Advice for newbies

General Discussion. Make yourself at home...read, ask and answer!

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PostPosted: Wed Jan 19, 2011 9:52 pm
Hi (and welcome!) Freddie...you can soda blast -- it's not like it hasn't been done before...it's just high-risk to the final outcome of the paint, that's all. If you are confident that you can neutralize and wash off all the residue (and I mean down to the last soda molecule), then you'll be fine. I hear you about being worried about all the time/money investment -- nothing worse than a beautiful finish that starts to have issues a few months after you are done.

Personally I wouldn't "blast" any panels at all. I prefer an aggressive disc on a D/A (36 grit takes paint off pretty quickly). Now if you have some rust pitting, some small areas of media blasting are fine...but if the rust is compromising the panel too much replace it or weld in a patch.

Just my take on it...the nice thing about this hobby is that there are always a couple decent paths to get to the same result (and a bunch of ways to screw it up, too ;-) )

-Chris



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PostPosted: Sat Mar 26, 2011 8:15 am
chris wrote:
9. You've learned everything, prepped your car, have a new gun and compressor, garage is all set up - you are ready to paint, right? No! Practice on a couple of old hoods and fenders from the junkyard, first. Your prized car project is not the place to work out kinks in your technique...trust me on this one. Shoot the junk parts first and you'll be much more confident moving to your real project. Some junkyards will give away stuff that is unlikely to sell. Make friends with your local salvage yard. Practice priming, sealing, color, clear...anything involving your spray gun.



Very good points and on this particular one a VERY GOOD source for practice metal is your local bodyshop who is doing late model collision repair. They will often have a large selection of clean fenders and such in a pile where you can pick and choose and go home with a nice rust free perfect painted fender or door to practice on. We have a bin the size of a one car garage FULL that we dump every month or so. A nicely painted late model fender that only has a dent in it is really nice to practice on because it doesn't take much prep.

Brian
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PostPosted: Thu Apr 28, 2011 3:07 pm
On the soda blast. It is a very time consuming ordeal to nuetralize, and you won't know you didn't do it right untill your paint starts flaking off a year or two down the road. PPG's prep guide for what to do after soda blasting and before priming is 7 pages long and they or me will not offer any waaranty on any soda blasted parts. I think your alot of money and time ahead to sand or chemically remove your old finish rather than soda blast. just to much stuff to go wrong. And there are methyl chloride free strippers out there that work great and won't harm you or the environment like aircraft stripper does
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PostPosted: Mon May 09, 2011 6:39 pm
Okay, Fred, take this for what it's worth. I have owned a furniture stripping, conservation and restoration company now for 32 years. We have acuumulated a great deal of tech. on both abrasive and chemical methods of paint removal. Blasting with abrasives has always been a rather straightforward situation with a chosen media (glass, sand, beads, corn cobs, walnut shells, deformable plastic, etc.). Chemical stripping has always been rather straight forward as well, from simple lacquer thinners to more advanced alkaline and acid acitvated meth. choride mixes ( that chemical is the modern workhorse base for almost all fast and effective strippers that "lift" paint from a surface). There are also many, as yet unrated, "safe" strippers on the market as well now. What changed all of this and blurred the lines of stripping was the Statue of Liberty restoration many years ago. That's the object that soda blasting was devloped for. It was not developed for steel applications hence the big deal with upsetting your metal's pH and then the need for squeaky clean neutralization so your paint doesn't fall off. My opinion, pick a method, abrasive removal, or chemical removal, but I personally wouldn't combine the two by going the soda blast route.
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PostPosted: Fri May 13, 2011 8:13 am
chris wrote:Personally I wouldn't "blast" any panels at all. I prefer an aggressive disc on a D/A (36 grit takes paint off pretty quickly). Now if you have some rust pitting, some small areas of media blasting are fine...but if the rust is compromising the panel too much replace it or weld in a patch.


Hi Chris,
I love reading this stuff what a wounderful way of sharing info on this subject of interest.
I just purchased a Fiat 124 coupe for future restoration. I have painted a couple of cars in the past but nothing real serious like a decent resto job.

My question is, if you don't bead blast in the tight nooks and crannies and I mean tight, some places inside boots/trunks and alike you cannot even get your hand in. How do you prep the paint for painting?

Thanks in advance

Graham

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PostPosted: Fri May 13, 2011 8:58 am
Well...of course some limited blasting in tight spots would be ok (maybe I shouldn't have said 'never') -- but if there's any significant rust in there the metal should be cut out and replaced. If rust-free then do the best you can with a Scotch pad. If you want to remove the OEM finish in every nook/cranny on the car and are going for a Concours level restoration then have the body dipped.

-Chris



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PostPosted: Sun Jul 31, 2011 7:29 pm
Please tell us how to go about totally neutralizing acid based metal preps (ex: Ospho, PPG DX, etc) I bought a project car in bare metal and all panels were protected/prepped with a metal etch (looks great BTW). The stuff is a lifesaver for a weekender as it can stave off the flash for a loooong time. I just want to know how to prep it for primer.
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PostPosted: Sun Jul 31, 2011 10:06 pm
Here's the thing that most people miss...back in the 80's when I actually painted regularly I had a few cars come to me just like what you have on your hands right now. Before you shoot primer on that car you have to actually RE-APPLY the metal etch treatment and while it is still fresh rinse it off really good with water. Soapy water if you want to go one step further.

You can't wash it off when it's been dried on there for a long time like that. Metal is porous and that stuff is locked in right now. You need to reactivate it, first.

-Chris



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PostPosted: Tue Aug 02, 2011 9:23 pm
Chris : thanks , and 10-4 on the re-application - I'll do it as I have read this elsewhere as well.



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PostPosted: Sat Nov 12, 2011 1:03 am
chris wrote:Hi (and welcome!) Freddie...you can soda blast -- it's not like it hasn't been done before...it's just high-risk to the final outcome of the paint, that's all. If you are confident that you can neutralize and wash off all the residue (and I mean down to the last soda molecule), then you'll be fine. I hear you about being worried about all the time/money investment -- nothing worse than a beautiful finish that starts to have issues a few months after you are done.

Personally I wouldn't "blast" any panels at all. I prefer an aggressive disc on a D/A (36 grit takes paint off pretty quickly). Now if you have some rust pitting, some small areas of media blasting are fine...but if the rust is compromising the panel too much replace it or weld in a patch.

Just my take on it...the nice thing about this hobby is that there are always a couple decent paths to get to the same result (and a bunch of ways to screw it up, too ;-) )

-Chris

What are your thoughts about soda blasting bumper covers? My 95 Mustang GT bumper covers have all kinds of weird sharp angles that are going to be a bear to sand smoothly, and since I am painting it black, I am trying not to get any sand scratches in them during the stripping stage.
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