Abrasive blasters

[dusty]

I understand that Boeing uses ice pellets.

It (dry ice) is widely used for industrial cleanup where mold and surface contaminants are involved.

http://www.icetech.dk/dib_1.asp

[JPG]

It (dry ice) is widely used for industrial cleanup where mold and surface contaminants are involved.

http://www.icetech.dk/dib_1.asp

That's even easier to clean up! NO effort required(ventilation needed).

Interesting that the release of CO₂ is not mentioned!

[mickyd]

Well, I made up a quick and dirty prototype of the soda blast system that I referred to in post 1. I wanted to try it for paint removal. I followed the instructions as specified except I didn't have the correct 7/16" diameter clear vinyl tubing or the small OD air nozzle. Instead, the tubing was the larger 3/8" diameter tube and the nozzle...about twice the diameter as that shown.

Stuck the vinyl tubing into a small box of regular baking soda and did a test hit on the nozzle level. The soda BLASTED out of the tube in a cloud. Pretty impressive so I took one of the ER castings that still had a little bit of paint on it and blasted it. In about 15 seconds, I used up the entire box of baking soda!!:eek: It DID remove the paint. There was about a section the size of a fifty cent piece that was cleaned right down to to the base metal.

The hose and nozzle diameter were definitely too large so I picked up the right stuff at Home Depot for less than $10. Tomorrow (actually today since it's 1:45 am), I'll give it a try and let you know how it worked. Also decided that the only way to do this is to use an enclosure similar to a blast cabinet so that I can reuse the soda. I'll make an enclosure using a big cardboard box and some glass for a window.

Picked up a 50 lb. bag of blasting soda from Harbor Freight for $30. The blasting soda is a little more course than the household soda so it should work better.

Not a believer yet but it may just have promise. I'll find out later

Against the professional advise from tom_k/mo, I continued my quest to develop the homemade "siphon" style soda blaster vs. going with the pressure pot method he suggested in post 2. Only reason....I am cheap!! The pressure pots are a bit pricey (low 3-digit) I needed to see if I was able to get a functional system at minimal cost. (helps keeps mama happy and when mama's happy EVERYBODY'S happy!!)

Lesson 1 - I built a blasting cabinet out of a big box so that I can reuse the baking soda but now I find out that they don't recommend that. The crystals supposedly explode when they contact the hard surface turning it into a much finer less aggressive powder.

Lesson 2 - When I first did my prototype test siphoning out of the small household box of baking soda, I was pretty impressed by it's paint removal action. This time, with the 50 lb. bag I purchased dumped into a 10 gallon paint bucket AND using the correct size hose and nozzle, I wasn't satisfied. The soda stream out of the hose was not consistent at all, and even stopped at times. It did however remove paint but too slowly. I wasn't in the mood to mess with it trying to figure things out so I called it a day. I think the reason may be that the siphon hose was down at the bottom of the 10 gallon bucket and that the weight of the baking soda above it was causing it to not flow as it did when I was drawing out of the small box.

I'll continue to evaluate the variables to see if I can get it to work. Too bad there is so little info on the internet about the whole process. I am on my own it appears unless I can find a forum that has some expertise in that area. It's probably out there but trying to find it may be tough.

It's unfortunate that you can't reuse the soda. Even though the soda is safe for the environment and you don't have to contain it, I am afraid that the 50 lb bag won't go very far and at $35 per bag.......

If this whole soda concept fails, I'll try to go with the reusable shell blast media (crushed walnut shell) in the cabinet.

[tom_k/mo]

Mike, I don't know why you don't just use AO or SC abrasive. Baking Soda blasting is really meant for things like removing paint from fiberglass or soft metals where the abrasive could damage the substrate. Walnut Hulls etc... is used in tumblers to shine brass cartridges for reloading ammunition. If you're blasting the cast housing of a MkV or the way tubes, AO (Aluminum Oxide) or SC (Silicon Carbide) would remove the paint MUCH easier and if you used 150 to 220 grit, wouldn't pit or damage your metal at all. AO also is recyclable many more times... I'll use a 50lb sack of AO 10-20 times before I have to replace it. You can even find "Black Beauty" blasting media (Coal Slag) that is cheap and works OK (once)...

