Removal of tar and junk

[Knestis]

I resisted even looking at this thread, but I know that it's 22* in the shop this morning and won't be any warmer for some time...

We are doing the ENTIRE Golf - bottom included - so I've become pretty familiar with the various types/quantities of stuff that they put in. Most of the sheet tar stuff on the inside floor and firewall popped out a quarter-sized piece at a time by dinging the edge with an old screwdriver and hammer. I don't like chisels because theys scar up the sheetmetal. Some pieces - for whatever reason - were more reluctant so we applied a heat gun to the BACK side of the sheetmetal, just enough to break it's grip, and stripped it off with a plastic putty knife.

Goof-off takes the tar residue off really well, with the proper gloves and a 3M pad. Wipe off the juice/tar snot with lots of paper towels and work to all-the-way clean.

The SnapOn Crud Thug that we borrowed from Jon Bonforte's shop does a GREAT job on the urethane stuff that VW uses in the fenders, engine compartment, and bottom but is less good on the tar.

The WORST was the sheets of tar-like stuff that were stuck to the firewall with adhesive and (even worse worst) the felt crap that's glued into the ceiling. The adhesive they used there seems to be a urethane and is solvent-proof.

K

[JamesB]

Kirk you make me so glad that the previous owner when through all the pain to remove this material. He did one interesting thing though, he removed all the major areas but left the stuff in the rust prone areas under the wheel wells and above the fuel tank. Even then I am going today to buy 100lbs of used weights so I can add ballast, I guess I am a little too thin and need to add some weight.

[Knestis]

The really ironic thing about our situation is that the rust we are having to repair developed UNDER the goo, between layers of floor and chassis where they overlapped. It might be due to a couple of whacks that the rocker took, or perhaps from a leak into the interior. We couldn't even see the holes until we got to poking at the urethane and tar.

K

[JamesB]

This car had some good rust repair in the same area your car is. There is a little bit more on the outside of the car, but budget means that wont be looked at till next year.

[backformore]

Take a look at the Bimmerworld website. They have an ongoing article about building a budget track car and in that article they address removing this stuff. In addition to the dry ice they provide a "recipe" for the concoction(sp?) that they use as well. Seems like it is 50% kerosene and 50% something else.

[tom_sprecher]

I know this is an old thread but I am finishing up stripping the interior and decided to share my observations.

1. Using dry ice and a hammer or scraper is not what it is cracked up to be (pun intended). Possibly due to the ambient temp but the amount of time for the tar to get cold in one spot was about equal to the time to remove the rest of the area with an air chisel. Grind the corners of the chisel so it does not dig into the sheet metal.

2. Mineral spirits and soaked shop towels to hold it in place desolves the small stuff that's left of the tar in about 2-3 beers. Use a 3M pad while everything is wet to remove the stubborn spots.

3. The sound deadening in 1st gen RX-7 weights 17# not including the small bits that was vacuumed up.

The undercoating is next. I'll try the wire wheel, the a #M wheel then ???

[Speed Raycer]

I just found a tool that works even better than the 3M wheels. It's available at home Depot. I'll see if I can find a pic of it, but it has 3 or 4 sets of 30 or so straight wires arianged radially. Works awsome for seam sealer and other crud.

[tom_sprecher]

I know what you are refering to and have seem them in Home Depot but could not find them on the 'net w/o looking through all the other "wire wheel" results. I'll try on if you say it works. Anything to speed things along. Thanks.

[Speed Raycer]

I shouldn't have said that they work BETTER than the 3M wheels because the 3M wheels rock. They do work better on the chunky stuff that the 3M wheels just heat up and smear, for anywhere therre's lots of metal edges that tear up the 3M wheels, and seam sealer in crevises.

[joeg]

What really works well is a dewar flask/tank of liquid Nitrogen and a wand to spray it with.

