Tuesday, 19 July 2011

Red Wooden Heart - Sanding and filling!

First half pre-sanding.
Right, now you should have 2 separate halves of your heart, some sanding sealer and some polish.

For this next stage you will need:
  • Coarse to fine sandpaper to fit your sander (I prefer aluminium oxide, 80 grit to 320 grit, but surface finishing may require some 400 grit wet and dry paper)
  • A palm sander (random orbital sander), and if you have the luxury of owning one, a detail sander to get in the top crevice.  I don’t have one, and managed ok, but it would have been easier with one.
  • If you need to fill some cracks, then pva glue mixed with wood dust, with a dash of red acrylic, or your more traditional wood filler.
  • A dust mask - wear it when sanding, unless you want to cough sawdust for the next week..
Starting to sand the edges off.
I probably don’t need to say it, as it will become obvious pretty quickly, but if you don’t clamp your work piece, you’ll just be chasing it round your workbench with your sander instead of actually removing surface material.  

I’ve got a cheap workbench, the kind that has holes in the top where you push in plastic stops.  For most jobs it’s a completely useless bit of equipment, but for this, it worked ok. Basically I put stops in around one side and sanded the other side, pushing against the stops, then swapped it round. But anything that prevents the thing moving around will work.

Start with the coarsest sandpaper and work all around the heart, keeping the base plate of your sander flat against the surface. You want to get rid of the steps in-between the layers, making the whole surface flat and smooth.  Graduate up to the finer sandpaper as the surface flattens out and you’re just trying to smooth it off, rather than shape it.

The pink bits are home made filler; pva glue mixed with sawdust & paint.
You’ll probably end up with a few places that need a bit of filling.  Usually I’d use wood filler, but as I know it doesn’t take stain very well, I decided it would be much better to mix my own.   

What I didn’t know was how the coloured polish would react with my home made filler.  I could have tested it of course, but as this whole thing was a bit of a test, I decided just to go for it.

So, I mixed pva wood glue with some sawdust (plenty of that around!), and tinted it with acrylic paint to be pink.  I wanted it to be red, but it turned out more pink due to the pva being white.  Incidentally I did try using some of the wood dye to stain the filler, but it didn't mix well with the pva, so I gave up on that idea.

In hindsight normal wood filler would probably have been ok, as with this method of staining the polish, the colour sits on top of the wood rather than sinking in too much.  If I was staining the wood first and applying a clear polish layer over it, it would have been a different story.  

Well, whatever filling method you choose, it’s time to smooth it on to fill those gaps.  See the photo for the places that I filled – they stand out pretty well, being pink!
One half done, one half just started..
 Then while that’s drying, tackle the other half of the heart.  Yes, more sanding!!  Trust me, it’s all worth it!

When you’ve got both sides filled and sanded to a pretty smooth finish, it’s time to join the 2 halves together!  Use a load of wood glue and leave it overnight to dry, ideally clamped if you can – it’s a tricky shape to clamp, so if that sounds impossible, even wrapping tape round it will help. Double check the edges are perfectly matched before you leave it to dry.

If there’s a slight gap between the 2 halves after joining them, then fill and sand that gap away!  

You should now have a heart that is 3D, with all the major sanding done and only surface finishing to deal with!

The two halves joined together, although it's pretty hard to tell from this angle!
So, you guessed it, surface finishing is covered in the next post!

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