Locating holes in fiberglass wheel pants

[PaulvS]

The plans call for the fiberglass wheel pants to be mounted onto metal brackets with screws into plate nuts and these screw holes need to be drilled "blind" because the fiberglass is opaque. Section 5.18 of the construction manual outlines a process for doing this with magnets, in 27 steps. Other builders have used a laser pointer to mark the spot to drill.

Another method is as follows and the concept is to wet mold the screw hole locations from the inside of the wheel pant.

1. Drill pilot holes #40 in the bracket where the screws will go and insert temporary rivets with tails pointing out. Cover the bracket with a piece of packing tape and push the rivets into the tape to form indents. Add some masking tape to the rivet heads to hold them in.


2. Apply a teaspoon of epoxy flox paste to the bracket and the wheel pant.



3. Carefully fit and hold the pant in position while the epoxy paste cures.


4. Remove the pant when the epoxy has cured and drill from the inside #40 through the indentations that have been molded into the paste.


5. Attach the plate nuts in the normal way using the pilot holes as a guide for the final size screw holes.

This process worked extremely well for me (YMMV). I tried the laser pointer first but the dot was too big to be sufficiently accurate.

 

[wirejock]

Technique

Very clever. I like.
Maybe wax the rivets and go ahead and push them all the way so there's a nice hole left behind in the flox.
That's pretty brilliant.

 

[Scott Hersha]

I have these little ball bearing-like magnets. They of course won’t stick to aluminum, but they are pretty powerful, and stick right where the platenuts are - right through the fiberglass pant. Clamp the pant in place and the magnets “stick” right over the hole with the installed platenut. To make it more “attractive”, put a steel flush screw in the platenut first.

….. after re-reading this post, it sounds like that’s what the plans are saying to do now. And I thought it was my idea….

 

[Webb]

Seems like a lot of work when you can sand some gel coat off and shine a light from inside the fairing.

 

[Walt]

Have used this kit multiple times when dealing with painted parts, works great .

https://www.aircraft-tool.com/detail?id=MAGFIND01