Now that my eye has recovered from having a piece of blasting abrasive dug out of it at the doctor yesterday and I can see the monitor again, I thought that maybe we could ALL benefit from a little roundtable pow wow about blasting. It is obviously the best option for total rust removal and the equipment is getting more affordable to buy and rent. I consider myself to be relatively intelligent and mechanically inclined, so I'm kinda thinking that I may not be the only one who has or is having difficulty achieving the proper setup.

I personally have used both siphon blasters and pressure blasters. I attempted to start blasting the frame rails for the F-1 this past weekend with only marginal success using the pressure blaster. Apparently, my major problems are resulting from both moisture in the incoming air and an inability to accurately adjust the mixing valve down enough to maintain flow and still not get too much abrasive for the amount of airflow my compressor can sustain. I tore the blaster apart and made some mods this afternoon that I think will help a lot. First, I replaced the ball valve that was installed for a mixing regulator with a gate valve. I think that this will work 100% better. I also added an 18" horseshoe of black pipe to the inlet to give the water in the air someplace to condense so that the dryer can collect it. Tomorrow night I'm going to install a 30' overhead run of black pipe across the shop from the compressor to the overhead door for the same purpose.

As for siphon blasters, my experience has been that they are effective but much slower. My blast cabinet uses a siphon gun and although it works well as long as the media is frequently filtered, it takes forever compared to the pressure blasting cabinet I have access to at work. George did Earl's entire chassis with a siphon blaster, so maybe he can share some of his experiences.

Lastly, I would not recommend that anyone EVER blast with just a hood or a hood and safety glasses. Sealed goggles are mandatory. I thought the hood and safety glasses would be enough. Well, I'm here to tell ya that sitting in a doctor's office getting coal slag dug out of your eye with a needle ain't the best way to start the week.

 

Wow. Sorry to hear about yer misfortune. Hope there's no perm damage to your eye. How exactly did it happen? Did the media burst through your hood shield? Or did it bounce it's way into your hood? What exactly is coal slag? )When I hear slag I think bits of metal, like from metal casting.)

Luckily I've had no problems blasting my F1 frame with a pressure blaster and #80 grit sand.(knock on wood) All I used was a blasting hood and respirator. Never had problems with media or debris penetrating my face shield or hood.(knock on wood again.)

There's some great sandblasting knowledge in the Garage forum too. Here's one recent thread you might find useful:

http://www.fordtrucks.com/forums/sho...hreadid=109337

 

Blasting takes a lot of air as your are aware, and when the compressor pumps steady, it will create water.

I run a seperator about 30 feet from the pump and another one at the blaster. I have found that leaving the drain valve partially open at bottom of the blaster trap while in use seems to help.

Also by using the smallest nozzle and changing it every 3-4 hours helps with air consumption. You can waste a lot of air and sand with a worn tip.

 

I like silica sand for rust removal. Coal slag is a bit gentle for rapid cleaning of rust. At least it seems that way during my limited experience with it. Silica should be used outside of course and a proper respirator is not at all comfortable in the summer. Moisture from a hot compressor is a definite battle. I used two air dryers and still had some problems here in the Mid-West. Let us know how the blaster mods work, mine suffers the same clogging problems I bet.

Hope your eye injury gets better soon. I've had more of those than I care to admit.

 

A couple of things ocurred to me after long hours using a blaster both outdoors and in a cabinet.

1. It's no surprise to this group that moisture in the air will really make the job difficult. I used a 50' hose from the compressor to a a small centrifugal water separator with an automatic drain valve. The output of the separator goes to a 20' hose and the blaster. By the time the air has traveled through the 50' of hose, it's cooled enough to let the water condense and separate out. Haven't had any problems using this setup so far. BTW, the big air separator right on the compressor almost never has any water in it since the air is still too hot there to let the water condense.

2. Joe's right about the personal protection equipment. When I run 125 psi with CrystalGrit, the stuff bounces off at least three surfaces before coming to rest. My polycarb face shield was actually pitted ON THE INSIDE from stuff bouncing off my neck protector. With Si02 (sand), you ABSOLUTELY have to have an OSHA respirator unless you want to risk Silicosis.

3. Huntsman's point is a good one too. I use the ceramic nozzles and even with something like CrystalGrit, they last a LOT longer than the steel. You also need to replace the air jet if your gun has one. A worn nozzle or air jet will really make the job tough.

