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Thread: Sand Blasting or Acid Dipping?

  1. #1

    Sand Blasting or Acid Dipping?

    Hello Everyone
    I am woundering what is the best way to strip a car back to bare metal for a complete restoration.
    The car in question is a 67 shelby mustang fastback.
    People have used sand blasting, acid dipping and sodium blasting.
    Which one is best to use and produces best results and has least problems that can go wrong example acid dipping lowering the body in to the acid tank could cause warping of sheet metal ect.
    Any information and tips on which way is best to strip the car back to bare metal is appreciated.
    Thanks
    Dave

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    Re: Sand Blasting or Acid Dipping?

    I opted for media blasting, plastic. Which from my research is not as good a soda blast but is not as bad as sand. The plastic does not warp as bad as some of the other medias. Lots of guys I know do acid but are concerned about the acid residue could affect the final paint if not completely neutralized.
    Racing Division Inc, Los Angeles
    Shelby American Heritage Apparel
    • 66 GT-350 Paxton replica
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    • 65 R-Model replica

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    Re: Sand Blasting or Acid Dipping?

    Quote Originally Posted by 67shelbygt500 View Post
    Hello Everyone
    I am woundering what is the best way to strip a car back to bare metal for a complete restoration.
    The car in question is a 67 shelby mustang fastback.
    People have used sand blasting, acid dipping and sodium blasting.
    Which one is best to use and produces best results and has least problems that can go wrong example acid dipping lowering the body in to the acid tank could cause warping of sheet metal ect.
    Any information and tips on which way is best to strip the car back to bare metal is appreciated.
    Thanks
    Dave
    Dave, I stripped mine at Redi-Strip in Illinois (and I'm in California). After looking at all the methods, I thought that was the best of many bad choices. I was concerned about any rust in the body ( because ALL Mustangs have rust in the unibody) and the only way to be sure it's eliminated is with the electrolytic de-rusting they do, which literally removes all rust.

    This is not to be confused with acid dipping - which can be very harmful. Redi-Strip uses an alkaline process (similar to Draino) which removes all paint, etc. without any acid. When it was finished, the shell looked like new sheetmetal! Now the caviat. I had heard that the alkaline fluid can reappear at seams if not properly flushed out, and my bodyman says this happened in areas that ended up stripping the primer and had to be repaired.

    There are various methods of blasting but almost all of them warp the metal in one way or another, even bead blasting if not done with the utmost care. Avoid sand at all costs! You need an aggresive media to get at the rust, and that's only the rust you can see, and even then it is not removed from the steel at a molecular level. Problem is there are now so many blasting stripping shops out there that do not have the equipment or skill to do it correctly. That and the reality that no matter how hard you clean-up you will always have residual dust from media blasting (even after the car is assembled) convinced me to go the Redi-Strip route. I do not regret it.

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    Re: Sand Blasting or Acid Dipping?

    Dave:

    I went with media blasting. I used orbital an sander to remove paint from panels. Take your time and be patient. I was told to be careful when using acid dips because the acid hides in tiny nooks and crannys. Even though you think you might have every drop of acid removed from the car it can still wick its way out of tiny areas that you don't have access to. Also acid dipping removes everything, I mean everything. Even the sealers between panels. So if you dont plan on replacing welded panels then chances are your going to destroy all the seem sealer between panels. (i.e. quarter panel to door frame sealers.)

    DO NOT BLAST THE BODY PANELS LIKE THE ROOF,WIPER COWL,FEDERS AND DOORS.

    I chemical stripped the doors, fenders and roof.(staying clear of the lead weld at the roof to quarter panel) Then DA sanded.

    If you blast the car make sure you get all the sand out of the car and frames and holes. Plan on using a blow gun for a couple hours to get it all out. And be sure to spray all bare metal areas with EPOXY PRIMER as soon as you can!

    There are several methods to media blasting. The point is get someone experienced and take your time!


    Hope this helps.



