Tuesday, March 15, 2011

Pulling fillets

Somewhat unexpectedly we ended up gluing & filleting the cargo bed and head tube mast last night. I was sure we would need another week to get everything ready but after cutting out the front & back head tube panels, the ones we completely overlooked when we cnc'd the parts, and trimming the forward head tube it was only 9.00pm. "Let's get gluing" announced Jeff and in short order we were mixing epoxy and laying sheets of plastic for the parts. Working with epoxy is icky, slimy work and it gets everywhere. Being asthmatic I have a particular paranoia about VOC's and gnarly particulates so I was fully encased in a jolly yellow hazmat coverall, respirator, goggles and gloves. Jeff nonchalantly opted for a dust mask & apron. For some reason we (or maybe it was just me) decided to go with orange tinted goop for the fillets. It felt a bit like caulking with salmon mousse. Pulling fillets is exhausting work especially when you have a corners to fill and this structure has a lot of corners. After three solid hours of this the front end was done. We are really not sure how straight this is going to be and going forward ensuring correct alignment will be critical. Right now we just want to get something built and so many of these questions will have to remain unanswered until after the rubber hits the road.

However we did start brainstorming ways to replace the goop with something that was easier and cleaner to apply. We created a plywood test piece with an assortment of rope, fabric, paper and carbon fiber strands epoxied into the intersections. We will let that set and come back for some destruction testing later. Ideally we need a material we can easily pre-cut to set lengths, dunk in epoxy and lay down with minimum mess & waste. I'm thinking laces from hiking boots.....cheap and available in all sorts of cool colors & patterns. We shall see.........

1 comment:

  1. Pulling Fillets.
    Used with success: wood saw dust, flour, polyester spheres.

    Easy fillet suggestion:
    thin wood strips, as used joining violin family belly/back to ribs.
    Brush epoxy (with some anti-sag powder in it) on to the seam were contact will take place.
    Lightly brush fillet strip (to ensure complete wetting).
    Place fillet on seam, press into place to remove excess epoxy from joint.
    Brush over top.
    For greater strength, later brush a second time.

    Wood strip fillets are thin, easily shaped, and can be curved with mild heat treatment. Compound curves are possible. Low cost, use local wood. Fast, as long strips can be prepared in bulk in advance to your fillet profile, and then cut to required length with shears or one stroke of a crafting pull saw, either from a cut list or custom fit by the piece.