Dustless blasting anyone?

[themechanic]

I haven't tried it but sure won't after watching this video.

 

[Dan64]

As far as media getting behind panels that happens with any type of blasting really. If you're blasting a car you are going to be looking behind panel because the car is going to be stripped down anyway. I had Dustless blasting come out to my house and do my 64' with recycled glass , i would do it again on the next project , hands down the best way to go. It is true that you have to make sure that the operator is using enough "Hold Tight" in the water mix. When mixed correctly it will give you 72 hours before flash rusting, i don't trust that number and figure more like 24 max

 

[69 MBee]

As far as media getting behind panels that happens with any type of blasting really. If you're blasting a car you are going to be looking behind panel because the car is going to be stripped down anyway. I had Dustless blasting come out to my house and do my 64' with recycled glass , i would do it again on the next project , hands down the best way to go. It is true that you have to make sure that the operator is using enough "Hold Tight" in the water mix. When mixed correctly it will give you 72 hours before flash rusting, i don't trust that number and figure more like 24 max

FYI, Hold-tite is considered a surface contaminant when it comes to coatings. I'm very familiar with the product and every coatings rep I have dealt with says it must be removed to ensure proper adhesion. Typically, means Phosphoric acid wash is in order.

 

[Bighouse]

They can turn the water off and just do it dry too. I had a frame done wet. Then when it came to the bottom of a car, he opted to do it dry. Both came out great

 

[gkent]

Nothing a rotisserie and a pressure washer wouldn't have resolved.

I think a lot of times the person having the car blasted doesn't think through the process or doesn't ask enough of the right questions or relies too much on the guy doing the blasting. Not many - if any - blasters own a rotisserie and even if they did the extra setup time would add significantly to the bill. A lot of them will put vehicles up on a forklift and the owners think that's the cat's *** and don't consider the **** sitting in the bottom end of the car.

 

[zyzzyx]

When I had my "X" blasted I had my buddies company do it while it was outside the body shop
mounted to a rotisserie. Round and round she goes and when she stops there is no media left
inside the body! plenty of blowing and turning and then straight into the booth for Epoxy and
color on the underside. Yeah, no one thinks about the swill inside when you wet blast!
nehttps://www.youtube.com/watch?v=Oed6o1Ugxlwver

 

[Dan64]

FYI, Hold-tite is considered a surface contaminant when it comes to coatings. I'm very familiar with the product and every coatings rep I have dealt with says it must be removed to ensure proper adhesion. Typically, means Phosphoric acid wash is in order.

I would say that the bigger problem would be the lack of Hold Tight or a watered down ratio. They claim zero residue, idk. This last car was the first time i used it. I do know that soda blasting has ruined a lot of paint jobs due to surface contamination and is not used very much anymore due to this problem. I experienced no problems using Hold Tight but than again i did did spray down the inside of panels with surface prep ( clean, forced air dry, no wiping down on inside of panel due to no sanding) outside of panels and larger areas of inside of panel with of course hit with 80 prior to epoxy. Don't you need to neutralize phosphoric acid with water prior to painting?

 

[HawkRod]

So I am not an expert on blasting by any means. But I have heard horror stories about just about every type of blasting/ surface preparation system, along with stories about how great it is too. Based on that, I have to come to the conclusion that these systems, when used by knowledgeable people for the right application, work well. However, when used improperly, they can result in issues.

 

[gkent]

Don't you need to neutralize phosphoric acid with water prior to painting

I think you're confusing phosphoric acid with phosphorous coating. When you wash down bare metal with something like Metal Prep, it leaves a phosphorous coating - usually a whitish residue. You can paint right over this or just wipe it with a scotchbrite or wax and grease remover. There is no need to rinse it off.

 

[gkent]

when used by knowledgeable people for the right application, work well. However, when used improperly, they can result in issues.

The same can be said for a screwdriver - or anything else for that matter!

 

[HawkRod]

The same can be said for a screwdriver - or anything else for that matter!

Yes, that's true. Yet we don't have threads that make people fear using screwdrivers.

 

[zyzzyx]

I used KleanStrip green Phosphoric acid on my car as a prep before Epoxy. The engine compartment was soda blasted
because I didn't want to warp the crap out of the firewall. I simply sprayed the acid on with a Zep bottle sprayer and
let it sit for about fifteen minutes and then wiped it down with damp wrung out towels. Blew it off with compressed air
and Epoxy primed it. This is what it's supposed to look like if done properly. If there is any powdery residue left, you
left it on too long.