    Jim
    #3000
    "DONT CRUSH EM' RESTORE EM"

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    Re: Sand Blasting or Acid Dipping?

    Dave,Last year I soda blasted our KR project in a weekend. Body inside & out,doors & fenders. It was on a rotisserie so that made it easier.We used paint stripper on the fiberglass before we got the blaster so I don't know how it works on that. I was very pleased with the results. It left the metal smooth & clean & doesn't harm chrome or glass.Clean up is easy just take the water hose & wash it off. Don't do this in your back yard it kills grass better than round-up. The unit we use is from Ace cost about 1800.00 & needs a large volume of air 18 cfm minimum.I see that Eastwood makes one now or there are companys with mobile units that come to you. Hope this helps. Saltman

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    Re: Sand Blasting or Acid Dipping?

    Plastic media is awesome. No warpage ( if done by someone who knows what they're doing), harmful residue and is safe on fiberglass. Won't completely take off heavy rust.

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    Re: Sand Blasting or Acid Dipping?

    Allot depends on how bad (old repairs and rust) the unibody is

    I would never use dip again and sand blasting (as other have mentioned) is not even a choice.

    Use the gentlest material you can use (soda, walnut shells....) and then have them use a slightly more aggressive material on spots where needed.

    In this task speed is not the important thing (though it will be for the blaster) care and taking the time to do it right is the focus.
    Jeff Speegle

    CU @ ConcoursMustang.com

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    Re: Sand Blasting or Acid Dipping?

    I think one of the keys is to remove as much grease and dirt off before it go's to any kind of blasting [power wash and using a scraper]. This= less pressure your media blaster will need to use to get the shell clean and reducing warpage. Soda can cause problems if not 100% cleaned. Dipping a shell, if not cleaned 100% can bleed in seams also found it to effect factory seam sealers. I like to have the shell done with a cut of fine alum oxide and walnut shell mix at low air pressure with the exception of the outter sheat metal. This I will dry sand with a D.A. sander if no surface rust is present. Any suface rust spots I do find, I clean with a wire wheel and metal prep. ALWAYS USE GLOVES, acid from your hands WILL come back as rust! Work in a dry area,try to get into epoxy primer A.S.A.P. If your going to send the shell out to get done, make sure its done by an expert. Ask for the most experienced person to do the work on your car, not the new guy! [2 cents]

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    Re: Sand Blasting or Acid Dipping?

    I just went through this exercise three weeks ago... I chose to use soda blasting and the results were amazing. The soda cleaned everything down to
    the factory electro-plate on the sheetmetal.

    In fact, it uncovered the last four (4) digits of the Ford VIN # written on the cowl ( both sides ) and exposed a manufacturers imprint/logo on two places on the roof.

    I'm pleased, and my painter is pleased as it only took a couple of hours to clean up after the process. I would recommend it to any one contemplating
    the removal of paint.

  10. #10

    Re: Sand Blasting or Acid Dipping?

    Thanks everyone for your help.
    Im still unsure as to what method to go with.
    The car is like many old cars has rust, its needs 2 new rear quaters(arches gone)
    a trunk drop off and in the engine bay the previous owner has cut a hole in each shock tower to be able to grease the joints of the upper control arm.
    Thats all i know of so far i havent gone over the car completely however im still stuck as to what method to use soda or media blasting i wont get the cowl, doors,roof or fenders blasted ill make a note of that.
    Thanks again for all your help
    plus if anyone has any photos of there results after soda or media blasting i would appreciate it very much.
    Thanks Dave

  11. #11

    Re: Sand Blasting or Acid Dipping?

    Here are some pics of my 1970 Boss 302 that I had soda blasted. Cost $800:

    Blasted Boss pics

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    Re: Sand Blasting or Acid Dipping?

