Sand-blast vs Wire-wheel

[BillGrissom]

I spent too many hours last weekend removing rust from front inner fenders. They were out of the car on the ground, with easy to access every spot except a few recesses and inner corners. I actually had 2 pairs of the larger ones (in trunk when bought, none installed), so figured why not clean them all.

I don't own a sand-blaster and wonder how it compares at this task and the hours I already spent in the engine bay and trunk. I used a simple wire brush on an electric drill (various sizes). The wire brush removes rust fairly quickly, but still takes a long time for a large area. Any loose undercoating, I pick off with a putty knive, then brush a bit more away to insure shiny metal under the rest. If it pops off easy, there is always rust beneath. In some areas, I can't get to shiny metal. What is left is a hard "black rust". I keep working a spot until no more rust dust comes off and/or the metal starts getting hot.

My questions are what are the pros and cons of a sand-blaster. From FABO postings, it sounds like its main use is to get into tight areas where a wire wheel can't go. For those spots, I first scrape with a screwdriver, then put sand-paper under the screwdriver, but can never get as clean as the open areas.

Questions:

In open, accessible areas:
1. Does a sand-blaster remove rust faster than a wire wheel? If so, how big of an air compressor do you need? I know it doesn't go as fast as painting with a sprayer, but does it go as fast as say a touchup gun or is it more like painting with an air brush, in terms of covering area fast?
2. Does a sand-blaster remove rust more thoroughly? Does it get into pits better and make them shiny? Can one do as good using Naval Jelly after a good wire brushing?

In tight recessed areas:
3. Does a sand-blaster clean as well as in the open? If you blast in a small cavity does the air-stream stagnate and stop working as well? Does it get too dusty to see the work?
4. How deep can you get into crevices with a sand-blaster? How close does the tip need to be to the surface to still work? Can you get into the front bottom trench in a Dart's front door where they love to rust? Does the sand build up and make it hard to paint well after blasting?

5. How messy is the sand? Do you need to move the car outside, preferably where your lawn could use a little sand?

6. How much sand do you use and the cost? It sounds like ~$8 per 100 lb bag, and that will do maybe 1 wheel well. I read that Black Diamond sand is the best at cutting without over-heating sheet metal. It sounds like soda is mainly good for removing paint without scratching. Some use regular concrete sand or "play sand", which is cheaper.

7. How much storage space is needed for the typical Harbor Freight sand-blaster setup, and can you leave the sand in the bin ready to go? Neglect the air compressor since I need that anyway.

8. Finally, what protective equiment do you use? Has anyone read of health problems? I imagine the rust becomes more airborne with a sand blaster than a wire wheel. Rust doesn't concern me since that is what makes your blood red (and clay soil red), but there can be other metal alloys in the dust and paint that aren't so good (Pb, Ti, Cd, Cr, Tn).

For those with experience blasting, thank for any info and any additional tips. I am sure many on FABO have the same questions. We all must put on the de-rusters hat on our projects.

 

[Mopar Al]

Not a good idea to sandblast fenders or any other large flat areas. Blasting creates too much heat and will warp the metal. Sandblast shops wont do doors, fenders, quarters, or roofs. Only I know that is safe on the metal is Soda blast.

 

[airwoofer]

Do you have air? I just used one of these this weekend. Works OK. I use "play sand" from Lowes or Home Depot which I screen through a strainer to remove larger chunks. You should also filter/dry the air with something like this:

[ame="http://www.amazon.com/Motor-Guard-Corp-M-60-Filter/dp/B000WZYKAE"]Amazon.com: Motor Guard Corp M-60 1/2" NPT Air Filter: Automotive[/ame]


http://www.jagorequipmenttoolandsupply.com/Products/template.asp?Item=1237

You asked <Can you get into the front bottom trench in a Dart's front door where they love to rust?>

I was blasting the bottom inside lip of my door and it is working just fine. Will have to replace thebody shultz. The surface rust inside the door will probably just get wire brished and treated with rust converter.

 

[prrc]

You will never acheive the same results as having the car blasted. Do not blast with soda. You will be opening a can of worms you will never forget. We send all our cars out to be blasted. our guy does all exterior panels. with no problems, no warping. 100x faster and better results than a wire wheel. plan on spending around 800 to do the whole car top and bottom.

