Overall a happy little nice project to have something fun to do when the time is right.
But i've learned something about sandblasting. I'm not unfamiliar with it since we did a lot of glassbeadblasting at my former workplace and the process is clear. Now i wanted to continue it at home in my garage or rather outside where the dust wouldn't cause a mess.
Yesterday i got a sodablastergun, a condensefilter for the air pressure line (to avoid soda getting clogged up from humid air) and a big canister of soda.
The target to blast was the burnt black bits of oil and residue on the aluminium block to get as clean surface as possible. I had washed it thoroughly with a metallic cleaner solution but it didn't get rid of the residue. I also tried powerwashing it and no result. So next on my list was sodablasting. It didn't help either and removed nothing. It removed paint from wood but the residue on the aluminium didn't budge.
So.. I then did some research to find out more about blasting basics and share it here (hopefully useful if you are planning on blasting at home).
Apart from sand- and glassblasting there's also soda-, aluminiumoxide- and dryiceblasting. What's the difference between them, what's best to use and what works and don't work?
The material ("sand") is often referred to as "media". There's not only these different medias in blasting but also a couple different ways to do it and different tools for the job but i'll tell what i've found out so far in general.
Sandblasting:
Even though the term sandblasting is used widely in general to describe blasting with whatever form of grain material, it is also a specific media and the oldest form of sandblasting.
Pros:
- Sand is cheap, but has to be specific sandblasting sand, not from some beach.
- It's pretty effective on the surface
Cons:
- If it contains quartz it is very dangerous and can cause lifelong silica lung syndrome which very dangerous
- Full protective gear needed
- Pretty high amount of dust
- Makes a big mess if used outdoors
- Might not be available in as fine grit as you'd want to use
- Can damage the surface, while being effective on the tough paint or residue, gets the job done fairly fast but might affect tolerances on the component like bearing housing.
Glassblasting:
Looks like very fine white sand powder but is in fact finegrit glassbead powder. The microscopic beads hit the surface and explode in pieces so the flow and media amount needs to be adjusted just right.
Pros:
- Most suitable for a polishing blasting
- Pretty careful against the surface of the object, also edges and details
Cons:
- Not so effective. If it clears the blasted surface you might have blast the edges to make the area bigger.
- Some dust.
- Eye and mask protection recommended.
Sodablasting:
Not far from bakingsoda powder in its consistency, Easy to use at home with any size air compressor, natural and non-poisonous, multipurpose type of "sand".
Pros:
- Least harmful of all sandtypes
- Won't damage your lungs
- Can be used to blast mold, paint, window frames (it won't hurt the glass), oil and dirt
Cons:
- Mostly useless to remove anything a powerwasher can't
- Most dust of all these sands
- Won't remove rust or burnt oil on parts
Aluminium Oxide blasting:
Similar looking to the glasspowder but with a tint of light blue.
Pros:
- More effective than glassblasting, but leaves a surface in between the glass and sandblasting result.
- Good compromise since the surface roughness will most likely not be too much to hurt any tolerances
- Save time and media with effectiveness
- Not that much dust
Cons:
- "I bet Aluminium Oxide is not good to breathe"
- Expensive
I don't know much about dryiceblasting but i've heard good things about it but i leave the blasting list at this, because i doubt dry ice is something i'd be likely to start using at home for blasting some parts randomly a few times a year. It seems to be a great way of blasting more precisely with less mess and even if there's some electronics etc (yes.. i saw some of the Mat Armstrong videos). But i believe there's companies that do it and the process with the dry ice is best to leave for them than bring home as a new headache.
The tools for outdoor blasting, like the blasting gun, really depend on the nozzle and have to be tested with trial and error. To find the right media and the right tool for the job is what matters to get the job done and hopefully not have to live in a dust cloud too long.
For the next step in blasting, from the basics, there's bigger tools but also handy blasting cabinets. These are handy as you can do it with less fuss about protective gear etc. I'd look at lighting for the cabinets and flow. You need a good light to see what you work with and a functioning cabinet.
There's two types of cabinets. One has air circulation only and the other washes at the same time as you blast. So the options are dust mess or water mess. Do you want the cabinet to be filled with dust that may restrict seeing the object you blast properly or do you want to see but wash the object at the same time?
My next step in the minibike project is to get aluminium oxide (instead of the failing soda) so i can get the parts properly cleaned up and continue.
