First I'd like to get a blast cabinet. Are the better ones with included vacuum systems such as from eastwood safe to use indoors. How much leakage is there. Can the risk be minimized by using different media. I have two young kids and would not want to take a risk.
Number two. I've read that carbide router bits can be used on aluminum (6061 in this case). Is this true. Also do I need to use a speed control on the router to slow it down or can it run full speed.
Exactly what do you mean by inside? Certainly not near or adjacent to your living space, IMHO. You definitely would want to use silica free, low dust generating media and exhaust it outside. Even so, some particles in the respirable size range are going to be floating around the blast cabinet and could move from a garage into your living space, unless you can maintain continuous negative air. You also have to consider any hazards from the stuff you're blasting.
Blast cabinets tend to lose a little dust, even with a good vacuum system. What I do is use a squirrel cage blower and discharge the exhaust outside. I live out in the country, where it's not a problem. If you live in a sub-division, that might not be a solution to your problem. I strongly suggest it as a solution if possible. It's cheaper and far more effective. Should you choose this direction, try to use a blower that doesn't move too much air. When you do, you also remove your media.
What's important is that you try for a negative pressure in the environment. Remember, you're discharging compressed air in the cabinet, along with making dust, so it has to go somewhere. The vacuum systems sold for such cabinets do a fair job, but they're clearly a PITA because they plug off and restrict air movement.
No dust is good for them, but avoid using silica sand, which creates serious health issues for everyone concerned. I'd suggest you invest in proper media, which costs more, but will last a long time and do a great job, and is considerably safer. Aluminum oxide is a good idea.
Speed in aluminum is virtually a non-issue. Fortunately, the carbide grade used for wood is also proper for non-ferrous metals, so you can likely get away with it, but be aware that metal grabs more than does wood. If you use large form cutters, you're inviting serious injury. Without knowing more, it would be difficult to give any solid advice, but, yes, in principle, you can cut aluminum with a router. If you find you're experiencing welding of chips on the cutter, try lubricating with some kerosene, or some WD-40, which smells much nicer and will do the same job. It is messy.
Wear eye, face, and arm protection as well. The system works just fine, but the chips come off blisteringly hot, and flying at high velocity. Even when it works without injuring you, it's often a painful operation. Same as cutting Al plate with a table saw... works fine, but HURTS!
Thanks for the advice. I think I'll get a good cabinet but wheel it outdoors for use and use some of the less toxic media. I will also try to rout my aluminum but plan to do it slowly taking only a small amount of material at a time. Even if it takes many passes.