I came across a blaster that I can buy for damn near free--

the plan: striping the car down to the tub,then blast to bare metal to do some cancer surgery ,then a complete repaint with house of kolor paints--

the question :

am I better off sending the rolling tub to a blaster

or

picking up the blaster I found .. putting the tub on the rotissaire and the hanging heavy plastic sheeting in my 3rd car garage to make a kinda booth and blasting it my self that way?

Find some place to acid dip it. Wink wink. But that's illegal for SCCA racing. You lose some structure rigidity (theoretically) and the car loses a lot of weight. SCCA specifically says against it.

But otherwise, I've worked on a lot of 356s that have been acid dipped and the results are very good.

For media blasting, farm it out. Setting up your own shop for it would take incredible amounts of time/energy and wouldn't be worth it unless you were doing a bunch of cars. And a huge mess too.

The size of compressor you'd need to do a whole car in a reasonable amount of time would be as big as a car. Farm it.

Farm it out. You will be diggin' sand out of your ass crack and ears for a month.

Blasting is probably much cheaper than acid dipping. I checked on Dipping and it was close to 1.75 per lb. Standard acid dipping will not hurt the intregrity of the chassis. You must use a much stronger acid to actually remove any metal.

a bit of hearsay, but I have heard of a 914 hood and thin panels getting messed up because one of his guys held the gun in an area trying to get the paint off and the heat warped the panel. I would farm out media blasting. At least a media blasting shop in Orange,CA told me that story because it happened at his place and he told me to have the car acid dipped and gave me the acid dip's phone number After bitching about the undercoating for about 10 minutes first of course.

So I am going to acid dip because sometimes you can't even trust the "pros" to get media blasting right apparently.

QUOTE (byndbad914 @ Feb 6 2006, 09:59 PM)

a bit of hearsay, but I have heard of a 914 hood and thin panels getting messed up because one of his guys held the gun in an area trying to get the paint off and the heat warped the panel. I would farm out media blasting. At least a media blasting shop in Orange,CA told me that story because it happened at his place and he told me to have the car acid dipped and gave me the acid dip's phone number After bitching about the undercoating for about 10 minutes first of course. So I am going to acid dip because sometimes you can't even trust the "pros" to get media blasting right apparently.

That's why you get baking soda blasting. No warpage.

Search for acid dips.. lotsa bad experiences here.

I've seen a couple of cars up at HPH that had been acid dipped. They looked absolutely incredible.

Talk to Andy about sand blasting and the beach he carries with him everywhere he goes..

Right, yeah. We've NEVER had any problems with acid dipping. That was just specified by SCCA and for that reason. I can pull it out of the rule book. I think I've got 2002 on disc. And we usually have our cars double or triple dipped to lose weight, and mostly just to defy said rulings.

I'm going to acid dip my car as stated and then do the rollcage and strength kits afterward.

And "pro" when it comes to body work usually means that he's affordable to the employer. Otherwise, he's not spraying sand.

QUOTE

Find some place to acid dip it. Wink wink.

Then your heater tubes are oatmeal. Wink wink. Unless you cut them out. Then... you've just cut the backbone of your car. Not my cup of tea.

I've got pictures of acid weaping out of a 914 tub a full year after it was dipped. Have fun. Don't say I didn't warn you. I'd rather have sand coming out of my car than acid weaping out of the seams all over my new paint job.

Soda blasting is by far the very best solution.

If you can find an expert sand blaster JOB IT OUT. You won't believe what a discusting task this is. I say expert because they need to know at what angles and with what pressure to blast otherwise your car is toast. Panels will warp with the pressures generated by most commercial blasters.

It does not generate enough heat to warp the panels. Calling 'Myth Busters', calling 'Myth Busters'

QUOTE (alpha434 @ Feb 7 2006, 12:04 AM)

That was just specified by SCCA and for that reason. I can pull it out of the rule book.

