Since I didn't actually make this guitar, I don't have any wood left over from the build to test some sanding, grain filling and staining techniques. To overcome this, I've brought some mahogany for bowl making from eBay as a test piece. It only cost about £6.50 so not too bad.
I started by using 220 grit wet-n-dry sanding paper. I used a 3M rubber sanding block so I kept a flat surface when sanding. After a couple of passes with the sanding block I hoover'd (or Dyson'd) the mahogany and the sanding paper and done another couple of passes. I'd heard its important to keep the sanding paper well dusted whilst sanding, and I really did notice the difference after it had been cleaned.
After the surface felt fairly smooth, which only took about 4 sessions of sanding and dusting, I moved up to 320 grit wet-n-dry and then 400 grit wet-n-dry and repeated the whole process with each grit. At each stage I sanded in the direction of the grain. This is so I didn't put scratches across the grain which apparently can become very visible once the lacquer is applied.
By now the test piece was really smooth and looking great. The next step is to test the grain filler. I'd found a great tutorial at
www.manchesterguitartech.co.uk about how to use Rustins Grain Filler, which apparently takes a stain very well. It was available in a variety of colours so I decided to go for one in natural and one in mahogany. My plan is to use the mahogany on the mahogany and the natural on the ash. I got them from Amazon and were about £4.80 each.
I thinned the grain filler with some white spirit until it was about the thickness of double-cream (as suggested by the tutorial at
www.manchesterguitartech.co.uk) and started applying it to the wood. I found it easiest to rub the filler into the grain using my fingers and then removed any excess with an old credit card. I left it to dry for about an hour and a half and sanded it again with 400 grit wet-n-dry.
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| The mahogany test piece |
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| Starting to look just as I wanted it to |
I was amazed at how smooth it was after the grain filling and sanding. The grain filler had done an amazing job, but, on closer inspection I noticed that there were a few grains which hadn't been filled. I think I may have been a bit quick on removing the excess filler and may have pulled some of it out of the grain. I've decided to give it another going over with grain filler and this time to leave it about an hour before removing any excess. As I'd run out of time for the day I thought I would just have a quick preview on how the finished product might look:
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| The mahogany grain filled test piece against the un-sanded or filled guitar body. |
It definitely looks 'warmer' which is the look I'm going for but I would like it to be a bit more brown as the mahogany grain filler has made it look very slightly red-ish. I'm going to try giving it a bit of brown wood stain after I've done the grain filling again.
The Second Coat
Once the bulk of the excess had been scraped off (and the sun had gone in!) it was starting to look more like the brown I was going for. I'll leave it for 24 hours before sanding again.
In the meantime, my ash burr test piece had arrived so I thought I'd test the natural grain filler. It isn't exactly the same as the ash burl on the guitar but it should give a good idea on how it will look.
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| Ash burr test piece |
I did exactly the same on the ash burr as I did with the mahogany: sanding with 220 - 320 - 400 then applying the grain filler. I left it for 30 minutes before scraping off the excess and the filler seemed a little wet still so I think 45 minutes is the right time to wait.
Ash Burr Failed
The Ash burr turned out to be a bit of a waste of time. The pieces I'd ordered were so thin I could barely sand them at all and without breaking them into pieces. So when the last piece of ash burr was destroyed by sanding, there was only one option left....the guitar was now the test piece...uh oh!
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