 

[64 AAR Valiant]

The trick to blasting body panels is to blast on an angle never straight on. Best to first start on parts like trunk and floors till you get a feel for it. Very messy job where a good respirator.

 

[sireland67]

I will answer a few questions from my experience.
I have a blast cabinet and a small hand blaster.
My 220v 5hp 30 gal tank air compressor wil not keep up.

The blaster will clean the metal much nicer and quicker than a wire wheel, but it also has to be clean, grease or under-coating will act as a pillow and just kinda smear around.

Use a resiporator the same as you would for painting, sand and black diamonds contain silicon. A hood and good leather gloves are a must if you are blasting outside.

I would not blast inside unless it is in a cabinet, If you blast open in your garage you will never get the sand out of the garage door tracks and everywhere else.

Black diamonds do not absorb moisture, so you can leave it in the pot for a long time.
Sand on the other hand absorbs moisture and must be dried before you can use it.

Black diamonds cut fast so you really dont want to use it on exposed sheet metal because it will warp, soda is much gentler but takes longer.

About any blaster will clean the corners of the doors on your dart.

You might just want to pay somebody do the blasting for you that already has the equipment. There is alot of up-front expense.

 

[rjsjea]

Not a good idea to sandblast fenders or any other large flat areas. Blasting creates too much heat and will warp the metal. Sandblast shops wont do doors, fenders, quarters, or roofs. Only I know that is safe on the metal is Soda blast.

Disagree. Several competent pro's in my area blast everything and do not warp any panels. Guy I just used left about the equivalent of a 120 grit paper finish on my fenders, very nice. He charged me $60 for two fenders and did them in about an hour. You CAN NOT get it as clean with a wire wheel-grinder as a blast job

Now blasting in your backyard with cheap equipment, using questionable sand (home depot bought playground stuff), and "wingin it" are all ways to hammer your metal

I have had about 4 cars blasted now using professionals and ZERO warping issues. I also have blasted in my "backyard" using a pot blaster with mixed results.

Skip the SodaBlasting IMHO

 

[duster wonder]

i use both... for parts with corners blaster is fine but large n flat wire wheel is fine maybe get a air drill for the wheel? spins it a lot faster.
as far as answers
1. sand will remove anything you point it at... but takes a ton of air and mity compressor
2.sand will take off anything but it sucks when parts are greasy.. wheel just takes grease and takes longer for rust but can be done.. if your painting getting to bare metal is important
3.definetly easier than a wire wheel sand can go wherever.. it will shoot sand everywhere tho so gogles, mask,gloves are required
4.it can easily be vacuumed out and wont hurt painting no need to clean it after blasting but is recomended
5.outside is best sands gona fly out everywhere and end up in places youd be suprised
6.sand sucks black diamond is better however you can see it everywhere unless you vacumm it.. and yea one bag should do a fender
7.not sure but the one we have attaches at the air compressor line and uses its air pressure, its like a 5 gallon bucket looking tank
8.full coverage!!! lol sand will get everywhere and stings any open skin there will be about a ten foot "blast" radius anything in that will get sand on it somehow

i usually use sand just for the hard places to get and the wire brush/wheel for everything else

 

[res1vw21]

At the restoration shop I work at we have everything media blasted. I know it's not sand some of it's garnet and some plastics but I wouldn't do anything any other way anymore. After we get parts back from the blasters we DA them off with 80 grit and epoxy prime them. This method ultimately results in the best quality finish job as all the rust/pain is removed and the metal has a good layer epoxy that ensures rust doesn't come back.

After the parts are sealed we will cut open the epoxy to do the metal work then bondo ...... finally everything gets resealed right before base coat.

The pics are of some Aspen parts I just did.

 

[needsaresto]

Just a suggestion.

Evaporust.

http://www.evaporust.com/

 

[mopardude318]

i agree with res. i have an 80 gallon tank with a 2 cylinder, dual phase air compressor...that thing will go off, catch up and fill the tank, and turn off, while I am still blasting!!! LOL

My blast cabinet is large enough to blast an entire fender.

