DIY Wet Sandblasting

[HizAndHerz]

A few weeks ago, I saw a segment on SpikeTV's Musclecar show where they "wet sandblasted" the rusty frame from a Pontiac LeMans. Basically, a $100 attachment turns a pressure washer into a wet sandblaster. They showed how wet sandblasting took the frame down to clean, shiny metal without the nasty cloud of sand particles in the air.

 

That was enough for me. Since my wife had been wanting a pressure washer for cleaning the patio and driveways, it was an easy sell. I shopped around and found a decent sized one on sale at Sears. Then, I found that Northern Tool had this wet sandblasting attachment for around $60. Elsewhere, they seem to go for $90 to $150.

 

I've only had an hour or so to use it, but it worked great at removing rust from an old crossmember and blasting off the old liner from inside a fender. Then I cleaned a grease-caked transmission housing in no time by pressure washing it with degreaser and then wet sandblasting it. Wet sandblasting doesn't seem to be as tough on old paint as the dry sandblasting we've done, but the advantages are awesome.

 

I started using Black Beauty abrasive, but the process goes through the media pretty fast. I Googled and found that some people use playground sand that can be had for less than $3.50 for a 50lb bag. I'll be tracking some down later today.

 

So, has anyone else had any experiences with this?

[Cruez]

From what I have heard, playground sand is a big no no because of the silica.

 

http://www.nlm.nih.gov/medlineplus/ency/article/000134.htm

[HizAndHerz]

From what I have heard, playground sand is a big no no because of the silica.

This is wet sandblasting. You'd have to snort the slurry off the ground to get silica/sand up your nose. Still a good idea to use a mask.

[Pop N Wood]

I have heard the same thing about sand in a sandblaster, but you have an excellent point about the water. Even asbestos removal is less dangerous when they inject the insulation with water first. As long as it is not airborne it is not a threat.

 

And $3.50 a 50 lb bag is Home Depot prices. It is $20 a ton at the local gravel quarry.

 

If you have to use box media, then I would say it is going to be too expensive since you can't recycle the media. But for $20 a pickup truck full.

 

Plus I would imagine you don't have to worry about heat warping sheet metal.

 

Makes me wonder why it is not the preferred way to do it.

[OlderThanMe]

Maybe because it sticks to everything you blast and everything within a 20 foot radius? If you made an enclosed room then it should be better.

I may look into this though. Seems like the way to keep from breathing the sand.

[Tony D]

Makes me wonder why it is not the preferred way to do it.

 

Most pressure washers put out around 2 to 3.5 GPM of water at pressure.

 

Blast for 8 hours a day, 480 minutes, roughly 1000 gallons of water contaminated with grease, heavy metals, et al that must be treated before being sewered legally.

 

Opposed to recycled dry media that can be easily sifted and reprocessed, with the dry off-takings being legal to landfill with no treatment whatsoever.

 

This is similar to it being illegal to dump a gallon can of housepaint in a landfill, but open it dump it onto boards or mix it with sand and let it dry...then you CAN landfill it!

 

Liquid waste is a bugger to treat and legally work with. This is a preferred way for low-cost grafitti removal, and for home usage.

 

But for someone doing large scale stuff, it would get costly having to deal with 1000 gallons, per day, per workstation of sewerage and treatment costs. Figure most shops usually have four to eight guys working jobs at the same time...you can see those volumes add up quickly.

[V8_DatZun]

well i live in a rural area.. the water and sand wouldnt hurt my land i dont think... and i have city water so i dont have to worry about it going down into my well water or something... i dont believe as dry as it has been here it would get past the first few inches of soil anyway... so for doing small jobs like maybe blasting surface rust etc... would this be a good option?

[jeffer949]

actually tony if you buy any sort of any decent powerwasher you should at least go with one at 4gpm and 4000psi i prefer going with a 5.5gpm machine that is 3500psi(im a powerwasher as a job so i have access to many different ones...) and top that off with a hot box... and crank the heat up to 190degrees and then your having some fun.. i havent used the wet sand blaster but i would think it would work great

[JIM73240Z]

I use to sand blast concrete forms for a living, the ones that form up your sidewalks. i used a suction hopper that would suck out #300 of sand in a day. i would fill up the evaperation pond every day with water. i would have to get a tractor every month to clear out the area but other than that it ws not to bad. the sand could not be reused because it would clog up immediatly. for a large auto project i dont think it would work that great because of all of the waste. small stuff would not be too bad, like blasting a front fender. i would not do the whole car though. huge mess. i still used a mask, just not the heavy duty one. i just finished sand blasting my car. have the doors to do but that wont take long.

 

jimbo

[JimmyZ]

I had a pressure cleaning business for 12 years. I used a wet sandblasting attachment a few times. It was good for taking graffiti off stone walls. For equipment go with 3000 psi because the majorty of the market's accesories are rated for it. (hose etc) Gallons per minute are better than pressure. I knew a guy with a 1500psi/12 GPM machine that could clean circles around my 3000psi/6GPM machine.

 

The thing to be aware of is how the pressure/media can warp thinner metals such as anything you would do bodywork on. (fenders, hood doors quarters etc) You will find that a wet blaster might only be good for heavy components such as diffs, frames and underbody. The other pain of using the suction system is when your media or feed hose interior gets wet. Suction blasters are a pain to use when the feed isn't constant.

