Sandblasting talk

[chrisf]

I've been doing quite a bit of outdoor sandblasting of large car parst with an old Tip portable blaster that has a 90-lb. pot, and using 30-mesh sand as the abrasive medium. My compressor has 10 hp. and is connected to an 80-gallon air tank.

With the 30-mesh, I find that a 1/8" blasting tip is the smallest I can use without clogging (I'm using a small tip so I can blast longer before having to wait for the compressor to re-charge the tank).

I've found that if I regulate the pressure down to 80 lbs. at the blasting pot, it still works well, I can blast longer than by leaving it unregulated (around 120 lbs.) and I don't get that big, wasteful blast of air containing no sand when I first open the blast valve, the way I do when I run it unregulated at the pot.

I've assembled an HF blast cabinet but haven't used it yet because I want to "do the mods" first and haven't got a round tuit yet. It will be nice to start using the cabinet for blasting smaller stuff because I will then be able to re-use the media.

So please tell me your experiences and words of wisdom about sandblasting!

Bill. re read your post. my 2 cents. 30 mesh (36 grit) is something i would use on a horrid semi truck frame (and i dont go that coarse). its not for automotive stuff. set it aside and find yourself some recycled glass. preferably in the 50-100 grit (45-100 mesh) or 30-60. 30-60 is the coarsest i go. 50-100 works great. its totally white metal. clean, no ghosting. i run. 30-60 grit and 40-70 rarely. 50-100 most of the time 100-200 for sheetmetal. your stuff will not be "peppered" and you dont have to open the valve so far to make it flow (saving some air)

#1 thing for good trouble free blasting is picking the right media as one media doesn't do every job well.
"sand" please stop using it. you already have heard the silicosis lecture i am sure but stay away please. and...sand sucks up more water. your making mud in your pot/flow issues

 

[harrisonm]

Spend some money on a decent cabinet. Scat blast are good for the money. The most important thing with a blast cabinet is GOOD lighting and a proper dust collector.
I just upgraded to this dust collector and it was money well spent. Ran the exhaust out of the building. It works about the same as their entry level collector but the difference in sound reduction is amazing. Skat Blast® USA 180-DC INSIDER II HEPA Dust Collector
I also have a small bench top HF cabinet that I used mainly for glassbeading small stuff like bolts. Best upgrade was to add fine wire inside so small parts cant fall thorough.

So you have a 10 HP compressor...is it three phase? What's the cfm? My 7.5 HP can sandblast continuous all day and the compressor cycles with a good deal of time in between. I run my big cabinet around 100-120 psi and the small cabinet at 80-90. CFM is around 25 or 26 @ 175.
You really should not have a problem with air supply on a 10 hp compressor unless its a single stage.

I need to go get my monster cabinet so I can get it set up at my house. Its around 12' long, a real beast.
I have a pressure pot but I despise outside sandblasting. Its so damn messy and even when its cool outside you still sweat balls with all the PPE on.

I TOTALLY agree. I bought a TP Tools Scat Blast cabinet about 15 years ago. It has worked flawlessly. I have tried out some homemade cabinets, and they did not work all that great. Now I am NOT saying that some of my FABO buddies could not make a cracker jack cabinet, but if you can afford it, I think a good cabinet like a Scat Blast is the way to go.

 

[Bill Crowell]

Bill. re read your post. my 2 cents. 30 mesh (36 grit) is something i would use on a horrid semi truck frame (and i dont go that coarse). its not for automotive stuff. set it aside and find yourself some recycled glass. preferably in the 50-100 grit (45-100 mesh) or 30-60. 30-60 is the coarsest i go. 50-100 works great. its totally white metal. clean, no ghosting. i run. 30-60 grit and 40-70 rarely. 50-100 most of the time 100-200 for sheetmetal. your stuff will not be "peppered" and you dont have to open the valve so far to make it flow (saving some air)

#1 thing for good trouble free blasting is picking the right media as one media doesn't do every job well.
"sand" please stop using it. you already have heard the silicosis lecture i am sure but stay away please. and...sand sucks up more water. your making mud in your pot/flow issues

I don't want to argue with anything you've said, chrisf, because you know more about it than I do. However, we need to bear in mind that you are working on rare and/or valuable cars. So, in defense of sandblasting with 30 mesh sand: although it does leave the bare metal surface a tiny bit pockmarked, one coat of primer levels it out perfectly and the slightly rough surface gives the primer an excellent tooth to adhere to.

I understand that using sand is not for everybody. For example, a restoration shop working on rare and valuable cars would never blast with sand because they feel it damages the metal too much. However, I'm working on an old Dodge Bros. car. These cars are not worth very much (about as much as a Ford Model T) because they are too slow and underpowered, so you can't drive them anywhere too easily. But the DB is one helluva car mechanically, and it deserves restoration for the sake of preserving history. For financial reasons, no DB car will ever be totally restored except as a labor of love, as I am doing. The steel used the DB body parts is extremely thick and hard, and can withstand sandblasting well. I think the sandblasted parts look pretty good after primer and paint.

 

[chrisf]

try the finer media. its does a better job and you use less media per hour. I use 150lbs/hr with 50-100 and 200lbs/hr with 30-60

The DB is an awesome car. happy to hear another one is being saved.