I use aluminum oxide, black garnet, plastic, and also glass beads...
i like the plastic, its nearly harmless, and it takes away paint and bondo, but does not remove rust. i then switch to a mix of "worn out" (or used) aluminum oxide and glass bead to take off the rust....works great for me....

never use that "playground" sand.....that stuff IS DANGEROUS....DO NOT breathe that dust it puts off!

 

[BillGrissom]

Thanks for all the helpful replies. It sounds like I have been missing some fun. I will watch craigslist and ebay. I still have the Dart interior to do, and want to de-rust every nook and cranny, otherwise just pretending. I also need to go over my 65 Newport, which was totally rust-free when I got it 20 yrs ago (SoCal car), but has spent much time outside (car cover). 1982+ cars w/ galvanized metal seem almost immune to rust.

Do you have air?

I have a 220V Rand 4000 horizontal compressor (20 gal?), probably similar to sireland's 67. I expect it could handle ~30% duty cycle sand blasting.

I like the Unitech spot gun in airwoofer's link. One can load dry grit for quick jobs, as needed, and it requires less air. Looks like it would fit inside the Dart doors, and takes up little shelf space.

Thanks for the tips on dry sand. I read another FABO post where it wasn't working because his sand wasn't dry enough. Sounds like the large bin type blasters are better for daily production use, not occasional home use.

res1vw21, nice-looking parts. The Aspen hood looks very similar to my 65 Dart, with similar braces and plastic blobs (who said F-bodies aren't FABO). I worry about rust working thru from inside the braces. I sprayed rust converter inside all enclosed areas, which is about all we can do without a dunk in a tank like some new cars get.

Re how much rust one must remove, some think of rust as cancer that inherently spreads to other metal. My understanding is that rust is porous and paint doesn't bond to it, so it allows moisture to get to the good metal. You don't have to remove every trace of rust, just provide enough solid metal to give a continuous bond to the paint. I suspect a surface can look very shiny when 50% bare metal and 50% rust. However, the bare metal scratches are close together and fully support the paint. A pitted surface is harder to clean and where a sand-blaster probably excels. I will prime my inner fenders with Rust Destroyer. It claims to etch bare metal, convert rust, and withstand 800 F. I used it in my engine bay, which I got to shiny metal everywhere except a few spots under the cowl. I used paint remover, wire brush, and Naval Jelly there. I'll see in a few years.

 

[TrailBeast]

Muriatic acid sounds like what you really want.
Disolves rust and mineral deposites both by spraying on with a squirt bottle.
Not dilluted, just right out of the jug.
Don't breath it though when it's doing it's job, use rubber gloves and rinse the area well after.
It'll find rust spots you didn't even know you had..

 

[CudaChick1968]

Those spot blasters are great -- if you only have a little spot to blast that'll be done in a minute or less. They don't hold much media at all, and if you'd use one on a rusty inner fender you'd have to stop working, take off your mask, eye protection and gloves and go fill it up every couple of minutes before you were down to good bare metal.

The wire brush is great to remove loose paint, scale and large rust flakes, but you don't want to put anything in your media that you don't have to. Grease, oil, and anything wet should not come into contact with the media under any circumstances. A good regulator is a must if you'll be blasting different metals and finishes. Too much air pressure and your media will pulverize and turn into dust before you know it; 90 psi is about as high as I'll go in my cabinet on rusty steel, and my pot blaster will put out six cubic feet of media in a minute so I only suit up and use it on big stuff when I have to.

There are quite a few different sandblasting threads that have been going for the last year ... all have great info, links to materials and equipment, and lots of good responses. The Search key near the top of this page can be your best friend sometimes.

Unlike paint, every bit of rust needs to be removed before I can start my powder work. These rusty early A Body inner fenders were blasted in my cabinet using Black Beauty slag in a fine grit at 80 psi.

View attachment IMG_5177.JPG

They were fairly pitted and, not surprisingly, I uncovered a couple pinholes.

View attachment IMG_5206.JPG

A little of my magic high temp metal filler and voila, the end result.

View attachment IMG_5216.JPG

View attachment IMG_5211.JPG


Hope this helps a little. Good luck with the project! Keep us posted on your progress.

