Sand blasting question

[STROIL]

I have a bunch of restoration projects to do on various painted parts of my tractors, Skidsteer, attachments, other tools, etc. I have done limited sand blasting on small parts in the past with the little "suction bucket" cheapo sand blasters (HF still sells one of these). I plan to buy a decent sized pressure pot sandblasting rig from HF. I have an abrasives supplier nearby that sells a wide variety of all the specialty blasting abrasives including soda, and they are good with advice on which to use for which application, and the stuff is not terribly expensive. One of the questions I have is what psi and cfm do you guys that have lots of blasting experience think I will need to use to efficiently blast off old paint and rust? I've used my regular 30 gallon, 5 horsepower, single-cylinder compressor at 100psi in the past. Not sure what the CFM of that compressor is. With the little suction pot blasters, it's pretty slow going. Clearly not enough CFM. So if I go out to buy a new compressor to max out my sandblasting ability, what CFM am I looking for?

Also, I plan to do the blasting out in the open air of my 30 acre rural property. I'll spread out about a 20x20ft area of heavy 4ml plastic and blast out in the middle of that. I'll wear a very-good respirator and a full face shield. The plan would be to blast one part, then move everything off the plastic sheet, and then pick the sheet up in a way to force all the abrasive to the middle, and recapture as much abrasive as possible. I realize all of the blasted off crap will be mixed in with the recaptured abrasive, but is that any reason to not re-use it? any abrasive that blows away in the wind... so what? It's not like I'll be doing so much of this that I will create a desert on my property.

If you're a guy that has lots of sand-blasting experience, I'm interested in hearing what you think of that approach and any other sandblasting advice you got. Thanks!

 

[paulwestski]

You'll need to make some modifications to the HF sandblaster.
The bottom tank valve is famous for clogging up. It needs to be replaced with some larger pipe and valve.
The POS nozzle valve that comes with the HF sandblaster will need replacement also. I bought a Northern Tool deadman style for mine.
See this web site, I borrowed the photo from there.

HF pressure sandblaster modification - Hot Rod Forum : Hotrodders Bulletin Board



Get as much air compressor as you can afford.
You also need a good redundant dryer, I just use two filter/water separator combos in series.

For reusing blast media get one of these to sift the trash out of the media.
I even sift new media, you'd be surprised at some of the oversize particles in it.

Abrasive Strainer | Cabinet Accessories| Northern Tool + Equipment

Northern Industrial Abrasive Blaster Deadman II | Guns Valves| Northern Tool + Equipment

 

[Hooked_on_HP]

Any sand blaster is only as good as the compressor powering it. For small items the compressor you have will be fine. But with larger items it wont keep up. I have the blaster you are looking at and for larger items I run it off of a 12hp twin cyl. gas compressor. I still have to stop and give the compressor a brake.
Bill

 

[ray66v]

A decent sandblaster can tax a good quality 10 hp commercial air compressor.

It is pretty expensive to buy a decent sandblaster, large enough compressor to keep up with it, air dryer, so you are not blasting the clean metal with moisture while you are cleaning it, get the right personal protective equipment, and buy the blasting media.

It can be cheaper, to just pay to have it done.

You can reuse the media, up to a point. Then, it looses it's effectiveness.

 

[kevin37b]

We used to do lot of blasting . We rented and eventually bought used a 185 cfm tow behind compressor . No shortage of air there .

 

[timster2]

Find yourself a used camping tent at a yard sale and you have an instant sandblasting booth. It will contain the blast media for reuse and make it easier to recover.

 

[Western]

We used to do lot of blasting . We rented and eventually bought used a 185 cfm tow behind compressor . No shortage of air there .

Same here, but still blast on occasion. I have a 185 CFM Atlas Copco, sitting right out the window, and have a 300# blasting pot with 100' hose. We bought the Air compressor from a rental yard, for about 5k. I also have a 100# pot made in 1948 and an extra 1960's model 125 CFM Leroi, but haven't used them in about 10 years!

CFM's is what you want and the best breathing apparatus you can afford (we use a total upper body helmet "suit" with filtered air from the compressor). For small stuff, like you have found, a 19cfm small shop compressor will "do" ,but is very time consuming. Probably works best in a small blasting cabinet. If you can get allot of stuff ready to blast, that would warrant renting a large pull behind AC, you'd be surprised at how fast you will get done.

As far as re-use of media, heck yeah. Best I have used is a dedicated blast room. Basically a 3 sided "room" with a canvas type "door" that can be moved out of the way when blasting. We used pallets as a floor and only run the sand/media through a typical window screen mesh. Works good on sandy type media, but a PITA using pecan hulls! The main thing is only using the driest media you can run.

If you're on a budget, I'd get a good 100# pot and respirator, then schedule all your blasting for one weekend and rent a pull behind AC. You could still use your shop AC for small tiny quick jobs with the large pot (to a degree) But bringing in a large AC, you could probably blast 4 complete tractors in a weekend (if you want to run your tail off :laughing

 

[Ehanson]

We use #10 &#4 glass bead in our two cabinet blasters and I hsve learned that turning up the air pressure is not ideal after a point because it shatters the glass bead to a powder and the cutting ability of the medium is greatly reduced.

 

[ray66v]

We use #10  glass bead in our two cabinet blasters and I hsve learned that turning up the air pressure is not ideal after a point because it shatters the glass bead to a powder and the cutting ability of the medium is greatly reduced.

The same thing happened with everything we used, over many years, including #2 silica, and silicon carbide, which is expensive, but did last the longest.

It all wears out with use.

 

[/pine]

you can use a good magnet to separate most of the rust scale from the abrasive...