dealing with windscreen fairing gap

How did you deal with this gap here, shown between the scrap angle and the skin?



I've procrastinated the windscreen fairing as long as possible and need to know what to do with the gap, shown here between the scrap piece of angle and the side of the top skin near the roll bar. Obviously, I'd like the fiberglass to lay flat there between the plexi and the bottom of that top skin where it overlaps the longeron. Question for others who have gone before me on this, should I:

1. Put some filler over the skin here and lay the fiberglass over it?
2. Lay up a layer or two of fiberglass, then fill, then lay more fiberglass on top?
3. None of the above?

Thanks for your suggestions.

Hey Steve,

Where did you get the windshield and what kind of tools did you use to put it on?

Would say to go try #1

Steve,
I spaced out the upper edge, corner of the alumnium to align to the windscreen. I screwed it in place with the spacer just like the windscreen.

Wet flox/epoxy mix is a suitable structural filler. Add a little cabosil to make it thixotropic if you're concerned about it running down the fuselage side.

A word about cabo...it will get lumpy in storage and be hard to mix into epoxy. Steal the flour sifter from the kitchen (or maybe your grandmother's kitchen). Same principle.

You may or may not choose to space the aluminum outboard (it is a good suggestion), but you do want it to be firmly fastened to structure before applying filler to fair the windshield.

DanH said:

Wet flox/epoxy mix is a suitable structural filler. Add a little cabosil to make it thixotropic if you're concerned about it running down the fuselage side.

A word about cabo...it will get lumpy in storage and be hard to mix into epoxy. Steal the flour sifter from the kitchen (or maybe your grandmother's kitchen). Same principle.

You may or may not choose to space the aluminum outboard (it is a good suggestion), but you do want it to be firmly fastened to structure before applying filler to fair the windshield.

Click to expand...

Yes, flox was my assumption based on one of your previous posts, Dan. Thanks. And I agree that Jeff's suggestion to use a spacer for the skin there at the roll bar is a good idea. Although that will only solve the gap problem at the last half-inch or so toward the trailing edge (and still require filler forward of that aft half-inch or so) at least I won't see that full thickness of flox when looking from the aft side.

DanH said:

Wet flox/epoxy mix is a suitable structural filler. Add a little cabosil to make it thixotropic if you're concerned about it running down the fuselage side.

Click to expand...

Any suggestions on what kind of ratio of flox to cabosil would be appropriate for this vertical surface? I know nothing about cabosil other than what it does and don't know whether I need be concerned about putting too much in. Normally, when using flox, I try to get about a thick peanut butter consistency. Will the mixture get thicker as I add the cabosil or does the cabosil merely make the flox stay where I put it?

alpinelakespilot2000 said:

Any suggestions on what kind of ratio of flox to cabosil would be appropriate for this vertical surface? I know nothing about cabosil other than what it does and don't know whether I need be concerned about putting too much in. Normally, when using flox, I try to get about a thick peanut butter consistency. Will the mixture get thicker as I add the cabosil or does the cabosil merely make the flox stay where I put it?

Click to expand...

With cabocil, I just add more until it is the consistency of axle grease. For most structural fills, I keep the ratio of cab to flox less than one part cabocil to three parts flox. But for a non-structural fill like this (that is, it carries no substantial structural loads), I might use only cabocil as the filler.

Wear a respirator when handling cabocil, it is bad for the lungs.

Thanks, Bob K.

Thanks Bob. How does cabosil sand compared to flox or microballoons? I'm already using flox to help glue the windscreen to the top skin, but for this location where it's purely filler overlayed with fiberglass, if cabosil alone is sufficient and if it sands/shapes easier than the other two, then it sounds like that might be the way to go. Thanks again.

alpinelakespilot2000 said:

Thanks Bob. How does cabosil sand compared to flox or microballoons? I'm already using flox to help glue the windscreen to the top skin, but for this location where it's purely filler overlayed with fiberglass, if cabosil alone is sufficient and if it sands/shapes easier than the other two, then it sounds like that might be the way to go. Thanks again.

Click to expand...

Cabocil sands pretty hard, way harder than microballoons. If sandability is what you want, and it's non-structural, I'd use microballoons instead, and put in just enough cabocil so that it doesn't run or slump off of your vertical surface.

Thanks, Bob K.

Steve,

I'm eager to see what you do here. I'm just about there, will be riveting top forward skin in place soon, and was pondering the same problem. I'd like to swing by and eyeball your FWF as well.

cln1owner said:

Steve,

I'm eager to see what you do here. I'm just about there, will be riveting top forward skin in place soon, and was pondering the same problem. I'd like to swing by and eyeball your FWF as well.

Click to expand...

Stop by anytime, Nate. I"ll put you to work helping me shoot the few last rivets on the longeron line. Been procrastinating on the windscreen b/c it's kind of like the canopy. Impossible to figure out until you do it once!