Undercoating

[61porsche]

Oscillating Multipurpose tool

Harbor freight-http://www.harborfreight.com/power-tools/oscillating-tools/oscillating-multifunction-power-tool-68303.html

Use the wide blades. Cheap; almost throw away.

Beats angle grinder with a twisted wire wheel.. messy stuff.. but does the job.

One of the 02 guys used a pnuematic scraper and made a 4" blade from a putty knife.

 

[Nicad]

I picked up that same oscillating tool today. Barely makes a dent on the white component of my undercoat.
So far this undercoat from Hell beats a heat gun, scraper, electric scraper. Only burning it off with propane seems to work. This is feeling like a ten year sentence to get my undercoat off. Going to try some solvents next to loosen things up (maybe Kerosene). I hate working with solvents.

 

[Peter Coomaraswamy]

Tried that-

When I was scraping, I used solvent, and I even mixed a potion of my own, combining mineral spirits, a small amount of brake fluid, some ATF and a little gasoline. I mixed it up and brushed it on and let it stand for 1 hour and tried... nothing Then I let it stand overnight...nothing It's scrape or "knock down" and re-undercoat if you're not going to dip or blast. After knocking down, re-applying and re-spraying in semi-gloss black I am very happy with the results and I'll be able to post some pics this weekend.

It's brutal!

 

[Nicad]

I came close to buying some Kerosene today, but they only had it in 9 litre jugs. I'd try diesel, but the smell would last too long. I like your recipe experimentation. I think if I had a scraper attached to a torch , that might work well. I do want to minimize my fume breathing though.

 

[decoupe]

Whooosh

I assume all of this is done with the gas tank out of the car, several appropriate (and large) fire extinguishers handy and 911 on speed dial.

Play safe!

 

[Nicad]

Doug, yup the gas tank is out. Dropped it off today to get a liner put into it. Just didn't want to deal with the POR 15 process over several days and no hose outside. (I could cut the grass in Toronto this winter).
I also had an extinguisher beside me. Still I do not like dealing with a torch while under a car and flaming undercoat dropping on the ground beside me. Who knows what gas this stuff gives off when ignited. The car is sitting over a piece of linoleum as well. I found a piece in the neighbours garbage and thought it would be great to lie on instead of cold concrete. So far it is great, because I can clean it up between work sessions to the point I can wear white clothes while lying under my Coupe. I will no doubt take a nap there by the time spring rolls around. ahhh productivity.

 

[Nicad]

Tried some Adhesive gel solvent today that I bought at Home Depot. I think this is gonna work. DId a test patch in the rear wheel area and managed to get to bare metal with scraping and then some coarse steel wool impregnated with the stripper. Will hopefully try some on the floor tonight. The Black layer of undercoat dissolves pretty fast. The tougher white stuff puts up a real fight. I have to be pretty careful with this stripper as it is nasty. Doesn't smell like anything, but lots of warning not to breathe the fumes and it burns through the plastic cup I put it in instantly. Burns skin too I might add. . I'll have to make some special glasses out of an old pair to fit under my respirator mask for this job.

 

[rsporsche]

Bob,

you better get some serious chemical gloves, i would use a respirator and goggles. stripper is nasty stuff.

 

[Nicad]

Got all those Scott. Thanks for the advice. Will also get some disposable overalls. I have a ventilation fan in my garage, but also need the heat for the stripper to work.

 

[HB Chris]

I have been following this thread as it has been on my to-do list to clean up the underside. I had it pressure washed yesterday and some of the undercoat was already flaking off. So today I spent about 3 hours on my back scraping it with a putty knife. I feel guilty admitting that a lot of it came off fairly easily but not all of it. It is still a pain working on the floor. I used some oven cleaner to get the remaining grey stuff off but it will remove the paint too so I won't use that again.

The underside is painted almost a Sahara beige, grey undercoat is sprayed on that. Over the years it turns black from dirt, oil, body resprays, etc. I did 2/3 of the driver's side from rear seat forward. I wiped it down with thinner, it looks pretty clean. I was going to post some photos but getting up from the floor, I used my knuckles, wearing mechanic gloves, and heard a pop. It didn't hurt but when I took the gloves off my right ring finger was hanging down and I couldn't lift it up. I was hoping it was a cramp but it looks like I ruptured the tendon so now it's in a splint. No more scraping for now! And I was finally back to 100% from my hamstring surgery in October, d***.

 

[Nicad]

Wow sorry to hear that Chris. I hope there is no pain today. I also injured myself yesterday doing my floor test. Hit my head on the part of the subframe where the diff bolts to. It was sharp and greasy. Heads do a lot of Bleeding. Anyone taller than me will be looking down at an ugly sight for the next week.

Anyway Chris when you get around to doing the rest, I suggest you buy that HArbour Freight oscillating scraper . (I believe it is sub $40 in the US). I paid $54 for mine. It really works well with the stripper I have been using. My test patch came off in a sheet, so I am hopeful I can deal with the whole underside before I lose focus on this tedious task. Still haven't figured out what I will do with the bare metal floor. I am thinking POR 15, then maybe a top coat of that Wurth undercoat. I would like the bottom to be Gray when done.

 

[HB Chris]

No pain, hoping for six weeks in a splint, worse case another surgery, known as mallet finger. Be sure to use the POR that can be top coated or use their primer or nothing will stick. I wanted to leave the paint but may need to go naked like yours if using stripper. Thanks.

 

[rsporsche]

I had it pressure washed yesterday and some of the undercoat was already flaking off..

say it ain't so ... water pressure washing underneath !!! really? i thought you guys signed the oath to never let water get close to our cars.

 

[HB Chris]

I had Murray's blessing.

Don't tell anyone but he had his cleaned as well (with water!) and then had the undercoat touched-up. He is headed to a concours in Palm Springs later this month.

 

[polaris68]

Stop injuring yourself Chris and take your car to Darrin and have him finish:idea:

 

[lafngrvy]

I know I'm joining this conversation late, but did you try dry ice? I have used it in foot wells and other horizontal panels to remove undercoating, and it works quite well. The stuff just chips off.

 

[Peter Coomaraswamy]

out of spec

I know I'm completely out of the original here but I wanted to have an undercoating that could be periodically power washed- so this is what I did. I hope you're not all cringing.

 

[HB Chris]

Two shots of original undercoat now flaking off of coupe. The grey undercoat has turned black from dirt and oil, underneath is beige paint.

 

[Stan]

Nice photo, Chris is that when you popper your tendon?
Stan

 

[HB Chris]

Yep, either getting up or down on the concrete floor, can't remember which. I will wear this splint for the next 3 or 4 months, kinda limits my coupe therapy for a while!