Sand Blasting Problems?

[Clapped out]

Hiya guys,

 

I'm a bit peeved off, got my car resprayed around the 9 years ago, got the car sandblasted, after lets say 3 years, the paint started to bubble. I thought..."humidity bubbles", yeah it happens.....so I didn't think twice about it. The time is now and I've got panels covered in all these "little bubbles", so on further inspection to find out that its actually rust. Not happy Jan! Long story cut short, cheap sand was used to blast the car (sand containing salt), causing what we have to date.

 

So, my question is

 

-Re-blast the panels?

 

-Strip the panels back by hand and deox?

 

-Should I go soda blasting? Will it removed the impregnated rust?

 

-Will any of the above guarantee the removal of the rust to never have this problem again?

 

I'm no panel beater by any means although this is going to be a learning curve for me.

 

Any one who has had an experience similar to me, I'm all ears!

 

Would love to know how you've gone about it,

 

Or if your a panel beater/spray painter, by all means, speak up!

 

Cheers!

Edited January 12, 2016 by Clapped out

[67Rolla-Ken]

That's really unlucky. I feel your pain, had a similar thing happen with my Rolla. 5 years after painting I found out that after stripping to bare metal, the car wasn't panel beated, just bogged back up. Bubbles started coming up on several panels. I ended up spending a fortune getting it all done again properly.

I would blast again but be picky about the medium.

[Mechanical Sympathy]

That's bloody disappointing. I'm surprised that anything could oxidise under a 2 pac sealer, stored in a shed.

[Clapped out]

That's really unlucky. I feel your pain, had a similar thing happen with my Rolla. 5 years after painting I found out that after stripping to bare metal, the car wasn't panel beated, just bogged back up. Bubbles started coming up on several panels. I ended up spending a fortune getting it all done again properly.

I would blast again but be picky about the medium.

 

That would really erk me, paying for the job to be done right then find out you've benn ripped, i'll have to look into blasting a little more, walnut seems to be the flavour of the month. I'll do some research as to who has the better rep that's local.

 

That's bloody disappointing. I'm surprised that anything could oxidise under a 2 pac sealer, stored in a shed.

.

 

I'm not sure how it happened as well, if I knew I'd let us all know. Your right, how does it occur under the sealer? It did take a couple of years to show its face. What bugs me the most is that I can never match the paint properly. As long as there is no rust.

Edited January 13, 2016 by Clapped out

[LittleRedSpirit]

Lawyer up

[Clapped out]

Company went bust not long after the car was done, not sure who they used to blast the car............

[styler]

Hmmm sorry to hear that, sand blasting as such is an old term though and generally now is known as media blasting.

There have been many developments in media blasting with the type of media used and "sand blasting" as such uses

a media called garnet which is the new "sandblasting" standard. Also there is soda blasting and many others, just about

anything really from walnuts to glass to steel shot to whatever works for the application.

 

Now to the tech, with "sandblasting" they now only use garnet media, not beach sand or other silica media. Use someone with some

experience in cars ie with thin sheet metal as they have the skills not to warp big flat sections of sheet steel vs thick steel castings etc.

Those in the know will tell you to do your big flat sections yourself, easy with various sanding tools and they will give it a light once

over with the rest to blend in. The flats sections warp too easily with pressure and heat, they are so thin and generally unsupported.

A possible idea is to use paint stripper on big flat easy to scrape / clean sections with plastic on top to aid the process during stripping.

 

I have heard that painters won't touch soda blasted cars as the paint doesn't like it too much afterwards, best check first.

Also have heard you have to prime the car literally straight after the blasting with most media as it strips away the passivation layer

if there is one from factory before the etch primer goes on. The moisture in the air will cause surface rust within the hour, even in the time

to transport it to another painter after blasting. Putting a stripped shell on a car rotisserie will get the shell done all over for half the price.

 

Use gaffa tape / cloth tape over sections you want to avoid being blasted, it works well. Also they can blast bog out but you will have

to redo the bog body work so if its good maybe leave it in there, food for thought anyway. Don't blast sections you can't paint or seal

with cavity wax as they will rust out in no time. Cover them up with panels/screws and tape for smaller sections.

 

Getting all the media out afterwards is nearly impossible, air compressor and a shop vac at the same time with half a day might do it if

the car is stripped on a rotisserie, it just seems there's always some of it somewhere!

 

Advice that painters have given me is to use the same brand during the paint process from bog to primer to paint to clear to avoid any

problems with one brand reacting badly with another brand. Oh and cut out rust and replace, there's no real treatment unless it removes it.

 

Acid dipping is another process they use but it strips out all the seam joins on the car and the sealer so not sure on how to redo that properly.

 

Good luck with it all... best check first this info was from what I remember a few years back now... hope it helps :)

Edited January 14, 2016 by styler

[altezzaclub]

A possible idea is to use paint stripper on big flat easy to scrape / clean sections with plastic on top to aid the process during stripping.

 

That's what we used on The Girl's KE70 when we found tiny rust spiderwebs starting to show through. Get the strongest, most environmentally unfriendly one you can, preferably with perchloroethylene in. The 'green' ones are pretty wimpy.

 

It wasn't difficult to get it back to steel and then we used the rust-converting phosphate chemicals on it before painting.

 

Its worked so far.. coming up 6years.

[Clapped out]

Thankyou so much for your input guys! Really appreciate it! I've convinced myself that i'll bite the bullet and redo the whole car, it just wouldn't be right by just fixing problem area's! I'll probably avoid the blasting of the car this time round, just because of what styler has confirmed. Few guys have told me the same thing that the car needs to be sealed asap after blasting, unless I'm there, I wouldn't know. So i'll just strip it right back, and start again.

 

Also, you can see with the indication of the bubbles as to where they have used bog, there is stuff all bog in the car, although i'll still remove the bog to make sure nothing is hiding under it.

 

Big shout out to all your help guys!

 

Cheers!

[greenmac80]

rust shouldnt form under the paint provided... the basted surface were prepared and sealed properly.

the shop may have used a single pack etch primer.. then a traditional polyester primer.. cheapest way to do it. but both products are porous.

when really either a 2 pack etch or a 2 pack epoxy primer shouldve been used.

don't be scared of using sandblasting its fine. the shop obviously didnt do something right.

[Clapped out]

Anything is possible, base and finishing coats were urethane, don't know about the primers. This time round I'm using just basic two packs, from start to finish, nothing flash.

[greenmac80]

just make sure your initial primers are epoxy and you'll be fine.

[Clapped out]

Sweet, cheers for that!

[oh what a nissan feeling!]

What greenmac said, the problem with acrylic paint is it is not 100% waterproof so it can take on moisture and then you have that issue. Epoxy is 100% waterproof so even if there was some sand residue on your panels nothing is getting through to start any reaction.