Cleaned by Pete: what a power washer does: wet soda blasting

Thursday, April 11, 2013

Media...... What is the difference? sand, soda, coal slag, walnut...

This is a follow up entry to the blog's entry on Media Blasting. I am writing this as only a person who has used the wet media blaster and what I have found out about using it with the different medias. I have not done a doctoral theses on the subject and some may not agree with all of what I have written. This is my opinion and observations from using the product with the wet media blasters Cleaned by Pete owns and uses. We have specialized in doing jobs and items that other sand blasters do not want to do for reasons of time, cost, size, to much labor, or are too odd. Clean by Pete works with each customer to see if we can help fit what you want with what we do.

Wet media blasting is defined as: the process of removing unwanted material with a water stream into which a media is mixed and is contained that throws abrasive particles against the surface with some force causing removal or the unwanted material.

"Media" is the product we add into the water stream to do the removal of the unwanted material, this media can be abrasive or nonabrasive. Depending on what is being blasted and what is being removed you will need the right type of media for different jobs. Wet blasting can use sand, coal slag, crushed glass, soda, walnut shells, and other different media. Then in each group different types or subtypes in each of these categorize and then the different grades of each. These are just a few of the media products that can be used. I will talk about the ones we use.

Are you looking for a factory finish?

Soda Blasting; first soda is also a cleaner, this make the soda media great to work with, for cleaning or using it as a material remover. Anything from removing grease and grime to removing paint and other materials, soda has a lot of uses in the cleaning field. Soda can be purchased in several grades the coarser the grade the larger the particulates are. The larger particulates cut faster and "explode" more removing material quicker but the coarser the grade the more the cost. Soda is a nonabrasive and can be used for blasting where sand and slag and other media can not. You can wet blast a motor compartment of a car with out worrying about the ball joints, steering knuckles or other moving parts. Soda will not hurt, inbed or alter the metal surfaces. This saves time and money you need not have to dismantle everything, it also washes clean. Soda will not hurt or etch chrome, glass or soft rubber surfaces. Soda is great for fire restoration and cleaning if you can get the water removed.

I used the word "explode" earlier, I'll try to clarify this term. Each type of media has its own reaction to the sudden stop when it hits the material it is trying to remove. Soda happens to be soft enough to blow apart upon impact. Sand, glass, and slag are harder they will fracture using sharp edges for cutting off or digging in, to remove the material. Soda impacts and the energy form it blowing apart removes the material like a little explosion or as a meteor hitting a planet a crater is formed in the material blowing it apart. Then the smaller soda particulates will be caught up in the water stream again and the process is repeated until the soda looses all its stored energy, until it is ineffective anymore. The big plus with soda is that it has been tumbling and bounces around all this time. The busted up particulates are like little erasers and pick up more and more grease and dirt, that is why momma uses it to clean the stove and sink in the kitchen it cleans and does not scratch.

A fine nonabrasive soda was used here. We did not want to alter the factory finish of the rims. Soda comes in different grades (sizes of particulars) the coarser the grade the faster it removes but the higher the cost.

You can see still see the milling marks on the face of the wheel and the pebble finish inside the wells. When restoring a car to a factory finish you can not alter the metal surface. Sand and slag would have erased the milling marks and may have gouged in removing metal too. Walnut shells were too large and can not get into and clean the pebbling. Fine soda is what was call for here.

When a car's total restoration counts, some people will spend a great deal of time and money finding the best correct parts. They don't want that distorted or blasted away. Soda blasting this rim will bring it back to factory specs, plus the water stream is clean and washes years of neglect and dirt away away.

Since we are here and are talking about car rims here are a few we have done for a BMW enthusiast. They restore one BMW a year and then "turn it" and move on to the next one. Sometimes these cars have rims we can help with. Here are two of them we have done. Moist of the "sand blaster" in town did not want to touch them told them they would distort or ruin the rims before they could get the power coat paint and the baked on clear coat off. The owner said one blaster said he would do it but he didn't really trust him. Here is what Cleaned by Pete did with them.