 

[Bighouse]

I used KleanStrip green Phosphoric acid on my car as a prep before Epoxy. The engine compartment was soda blasted
because I didn't want to warp the crap out of the firewall. I simply sprayed the acid on with a Zep bottle sprayer and
let it sit for about fifteen minutes and then wiped it down with damp wrung out towels. Blew it off with compressed air
and Epoxy primed it. This is what it's supposed to look like if done properly. If there is any powdery residue left, you
left it on too long.View attachment 1220498 View attachment 1220499 View attachment 1220500

Perfect!

 

[69 MBee]

I would say that the bigger problem would be the lack of Hold Tight or a watered down ratio. They claim zero residue, idk. This last car was the first time i used it. I do know that soda blasting has ruined a lot of paint jobs due to surface contamination and is not used very much anymore due to this problem. I experienced no problems using Hold Tight but than again i did did spray down the inside of panels with surface prep ( clean, forced air dry, no wiping down on inside of panel due to no sanding) outside of panels and larger areas of inside of panel with of course hit with 80 prior to epoxy. Don't you need to neutralize phosphoric acid with water prior to painting?

I'm in the coatings industry. Not flexing, just have a bit more insight
In the world of SSPC, Magnification, mil profile, surface contaminates.
That being said, most "blasters" don't know how to measure or seek a 1-2 mil profile... for proper installation of a primer ....problematic.
Hold Tite was designed for structures that could not be immediately coated.....bridges, tanks, ect.
Now enter into class 1 coatings. Automotive coatings. People assume products like Hold Tite cross over. Ask your supplier PPG, Axalta, ect all claim it as a surface contaminant.
I have rarely seen coatings fail due to product failure. It happens, but not as often as you'd think. The painting golden rule is clean, dry and sound, it's all about surface prep, no matter what stage it's in.
I have seen many epoxy coatings fail after soda blast, why? Easy, little tooth (no profile) and surface contamination, lack of prep. You need a chemical bond in this scenario and it must be clean. The epoxy coating typically gets the blame by the installer/customer due to lack of knowledge. Surface must be clean to have the benefit of a chemical bond.
Media blast...be your own boss......the influx of Sunday morning commercials created opportunity. Time is money and most use far too aggressive media and pressure and have little to no knowledge how to measure mil profile (mechanical tooth). Under magnification it looks like a mountain range. Now think about coatings/films like Hold Tite or Epoxy primers. You apply them, they look good and solid but there's more factors Wet Film Thickness and Dry Film Thickness that apply to the Mil profile. (The film/coating sit's in the vallies and leave the tops exposed)
Too little, the tops of the "mountains" are exposed, too much you pushed the boundaries of the film thickness causing premature failure with improper cure due to over building the film.
For the above reasons, I manually strip coatings on body panels (DA, Contour SCT works great) and save blasting for hard to detail and rust prone areas. Sanding the profile 80-100 grit after blasting.
I typically use Phosphoric acid, then Zinc Phosphate and yes it must be neutralized with water. Zinc phosphate is an additional step but stabilizes the surface if you're storing in a good/stable environment.
There is another product I used a few years back a local fabricator gave me to try... a wipe on conditioner that he leaves cars in bare for very long periods of time, I will check on the product name and get back to you. If I recall it was pricey and the reason I stayed with Phosphoric acid.

 

[Dan64]

I'm in the coatings industry. Not flexing, just have a bit more insight
In the world of SSPC, Magnification, mil profile, surface contaminates.
That being said, most "blasters" don't know how to measure or seek a 1-2 mil profile... for proper installation of a primer ....problematic.
Hold Tite was designed for structures that could not be immediately coated.....bridges, tanks, ect.
Now enter into class 1 coatings. Automotive coatings. People assume products like Hold Tite cross over. Ask your supplier PPG, Axalta, ect all claim it as a surface contaminant.
I have rarely seen coatings fail due to product failure. It happens, but not as often as you'd think. The painting golden rule is clean, dry and sound, it's all about surface prep, no matter what stage it's in.
I have seen many epoxy coatings fail after soda blast, why? Easy, little tooth (no profile) and surface contamination, lack of prep. You need a chemical bond in this scenario and it must be clean. The epoxy coating typically gets the blame by the installer/customer due to lack of knowledge. Surface must be clean to have the benefit of a chemical bond.
Media blast...be your own boss......the influx of Sunday morning commercials created opportunity. Time is money and most use far too aggressive media and pressure and have little to no knowledge how to measure mil profile (mechanical tooth). Under magnification it looks like a mountain range. Now think about coatings/films like Hold Tite or Epoxy primers. You apply them, they look good and solid but there's more factors Wet Film Thickness and Dry Film Thickness that apply to the Mil profile. (The film/coating sit's in the vallies and leave the tops exposed)
Too little, the tops of the "mountains" are exposed, too much you pushed the boundaries of the film thickness causing premature failure with improper cure due to over building the film.
For the above reasons, I manually strip coatings on body panels (DA, Contour SCT works great) and save blasting for hard to detail and rust prone areas. Sanding the profile 80-100 grit after blasting.
I typically use Phosphoric acid, then Zinc Phosphate and yes it must be neutralized with water. Zinc phosphate is an additional step but stabilizes the surface if you're storing in a good/stable environment.
There is another product I used a few years back a local fabricator gave me to try... a wipe on conditioner that he leaves cars in bare for very long periods of time, I will check on the product name and get back to you. If I recall it was pricey and the reason I stayed with Phosphoric acid.