 

Here's a page I made for guys like us. I'm no expert but I've done a few cars and learned from mistakes.

http://warbuddies.homestead.com/RestoHelp.html

 

I liked my harbor freight pressure pot. (Air) I did find that it would warp our thin panels though. (Did hod both sides and had waves like an ocean in the metal) Used a 7hp and 5hp coupled to provide constant air pressure/cfm's to run the pot.

2c

 

Jim

[MatMan]

As I was reading this thread, I was thinking to myself, Self - this is a really great idea, until I read Tony's post, which brought up a few good points. My water is from a 100' well, and I constantly worry about contamination.

 

I came to the end of this thread, and VIOLA! there is a Sponsored Link to a DRY ICE BLASTING SERVICE! I wonder if they do housecalls? Wouldn't that be a kick? Besides, sublimation KICKS A$$!

[Metallicar]

I came to the end of this thread, and VIOLA! there is a Sponsored Link to a DRY ICE BLASTING SERVICE! I wonder if they do housecalls? Wouldn't that be a kick? Besides, sublimation KICKS A$$!

 

Great! I wonder what this means for me, as I came to the end of your thread;

 

http://www.usexplosive.com/

[Careless]

i saw that on tv too, and i wanted to get an attachment for my 1500 psi electric unit here.

 

albeit it wont be nearly as strong, but my neighbour across the street got a 3500 psi unit, and I'll ask him if he wants the kit. I'll buy it for him, and he can keep it, as long as I can use it with his power washer

 

but for now, i ordered the 1500 psi version to use on my own machine.

 

we'll see how it goes. I'm going to sandblast my subframe and rust-bullet spray it.

[alexideways]

Take a look at soda blasting, I read a lot about this subject and IIRC, I read something about WET soda blasting.

 

Soda blasting is neither armful to your health nor the environment plus, since it dissolve in water, you can just wash it away and you'll only be left with what you blasted off to pick up.

 

One nice side effect is that as long as you leave it on the surface you're working on, it gives a good rust proofing cause, rust is an acid & soda is a base so, they kinda cancel each other.

 

Just run a search on soda blasting here on HZ, I started a few treads on the subject.

 

Also take a look at these.: http://www.sodablast.ca/

http://www.natriumsodablast.com/

http://www.sodablasting.com/

[JimmyZ]

Soda blasting =$$$$

I once got a flyer for the equipment. It was pretty cool but very expensive. (Necessary for some jobs up north though)

 

Just get two gallons of Aircraft Remover ($40-50) strip an area/ panel at a time then sandblast the rusty spots. A inexpensive siphon unit is all you need although a pot is nicer. A D/A (What you don't have one??) can remove the leftovers and speed up bodywork later. Follow up with Ospho and remove opsho after 24hrs then treat with DX520 to be sure. (This is overkill but at least nothing is coming back) Coat with epoxy primer and it's good for up to a year. You can do an entire car in two to three days with this method... I have. Took the car down to bare metal 15 years later and found only minimal sheet rust in areas. (Possibly due to Florida humidity during primer coating. This is the best you can do.

 

The only advantage to wet blasting would be that dust wouldn't work it's way into hidden areas. You can minimize this with masking though so why not just get 'er done?

 

2c

 

Jim

[HizAndHerz]

btw, Jim, I printed out your restoration tips webpage. Good stuff there. Thanks for sharing that.

[HizAndHerz]

I did buy 200lbs of leveling sand for around $8. Then I wet sandblasted another old fender and some suspension parts. No warping that I could detect on the fender. I like the way everything turned out and how fast it was. Not mindblowing - just another option for small to medium rust removal jobs.

[alexideways]

Soda blasting =$$$$

I once got a flyer for the equipment. It was pretty cool but very expensive. ...

 

 

I was not saying buy the soda blasting rig, what I meant was MAYBE he could use soda as a media in his wet blasting attachement for his press. washer???

 

Think it would work???

[Careless]

 

The only advantage to wet blasting would be that dust wouldn't work it's way into hidden areas.

 

on the contrary, sand mixed with water will dry up and become a sandy haze within every nook and cranny it gets into, therefore, you will- at some point, have sand inside every nook and cranny.

[JimmyZ]

Hi Alex,

In the context of wet blasting using a standard pressure cleaner..

The size of the media determines how fast you can remove finishes. I think the soda might work OK for metal that was bare. (I'm assuming it is fine stuff.. Finer than glass beads) It would be kind of like using 400 grit paper that could reach into very small pits pockets in the metal and root things out. Regular sand would need to be used for removing paint/undercoating of course. You are going to end up using phosphoric acid after the wet blasting so reaching into pits,etc isn't as important. It was neat to see the giant air rig in one of your links. I was mailed a pot style advertisement that you used with a pressure washer.

 

His and Herz,

 

Thanks! I figured that making such a page might help someone. It would have helped me 20 years ago when I started playing with paint.

 

Just curious about your wet sandblasting tryout... Was it on a Z fender or a thicker skinned part? (My 57 Chevy fenders could take anything I threw at them) Did you run your hand/palm across the fender before and after cleaning? I had a Z hood that was straight until I used my pressure pot sandblaster on both sides. When I ran my hand across it after stripping it was waaaay wavy. Had the same thing happen with a couple other spots. It's funny how sandblasting can seemingly "suck" the metal out towards you.

 

It might be that you had a weak pressure cleaner which didn't exert too much force. Was it one of the 1500 psi/1.5GPM models. Using one of those with a 4GPM tip in your wet blaster would be fairly gentle. Maybe you found something:)