You would need to fabricate the wand and the deposit on the dewar flask is mucho $$$. This is also a somewhat dangerous operation (you can suffocate or suffer burns), but it works well.

Personally, I have done the operation with Aircraft stripper--lot's of it--and elbow grease, instead.

Cheers.

[orlando_wrx]

The SnapOn Crud Thug that we borrowed from Jon Bonforte's shop does a GREAT job on the urethane stuff that VW uses in the fenders, engine compartment, and bottom but is less good on the tar.

[/b]

Crud thug rocks! it's a bit of an expensive proposition if youre only building your own car, but if you can find one to borrow it's a god-send. What I noticed on my MR2 is that the tar inside was so old just lightly tapping with a claw hammer would crack it apart, then the little bits left easily came off with a heat gun combined with the crud thug. The undercoating on the MR2 is VERY thick, and the crud thug is a MUST for this, so depending on the thickness of your undercoating some people may want to bite the bullet and get one.

[e36its]

The SnapOn Crud Thug that we borrowed from Jon Bonforte's shop does a GREAT job on the urethane stuff that VW uses in the fenders, engine compartment, and bottom but is less good on the tar.[/b]

Curiousity drove me to look up the Snap-On Crud Thing. What makes this thing such a godsend? It appears to be visually similar to a common angle grinder for which a variety of wire wheel styles are available.

tom

[orlando_wrx]

What make it different is rather than a circular contact patch where your wire wheel would just rub in circles on the target material, the crud thug rotates 90 degrees to the target material; grabbing the "crud" and pulling it away. The "thug"s are available in varying "grits" for rough removal and fine finishing. They are like tiny wire fingers clawing at your target. The "fingers" are quite stronger than a typical wire wheel, but are mounted on a rubber ring to allow just a tad bit of flex if you put a little too much pressure on your work. Ask around if someone has one you could borrow, and give it a try. I guess it's one of those things you can't quite appreciate until you've used it. With a wire wheel on a angle grinder I spent about 7-8 hours on one wheel well, with the crud thug I finished the other 3 in about 6 (times are a bit much because i was taking frequent drink and cigarette breaks, but are an accurate relation to each other). Word of warning: the air tool runs $350+ and a box of 5 or 6 wheels is somewhere around $60.

[tom_sprecher]

I think the secret to the Crud Thug is the wheel. It is similar to what Scott described and I have seen at Home Depot. It is a wheel/drum with 3-4 rows of 30-40 steel wire rods that have one end attached to the wheel by passing a pin through the loop end of the wire rod like on an oxy-acetylene torch orifice cleaner.

I have tried on and off for the past 2 days to find a link to one but have failed/given up due to too many search results for wire + wheel + stripping + clean + whatever. I might have to do it the old fashioned way and get up off my a$$ and drive to the store.

Scotty, do you have a 3M part # of the wheels you have found work best? I got a couple of 3M-like wheels that I was not too impressed with.

[Speed Raycer]

I don't have the #'s off the top of my head... but they've got to be the 3M's or the Nortons. The Harbor Freight/Cummins Tools ones are less than stellar and hit or miss.

I like the 4"x1/2" for areas that I need some flex (floorpan creases) and the 4x1" to really get to work on large areas. Buy some of the smaller (1.5"?) ones too for those tight areas and corners.

Remember to make sure the Blackwheel is turning across the edge of the material, not turning into it. Grabbing an edge will make short work of the blackwheels.

The Crud Thugs attachment is almost exactly like the piece at Home Depot... in fact, that's what caught my eye about it.

Norton RapidStrip Wire Brush

[lateapex911]

It looks like the wire tips are bent forward, and in three blocks, so only 66% of the circle is used.
Too bad the replacement wire wheels look like they will only fir what appears to ne a proprietary 2" or so arbor that fits the Snap on machine. Because otherwise, it looks like it's just a right angle grinder with a fancy (or specific use) wire wheel.

Anyone in the NE want to rent or sell me theirs used?