[mickyd]

Mike, I don't know why you don't just use AO or SC abrasive. Baking Soda blasting is really meant for things like removing paint from fiberglass or soft metals where the abrasive could damage the substrate. Walnut Hulls etc... is used in tumblers to shine brass cartridges for reloading ammunition. If you're blasting the cast housing of a MkV or the way tubes, AO (Aluminum Oxide) or SC (Silicon Carbide) would remove the paint MUCH easier and if you used 150 to 220 grit, wouldn't pit or damage your metal at all. AO also is recyclable many more times... I'll use a 50lb sack of AO 10-20 times before I have to replace it. You can even find "Black Beauty" blasting media (Coal Slag) that is cheap and works OK (once)...

Tom,
Quite honestly, I fixated on the concept of soda, especially after watching a few of the youtube examples. I'll go with the media you suggested. Can I use via siphon method without a pressure pot? (remember....happy mama)

[tom_k/mo]

Tom,
Quite honestly, I fixated on the concept of soda, especially after watching a few of the youtube examples. I'll go with the media you suggested. Can I use via siphon method without a pressure pot? (remember....happy mama)

Absolutely you can Mike. You can also pick up a commercial syphon blasting setup like THIS cheaply and it handle your requirements. I have a syphon setup I got from Grainers years ago to remove rust from iron/steel and it worked fine. It's not quite as fast as a pressure pot, but it worked well for it's purpose. I filled mine with something called FlintShot. It is white, and looks like white (sugar) sand, but it's actually small broken shards of flint (with sharp edges) and cuts MUCH faster than sugar sand. I got it at a material/lumber yard. Today, you should be able to get AO or SC at your neighborhood Harbor Freight or Grainger's warehouse.

If you know any facility/fabricator that has a water-jet cutting system, they use a jet of high pressured water with SC in solution to cut stone/steel, etc... They only use the SC once and usually have a LARGE volume of used SC to dispose of. You can usually get it from them for free if you pick it up yourself. Just spread it out and let it dry THOROUGHLY before trying to blast with it again.

[mickyd]

Absolutely you can Mike. You can also pick up a commercial syphon blasting setup like THIS cheaply and it handle your requirements. ........

Tom, that looks good. HF doesn't have the 150 grit you suggested but they have 220 although the description doesn't say paint removal for that grit. How about the 80 grit? And how about glass beadvs. SC or AO

Also. any thoughts on this?

[tom_k/mo]

Tom, that looks good. HF doesn't have the 150 grit you suggested but they have 220 although the description doesn't say paint removal for that grit. How about the 80 grit? And how about glass beadvs. SC or AO

Also. any thoughts on this?

Mike 220 is a bit fine for paint removal... I used to use 220 in glass etching and it produced a nice smooth surface, but took quite a bit longer than the 150 I'm using now. HOWEVER.... 220 AO would STILL cut faster than baking soda. Glass bead media may cut a bit faster than 220, but not as fast as 150, and remember, unless you get a cabinet, it's going to be basically blast once and it's gone, there's no recycling so you need to factor in the cost of glass beating as well.

[mickyd]

Mike 220 is a bit fine for paint removal... I used to use 220 in glass etching and it produced a nice smooth surface, but took quite a bit longer than the 150 I'm using now. HOWEVER.... 220 AO would STILL cut faster than baking soda. Glass bead media may cut a bit faster than 220, but not as fast as 150, and remember, unless you get a cabinet, it's going to be basically blast once and it's gone, there's no recycling so you need to factor in the cost of glass beating as well.

How 'bout my other 2 questions....re 80 grit and the blaster bag?

[tom_k/mo]

How 'bout my other 2 questions....re 80 grit and the blaster bag?

Mike, sorry I overlooked that. 80 grit would definitely cut the paint. 80 grit is used quite often on granite/marble for engraving grave markers. If you hit the way tubes too long you would probably find some fine pitting on them, but if you just hit it long enough to remove the rust you should be fine. 80 grit shouldn't hurt the castings at all, although (no matter WHAT grit you use) I wouldn't use it on the bearing/bushing surfaces.

The blaster bag would be a waste of time (IMHO). That is a SPOT blaster. The rubber tip is pressed up to the surface of the object being blasted, and the material is sucked out of the bag, hits the surface and falls back in the bag. It's really meant to remove spot rust from an auto body without removing a lot of surrounding finish. It would take FOREVER to do paint removal on a headstock with something like that, AND there would be a number of areas like certain areas INSIDE the headstock that you wouldn't be able to fit the gun inside and press it up to the surface. With the standard syphon system you could just shoot it from the outside of the headstock through the hole.