Joining Two Parts Together

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#1

I’m fabricating the nose cone for this years Formula Hybrid team. Due to the size and curvature I decided to mold it in two sections. was wondering if there were any suggestions on joining the two pieces together. They’re floppy two layer fiberglass panels and due to my not so great application of bondo the joining edge doesn’t fit perfectly as well.

I was thinking about putting some supporting face inside, maybe think aluminum sheet, and then filling the gap with layers of fiberglass and sanding down smooth but I would like to know if there is a better way.

Also before you guys ask the horrible splotchy black is due to some bad dye that didn’t mix well in the epoxy.

Thanks in advance

#2

Have you thought about fiberglass or kevlar tape? They make rolls of the material you wet out and then apply along seams in layers.

#3

Are the sections just butting upto each other or is there some overlap?

#4

A tiny bit of overlap. I wasn’t sure whether I should cut them flush or work with overlap.

#5

At my dayjob I frequently do something similar. We have a part that fits a Ford fullsize van, however when we install it on a Chevy fullsize van we need to narrow it by 5".

To do this we cut it up, fit a BUTT joint, then grind a bevel 16:1 the thickness of the part on either side of the joint (halfway through the part).

Since the parts are CSM to start with we lay in strips of CSM into the V-bevel that is now cut into the part. Once cured we flip the part and grind another 16:1 V-bevel into it and fill that in with strips of CSM. Make sure your bevel touches the new glass that you added on the other side so that the fibers end up right next to each other and you don’t have a strip of resin only.

As an example for a 1/8" thick part the bevel is 2" on either side of the joint line for a total repair width of 4".

I hope that makes sense…

#6

That completely makes sense. The parts in question here are extremely thin, 2 layer fiberglass but since you’ve brought it up it makes the most sense and I think I’m going to go that route. Thanks for the tip!

#7

place flash tape on the bigger part at the edge… the plastic blue stuff thats semi clear. then get 2 layers of carbon tape and lay up a doubler. id go with 2-4 inches wide. then bond it tight to one side and slip the other over and bond.

id use #40 clecos to pull it all tight. the more the better… even then you could use thin plastic on the outside as a backup to keep it from waving on you and give you even pressure.

#8

a nice strong scarf is like 50-1 up to 100-1 for overlap iirc