I have always wondered, just how would anyone know that you acid dipped your car if you didn't tell them? I know that may sound stupid but really? how would they know?

If you media blast, make sure to dig out the foam crap that in the top front and top rear corners of the rear fenders. Stupid foam.

QUOTE (johnmhudson111 @ Feb 6 2006, 09:17 PM)

QUOTE (alpha434 @ Feb 7 2006, 12:04 AM) That was just specified by SCCA and for that reason. I can pull it out of the rule book. I have always wondered, just how would anyone know that you acid dipped your car if you didn't tell them? I know that may sound stupid but really? how would they know?

Hehe. Don't tell everybody, or everybody will do it.

Actually, its not just 356s that I've worked with when it comes to acid dipping. Taildraggers too. After paint, you can't tell at all.
So the acid dipping thing is henceforth top secret. Go forth and have an edge over your opposition.

The acid leaking out of the heater tubes can be true, though. You have to carefully check how the shop processes the vehicles. They should dip it in another solution to clean the acid off. A lye solution, to nuetralize the acid. It dries off.

Or just cut out the stupid heater tubes. Then put in reinforced steel in its place after the fact.

This is what a local media blast place told me ...

When blasting yourself - the air supply will determine how long/ how
much work can be accomplished in an hour and that is a function of
nozzle size. A nozzle of 5/16" will require 191 cfm @ 110 psi and use
485 lbs of walnut shells per hour -

Wavy panels are not as a result of heat - the typical heat rise of a
blasted surface with paint Vs one without using temp probe is 5 degrees.
The differential of your car in the sun on a summer day can be 100 degrees.

Warping is a result of peening the metal - stretching one side so that it
is longer than the other - This can occur with any abrasive

A typical car will cost $ 1,000.00 - $ 1,200.00 to strip paint from
exterior surfaces and priming using Dupont 615 Vari prime will add an
additional $ 400.00

I am a DIY kinda guy.
This is what I would do....
Sand entire car as much as you can back to bear metal.
Walnut shell blast the areas dificult to sand
POR 15 prime and some kind of top coat.
You need a damn good compressor, line dryer, and a good blast unit.
I do not like acid dips for the reasons stated above. I work at a hvy line shop and we blast 400-500 chassis a year , 18 wheeler type.
By all means make sure to wear correct breathing protection. Blasting is not faster but gives a better surface for paint to adhear to.
MY 2cents worth.

QUOTE

The acid leaking out of the heater tubes can be true, though. You have to carefully check how the shop processes the vehicles. They should dip it in another solution to clean the acid off. A lye solution, to nuetralize the acid. It dries off. Or just cut out the stupid heater tubes. Then put in reinforced steel in its place after the fact.

It's not acid leaking out of them. It's acid simply destroying them. So the tubes are basically plastic, rubber, asbestos, cardboard and some metal. I'd be interested in the 'process' one would use to 'protect' that in an acid solution.

You can cut out your 'stupid' heater tubes but I wouldn't recommend it to my friends. The longitudinals are quite simply the backbone of your car.

Would you submit to back surgery if you didn't need it?

I've seen this first hand, a number of times. My first experience was in restoring my 66 911. There's a spot in the passengers footwell that traps acid. Because of the way the car was constructed you can't get at this from the front or back. The same spot is in a teener tub. It weeps. Also, the seams weep. On a recent tub, there was 10 additional hours of prep because the acid was weeping and beginning to damage the primer at the seams.

Soda blast. (please)

I agree.

the acid does weep from the seams, and you have to keep dicking with it.

I cant imagine a car being exposed to both acid and lye, or having it both weep from my car...or touching it.

woah

soda blasting works well...cant afferd it tho.

b

acid+alkaline nutralizes to water. Usually the most pure water that you would ever see. No impurities, because its artifically manufactured. So the problem is getting it dry quickly after the process, or your car will be right back where it started. I wonder if anyone in the acid dipping business has ever though ahead to offer a dip in primer as long as everything's being dipped.

