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Posted: 12/29/2015 4:52:48 PM EDT
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Is sandblasting 7075 aluminum the only way to achieve a nice matte finish?
When anodizing I normally etch in lye to clean and rough up the surface a bit. However, my normal process just don’t work well on the AR’s 7075 aluminum. I suspect the aluminum on the surface gets eaten away revealing just the zinc and/or copper. The lower then turns black and any etching/roughing of the surface is stopped. Anodizing and dyeing work just fine, but I end up with a way shinier surface than I’d like. Debating if it’s worth investing in any sandblasting equipment or just settle for shiny lowers. |
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Quoted:
Is sandblasting 7075 aluminum the only way to achieve a nice matte finish? When anodizing I normally etch in lye to clean and rough up the surface a bit. However, my normal process just don’t work well on the AR’s 7075 aluminum. I suspect the aluminum on the surface gets eaten away revealing just the zinc and/or copper. The lower then turns black and any etching/roughing of the surface is stopped. Anodizing and dyeing work just fine, but I end up with a way shinier surface than I’d like. Debating if it’s worth investing in any sandblasting equipment or just settle for shiny lowers. Glass beading, with the right sized media, will leave nice micro-craters on the surface, making a good matte finish. Etching will not leave near as rough a surface, especially after the anodizing process evens out the surface. |
| Just buy a cheap sand blast gun from Harbor Freight ($25.00) and a 50 lb bag of sandbox sand at Lowes ($3.50) and go for it. This will leave a nice, uniform, matte finish on the aluminum in advance of anodizing or finishing with Moly Resin or Cerakote. Reduce air pressure and shoot from farther away will yield a smoother surface. |
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Quoted:
Just buy a cheap sand blast gun from Harbor Freight ($25.00) and a 50 lb bag of sandbox sand at Lowes ($3.50) and go for it. This will leave a nice, uniform, matte finish on the aluminum... And possibly leave you with silicosis as well. Use either glass beads or aluminum oxide. If you insist on sand be sure to use a legit respirator (not a dust mask) |
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