4. There are a lot of different kinds of media for various jobs. Both Joe and 'fenders suggested good options with the Si02 and coal slag. I use CrystalGrit exclusively now after trying about 5 or 6 different types of blasting media in my cabinet. I've blasted everything from cast iron to 18 gage sheet metal and had good success. There are two reasons this stuff works so well. First, it's far denser than most media types. That means it hits the surface with a lot more energy. Second, when the particles break, they break into smaller particles with sharp corners. SiO2 and many other grit types tend to round off and you end up shoot tiny ping-pong ***** at the rust and crud.

For outside work, the CrystalGrit works fine but is a bit expensive unless you have a way to recycle almost all of it. I used a 20' x 20' plastic tarp to collect Si02 grit and that worked on the frame rails. I used the same setup with CrystalGrit on some other parts and it worked about three or four times faster.

 

Thanks for the concern about my eye mishap, but I'm doing much better today. Just a minor irritation now and by morning I'll have forgotten all about it. George is right on the money. It got up under the hood and ricocheted around until it got under the safety glasses too. It was moving fast enough when it hit that it embedded itself in my eye. I really didn't notice it until later that night and didn't find out that it was still in my eye until yesterday morning when it began clear that after two days of irritation, it wasn't just scratched. Yesterday was one of the most painful, miserable days of my life after the antisthetic wore off. Don't take the risk. Get some goggles.

Lotsa good feedback so far! I chose coal slag because Menards had skidloads of it and I didn't want to use silica sand without a respirator. Dewayne is right, though. It doesn't cut very fast in comparison to silica sand. I had a 16x20 tarp under my outdoor work area and out of the 250 lbs. I used before I gave up, I was able to recover 125. That's not too bad. Unfortunately, at $5/50 lbs. vs. half that for silica sand, it's still pretty expensive. I got a HEPA respirator from the industrial hygenist at work and will make my next attempt with silica sand.

The black idea came from a TP Tools sale ad. They highly recommend it vs. hose for moisture removal. Of course, it's impossible to operate without some hose, so I decided to do the run across the shop with a dryer immediately before the hose and again at the blaster. We'll see how that works out.

Hey George, what are you doing for ventilation and dust removal in your cabinet? I bought an 8-gallon Shop Vac and it works TOO good! I've got a HEPA filter bag inside it and it's still sucking enough dust into the motor that at only 3 months old, the bearings are already squalling occassionally. It is also pulling an enormous amount of abrasive out of the cabinet into the bag. The vac was only $40, but I'd rather find a more permanent solution besides buying a new vac two or three times a year.

 

Joe, glad to hear it wasnt a permanent injury.

Im using an import 100 lb capacity pressure blaster with mixed results. Did an all steel 4 x 8 utility trailer on Monday.

Black Beauty extra fine gets down to white metal but repeatedly clogs. Switched to silica but it didnt dig deep into the rust but was real quick to get off many layers of paint and all the loose rust. Maybe Im using a too fine a grain.

In any case, it was good enough for a coat of Zero Rust red oxide and yesterday I topcoated with some ultra cheap Western brand Safety Red.

Id be interested in hearing more about the blaster mods as well as media choices for outdoors.
Ive got to do a 2 axle car trailer next but it looks like rain for the next 3 days.

 

Ya been there done that. The Dr. had to use a dremel tool to dig out the piece in my eye. Made a full recovery. I don't know wich hurts more, that or a really good flashburn. Good to hear your going to be fine.

 

Joe, I'm using a siphon blasting unit. I've never used a pressure pot unit so I don't have a comparison point as far as speed goes. With the siphon unit, I started with 300 lbs of SiO2 (silica sand) and after five rounds of recycling it I had both frame rails done and had something like 275 lbs in the tub after cleanup. It might be that my siphon unit doesn't spread it around as much as your pressure unit or it might be that I only had 100 lbs of silica sand and 175 lbs of rust in the tub at the end.

Check out the tech article on building your own blasting cabinet. I put a fairly good description of how I handle it in there. Of course, if you still have questions I'd be glad to hear 'em.

