sand or soda?

da-man · Post by **da-man** » Sun Nov 25, 2007 11:05 pm

Hay guys:
Getting ready to have the body stripped, prior to doin' all the body work / sheet metal replacement.

1) Should I have it soda blasted, or is sand ok? I've heard that sand can warp the metal, but I've heard that soda can leave alot of rust and scale.

2) what should I expect to pay for this? Body is completely stripped of everything..... (including hood, trunk lid and fenders)

3) What should I coat it with immediately afterwards to keep it from oxidizing while I'm working on it?

thanks

Nissanman · Post by **Nissanman** » Sun Nov 25, 2007 11:59 pm

Do some research on the soda.
It appears that while it is excellent for cleaning, it is very difficult to paint a surface that has been soda blasted.
Ask your painter or paint supplier if the primer you intend using will cover a panel cleaned by soda blasting.
I was all set to go soda until I read some reports on a Hot Rod Forum that poo pood soda.
http://www.hotrodders.com/forum/soda-bl ... 83749.html
http://spi.forumup.org/viewtopic.php?t=156&mforum=spi
It is virtually impossible to fully neutralise any residue especially in cracks and crevices.
Also, because the soda leaves an inactive surface, you have to use some sort of abrasive to activate the metal to give the etch primer a chance of sticking.

Sand or garnet blasting if done very gently will not warp a panel.
By gently, I mean use a home syphon gun @ 100psi max.
The big sucker blasters may be too powerful.
Once again, talk to a few blasters and tell them what sort of job it is.
If they are willing to "give it a go", ask them to do their own car first

You need to find someone who has done it, successfully, and is recommended by body shops

Soda was great for cleaning the Statue of Liberty apparantly

Skyman · Post by **Skyman** » Mon Nov 26, 2007 11:29 am

I had the entire underneath of the body sandblasted. All that undercoating was tough to get off. I wouldn't recommend blasting the exterior body panels. Had my hood and deck lid blasted, looked great until they started the body. They were both mildly warped. The body guy kept chasing one spot all over the hood. I can still see it. Drives me nuts. In hindsight, I wish I would have not had it blasted. The body guy gave me a hard time for having them blasted.

FWIW,
Kyle

da-man · Post by **da-man** » Mon Nov 26, 2007 1:44 pm

OKAY, so, in y'all's opinion, if I've got the doors, front fenders, hood and trunk lid all removed, am I safe having the rest of the body blasted? Do I need to have 'em lay off the flat areas of the rear fenders too?

and is "Y'all's" a word?

datsunrides · Post by **datsunrides** » Mon Nov 26, 2007 9:03 pm

Here's what I did with mine, follow at your own risk.

I used 30 mesh sand in a pressure pot blaster (harbor freight special, tried a suction blaster and it kinda sucked-no pun intended) set @ 75 psi.
The sand is fairly coarse so I started blasting unseen areas like inside the tub, underbody, etc. After the first use, it "softens" up enough to use for the exterior panels (I recycled the sand usually 3 times before it was dust). Worked great, did not warp any panels, and left a finish perfect for the epoxy primer. Also, after blasting, I guess the silica residue it left is a pretty good rust inhibitor as I was able to blast the whole tub over the course of a couple weekends without much flash rusting. Those industrial blasting joints use too much pressure, IMO, for a car body if not in skilled hands.

Mark

Post by **itsa68** » Mon Nov 26, 2007 10:40 pm

Another few words of caution on sand blasting.
When I had my engine compartment and inner fenders blasted many years back, a lot of the media got caught up inside the inner fender channels and sat there.
This held water like a sponge up against the firewall and inside the fender channels, which is not a good thing.
Rust from the inside out started where ever the sand had been sitting.
Make sure you vacuum out all those inner fender channels (and other hidden open ended boxed sections) if you're sand blasting.

Ray B.

Nissanman · Post by **Nissanman** » Mon Nov 26, 2007 11:21 pm

Make sure you vacuum out all those inner fender channels (and other hidden open ended boxed sections) if you're sand blasting.

Alternatively, use a hand held air nozzle driven at 100psi.
Iv'e got a gun which has a long extension nozzle fitted to it so you can keep your distance from the flying grit.
That will shift any residue from cracks and crevices.
Of course, goggles and face mask required

Then you can vacuum or sweep up the grit to be recycled

da-man · Post by **da-man** » Mon Nov 26, 2007 11:24 pm

all good advice.

I actually, just this evening, found a guy who has been doing nothing but media blasting since he got too busy ti run his body-shop too, some 10 yrs ago.
Apparently he doesn't advertise, other than hand out cards at the car shows.

He'll do the whole thing for $400. He's using a plastic media with what he called "starbursts" in it, to get the "tough stuff".

Says it'll come out really nice. And I feel safer taking it to somebody who has been doing it for awhile.

I'll let ya know how it turns out.

windy311 · Post by **windy311** » Thu Nov 29, 2007 8:27 am

Remember your health when using sand SILICOSIS can happen.

da-man · Post by **da-man** » Thu Nov 29, 2007 12:30 pm

windy311 wrote:Remember your health when using sand SILICOSIS can happen.

That's what my doc told me when I told him I didn't like the taste of the little bag in the bottom of the Beef Jerky!

Nissanman · Post by **Nissanman** » Thu Nov 29, 2007 5:43 pm

Reminds me about those All Day Suckers you find in the tray of mens urinals.
They taste 'orrible, but they really do last all day

I purchased a pressure pot blaster recently on ebay so I'm going to try that out with garnet sand to do the body of my '65.
http://cgi.ebay.com.au/ws/eBayISAPI.dll ... :IT&ih=021
I'm sure it will great for the folds, cracks crevices and such, just have to see if I can do the larger panels too.
They claim it is 30% more effective than a syphon type and can run on 60-125psi.

datsunrides · Post by **datsunrides** » Thu Nov 29, 2007 10:31 pm

That's the same model (or very similar)that I use to do my work. It will work just fine. One note, the shutoff valves are crap and will stop working after a few bags. You may want to change them before you put it in service as they will fail. May want to pick up an extra pack of nozzles if you can.

Mark

windy311 · Post by **windy311** » Fri Nov 30, 2007 1:53 am

Im getting one of these soon and i had the intention of using (baking soda) in it, oh well garnet it is then.

SlowBoy · Post by **SlowBoy** » Tue Dec 11, 2007 1:28 am

Nissanman wrote:I purchased a pressure pot blaster recently on ebay so I'm going to try that out with garnet sand to do the body of my '65.
http://cgi.ebay.com.au/ws/eBayISAPI.dll ... :IT&ih=021
I'm sure it will great for the folds, cracks crevices and such, just have to see if I can do the larger panels too.
They claim it is 30% more effective than a syphon type and can run on 60-125psi.

Well, I used that twice and went with something else. That was far worse than a day at the beach. Regardless of how well I covered up and taped up, the media still got to me. The clean up was awlful.

I finally got a box with a syphon for the big stuff and a hand held gravity fed gun for the stuff that did not fit in the box. The hood and larger went to the strip shop.

DatsunDave · Post by **DatsunDave** » Tue Dec 11, 2007 10:26 pm

Dipping isn't considered a viable alternative?

There are pros and cons of all three options.

Dipping gets everything which soda may leave and doesn't warp the panels like other media blasting. The downside is unless the body is entirely clean of the acid the new pait will fish eye. The acid can hide is some nooks and crannies. Another con is that because the acid strips everything everything needs to get paint to prevent rust so those nooks and crannies may not get painted.

Discuss...