Undercoating removal - tip - this is working....

Undercoating removal - tip - this is working....

I also posted this in Chassis restoration...

I had posted ealier this year on methods to remove undercoating. Well after a long summer/fall without extra cash - I have finally got the body off and started removing the undercoating. The best trick I have found is - in those areas where you have access to the backside of the panel - heat from that side. I have tried multiple methods with torch, electric heat guns, and heat lamps, with some success but with the heat applied directly to the undercoating. By accident I placed my halogen work light in the trunk (250 watt), I found the undercoating on the opposite side softened very quickly and would easily scrap off. Now I just place the light less than 6" from the back of the suface I am working on and scrap away. (My light has a metal gaurd in front of the glass so I just rest the metal gaurd against the surface) The softening begins in just a few minutes and after about 5 minutes it gets almost to soft so I move the light to the area I am going to do next. I am sure the heat is several hundred degees and could burn paint or other cumbustables so I try not to heat anything to long. Each light placement position allows about a 1 square foot area to be cleaned. I still have the nasty task of cleaning residue and then getting a good rust free surface for paint application. This job was certainly alot easier without the frame and undercarraige hardware in place.

 

Using heat just makes a mess. You are creating more work than you need to for your project. I have removed the undercoating on several cars. I use a tool called a "needle gun" which is used on boats to remove barnacles. Looks like a squid, long air cylinder with small, long finishing nails on the end. The needles dance/vibrate and easily removes the hardened undercoat. Did a whole car in about 2 hours, lying under it, sitting on jackstands. Use protective googles and go at it!
When you are finished, you will have a clean surface and no marks. If you have any residue, use mineral spirits to clean the surface. I re-undercoated my cars. Adds to sound deadening and prevents rust!

 

Well your a lucky man !!! My car has had 2 additional coats of aftermarket undercoating. it is very hard on the surface, the base undercaoat in those places the factory had applied are much softer but most of my car appears to only have factory undercoating neat seams or edges. Some spots are near 1/2" thick from the aftermarket applications. I have found that by applying the heat from the backside, it scrapes very nice, when I apply it to the front side it gets to hot and your correct - a mess. Can you provide a link to the tool you speak of? Not something I would see here in the frozen tundra of the upper midwest. Sounds like it would be a great follow-up vs grinding or sanding. George - what do you use to finish the cleaning process? (chemical ??) I will be going the POR15 route - then top coat....

 

I finish the cleaning process with a wipe down with mineral spirits. That leaves the factory under paint/primer. I then apply new undercoat. I don't have a link for the tool. I can take a pic and post it here tonight! I bought it from a pawn shop with a collection of other tools. You know the saying "Right tool for the right job" What a tool! Mean Machine, so easy to use!

 

Geoge, missed the part about mineral spirits. I will need to find something that is not flammable - as I am in a heated garage and fumes will be a problem. Any suggestions ? (to cold here to be on the floor with even a open door for more than a few minutes) Also would you have a picture of this tool you could post ??? If I can get my hands on something like you speak of it may be worth a shot in the open areas I have left (floor pan) trunk and axle area are about done. Does this tool also clean off the paint and or surface rust ???? I have a good air compressor so I am in shape there assuming it doesn't require a huge amount of air overa nd above a normal air tool. Maybe you could rent it to me !!!!

 

George, we must be on the board at the same time.....I am posting while you are responding to my previous post. Anyway - seriously - would you rent this tool ?????

 

I don't know if you can rent this tool. I have not seen it anywhere. As for me renting it, you know the saying "Two things you never loan in your life........your tools and your wife!"

I bet you can use Castrol SuperClean on it. That is NaOH (Lye or Oven Cleaner) spray it on and let it sit. Then either wipe it off or hose it off. Leaves a super clean surface.

I will send a pic tonight of the tool. The "needles" are hardend steel rods. The harder you press the more it removes. I will also remove scale and rust.

 

Wow, it does sound "slick". To bad I can't have your 72 you have for sale, then maybe you could leave it in the trunk by accident !!!!! Off the subject - do you still own the Blue GS you have on your Buick site ????

I will also check that Castrol cleaner out - Thanks for the tip !!!

 

Still own the blue 70 that is my avatar. Also have a 71 GS350 conv and a 70 Skylark conv I just bought. Also, long time project I have is a 70 GS455. Here is the pic of the needler tool. Maybe you can find one somewhere!

 

Scott,

The tool is called a "needle scaler", and Northern has them for about $60 I think..

Never seen one like George's, they are usually more like a pistol grip thing, similar to an air hammer.

Also works good for re-creating the "rough" surface of an aluminum casting, after you mill the "Edelbrock" name off it.. :eek2:

But that's a whole 'nother conversation... uzzled:

JW

 

Thanks Jim, now you let the Wildcat outta da bag!

Darn it, got to keep some secrets, right???????
:grin:o No:

 

Ya George... I'm horrible at keeping secrets..

Although I have kept one very important secret... that one a customer spent some $$ to have done, so my lips are sealed..

JW

 

Jim, do you use one of these in your shop for the same purpose ??? George - I'll bet both you and Jim have more secrets on these Buick's than anyone would ever know !!!!

 

Scott,

With the convinences of a 4800 SQ FT shop, we can just put the body on a rotisserie, and break out the pressurized blaster, and a 100 lbs bag of black beauty, and remove the undercoating, rust, paint ect.. all in one shot.

Since we moved into the new shop, we have not reached that point on any of the projects yet, but will be shortly.

I have done a couple trunks.. and let me tell you.. makes short work out of removing trunk spray.. obviously, you can't do the inside of the quarters that way, but it does work great on the trunk floor, and the quarter panel supports. We still have to sand it off the quarters.. unless they are new (which they usually are)

But it was a $500 blaster.. but if your in the business, you just bend over and buy the tools..

I'm getting used to that now.. ou: and the investment pays off in the long run.

I did in fact use that tool back in the old shop, for that purpose, and it worked pretty well.

Wheelwells are the toughest..

JW

 

I used to use one of those tools to remove welding slag when I was a welder (before I came to my senses). They had the secondary effect of 'work-hardening' the weld surface too. They're pretty violent from what I remember. I would have thought that if you used it on an auto body it would fill it with little dents. :eek2: George, can you adjust it in any way?

 

There are two ways to adjust the intensity:

1. Reduce or increase air pressure

2. Reduce or increase the amount of force you apply
to hold the needles on the surface.

I initially tried the "scrape it with putty knife" method
but that took way too much time. This is the tool.

My Dad always said if you use the right tool to do the job once,
it is paid for in time, money and effort!

 

George, found a bunch on the web under "needle scaler". I will take a run to Northerntools today and pick up one like Jim mentioned and give it a try...... Thanks again for the tip !!!!

 

Well I picked up a needle scaler at Northern and gave it a shot. It will work in some areas - but I think this crap is just to thick and soft. I am now back to scraping and will finish with the needle scaler before I clean with chemical....

 

Hmmm...

It is a tool that is commonly used by welders. At least in my experience anyways.

Frankly, I've never used one at ANYTHING less than 120 shop pressure, so I'm stunned that you could use it on sheetmetal.:eek2: :jd:

o No: o No: o No:

 

You can use it on sheet metal but need to apply very light pressure so the "needles" dance/vibrate on the surface effectively scouring the surface of any undercoating.