    I had my 69 GT 350 dipped at Redi Strip in Evansville, IN. I was 100% happy with the results. Would definitely do it again. In my case, I wanted all of the old undercoating, gunk, scale, etc removed from the undercarriage, frame rails, etc etc. The car had been in a damp storage environment and had a lot of crap on it that I didn't want to scrape off (the local media blaster wouldn't touch the undercarriage unless all grease, undercoating, etc was removed prior)

    I had zero problems with leakage, however, my car did sit for quite a few months before it was painted. If you want ALL of the old sealer, bondo, etc removed, then I think dipping is the way top go. If you only want old paint removed, then blast it.

    It cost me $1050.00 3-4 years ago
    I can send you pics of my car after dipping if you desire, let me know.

    My .02

  13. #13

    Re: Sand Blasting or Acid Dipping?

    Hay everyone thanks for photos
    yh shotgun would love some photos of your 69 gt350 that was acid dipped would really appreciate it.
    Thanks again for all your help
    Dave

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    Re: Sand Blasting or Acid Dipping?

    What is your email address, I'm too dumb to post pics on here!

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    Re: Sand Blasting or Acid Dipping?

    Quote Originally Posted by hamiltoncox View Post
    Dave, I stripped mine at Redi-Strip in Illinois (and I'm in California). After looking at all the methods, I thought that was the best of many bad choices. I was concerned about any rust in the body ( because ALL Mustangs have rust in the unibody) and the only way to be sure it's eliminated is with the electrolytic de-rusting they do, which literally removes all rust.

    This is not to be confused with acid dipping - which can be very harmful. Redi-Strip uses an alkaline process (similar to Draino) which removes all paint, etc. without any acid. When it was finished, the shell looked like new sheetmetal! Now the caviat. I had heard that the alkaline fluid can reappear at seams if not properly flushed out, and my bodyman says this happened in areas that ended up stripping the primer and had to be repaired.

    There are various methods of blasting but almost all of them warp the metal in one way or another, even bead blasting if not done with the utmost care. Avoid sand at all costs! You need an aggresive media to get at the rust, and that's only the rust you can see, and even then it is not removed from the steel at a molecular level. Problem is there are now so many blasting stripping shops out there that do not have the equipment or skill to do it correctly. That and the reality that no matter how hard you clean-up you will always have residual dust from media blasting (even after the car is assembled) convinced me to go the Redi-Strip route. I do not regret it.
    Dumb Question here:
    When NEW, the Cars were Dipped in the Primer to assure complete coverage. When you Dip (Redi-Strip or Acid Dip) the Car, how do you go about Primming it afterwards to make sure it is COMPLETELY covered, there are many areas that a Paint Gun can't get to Spray the Primer.

    David.

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    Re: Sand Blasting or Acid Dipping?

    Quote Originally Posted by tesgt350 View Post
    Dumb Question here:
    When NEW, the Cars were Dipped in the Primer to assure complete coverage. When you Dip (Redi-Strip or Acid Dip) the Car, how do you go about Primming it afterwards to make sure it is COMPLETELY covered, there are many areas that a Paint Gun can't get to Spray the Primer.

    David.
    David, Modern cars are dipped in a process called "E-Coating" where the unibody gets a positive charge and the primer gets a negative charge (or visa versa). This assures that there is primer in every nook ad cranny. The '67 Mustangs, on the other hand, got the primer sprayed on the bottom. If you look under the dash or under any coating that might have come loose under the fenders you see bare steel. Just yesterday I was looking at a donor 67 I have been cannibalizing for fasteners. It's a California car with no visible rust and I noticed that there is horrible red rust that has eaten through some areas. Glad I derusted mine!

    There is a place in the Midwest that will e-coat a classic car, but it wouldn't be technically correct. According to the Ford assembly books, there is supposed to be some sort of seam sealed applied to the metal before it gets spot welded, but having seen lots of chopped up Mustangs at the local classic car wrecking yards I have never been able to see anything inside the joints. Mustangs rust. Ford didn't plan for them to last 40-odd years.

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