Good to know and thanks for the additional info regarding Hold Tight. In hind sight i'm sure glad i hit as much as i could on the panels with 80 before epoxy. I can't imagine someone priming over the exterior side of panels without hitting it with 80-100 first but i'm sure someone out there has.

 

[eldubb440]

Good to know and thanks for the additional info regarding Hold Tight. In hind sight i'm sure glad i hit as much as i could on the panels with 80 before epoxy. I can't imagine someone priming over the exterior side of panels without hitting it with 80-100 first but i'm sure someone out there has.

to add to your point...... I wont even use 80 on a DA as it tends to wear out and "polish" the metal....... I always thoroughly scratch the clean bare metal with fresh 80 grit by hand...... anything else is risky

 

[Photon440]

I'm in the coatings industry. Not flexing, just have a bit more insight
In the world of SSPC, Magnification, mil profile, surface contaminates.
That being said, most "blasters" don't know how to measure or seek a 1-2 mil profile... for proper installation of a primer ....problematic.
Hold Tite was designed for structures that could not be immediately coated.....bridges, tanks, ect.
Now enter into class 1 coatings. Automotive coatings. People assume products like Hold Tite cross over. Ask your supplier PPG, Axalta, ect all claim it as a surface contaminant.
I have rarely seen coatings fail due to product failure. It happens, but not as often as you'd think. The painting golden rule is clean, dry and sound, it's all about surface prep, no matter what stage it's in.
I have seen many epoxy coatings fail after soda blast, why? Easy, little tooth (no profile) and surface contamination, lack of prep. You need a chemical bond in this scenario and it must be clean. The epoxy coating typically gets the blame by the installer/customer due to lack of knowledge. Surface must be clean to have the benefit of a chemical bond.
Media blast...be your own boss......the influx of Sunday morning commercials created opportunity. Time is money and most use far too aggressive media and pressure and have little to no knowledge how to measure mil profile (mechanical tooth). Under magnification it looks like a mountain range. Now think about coatings/films like Hold Tite or Epoxy primers. You apply them, they look good and solid but there's more factors Wet Film Thickness and Dry Film Thickness that apply to the Mil profile. (The film/coating sit's in the vallies and leave the tops exposed)
Too little, the tops of the "mountains" are exposed, too much you pushed the boundaries of the film thickness causing premature failure with improper cure due to over building the film.
For the above reasons, I manually strip coatings on body panels (DA, Contour SCT works great) and save blasting for hard to detail and rust prone areas. Sanding the profile 80-100 grit after blasting.
I typically use Phosphoric acid, then Zinc Phosphate and yes it must be neutralized with water. Zinc phosphate is an additional step but stabilizes the surface if you're storing in a good/stable environment.
There is another product I used a few years back a local fabricator gave me to try... a wipe on conditioner that he leaves cars in bare for very long periods of time, I will check on the product name and get back to you. If I recall it was pricey and the reason I stayed with Phosphoric acid.

This is excellent information, and makes sense.

However, it makes me wonder how the factory got paint to stick with freshly stamped, never sanded or blasted shiny steel panels.

 

[gkent]

However, it makes me wonder how the factory got paint to stick with freshly stamped, never sanded or blasted shiny steel panels.

Yup !!

 

[zyzzyx]

The red 3M paper won't dull as the abrasive is designed for use on steel and it won't break down.
The "Gold" paper is designed for cutting primer, paint, and body filler. Whole different animal!

 

[gkent]

However, it makes me wonder how the factory got paint to stick with freshly stamped, never sanded or blasted shiny steel panels.

Not just "got", "gets" !! To this day the factories spray directly on bare SMOOTH steel. May the "bake" process has something to do with it ?!?!