I guess you'd have to be out there to run high pressure aire through the heater ducting as soon as it came out.

QUOTE (McMark @ Feb 6 2006, 09:21 PM)

If you media blast, make sure to dig out the foam crap that in the top front and top rear corners of the rear fenders.  Stupid foam.  :(

can any one show me a picture of where the foam is? I am geting ready to send my car to be soda blasted in 2 weeks, and i am trying to get all the prep work DONE!

QUOTE (alpha434 @ Feb 7 2006, 08:33 AM)

acid+alkaline nutralizes to water. Usually the most pure water that you would ever see. No impurities, because its artifically manufactured. So the problem is getting it dry quickly after the process, or your car will be right back where it started. I wonder if anyone in the acid dipping business has ever though ahead to offer a dip in primer as long as everything's being dipped. I guess you'd have to be out there to run high pressure aire through the heater ducting as soon as it came out.

As I recall from chemistry, several decades ago, acid and alkaline mixed in the appropriate amounts create a harmless salt with a balanced pH.

QUOTE (alpha434 @ Feb 6 2006, 09:28 PM)

QUOTE (johnmhudson111 @ Feb 6 2006, 09:17 PM) QUOTE (alpha434 @ Feb 7 2006, 12:04 AM) That was just specified by SCCA and for that reason. I can pull it out of the rule book. I have always wondered, just how would anyone know that you acid dipped your car if you didn't tell them? I know that may sound stupid but really? how would they know? Hehe. Don't tell everybody, or everybody will do it. Actually, its not just 356s that I've worked with when it comes to acid dipping. Taildraggers too. After paint, you can't tell at all. So the acid dipping thing is henceforth top secret. Go forth and have an edge over your opposition. The acid leaking out of the heater tubes can be true, though. You have to carefully check how the shop processes the vehicles. They should dip it in another solution to clean the acid off. A lye solution, to nuetralize the acid. It dries off. Or just cut out the stupid heater tubes. Then put in reinforced steel in its place after the fact.

So you require a method of illegal weight removal to "have an edge over your opposition." to get your " "?


Whatever floats your boat I guess, I could sleep easier after a win knowing that I did it by skill and finesse, and those being all I needed to have an "edge over my opposition"...

QUOTE (alpha434 @ Feb 6 2006, 10:28 PM)

So the acid dipping thing is henceforth top secret. Go forth and have an edge over your opposition.

Top Secrect???

Let's see, it was done to the Ford Boss 302 Trans-Am cars in '69 or '70, it's not something just invented in the last few years......besides, there is hardley "anything" that you or your shop does that is a secret or has not be tried before....these 914's have been around for 30 years and just about everything has been done or attempted at least once...even your idea of replacing the heating ducting with metal tubes for additional strength.

one of the reasons the SCCA bans the acid dipping is make a more level playing field, not everyone has access or can afford to go to that extreame measure.....



the acid starts to attack the heater ducting as soon as it comes in contact with it.....it's too late to do anything once that happens....and yes, most places that do acid dipping can spray a primer on it after the acid is neutralized

back to the main subject...farm it out, even sand blasting small items like the suspension can be a PITA at home.....

Guys,

Not all of those dip processes are acid.

American Metals refinishing in Cinci uses a dip tank and electric current.

Not sure what is in the tank, but it isn't removing material-unless it's rust. Seen engine blocks come out with the bores looking great. Did a great job on my hood and fender.

If it's acid dip, buy some baking soda, a cheap sprayer and go over the car. Baking soda is unique as it turns acid and base solutions to a neutral ph.

Ya guys know that ospho is an acid. Does it leach? I use a 2 bottle Dupont metal prep. The first one eats and nutlraizes the rust, the second neutralizes the first..

