is epoxy strong enought to do this?

Discussion in 'Luthier's Corner' started by mike_odonovan, Jun 4, 2005.

  1. i have shaped my bass body a bit too much and am wondering if i can build it back up in a couple of areas using a tin of epoxy.
    i took too much off the armrest curve and now it doesn't feel right.
    basically how good is this stuff at sticking to wood?
    anything i can do to help it stick?
    like scoring the wood beforehand?
    in 3 years time will the stuff crack off when i bump the bass getting into the van?
  2. You're on the right track but it's not epoxy you need to use to reshape it - it's Bondo. The stuff used in auto body repair. They sell it at Home Depot now. Mix it up and trowel it into the rough shape. Once it sets - in about 15- 20 minutes, you begin shaping and then sanding. There's a window of work time of a coupla dozen hours before it gets real hard and more difficult to shape. By that time, you should be into final sanding and getting ready to prime and paint.

    You would be surprised how much of this or similar stuff is under the painted surfaces of guitars out there :eek:
  3. nateo

    nateo Schubie Fan #1

    Mar 2, 2003
    Ottawa, Ontario
    I've used automotive glazing putty with decent success. It's thinner than Bondo so it does a good job of filling little imperfections under the paint.

  4. Nate, that's what the glazing putty is good for. But read it's label and it will say that it shouldn't be used for anything deeper than surface pits and scratches. I know this because I've tried it thicker :rollno: It just doesn't set up at all quickly and it tends to shrink considerably. That's what the Bondo doesn't to because it's got much more of the solids in it.
  5. nateo

    nateo Schubie Fan #1

    Mar 2, 2003
    Ottawa, Ontario
    Like so many things in life, you can get to where you want if you have some patience. I've used glazing putty to fill deeper nicks and dents, but it has to be done in a whole pile of thin coats. It takes a long time, but shrinkage becomes a non-issue. Even stuff like Bondo is supposed to be kept as thin as possible to minimize shrinkage.

    The last time I did any autobody work we learned that it's a whole lot easier to shape sheet metal than it is to shape filler. I suppose the same thing goes for wood, in that it's always nicer to get it right the first time. Unfortunately, mistakes will be made.

  6. This works great. 10 years ago, I did some major renovations to a house. One thing I did was to repair some nice red cedar doors and windows (35mm and 45mm thick), that had some large pieces missing from the edge. Another thing was to repair the wooden eaves (25mm thick) on the outside of the place that had very large chunks damaged from rot (the hole was roughly 120mm x 900mm). I used car bog for both jobs. 10 years on and still going strong, even the eaves (handles the weather very well), no cracks or splits.
  7. Boy you got that right - There are two situations and two approaches to take in these situations - the first is making cuts that should be precise and the adage to use there is "Measure twice, cut once". The second is doing things like contours whose shape can be a subjective call. For these situations I try to keep in mind "Don't work it to death - Better to stop early than too late" or "It was probably perfect 2 minutes ago".

    Wood - it's easy to take off and a real pain to put back. :D