Dustless blasting anyone?

[69 MBee]

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.

The bodies "in white" went through wash vats, then onto dip primer that went about 10" or so up from the rocker line.
Paints today do not have the volume solid nor the Organic compounds it once had as they were solvent based.
Today, every car plant has wash, chromate and water borne finishes. The baking process simply speeds the curing process.

I just got out of the booth. 20 mins at 120 degrees and pull the tape...pull it out.

 

[Dan64]

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

Yup, you can see the difference in the metal color/ texture when you change the disc and go back over the last part you did with the worn out one.

 

[69 MBee]

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!

I agree, paper quality is a big deal.

 

[Photon440]

The bodies "in white" went through wash vats, then onto dip primer that went about 10" or so up from the rocker line.
Paints today do not have the volume solid nor the Organic compounds it once had as they were solvent based.
Today, every car plant has wash, chromate and water borne finishes. The baking process simply speeds the curing process.

I just got out of the booth. 20 mins at 120 degrees and pull the tape...pull it out.

Oh, I know about the dipping vats, special washes and prep work. It still adds up to much less 'tooth' on the metal finish compared to a simple sanding no matter what type of paint is eventually applied. Perhaps 120 grit is just plain overkill? And the factory uses a lot more than 120 degrees - that might be fine for a repaint shop that doesn't want to melt the interior but the factory bakes the car before the rubber, cloth and plastics are attached; 140C is a more normal temperature, or 284 degrees f.

 

[69 MBee]

Baking has nothing to do with the bond of a coating. It is a curing process.

There are only two types of bonds.
Mechanical = abrasion or "tooth"
Chemical = accomplished through resin chemistry.

In order for either to be accomplished the substrate must be clean (oem dipped them), dry and sound. It really is that simple.
The variables come in with too large of profile or tooth as the OP was inquiring thoughts on blasting. Example, aggressive media blasting that creates microscopic pits in the metal or using 36 grit grinder (a bit extreme) and expecting primer to fill and surface..... I trust very few with a blast nozzle. I have a 500lb Clemco and a water injected 100lb rig. I wouldn't touch any car of mine or yours (with exception to small trouble areas) with them.

Anything I have blasted will still get sanded as the media imbeds the surface. Then I wash and prime. As stated, I steer clear of what paint manufacturer's deem surface contaminants and they clearly state Hold tite is to be removed prior to coating.
Tech Data Sheets and product specifications are published for a reason.
That is my 2 cents, do it by hand or chemical dip if you have access.

 

[roadrunner57]

so........what does it cost to dustless blast a car?

 

[Ceedawg]

Having worked in a small body shop in the late 60s I’d say the paint then was WAY different then now. I didn’t paint but did sand-tape, 220-320 only. Owner really got on us if we didn’t get the tape perfect because ANY little paint line was a bitch to get off it stuck so well (DuPont enamel) Like he said you sand to get the dirt and wax off the original paint.

 

[Mr. Mike]

so........what does it cost to dustless blast a car?

Watched a promo video on YouTube guy said about $1k.
Seems the guys buy this franchise because all the burger and soft-serve ice cream ones sold.
I wouldn't trust my car to them.

 

[Dan64]

@Psycho Dad what part do you disagree with?

 

[Old Sparky]

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

HO LEE ****.....THANKS

 

[Hemirunner]

I’m struggling here. I’m hearing that wet blasting is good, and bad, too coarse is bad, too fine is bad... everything needs sanded. Crazy. Lots of confusion and conflicting info. Experience tells me that blasting with silica sand back in the day works and using DTM epoxy primer directly over the blasted surface also works. Apparently glass is too coarse to do this from what I read and silica sand is not available and a health risk?? Any clarity you experienced blasting guys cam provide will be appreciated.

 

[zyzzyx]

The bottom line is if you don't have the right equipment and /or don't know what you are doing,
don't attempt to blast yourself. Alot of media is not good for your lungs and you need the right PPE
to use it. We blasting is good because the water keeps heat from warping panels, but as you can see
from the pictures and videos that there is "collateral damage that must be addressed. You want to
strip your car safely? Use a D.A. sander with 3M 80 grit red psa paper and a 3M respirator. And yes,
after you're done use DTM Epoxy primer. I had my underbody done by professionals as you can see
in my video because I don't want to kill myself and they did the whole job in eight or nine hours
for $1400.00. All I had to do was sweep up afterwards.

 

[Hemirunner]

The bottom line is if you don't have the right equipment and /or don't know what you are doing,
don't attempt to blast yourself. Alot of media is not good for your lungs and you need the right PPE
to use it. We blasting is good because the water keeps heat from warping panels, but as you can see
from the pictures and videos that there is "collateral damage that must be addressed. You want to
strip your car safely? Use a D.A. sander with 3M 80 grit red psa paper and a 3M respirator. And yes,
after you're done use DTM Epoxy primer. I had my underbody done by professionals as you can see
in my video because I don't want to kill myself and they did the whole job in eight or nine hours
for $1400.00. All I had to do was sweep up afterwards.

I did my first one myself 30 years ago with silica sand in a pot blaster for about $75. I’m looking to do another one and just trying to find the best option.

 

[Ceedawg]

I used the pressure washer and media type, did great and no dust! Then sand with 120 paper. Rotate on the rotisserie to get all the grit out, osfo to stop flash rust wash then prime then sealer then paint.