Ken

Ken

QUOTE

can any one show me a picture of where the foam is? I am geting ready to send my car to be soda blasted in 2 weeks, and i am trying to get all the prep work DONE!

Dear Cheesehead...

Seeing as how Alphster hasn't jumped in with the 'absolute top-secret, foam delete option M412' facts as to where the foam is, let me take a shot at it.

1. Under your sail panel along that section as it comes down to meet your quarter panel.

2. Above the tail lights where the quarter rounds in toward the trunk lid.

Thanks Eric, I wil have to look for it and eradicate it if possible!

It will be tough... maybe put on a mask and spray carb cleaner up there? Might melt it? Anyone try that? Alphy?

you guys are probably right that the panels were warped by pressure not heat - it was about 8 yrs ago that I looked into it (tells you how long I take to do a project!!!) and my memory could be hazy. I specifically do recall his statement that he basically had to buy the guy another porsche because every panel was warped and since the fenders don't just unbolt...

In terms of the acid deal... I considered the heater tubes originally, but now that I am doing a tube chassis car and just using the body and longs as a shell (the longs are being left in for nothing more than door/body supports basically) I am not concerned.

However, excellent point Eric for other cars - that I had forgotten to mention since I wasn't concerned for my own. Also, the shop I talked to uses the electrical current thing - again hazy, but they assured me that it cost a bit more to do that process but it would work out much better in the end than a "regular" dip (I asked them why most guys weld all the seams after acid dipping a Pcar tub to burn out the acid).

I am NO expert in either of these, so for all I know they were filling me full of (that icon is called Stromberg - how funny) and charging me an extra $100 for it

Anyone else out there actually acid dip their cars and have a good experience?? I may start a new thread... sorry to sorta

QUOTE (Eric_Shea @ Feb 7 2006, 02:24 PM)

It will be tough... maybe put on a mask and spray carb cleaner up there? Might melt it? Anyone try that? Alphy?

I've been burning it out. Chemically, nothing seems to touch it. I've got a fender off, burning it out with a propane torch, digging with various pointy things, and it's STILL a pain. I can't imagine doing it with the fender on.

It's not just foam.. In the front of the rear fender it's expanding foam, with seam sealer liberally applied on top, and then in most cases undercoated on top of that.

In the rear it's a precast foam block shoved in there, with expanding foam to seal it in, and then the seam sealer and undercoating.

All of this is put on over bare unpainted steel, and it doesn't stick that well. All is fine until the seam sealer that's protecting it all cracks... then it rusts from the inside out.

you will prob have to rent a huge screw type comperssor. it will be petroleum powered so you will have fuel costs. a homeowners type comp will be in a constant duty cycle. it will never keep up on a job of this scale and you might even burn it up. what ever media you use, you will have a pretty damn big mound of crap left over and no matter what you do it will be everywhere. you are going to need a first rate breathing system. preferably one with an independant air supply, or take a chance on silicosous(sp) and damaging you eyes. it will take a long time and you will not enjoy this task.

k

Seems to me that the way to go is to use those 3M paint stipper disks and then spot blast the areas you couldn't get to.

This way you don't have to worry about the acid.

No harmful chemicals.

What do you guys think?

QUOTE (blitZ @ Feb 7 2006, 11:47 AM)

QUOTE (alpha434 @ Feb 7 2006, 08:33 AM) acid+alkaline nutralizes to water. Usually the most pure water that you would ever see. No impurities, because its artifically manufactured. So the problem is getting it dry quickly after the process, or your car will be right back where it started. I wonder if anyone in the acid dipping business has ever though ahead to offer a dip in primer as long as everything's being dipped. I guess you'd have to be out there to run high pressure aire through the heater ducting as soon as it came out. As I recall from chemistry, several decades ago, acid and alkaline mixed in the appropriate amounts create a harmless salt with a balanced pH.

Water and salt actually, but I don't know how harmless that salt would be in a poisonous-to-human-sense.