Removing the factor power coat and baked on clear coat for a restoration on a BMW. We had to use a two step process with different types of media to achieve this result.

Media blasting with water and soda Cleaned by Pete.

In this close up you can see the paint and factor finish is removed we are down to the original factor metal and have not distorted any fine details. The owner told us these are magnesium centers and are hard to find, that is one reason why no one wanted to blast them.

You can see that the factory power coat and finish is wearing off the turbo style centers. Again the owner came to us since he had such good results with us on the first ones. We used the same two step media process to restore these centers too.

Readying the center for the wet soda blasting, we have a soft plastic backstop to help absorb the energy reducing bounce back and splattering of the media (tricks of the trade) helping us to work faster and more effective.

The group have been blasted once and will now be having the finial grade of soda blasting applied.

After the process and the drying time our BMW center looks like. This is now down to the original finish of the metal before being power coated and clear coated, without gouging or distortion of any kind.

A bit closer picture showing the finished item Cleaned by Pete's Wet soda-blasting service.

I will end this entry here and pick up when, Cleaned by Pete soda blasts a '55 Thunderbird rear end in the next entry. Seeing that I have a lot to cover I'll break it up in smaller parts and entries. Let us know in the comment box below about your work with "wet blasting". Thanks for the viewing.

Thursday, April 4, 2013

Attachments: the "Media Blaster"

Media Blasting, Sand, Coal Slag & Soda

As promised this entry is about our media attachments, yes attachments we have two different types, which we use for different needs and jobs. When first setting up and studying on this entry up I found out there is to much information to cover in one short entry so I am going to break it up a bit and today hit the highlights and then go into a bit more in the later entry or entries.

There are several "pluses" and "negatives" of each method or for "Dry VS. Wet" blasting. I will touch on these points and different media in the later blog entry. For now we will discuss the attachment and how and why it works.

Media can anything that can be drawn into the water or air stream. Common media can be screened sand, coal slag, crushed walnut shells, cobs, soda, crushed glass and other products, each of these have different cutting abilities and come in different grades in-order to fine tune your job's need. Wet media blasting or wet sand blasting is using our pressure washer to supply the water stream and the pressure needed to push this media to the unwanted material and remove it. Some of this media is made to cut off that material, some is made to roll thus more or less erasing the material, and then there is some that hit and fracture or explode removing the material more in a later blog entry. The first thing it to get the media into the water stream.

This is the mixing nozzle that draws in the media and them mixes it into the water stream. Picture form Cleaned by Pete

These tips have to be fit to the power washer as are all nozzles we use, as we learned in earlier entries to big of nozzle reduces pressure to small causes other problems and can harm the pump. This nozzle has a tungsten insert to reduce ware form the media (the one pictured below has a ceramic / metal tip combination). In order to draw the media into the nozzle we have to create a low pressure zone. This low pressure zone is created inside the nozzle it will be filled by air being drawn in and in that air will also be the media drawing it though the pickup hose. Drawing different media takes different pressures the nozzle above does not adjust for media flow, so we made special inserts to put into the hose drawing the media to help draw at different rates for different medias. The setup below has an adjustable flow there is a small lever on the side-handle which helps to regulate the draw of different media. To much media in the water stream will slow down the blasting process and will not work as effective, and has more waste.

The small lever on the side handle will help to adjust the media flow, Cleaned by Pete

That is the simple description and function of the media blaster. I will have more on it later in following blog entries as well as different media we use for blasting and why. The following pictures are the media blasters we use, and our setup.

This is a 16hp motor with a 4 gpm @4000 psi nickle plated head AR pump, the tank on the side is a simple hopper to hold the media or we can use it out of the bucket on the right. Photo from Cleaned by Pete

Cleaned by Pete's media blasting washer.


Cleaned by Pete's Landa media or sand blasting wand and sand probe setup.

The below pictures are of each unit the first one we had set up for soda blasting though we can use it for sand and other media it main job is for soda blasting. The other unit is made by Landa and we use it for all other media we use in blasting.