I'm working on a pretty rusty '37 Buick. I've replaced about 40% of the sheet metal on the body and more to go on the fenders. Even though this is an OT vehicle for this forum what I did could be used for any vehicle.

I welded patches in the rockers and rear wheel wells and wanted a good, clean surface to apply epoxy primer and body filler. I blasted the area that I felt could take the blasting but the flatter, more open areas like the roof I didn't want to take a chance and warp them by blasting them. The roof had old paint and surface rust. I started using a fiber disc on the old paint and surface rust.



This disc got all of the gummy, old paint off and seems to be lasting a long time. Saved on a lot of sand paper. It also seemed to not dig into the metal too badly, it did make sparks but I tried to not to make sparks as much as possible. After I had all of the paint removed I went over the area with 180 grit paper on my DA sander.

There was still some surface rust remaining, some was fairly deep and had to be removed before I can prime the metal. I first tried a rust removing gel product from Permatex.



I followed the instructions and it didn't seem to do much to the rust. I applied a second coat and left it set a little longer and still, it didn't seem to do much. I then tried this product:



I sprayed this stuff on and first used a tooth brush to agitate it and then used a wad of steel wool. The steel wool worked pretty good and I was able to get all of the rust off, even in the pitted areas. This product is also suppose to prevent flash rusting for up to 12 months if left on but I rinsed it off with clear water last night. Tonight there's no sign of rust.

 

What is the active ingredient in the KrudCutter? That's pretty impressive, if it looked as bad as to the right.

 

I should have added that the Krud Kutter has phosphoric acid, same as the gel. It's a mild acid but make sure you wear gloves, as instructed on the label. I didn't, I was foolish, and my hands were dried out and burning last night and this morning. I applied hand lotion this morning and it helped some. Tonight I'll be wearing gloves.

Yes, the clean area looked just like the area to the right.

 

I've seen some before and after pics of this Buick. Bob's not joking or exaggerating when he says he's replaced about 40% of the metal. He's done more with minimal tools and equipment than most people would ever dream of.

Thanks for the info on the Krud Kutter. The car is really coming along
Bobby

 

Thanks Bob
One thing I have lots of is rust
I've used phosphoric acid before - I cut it 5:1 - I've only used it on small parts - I used some plastic tubs I got a Lowes Garden Center - After soaking for awhile I fished them out and dunked them in a 5 gal buck of water
Getting rid of the acid took more effort then mixing and derusting did - Lots of Arm & Hammer baking soda mixed real - REAL - slow - Once I got the PH balenced I was able to water some of my evergreens

 

If you have serious rust and not afraid of the fume danger, muratic acid, pool variety, will flat remove rust and right now. Use it outdoors only and stay up wind. I do not recommend it for most applications and it must be properly neutralized. Do not even think about using it on cast iron.
Back to the product Bob demonstrates. Yes, it works well, as does most of the phosphoric acid based products. Ospho and Prep and Etch are two of my favorites, been using them for years, purchased in gallons. Matter of fact, I have that on my shopping list.

 

I had to use muriatic acid last summer to clean some copper buss bar, man, now that's some nasty acid. I opened the jug in my shop. Luckily it was summer and I had the doors open. I immediately took it over by the overhead doors. I poured the acid in a plastic tray and it just steamed. I placed a box fan on the table and blew the fumes out the door. After I was done I did as you did Dick, bought a few boxes of baking soda and diluted the mess. I will never use that again. Unfortunately I ran into it again a couple of months ago. My wife told me my farmer son had a gallon can of lacquer thinner in the milk house storage room and it was getting hot and bulging. She asked me to take it to my shop. My other son asked what I wanted to do with the can because it was leaking on the floor of my shop. I realized it wasn't lacquer thinner, my brilliant farmer son used an empty metal lacquer thinner can to store his muriatic acid he uses to clean his milking equipment. I didn't know this until it started leaking on the floor. I diluted it again and got rid of it but not before the fumes attacked the Buick and some of the new sheet metal patches I just had welded in. That stuff is wicked.

 

My neighbor used muriatic acid last summer in his garage to derust some car parts, he said it worked great, cleaned the parts to bare metal. The only problem was the next day when he went into his garage all of the surfaces on his lathe and mill and other metal items had a nice layer of surface rust. The fumes will go everywhere.

 

Been there, done that. Wife's father broke a gallon in my garage. Ate at my machinery and nearly took him out.
Then there was the day he broke the gallon jug of lab grade hydrogen peroxide. Did you ever see a curbside garbage can that spontaneously combusted? Still got a stain on that sidewalk.

Y'all be careful out there.

 

I just finished up the front quarter. Just to compare the before and after.

 

Ospho good for removing minimal surface rust ? Body shop person is finally making some progress on the stock truck cab . Retrieved the new bed strips & tailgate out of the shop attic the other day .The both were sealed in a card board box .I figured the hot dry attic was a good place for storage . NOT !! Both have some very minor film rust . Sand blasted the bed strips & delivered to body shop for primer . The tail gate has some areas on the bottom middle where I had carried it .

Speaking of explosive hydrogen peroxids Back in '75 hot girl friend & I attended the Gator Nats. in Gainsville , Fla. A man named Russell Mendez had a hydrogen peroxide rocket car . Very small high thrust engine that ran on the H.P . Talked to him sat. morning . Interesting fellow . Seen him make the last run of his life . His H.P . powered rocket car made made a right turn after a 323 MPH pass in the 1/4 mile & disintegrated going thru the guard rail . Will never forget it .Google his name , all true with you tube video .

 

I guess I failed to mention that I was using this Stripper under a wood roofed open sided carport attached to a wood garage