Tuesday, August 5, 2014

See some old friends

Took the day off and went to see some old friends. Just like in this song, it is good for the soul. Stopped in at the old workplace and saw some folks. Had a coffee. Shot the shit etc. Going to have to do that again soon! :-)

So with lots of time on my hands to think I keep looking back at all the work that went into the outside of the hull. I really cant fathom that I actually did all that. It seems kind of surreal in that I don't remember doing half of it! ;-)  Back to the thinking part. I have tinkered with 'Vacuum Resin Infusion' method of making small fiberglass parts. A few years ago I tinkered together a fiberglass on foam cover for our sump pump hole. The cats kept knocking stuff in there gumming up the pump switch.
The whole process is pretty simple. You cover the core (styrofoam) with fiberglass. Enclose the whole thing in a plastic bag, apply a vacuum at one end and resin inlet at the other end. The resin 'infuses' the part leaving you with an ideal resin to fiberglass ratio. The whole process is pretty clean (if you don't spill the resin on the basement floor) (and especially don't just drag an old carpet over it to cover it up). :-)
There's a wee bit more to it than that but you get the idea. You keep the vacuum on the part till the resin cures then you remove the plastic film etc. and you have a perfect part.
Repeat the whole process again and you have the part that appears in the first picture above. Anyhow, what's all this got to do with building a boat. Well resin infusion techniques have been used in boat building for ohhhhhhh 15 yrs or so now, maybe longer and today it's almost the industry standard for new boat construction. Here's a quick example.

The benefits are:
  1. Dry layup of reinforcements
  2. Lighter & stronger composite structures
  3. Tighter control of the production environment
  4. More environmentally friendly (no solvents etc. enter the atmosphere)
  5. and most importantly, NO FRIGGING SANDING! :-)
I'm sure there's others I just can't think of them right now. As to the downsides:
  1. More technically challenging
  2. Expensive consumables (that don't become part of the structure)
  3. Resin is generally more expensive
  4. When it goes wrong, it really goes wrong!
Here's the consumables that get thrown away for just that little part in the picture above.
I don't think any of it is recyclable. Not around here anyways. This is probably the single most important factor that keeps me from using the infusion method more but after all the work that went into the outside of the hull I'm starting to reconsider it again. I know the inside of the boat is too big for just me to get all the layers of fiberglass on 'wet on wet' (the ideal method) so I'm considering infusing the inside.

I have the equipment (except a backup vacuum pump) and I've watched just about every Youtube video of the process being used on boat construction and read every forum & blog about resin infusion. I'm pretty sure I can scale up my experiences to do the inside of the hull. It'll take some balls & patience but I'm sure I can do it. I sat down tonight to crunch some numbers to see what it'll cost. Here's what I came up with so far.

The top part of the spreadsheet is me figuring out the surface area to be covered and the weights of the fabric that will go on each. If I'm assuming a 50/50 glass to resin ratio (pretty good) I'll need approx. 16 gallons of epoxy. I'm pretty sure I used almost 50 gallons on the outside of the hull. :-( A lot of which got sanded back off to fix my mistakes.

You can see the single biggest cost is the resin itself. I've looked far and wide to locate the best price on epoxy resin suitable for infusion. The consumables are actually a much smaller percentage of the overall cost than I expected. :-)  When you consider this is a lot less than half of what I figure it cost me to do the outside of the hull and there's no sanding or wasted resin or messes to clean up it actually makes some considerable economic sense. The downside is I'll have to wait till next spring to actually do it. Ideal weather (temperature) conditions are very important to the process and I don't expect I'll have enough saved up to buy the resin & consumables before spring anyways.

So to get the through the rest of this year there's these things to do:
  1. Sand the keel
  2. Paint the keel with anti-fouling
  3. Flip the boat over
  4. Fill the kerfs in the bototm panel
  5. Sand the inside seams, fillet & tape them
  6. Fix the shed roof.
That's it. That's all that will get done this year. I'll have to find another hobby!  :-)