Soda Blasting and primer adhesion

[James(Western Canada)]

Moderators: Not sure where this belongs, but it was discussed to some degree before the great crash of '10. I'm not really sure what category it belongs under, so if you want to move it, feel free!

Yah, I know this is a METALWORKING site......but the reality is most of it (the metalwork) eventually gets covered up, starting with a good quality primer....well, have a look at this thread off the spi users group on the subject of soda blasting.....and don't say we haven't warned tou....and in the now gone thread from before the crash, it was mentioned that DuPont WILL NOT WARRANTY and problems if the substrate was soda blasted...

http://spi.forumup.org/viewtopic.php?t=156&mforum=spi


James

[oldgoaly]

James
I do believe it would come under patinas and coatings sub-forum, If you would like to pose the question there, but references to the crash and other forum debates could be left out. What are you going to get blasted and then prime? something you are restoring? tt It took me awhile to find the right sub-forum, there are much faster moderators than I......

[CARS]

It's been a few years since I painted anything that was soda blasted but lets see if I remember what I did...

First, I washed it down with vinegar to neutralize the soda film (or what ever it is called) and then, basically because I don't trust a smooth surface, I D/A'ed the surface with 240 grit. Then I cleaned the surface with wax and grease remover, wiped with a tack cloth, and applied an epoxy primer.

I would think that one of the paint companies would offer some guidance, but like you say, they are scared of the media.

[warrenoutrides]

Well I hope it will stick. I have a '70 C/10 going to soda blasters soon. Thinking of using a etching primer after cleaning off soda film. :o

[James(Western Canada)]

TT: edit as you see fit & move to the appropriate forum....and I don't have any plans of blasting anything, someone posted the link to the spi thread over on canadianrodder forum....

James

[jonathannc]

Hi.

When we paint media cleaned body shells, its a total must to use Etch primer without any doubt nothing else will do the job as well to start the paint process.

As we don't use soda can't comment on it, we use J beads with glass mix or recycled plastic bead mix that leaves very little residue behind, all media blasted surfaces are cleaned with a solvent

Having a slightly abrasive surface increases primmer adhesion rate many times, hence getting the correct finish from media cleaning / grit blasting is important.

[Derald Timm]

When I painted my truck after having it soda blasted, I washed it down with
a mild soap and water before priming with an epoxy primer.

I haven't had any problems with the paint lifting and that was a few years ago.

[CrazyTalkCustoms]

As a shop, we've been media blasting for 15+ years. The soda blasting equipment "salesmen" have come and gone throughout those years and have never been able to sell us on what I just assumed was common knowledge...."What does water do to bare metal?" It RUSTS!!

The point of blasting is to remove rust or other contaminants. So why bring the #1 cause into the mix?!?! I've asked this simple question to numerous sales people and like what was mentioned in the other forum, the answers usually varied. The most common response, however, was usually that of, "the protective layer...blah blah blah".

It's a good thing we didn't invest in the equipment because we were getting sales pitched long before the knowledge of the "protective layer" eats paint was available.

It is unfortunate if you have been a victim of the bad side of soda. If you have had fairly decent luck with it, congrats. However, I would interest you to check over your vehicle in areas like pinch welded seams, drip rails, door jams, deck lid jams, and inside your cowl. Areas where water tends to get hung up and sit. It is in these areas, that even though you may have went through the "wash process", the coating will mix with the water and flow into unseen areas. Eventually eating your paint.

Dipping is one in the same with soda as far as I'm concerned, but that is a whole different subject.
Just my 2¢ fellas. Have a good day.

[CARS]

Same goes for Metal Preps and Rust Converters. Really? You want me to rinse it off with water????

In all honesty, I have tried so many different products that required "neutralizing" that I am surprised I haven't been sued yet. Thankfully in the world of restoration, 99.5% of my customers never let their cars get wet anymore.

[Tisdelski]

I do walnut shell blasting in my shop.

When i first looked into the different medias , i learned that soda is a base an the ph scale. it was first used to strip airplanes as its real gentle, but after a while there were planes corroding at the seams.

Gary