Needle scaler for undercoating

[rvannly]

Hi guys, I had just cut out my floor pan and need to get the undercoating off. Primarily the edges where I am going to be welding the new sheet metal to. There is a lot of different materials under there: three layers of paint, sound deadening material/tar, and aftermarket undercoating.

 

Ive gone through a few threads on this subject and since it'll be on jackstands, dry ice won't work. The heat method I would like to leave for my last option, since it's so messy. I read about the snap-on crud thug, but that is just too expensive.

 

I remember learning how to weld on a arc welder and remembered an air tool used to get the flux off of the welds called "air scaler"? Harbor freight has them for cheap and since this is a one time project I think it will be worth it. Here's the link to a pic/spec. http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=96997

There are two versions. Another larger one for 50 dollars

 

 

Has anyone tried this for undercoating removal?

 

Also, the only air compressor I have right now is a small 4.5 gallon compressor. Its rated at 6.2 SCFM @90psi.

 

What is "SCFM" vs "cfm"?

 

The tool says 4 CFM @90 psi, so will my compressor work?

 

Sorry for the newb and lengthy thread, and thanks

[proxlamus©]

dry can be applied to the floor pans from inside the car.. the intense cold will transfer through the metal.. allowing you to knock the bottom of the car with a hammer.

 

I have highly considered a needle scaler though.. anyone have any success stories??!

[PETEW]

I used a needle scaler to do the entire underside of my 280 Z. For the most part it worked really well. There were some spots it was still gooey so I still had to scrape some off, but it really did a nice job of prepping the underside for POR-15. Make sure you get some ear plugs, they are LOUD!

[DeleriousZ]

I used an angle grinder with knotted bristle wire cup, kicked the unholy crap out of the undercoating and anything else in its way.

[rvannly]

Great thanks for the input everyone. I think I am going to try the dry ice method since I've gone that route in the past. There a a lot of spots where it is thick and soft so the wire wheel and scaler wouldn't work very well.

[Cobra_Tim]

The scaler will leave small dents and scars all over the metal... We started to use one when we replaced the floors and pans in the carcar, but decided against it when we saw what it was doing. Took the stuff off though

[Meph]

that 4 CFM is probably average (say 25% running time) its continuous is probably like 16 or something huge. Air tools require a lot more than 4 cfm usually. I have a similar compressor and I can barley count on it to power spray guns. Id be weary of it

[Scott_M67]

We used mineral spirits in a spray bottle and some scrappers that worked pretty good, messy though.

[tube80z]

On some rally car prep sites they have been talking about using liquid nitrogen for removing sound deadener/undercoating. Google should give you many hints. If I had to do this again I'd seriously think about it.

[johnc]

I used an angle grinder with knotted bristle wire cup, kicked the unholy crap out of the undercoating and anything else in its way.

 

Depending on how powerful the grinder is, they can kick the crap out of you too. Snag one of the knotted wire brush cups on a corner with powerful grinder and its going somewhere real fast. I use them too and they work well but I don't have the cup on a very powerful grinder. A small DeWalt works fine for me and my shoulders.

[jkgts1]

I used the harbor freight needle scaler on my 260 and worked great for me. I did not notice any dents when I did it. The instructions tell you to angle the scaler and not to use it perpendicular to your work surface. As long as the undercoating is fairly dry it should work, if it is soft it will not work too good.

Good luck.

 

Thanks

[DeleriousZ]

Depending on how powerful the grinder is, they can kick the crap out of you too. Snag one of the knotted wire brush cups on a corner with powerful grinder and its going somewhere real fast. I use them too and they work well but I don't have the cup on a very powerful grinder. A small DeWalt works fine for me and my shoulders.

 

Aye I got covered pretty damn quick with the ♥♥♥♥ that was coming off the underside. Also when the wires come out of the cup and hit you it really hurts if it hits an unprotected part. Full face shields are a must. I had one hit me in the chin before donning the shield, and it stuck in about 1/4". I pulled it out not even knowing it was in that far, but damn did it sting, can't imagine if I got it somewhere more sensitive.

 

I used it with a 4.5" angle grinder that was from home depot or something, not powerful so even when it kicked it wasn't too bad.

[logan's 240z]

I used a propane torch with a wide angle heating tip.Warmed the undercoating just enough to start a wide scrapper underneath.Keep the torch moving along with the scrapper.Anything that hit the concrete floor easily cleaned up when it cooled.I did a whole inner fender in about 10 minutes.Then walnut shell blasted.Turned out great.Roger

[rvannly]

During the week I did a few test runs of different methods. I have a rust hole above the frame rail in the fender well that I want to fix so that's where I began the experiments.

 

I started with aircraft remover. It didn't really do much damage to the undrcoating, which was pretty hard and thin. All it did was soften the undercoating, barely. It took multiple layers of aircraft remover after manually scraping of material with a metal scraper.

 

Next, I used a wire wheel on a grinder. This worked great, but scary. needles of wire flung everywhere and the grinder was hard to maneuver around. Yet, very effective. After most of the material was off the panel I used the aircraft remover to get rid of the rest.

 

I have a gas torch that I want to try, but it has been 90+ degrees outside the past few days so I will wait on that.

[Careless]

I've had a worthy/mentionable experience doing this.

 

The best method I found was to heat it up so it becomes brittle, then to hit it with the wire-wheel. This is best done in the areas that are tight fits with the wire wheel, because it makes the undercoating very brittle. You can then use a brass brush too.

 

When a wire wheel won't fit, you can get a "wire sprout" or a "wire cup" to fit into the tight areas.

 

I find attaching it to a regular corded drill is the best way. And if you have a hammer drill that has a side-arm attachment that you can use, and a switch to put it to non-hammer mode... that would be your best bet.

 

A needle scaler will work just as well, but you MUST heat it to the point where it gets crusty, or you will just waste your time.

 

The only downside is that you have to do it outside if you're heating it up, as the dark fumes that rise from the embrittlement of the undercoating tend to linger and hover at your ceiling, and overnight they will land on whatever is closest to the ceiling. So anything that is set up high will have a nice filmy black dust on them.

 

A good idea is to have a wet-dry vac ready to suck in the fumes using the air-borne element filters.

Edited August 31, 2009 by Careless