Introduction: Stabilize Corn Cob (or Wood Etc) for Knife Handle. on the Cheap...
This is an instructable on how to 'stabilise' a corn cob, or wood, or various other things. And, being me, this is how to do it on the cheap. You could buy a vacuum chamber and proper stabilising solution, but where's the fun in that?
Ready? Off we go :
Clutch bleeding kit - (less than £20)
Old mayonnaise/pickle jar - free
Rubber bung - Mine was from brewers airlock (£2)
Acetone (nail varnish remover) - (less than £5)
Polyurethane varnish - Mine was from the pound shop (£1 duh)
Epoxy glue - Mine was from the pound shop (£1 duh)
Corn cob - (£1)
Steel or brass rod 6mm - (£3up)
Step 1: Low and Long. Low and Long.
Dry your corn cob in a low oven (75c 175f) for maybe 8 - 10 hours. It has to be completely dry right through to the core .
You could skip this step and buy a dried cob from the pet shop (about £1). But that would be cheating...
Step 2: Constructing the Vacuum Chamber
Make sure that your jar has an airtight lid and make sure it's large enough to fit the cob with some space to spare.
Drill a hole in the middle of the lid a roughly similar size to the hole in the bung.
Glue the bung to the lid with some contact adhesive.
Poke the tube from the clutch kit through the bung and make sure it's a tight fit.
You now have a vacuum jar. Test that it can create and hold a vacuum. I got mine to 400 thingamibobs, but any reasonable level of vacuum will work. More vacuum will work more quickly.
Step 3: Chemical Brothers
Make a 50/50 or higher mix of acetone and polyurethane varnish. The mix needs to be thin as it has to seep right into the cob.
The job of the acetone is to thin the polyurethane enough to carry it through to every part of the cob. It will then evaporate
Put your cob in the jar and put in enough fluid to cover it when it inevitably sinks. It is important that you leave a reasonable gap at the top of your jar as it will expand under vacuum.
Step 4: You Suck
Squeeze the lever and get that vacuum going. Make the vacuum as strong as you can.
If all is well, the needle on the gauge will rise and you should see bubbles/froth coming out of the cob. This is your fluid being sucked into the pores and replacing the air. Woohoo!
As you can see in the photo, the cob and the bits of wood are all floating. As the air gets replaced with polyurethane they will sink.
If all is not well you need to figure out the problem. Is the jar not sealed properly? Is the tube or pump leaking?
The vacuum should be able to be sustained. As air is leaving the cob the vacuum will reduce so you will need to pump up the vacuum every now and then.
There is no rubber bung in this picture as this is Mk 1 and the plastic grommet that came with the clutch kit melted with use. Once I added the bung as a stand-off, it all worked much better. Learn from my mistakes my son...
Step 5: Leave It...
You now need to let the fluid do it's magic. I found with mine that 3 days worked wonders, topping up the vacuum every now and then. When increasing the vacuum doesn't create any more bubbles (2 days in my case), you are probably as done as you are likely to get, but adding a day doesn't do any harm.
Step 6: Leave It Some More...
When you get your cob out you should instantly note that it is much heavier. This is because the air has been replaced with polyurethane.
Hang it to dry somewhere where the smell won't bother your partner (sorry Rebecca).
Acetone obviously dries pretty quickly, but I left mine a full 24 hours.
Step 7: Boom!
You should now have some very tough stabilised corn. Tough enough to cut, drill, sand or throw at someone.
I cut mine with a circular saw by gluing it to a piece of wood with epoxy. That way I could cut it neatly into slabs ('scales') for the knife handle.
Step 8: Prepare Your Blade
In this case I made a rough and ready bread knife. I'm not going to go into the how. You could just take the handle off of a knife, I just prefer to do the whole thing.
Drill holes in the 'tang' (handle part of the blade). 2 for a small knife, 3 for a large knife. The holes need to be the same size as the 'pins' (metal rod) you are going to use. I think I used 6mm.
Step 9: Fix the Handle
There are various ways of fixing the scales on. Here's what works for me:
1. Cut the scales a bit too large for the tang. Cut the pins too long for the handle width.
2. Using the tang as a template, drill through the first hole and into the scale.
3. Put a pin through those holes to temporarily hold it together.
4. Repeat step 2 for the next hole. Pin that one too. Repeat for the next hole.
5. Do the same for the other scale.
6. Glue it all together with epoxy. Clamp until dried.
7. Sand the handle to shape, making sure you sand the pins flush.
Step 10: That's It!
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