 

[BillGrissom]

Updating this post since I got a hand-held sand blaster (~$15 ebay). Forgot the model, but all look like from same factory. I used it on all steering and front suspension parts of my Valiant plus 3 extra inner fender splash shields that came with the Dart. I had already gone over all parts with a wire wheel, but the blaster was good at getting in the nooks, like the inner surfaces of the LCA. It left a dull white finish like rest1vw21 shows. Since a CA car, there wasn't much rust except the UCA. The splash shields were probably from a Reno car and worse than CudaChick1968's photos, with some rust thrus.

After pricing Harbor Freight's bags (Al2O3 or garnet), I bought Home Depot bagged sand ($3/bag), not even the more expensive "playground sand" since looked the same size. If I had a cabinet to recover media, I might use the $30/bag good stuff. I used 1.5 sand bags and sprayed outside, over a place where I needed sand anyway. I spent ~8 hrs, mainly due to operating issues. I used a mask, face shield, and nylon hood, but still had sand in my eyes and ears, but no worse than my child-hood days playing in Florida sand dunes.

The good part is the sand removed the rust fast and the metal never got warm. It was great on the large splash shields with front undercoating. I had already picked off any loose undercoat. The blast cut away the edges of the undercoat until I hit bright metal, where I left the solid undercoat on. The stream was fairly thin, so like painting the surface with a magic marker. Sand usage wasn't bad and I only had to refill the canister about every 2 minutes, when I needed to let my air compressor recover anyway.

The bad part is that I started having problems with sand pickup. It seemed worse later on. Shaking the blaster seemed to help. I even took it apart to look for clogs or debris and found none. It is just a weighted rubber tube going to a venturi. At times it seemed to just blow air, though I could feel a few stings from sand with my hand in front, then a good sand stream would continue. I suspect the problems were from moisture. I had a wall mounted filter and left its drain cracked, as well as the compressor tank's, but still found water in the air lines. The sand in the reservoir appeared dry, but perhaps even a little moisture hampers the flow. This was in April in northern CA with some clouds, ~70% humidity. Maybe I'll try to blast only during our bone-dry summers in the future. Another big problem is that the plastic trigger on the blaster was hard to push and started wearing out my fingers.

In sum, the portable blaster works OK on small parts and to get into nooks and crannies, for occasional blasting. It should work great on my Dart's interior (just starting), such as inside doors. If I do panels again, I will just wire-brush, maybe wet with muriatic acid, and use rust converter. The wire brush gets loose rust but leaves a hard "black rust" surface on badly pitted areas. Still, the converter should seal those OK for places like floors where you don't care about appearance. It takes too much time with the blaster, unless I got a big $200 model, plus giant compressor, etc. But my family doesn't appreciate my classic car work, even on the cheap.

 

[metallidart]

Here is my experience with blasting.

Been doing it almost every day for over 6 years now, at work I use a HUGE cabinet, at home I just have a small old sears siphon feed bucket.
When I first started, I used play sand in the small one at home, and I got good results, but I wasn't really satisfied.
Since I started doing it daily, I've learned quite a bit. I use glass bead in my blaster at work, and I make sure I have a tip with a really wide pattern if I am doing thin metal. I never stay in one spot, I go back and forth, up and down, watching the metal and rust/paint/etc. Because I am SUPPOSED to be doing locomotive engine parts, my pressure is kind of high at 60lbs. Destroys the glass beads pretty quick, but it takes scale/industrial paint/etc off really quick. I'm used to blasting with that pressure, so I just move around alot, if it has spots that won't come clean, I will take a small pick and pick some of the scale/paint off and keep blasting around. Sometimes, it also helps to use a sanding disc or fiber pad (again, keeping the metal cool) to take the thick stuff off before you blast. Make sure you clean the surface really, really good when you are done, that media dust gets down into the surface imperfections a little bit and can be a pain to get completely clean. Now that I know how to blast, I hate using any other method.

When I'm at home blasting, i buy some clear plastic dropcloths, and a tarp, tape it all up so the media kind of funnels to a low spot, and I just leave my shop vac running to suck up the dust and media. Makes it a little easier to filter and reuse, but you go thru filters a little faster than normal.

