. (don't use epoxy on polyster fuses or poly on epoxy fuses).  One of my local buddies showed me this method several year ago, have seen this method done on many high-end fiberglass kits and I now only install formers this way as I find it very easy to do.

What you need before you install your formers in the fiberglass fuse.

  • You need to test fit the formers
  • Mark the location of the former on the outside with a Sharpie pen
  • Sand the inside where you have marked and clean the inside from dusts
  • Rub the inside with cloth damped with Acetone

What you need to get started.

  • Epoxy. You will need something that is similar to West System Resin #105 and hardener #206. West System is a low viscosity epoxy resin and does not require any thinning agents. The 206 will dry rock solid in less the 24 hours at 70 degree and can be handled in 6-8 hours. The #206 hardener can be used before it starts to gel in about 20-30 minutes depending on temperature. The product does not recommend adding any thinning agent as it affects cure rate and physical properties.
  • Fiberglass tow.  You can purchase this in a roll or you can purchase a heavy woven roving material 40oz per square yard. A single yard of this stuff will last a lifetime.
  • Acid Brush, mixing cup and a cardboard you can throw away.



Installing the former

  • First, place your former into the fuse and CA in several places so that it will not move when you apply the fiberglass tow.

  • Second, separate a cord from the woven roving, be very careful that you do not handle the tow too much or the tiny strand will start to separate (fray). Place it on a cardboard immediately and apply your resin. Follow the instruction on mixing your epoxy or polyester resin.

  • Third, wet the tow. Do not worry about the length of the tow and do not cut it while it is dry,  it will fray and become a big mess. It is easier to cut it with a scissor when wet and much easier to handle and put inside the fuse. It does not have to be a perfect perimeter length of the former, it will be easier to install them in two short pieces than one long one, you can overlap short pieces together. Brush the resin while holding one end of the fiberglass cord then proceed to wet the entire cord. You can help the resin soak into the tow using firm brush strokes.

  • Cut the tow to size and you need to position it near the edge of the former. You can use your brush to position it between the former and the fiberglass fuse. The example shown required the use of an extension on my acid brush as the former was near the small tail portion of the fiberglass fuse. I suggest practicing on a former that is easily accessible.  

  • Work the glass tow toward the edge of the former and have it meet up with the glass fuse.

You see there is nothing to it. You now have a strong joint to the glass fuse and a stronger former to boot. You can also apply tow to the other side of the former and make it stronger... the formers in this picture are only to keep the fiberglass fuse from collapsing during transport, in this case I installed tow to one side only. The next picture is a tail wheel former which I have applied tow to both sides. You can also use carbon fiber tow to special formers for added strength.


Good luck and I hope this method will work for you as it has for me.