Sandblasting 101: A Course for Beginners

brrrrrump! clang!

"Thank you. Thank you. Doug will be here at the Ramada every weekend for the next month. And don't forget to try the roast beef. G'night everybody."

 

Funny this thread should show up now. I had to do a little sand blasting today on a pair of headlight buckets from a 56' Ford F100. We have a small sandblaster that holds 40lbs. of media. It's great on small parts, but we lose a ton of sand each time we use it. So I figured out a way to save the media so we can re-use it. I took a large metal pot ( holds about 4 gallons ) and cut a plexi-glass top for it. We cut a hole in the plexi-glass just big enough for the nozzle of the sand blaster to fit through. I took one headlight bucket at a time and propped it up on a plastic flower pot inside the larger pot so the force of the sand would not knock it over. We then taped the plexi-glass on the pot and taped a towel around the hole like a sleeve. I wrapped the towel around my hand and arm and blasted away. It worked like a charm. Other than not really being able to see what I was doing from the dust build up in the large pot, the parts came out rust free and we lost almost none of the sand. I did wear a dust mask and leather gloves while I was blasting away. This is going to be our temporary blasting cabinet until we get a REAL one. Oh yeah. I didn't get any sand all over me! That's a first for me.

 

This is great info. Keep it coming. I am curious as to what type of respirator you guys have for sandblasting. I can't seem to find a pic and specs of one online for sandblasting. Would it be smarter/safer for me to blast with another type of media? Say, plastic, or walnut shells, or corn cob, or .....? Would I need as heavy duty a respirator for that type of media? My plan is to degrease and clean the underside, and then use the sandblaster to remove some slight surface rust where some of the paint has worn away, and then paint/undercoat the whole underside. My plan for the engine bay is to blast is completely clean of paint, and the repaint the whole thing in the factory black color. Does anyone have experience with these other types of media, and how did they work for you? Thanks!
-Corbin

 

A lot of great advice here. One more thing you need to be warned about is to not get caught up in the moment and sandblast everything in sight. The first time you try to sandblast that nice grabber hood or decklid, well, I just hope you have some spares. No matter how easy on them you are, the sand will warp the hell out of them. Doors and fenders aren't too bad if you keep the nozzle a good distance away and at about a 45 degree angle. You still have to be very careful because the sandblasting heats the metal up extremely hot and it will warp before you even realize it.

It's pretty safe to blast engine compartments and undercarriages so I'd say go to town. I just did my blue car using a pressure pot blaster and 12 100lb bags and that did engine bay, fenders, doors, valances,( just be careful on those last three) the dash, and a light sweep of the interior area. I probably swept up and recycled about 3 bags worth.
Like Dennis said, keep good nozzles. If you use a worn out nozzle you'll go through the sand before you know it. You also need to make sure your compressor will keep up with the blaster. Low air pressure will hurt you badly also...more sand and a lot less effective.
We have a new guy in the area that runs a mobile service that I'm anxious to try. He does soda blasting and charges $100 per hour. He claims to be able to do an entire car in 3-5 hours. It supposedly doesn't hurt the chrome or glass so the car doesn't have to be stripped to be blasted. It seems to be the going thing now. You can probably search it on the Internet and find out more about it. Next time I need a car stripped in my body shop I'll probably give it a try.
Anyway, I wish you luck if you try it. You'll probably make some mistakes and regret it but I've done probably 20-25 cars and seems like I always wished I had paid somebody to do it but I guess I'm just a glutton for punishment...always going back for more. Good luck and have fun!!!

 

We have had large parts like truck fenders and hoods soda blasted in the past, and it leaves the metal quite smooth. The only problem we faced was in getting ALL the baking soda removed from the surface to be primed and painted. We had never had parts blasted that way before, and we found out the hard way that every last speck of baking soda has to washed out of every nook and cranny that it can get into. If even a little of it gets missed, the soda will leave behind a residue that will cause the primer to peel off. Aside from that little setback, we were very pleased with the way the parts came out after they were blasted. As I said, they were smooth and not pitted the way sand can pit metal, and nothing came back warpped.

 

I thought I heard somwehere of blasting being done with dry ice. After blasting....all the ice just "melts" leaving absolutly no clean-up.

 

That dry-ice thing sounds like a great idea (assuming it's feasible).

 

They are correct, stay away from blasting flat surfaces such as hoods, doors, decklids etc. Blasting with dry ice? That sounds interesting. I wonder how they freeze it that small?


I think my engine bay took about 5-6 hrs.

Seth

 

Wonder if you can blast with dynomite?

 

Yeah, you can, but it has a tendency to warp the metal!!!

 

HERE IS SOME INFO ON THE DRY ICE BLASTING......


i use it at work.....this is how it works....you have to have a machine that does it of course....they are expensive...

then you have to get 20 pound blocks of dry ice.... you can buy these fairly cheap...but the machine is Expensive to say the least...

but if you have the funds...it works GREAT.... we use this method to get the chemical realease agents off of our compression molds on our compression presses......we use these presses for making composite missile parts....

they dont take resin off very well...but paint...wax...stuff like that....say bye bye...

 

http://www.abrn.com/abrn/article/articleDetail.jsp?id=130652

 

for the small stuff I have a blast cabinet from harbor freight. Loaded it with 25 pounds
of glass bead media and have at it. Just finished taking the paint off a column for my
dune buggy project. My cabined is the larger floor model which is big enough to blast
valve covers and air cleaners. wish it was big enough for fenders but that would have
cost 4 time as much.
Robert

 

Other than saying that total removal of paint is usually unecessary, here's additional info on the cost. (Cool link, Dan. Thx)


Excerpt:

"Dry Ice, Anyone? John Hughes, refinish paint specialist, Ford Custom Service Division, generally recommends plastic media blasting. “Aluminum oxide is only used for rust removal because it will remove phosphate metal coatings, causing flash rust from finger prints and humidity. Dry ice can also be used but facilities are limited.”

Did he say dry ice? Yes, he did. While media blasting is rarely used, dry ice is even rarer as the medium of choice. It does, however, offer a significant advantage: Because it converts directly from a solid blast pellet to a vapor (carbon dioxide), the media reclamation requirement normally associated with sand and wet-blasting systems is eliminated. That same advantage also removes the need for a containment room.

But, as noted, it’s expensive. To start with, there’s the equipment, which costs $10,000 to $30,000, according to Bob Foster, a marketing specialist for Coldjet, Inc. a supplier of dry ice for industrial purposes. “To use dry ice,” says Foster, “you need at least a 20-hp air compressor. The ice itself is 25 cents a pound and media blasting uses about two pounds a minute.” What’s more, he says, dry ice is not highly abrasive, so the operation may take longer than other media blasting methods.

This characteristic may be an advantage, however, in the rare instance where a shop is working on aircraft. The metallic skin of an airplane is thin and expensive to replace. The tiny dry ice particles will remove the paint, but leave the surface undamaged."