 

[SRT_DSTRHOLC]

Updating this post since I got a hand-held sand blaster (~$15 ebay). Forgot the model, but all look like from same factory. I used it on all steering and front suspension parts of my Valiant plus 3 extra inner fender splash shields that came with the Dart. I had already gone over all parts with a wire wheel, but the blaster was good at getting in the nooks, like the inner surfaces of the LCA. It left a dull white finish like rest1vw21 shows. Since a CA car, there wasn't much rust except the UCA. The splash shields were probably from a Reno car and worse than CudaChick1968's photos, with some rust thrus.

After pricing Harbor Freight's bags (Al2O3 or garnet), I bought Home Depot bagged sand ($3/bag), not even the more expensive "playground sand" since looked the same size. If I had a cabinet to recover media, I might use the $30/bag good stuff. I used 1.5 sand bags and sprayed outside, over a place where I needed sand anyway. I spent ~8 hrs, mainly due to operating issues. I used a mask, face shield, and nylon hood, but still had sand in my eyes and ears, but no worse than my child-hood days playing in Florida sand dunes.

The good part is the sand removed the rust fast and the metal never got warm. It was great on the large splash shields with front undercoating. I had already picked off any loose undercoat. The blast cut away the edges of the undercoat until I hit bright metal, where I left the solid undercoat on. The stream was fairly thin, so like painting the surface with a magic marker. Sand usage wasn't bad and I only had to refill the canister about every 2 minutes, when I needed to let my air compressor recover anyway.

The bad part is that I started having problems with sand pickup. It seemed worse later on. Shaking the blaster seemed to help. I even took it apart to look for clogs or debris and found none. It is just a weighted rubber tube going to a venturi. At times it seemed to just blow air, though I could feel a few stings from sand with my hand in front, then a good sand stream would continue. I suspect the problems were from moisture. I had a wall mounted filter and left its drain cracked, as well as the compressor tank's, but still found water in the air lines. The sand in the reservoir appeared dry, but perhaps even a little moisture hampers the flow. This was in April in northern CA with some clouds, ~70% humidity. Maybe I'll try to blast only during our bone-dry summers in the future. Another big problem is that the plastic trigger on the blaster was hard to push and started wearing out my fingers.

In sum, the portable blaster works OK on small parts and to get into nooks and crannies, for occasional blasting. It should work great on my Dart's interior (just starting), such as inside doors. If I do panels again, I will just wire-brush, maybe wet with muriatic acid, and use rust converter. The wire brush gets loose rust but leaves a hard "black rust" surface on badly pitted areas. Still, the converter should seal those OK for places like floors where you don't care about appearance. It takes too much time with the blaster, unless I got a big $200 model, plus giant compressor, etc. But my family doesn't appreciate my classic car work, even on the cheap.

what blaster and compressor did you use? i am very interested!

 

[BillGrissom]

The yellow "Ace Air" in the photo is the one I used. The difficult trigger is its worse part. My compressor is a 2 HP Rand 4000 single cylinder, wired for 220 VAC. It might be marginal because the motor would stall at 120 VAC, and even now when the oil is cold.

Since then, I got a wand-type blaster (Cambell-Hausfeld AT 1251) off craigslist for $40. I see new ones for $120 on ebay. It says "3 HP compressor or larger", so I won't run 100% duty cycle. It has a large sand hopper w/ shoulder strap. They both use the generic white ceramic nozzle, with the sand is sucked into a venturi ("siphon-fed"). I looked at Harbor Freight's today. Their wand is bigger and uses a different ceramic nozzle (big, red). The sand comes off the bottom of a pressurized reservoir, which they say flows twice the rate of siphon-fed. The trigger blocks the nozzle exit with a metal plate. I didn't have trouble with sand flow-rate in the Air Ace except when it stopped completely, probably due to moisture.

About to start blasting the Dart's interior. The wand should get into the crevices better. The HF's wand is bigger.

 

[needsaresto]

Bill,You will find that the siphon type blaster works MUCH better when you pressurize the feed tank/ All you need do is put a T air fitting into the bottom of your blaster,and hook the extra port to a short air line. Then feed this line into your sand pail,but control the pressure with a gauge and ball valve. I use plastic 5g wine buckets,they come with a nice tight fitting lid. Even 5 psi will completely eliminate clogs in your feed line and you will be able to dig out much deeper rust with this setup.