OK, time for a quicker-to-write and less bizarre update. Regular shenanigans will return soon, but this time, I wanted to share some wisdom that might help future race car builders who read this otherwise nonsensical slurry of silly. This is the removal of the underlay, or that material that is both tar-like and rock-solid at the same time somehow.
What is underlay?
Well, the underlay seems to be there to reduce NVH (Noise Vibration Harshness). It's a hard and gooey mat of material on the floor of your car that dampens vibrations. It's also apparently placed in a way that allows it to overlap seams, so it probably prevents squeaking there too.
Why do racers hate it?
We don't hate it. We hate weight. A lot. If I can cut it, burn it, drill it, or smash it out of my race car; or otherwise make something that exists--that I don't like--not exist anymore, I will make it not be in the car. Also, you can't weld to this stuff, and I'm pretty sure I don't want to be near it if there is fire around.
What did the underlay ever do to you?
I told you this wasn't going to be silly. Don't ask silly questions.
Why did you make a post about underlay? Just remove it and be done with it.
This stuff is tough to remove! It seems to be rock solid, but it could also just be an absolutely ghastly-viscous fluid. If you grind it, it makes a mess and takes forever. If you try to scrape it, you'll be at it forever. It's really tough, and scrapers are hard to get under it. This stuff was meant to last all the way into the big grinder at the recycler. I'm not even sure how they deal with it there, because they'll have chips of metal with this stuff stuck to them. Maybe they just burn it.
The best way to remove it is with dry ice (that's Martian Snow for you astrophysisists out there). That's what I did, and the results were better than I expected. What I want you to take away from this is the importance of the dry ice and maybe a few lessons learned.
1.) Don't just dump it all in at once. Pick two sections, cover them well with perhaps Aluminum foil (Aluminium foil for my non-American friends out there), and the keep the rest of your dry ice in a cooler. I dumped it everywhere at once and some sections evaporated before I got to them. Just freeze the section you're ready to work on.
2.) Be smart. This stuff isn't just cold enough to burn you, it's also toxic. It can kill you. It probably won't burn you or poison you, but keep in mind that you'll be working with it inside a car. That's an enclosed space with a solid poison that is turning into gaseous poison as quickly as physics allows. You also may be wearing safety gear and things which may limit your peripheral visibility... make sure you don't sit on the stuff.
3.) When baking, consider this change when dealing with butter. Instead of softening it for cookies or brownies, melt it instead, completely. Do this on the stove. Don't stop the second it melts, though. Continue on until it turns a nutmeg brown color. This will enhance the overall flavor of the cookies by bringing sort of a nutty, caramelized flavor into them.
4.) Be patient. But go quickly. Kind of a fast slow. Give it time to freeze the underlay, but not so much time that the stuff in your cooler evaporates. I had a cardboard box, not a cooler. But this works too.
5.) Use the right tools. I thought a straight up hammer would work, but light impacts did nothing, and heavy blows would damage the car. So I got my air hammer, a chisel attachment, and went to town. This was the best strategy I could come up with.
Where do I find dry ice?
Well, the internet will have you believe that it's
EVERYWHERE! Grocery stores, hardware stores, every welding supply shop, Walmart... pick a business! They sell dry ice!
Nope.
If you live in the country, like me, none of those places have it. None of them.
Just Google for a dry ice store and call around. I had to go pretty far from home to get it, but that just meant I could get it on my way home from work.
How much do I need and how much does it cost?
I used 15 pounds. That's a nice load of pellets in a 10 inch cube box. I would use 25 or more if I did it again, but 15 was enough.
Where I got it, it was $3.00 per pound if you bought 10 pounds or more. It is not expensive.
How much time did you save?
A lot. The colder it gets, the more brittle it gets. The air chisel gets under it and it just explodes in chunks. I did 90% of the underlay in 10 minutes. The other 10% took another hour or more. The other 10% was not well frozen due to slopes or a lack of coverage in general. Running the air chisel through that takes effort and feels like running through a smear of bubble gum.
I hope this was coherent and helpful! I'll edit it tomorrow if it's badly written. Happy chipping!
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