bobb

Hi Guys,

When you have your sheetmetal "dipped" to remove all the old paint and rust......what is it exactly they are dipping it in? I know there are two ways to prep sheetmetal for paint........chemically or by media blasting. I'm interested in the chemical solution. I also recall reading about people back in the 60's "acid dipping" sheetmetal to make it lighter. Is this acid dipping what is done today when you bring your sheetmetal to a dipper?

I'd like to find a way to "dip" the lower rear front fenders (70-72 Cutlass) to ensure any rust between the outer skin and the inner brace is totally removed. Abrasive blasting can't get in between the two panels....but chemicals can. I'd really like to do this at home instead of lugging sheetmetal half way around the country to the few places that do it.

So can anyone tell me what it is I should be dipping my metal in?

thanks,
bob

J-(Chicago)

It's probably an electrolysis bath.

You can do it yourself if you have the space.

Parts are zapped with DC current, and the leftover oxide is removed with a light acid wash.

69442C

Bob, the problem with dipping that section of the fender is that you can't get any primer back into the area when it's done and you'll have bare metal in those nooks. I removed the braces on set of 69 fenders because of the very reason you mentioned. With it apart apart I hit eveything with a light sandblasting to clean it up, applied epoxy primer and put it back together. If you can weld or know someone who can it's pretty easy to do. It's just a matter of drilling out several spot welds. If you do this, drill a couple of 1/8" holes (not in the spot weld areas) that will pass through the fender and the brace, like inisde the rear jam area, under the top rear chrome molding and along the very bottom. Install a couple of screws and then remove them. Now you have alignment holes to use when it goes back together. Just put the screws back in to align everything together, clamp it as you go and weld where the spot welds were. When you remove the spot welds, just remove the metal on the fender and not the brace. Also, you'll need to clean the primer off of the area where you will weld so use a little weld-through primer on those areas to keep them from rusting between the panels. After you weld the old spot weld areas with a plug weld, remove the screws and weld those small holes closed. A little grinding and finishing and you'll be good for years to come.
Brian

bobb

J - The electrolysis is an interesting idea. Finding a tub to submerge only the back lower part of the front fender shouldn't be hard.....and I went out and bought the proper batter charger for electrolysis work a few months ago. Actually, I bought it for myself at Christmas.

Brian,

What you're saying makes perfect sense. My only issue is that from my past welding experience I've found that weld-thru primer doesn't really prevent rust from forming at the weld. The heat is so intense it burns the primer off at the weld....and it rusts.

I've got a few fenders that need rust repair and I'm definitely going to do as you suggest for some. Drill out the spot welds and seperater the brace from the outer skin. What I was thinking for the pair I decide to use on my car was to dip to remove all the rust, then seperate, fix and reweld, re-dip to remove the welding residue, and then thin down some POR-15 to a water-like consistency.....and dip the lower repaired part of the fender in it a few times. I've had good luck with POR-15, but I've never thinnned it before.

The totally **** option is to hand fabricate both the inner brace and the outer skin out of stainless steel. Not sure I want to invest that much time fabricating panels, though.

Thanks for the input guys,
bob

70Post

On the electrolysis method...you might check on whether or not it only works on a "line of sight" basis with the thing you hang in the bucket (the electrode that the rust is drawn to). If so, this method may not be effective on those hidden areas.

tndrtgr

My husband did his 59 Plymouth Fury in an electolisis bath last summer.

He wrote about it on this site and also at http://www.forwardlook.net/forums/fo...ts=134&start=1

Or you can e-mail him at bigmauto@colusanet.com and he can answer your questions.

442scotty

Just had a look at the work on the Fury...wow! that is a project! Do you ever get to see him? The hours involved are incredible...

O.P.LARRY

I had my fenders and doors dipped in a caustic solution.The main problem with using an acid dip is that the rinse tank never gets all the acid out of the seams. After I caustic dipped them, I took them and had them dipped in an E-COAT.When I get home I'll look up the phone number for ya.

O.P.LARRY

Por-15 is made to bond to rust.If you do decide to go that route,I've used Acetone to thin POR-15 and spray it with a LPHV spray gun.I think a better optin would be to get some acid etch primer and soak the area with that.

This is what I have used at home for rusted nuts and bolts.This stuff works great!!
http://www.evaporust.com/evaporust.h...FaZx5QodWSPwZA


Here are the phone numbers to the places i used-

American metal cleaning(Caustic solution dip)- 1 419 255 1828 Toledo OH
Burkard Ind.(E coat)- 1 586 791 6520 Clinton Township MI