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Cleco?s in Fibreglass

Jamesey

Well Known Member
May have been thought of before but can find nothing on this forum. When using cleco?s in fibreglass I find the don?t grip very well. Found this especially with the cooling duct. Used an old offcut from the wing ribs. Cut a slice about 3/16? wide. Marked it same dimension along the length, centrepunched then drilled #40 each square then cut the squares with tin snips. Gives a handful of small square washer which when used on the back of the cleco?s improves the grip substantially in fibreglass. Worked for me.
 
Not sure what you're working on, but it is often easy enough to bond a strip of aluminum, or small pieces of aluminum, to the backside of your fiberglass part. Not only for clecoing, but to give your rivets something suitable to bite into.

I don't know about others, but it seems that my fiberglass work always involves grinding/sanding down those flange thicknesses to get a good fit. Those thin spots seem like a good place to have a bit of extra meat, i.e. thin aluminum to back it up.

Any of the tip fairings, including wingtips, seem like a suitable spot for this.

ShoeGoo glue seems to work well to attach the aluminum. Proseal, or any other flexible glue should be OK. Epoxy resin doesn't stick as well, but can be used too... just don't push too hard on that drill bit or cleco.

I also keep a stash of aluminum washers handy. Interestingly, they can often be found in the aluminum gutter section of the local aircraft big box store. Or just go to online behemoth Amazon and search for 1/8 aluminum washer
 
I don't mind backing strips but in some places it's a pain and scraps of aluminum look just awful. But it's pretty easy to find washers that fit the rivet and they look super neat.
 
You'll want to grease up your Clecos so they don't bond to the fiberglass. I used AN960-4 washers (also greased up) on the back side for a better grip. After the epoxy is set up and the clecos and washers are removed, clean the area with wax and silicone remover (Prep-Sol), then fill in the remaining holes with flox. Peel ply on either side of the holes will keep the epoxy from draining out leave a fairly flat surface, ready for final finishing.
 
Baffle Washers

Instead of shaping and glueing a metal backing strip, I suggest using baffle washers . They're inexpensive and far easier to work with when riveting or cleco'ing and still do the job of distributing force across the fiberglass, in much the same manner as is done for baffle seals. And less material too, for the weight conscious folks...
 
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