 

I am not sure why other have not tried it but I was able to purchase a sand blast kit from wallmart the fit my Costco Honda motor driven pressure washer to draw the sand out of the bag and blast the frame of my 50 f1. The pr washer is 2400 lbs and about 3gpm. But when hooked to the pressure washer it does not use the hight pressure but I would guess somewhere near 300psi mixed with water it is a lot safer to use and will NOT warp metal as it is cooled by the water. Used it last week to remove graffiti from the church block wall. I liked it and it worked well, and I have both a pressure and syphon blaster and a 2 stage air compressor. Ed ke6bnl So. Calif

 

I can recommend the 10 cent blasting cabinet:

1) get a big clear thick plastic bag.
2) put what you want to blast inside the bag.
3) put the nozzle in the bag, wrapping the mouth of the bag around the blast gun/air and media hoses and holding it loosely so air can escape
4) put on your respirator
5) blast: the bag inflates, almost all the sand stays in the bag

YMMV: I was using a siphon blaster, and it didn't tear through the plastic bag, although the plastic didn't stay very clear. Extra lighting helped.

With a really large bag you could blast fenders. Or, cut a hole in a bag and tape it over areas you need to spot blast.

 

I tried this method and it does work. Three biggest problems I had were:

1. Visibility
2. Visibility
3. Visibility

I know you mentioned this Angus, and maybe it's the fact that my eyesight isn't so good anymore, but I could only blast for about 2 minutes before it got impossible to see what I was doing. Even in a 4' x 4' x 4' cabinet unit like the one I have, I have to move a lot of air through the cabinet to see clearly. With the current high volume air system I'm using, I can blast continuously without dust buildup inside the cabinet. The limiting factor now is that the polycarbonate film covering my viewing window gets so pitted and dirty that I can't see anymore after an hour or so. Then I have to stop, remove the old film, and use masking tape to put a new piece of film over the glass.

BTW, I used the same polycarbonate film over my face shield when working outdoors. Before I found this tip on a web site, I ended up with two brand-new face shields so pitted that they looked like frosted glass and were impossible to see through clearly.

I'm very interested in any feedback on the tech article about the home-built blasting cabinet. I'm certainly not trying to hurt my arm patting myself on the back - I really want feedback and ideas to improve what I've got. It works pretty well right now but there's always room for improvement.

 

I work in a sign shop. We sandblast alot, the most important thing to have is an air-fed hood. It makes my lungs hurt just thinking about it. The one I was using went bad and I had to refuse to blast anymore until I got a new one. They cost about 450 dollars, but when using silica sand I can't stress enough that you don't want that dust anywhere near your face. I wear a respirator when I'm loading the pot. Silica works well on metal and is about $7 per 75lbs. wear a respirator under the hood at the very least if you don't have an air-fed. It doesn't take much to do serious damage.

Gary

 

OK, so the second most important lesson I have learned so far after always where sealed goggles is that should you ever get something stuck in your eye that requires medical attention for removal, don't go to Urgent Care. See an emergency room or your optometrist first. I had the pleasure of paying another visit to Urgent Care today so they could finish the job that they started Monday. My eye was still bothering me this morning, so I had the nurse at work take a look at it. 'Ole Boy down at Urgent Care apparently was so fascinated and intent on removing the obvious contaminant on the edge of my pupil that he neglected to inspect the rest of it and missed another tiny piece in the corner. Oh, well. Maybe by the weekend I'll finally be able to see right again without squinting and constantly blinking.

Carl,

I was in the shop hanging pipe this evening and hope to finish it up by Saturday AM. It is impossible to gather every part of a plumbing project in one trip as you never can calculate exactly how long each piece will have to be to get from A to B if you have many fittings in between! Assuming my eyes are up to it, I hope to try out the new plumbing and the blaster mods (my blaster is similar to yours) Sunday afternoon. I'll report my results.

George,

I'll go reread your cabinet building article for pointers on ventilation. As soon as I get all the chassis pieces finished, I'm going to tear the cabinet down for an overhaul and a few mods of it's own, so that would be a good time to rethink the ventilation system. I'm also going to have to look into the liners that you are using as my glass is getting pretty pitted. Rather than the tedious process of taping them on, I wonder if there is some sort of rigid or semi-rigid material that can be used with a home made frame for a slide in/out glass protector? It might be worth looking into. It sure would be faster. Also, my reported recovery rate with my rail blasting experiment was a typo. Out of 250 lbs., I recovered 175. I could save more if I had a bigger tarp, but approx. 2/3rds is good enough for me on those big rails.

Ed,

I've never heard of that setup, but I have no doubt that it would work. My only concern is that the water would accelerate the flash rust when blasting steel to a point where one end would already be turning orange before you got to the other if it were a large part.

Angus,

I'll remember to try that next winter on the big stuff I can't get in the cabinet and it's too cold to do outside.