Media blast or acid dip?

My donor T shell (which is in generally excellent condition throughout) is shortly due to be media blasted and all shutz scraped off by hand but we are also considering acid dipping the shell as a cheaper and quicker alternative with the added benefit of total coverage, and then after several rinses, applying an e-coat after the metalwork has been completed and new panels fitted.

However before we make a decision, I would be grateful for any advice from those who have actually done both firsthand (as opposed to anecdotal advice) in terms of pros and cons of each method and particular things to watch out for.

Also, are there any other methods for stripping back to bare metal worth considering?

Thanks.

Hi Matt, i opted for blasting, Kirk had his dipped. I am sure he will be along shortly with his opinion. Everyone i know who has dipped said they wouldn't choose that path again. In my eye's it always seems to be the dealers/ restorers who champion the acid dip route

Once the 12 month defect warranty expires will they rectify any yellowing of your paint a few years down the line.??

umm i would say sand before acid. The acid is good for small pieces of specific things... I know that cars are washed well afterwards, but if it stays inside a pillar or in a seam a little... it will stay... in a few years you will have more serious rust what we are trying to clean up. believe....

We used hydroblast on the bottom of mine. Worked very well.

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Originally Posted by stretch

Hi Matt, i opted for blasting, Kirk had his dipped. I am sure he will be along shortly with his opinion. Everyone i know who has dipped said they wouldn't choose that path again. In my eye's it always seems to be the dealers/ restorers who champion the acid dip route

Once the 12 month defect warranty expires will they rectify any yellowing of your paint a few years down the line.??

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Thanks Dave.

I’ve pinged Kirk a message on WhatsApp to see who he used and what he thought of it, especially as it’s been a few years now since he had it done, passage of time being the true test.

However, sounds like E-Coat is used by all the major manufacturers in various guises, including Porsche Classic with their cathode dip, so there must be a general consensus in the industry that this is the way to go.

There billion pound operations Matt. I doubt an outfit in an old industrial unit in the back street of the north can get all the acid residue out with a karcher.:D

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Originally Posted by stretch

There billion pound operations Matt. I doubt an outfit in an old industrial unit in the back street of the north can get all the acid residue out with a karcher.:D

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Yep, accept that Dave, but several fully-submerged rinses should reach all the areas the acid reached? (Heineken-style?;))

the rust in many cases has a crust. If this crust only reaches an immersion of acid... Even if you rinse several times the acid will have gotten into that crust. In time it will come out... I think. Working internal parts with acid is complicated. Try a small piece. Leave a crust of rust and apply some "that acid" I guess phosphoric. Then, after the acid bath, rinse it as many times as you want and leave it to air. You will see how it continues to stain with rust or... how it continues to rust in a "faster" way

Rank amteur here. Still an unfinished '67 body shell. Took everything off (doors, hood, fenders etc.) and had them acid dipped. Then e coated. They hang everything up to drain. E coating has lasted fine for 6 years. Real slow projuct. Body shell was then blasted and e coated. Also held up well. Don't know the changeover year but the metal heat tubes went to some type of fiber. Acid will destroy those. On my car we had to replace those anyway even though metal since shot to sh--t. Mobile blasting service I had do the shell was very gentle process but the clean up of the slurry was a bitch.Attachment 574893[ATTACH=CONFIG]574894[/ATTACHAttachment 574897

Don't know if the blaster is still in business. Was out of New Paltz, NY. The smilling guy in front of his acid tank is now out of business. Massachusett's regulations. My panels and a complete pontiac GTO convertible were his last projects

When I worked at the Porsche shop, we tried everything. Chemical removal, sanding, blasting and dipping. The way that seems to work best with early, non galvanized cars is to dip, do metalwork and rust repair, dip again to remove flash rust and then e-coat. You really can’t dip without e-coating or you are leaving all the internal cavities and seams bare metal. Because of the multiple trips, it’s not cheap. Plan on $10-15k depending on how much it cost to ship the tub back and forth x 2. I have a ‘67 getting ready now. The nice thing about the early cars is the heater tubes are metal so they won’t dissolve (unless they are rusty as well). The later ones dissolve in acid and require you to open the longs and remove/replace.

This isn’t the only way to prep a chassis for bodywork but it’s one way to make sure the rust is completely gone.

Now that’s what I call good, solid, advice. Appreciated.

I’ve contacted Envirostrip here in the UK for a quote to dip, dip and e-coat and will see what they say. If it avoids the dreaded tinworm for many years to come, I’m all in favour.

I like the acid dip myself, in my case it was neat that it preserved the factory stamping of the floor metal from early 1965.


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Thanks. Acid dip seems to have strong support from those who have used it.