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Suggestions for cleaning the underbody

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bobs51

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Sacramento, CA
I wish that I had the time, money and experience to do a body off restore but I don't.

Under the truck (51 GMC) is not terrible but there is a fair amount of gunk, rust (but no holes), built up dirt, etc on the underside of the truck and I'm looking for some feedback on how to clean it up.

The truck doesn't drive right now but is sitting nicely up on blocks so I can get underneath on a crawler.

I'm pondering a hand held sandblaster ( something like: http://www.harborfreight.com/1-liter-abrasive-blast-gun-92857.html), I have a compressor but not sure what to blast with (walnut, sand, etc).

I've been trying to use a wire brush but it's very slow progress.

Thanks for any suggestions,
bob
 
A couple of considerations...

First, I do not know how to clean it up...I have used my own time tested method...the wire brush! And, sweat and time, too!

No holes? I would not say that too loud around your truck. They have souls that hear what you are saying and thinking and they try to prove you wrong. It is amazing how much junk builds up under there. I believe that sandblasting is one of the ways that you can find holes (as, proven by some past comments by many on this site). Recently, I have been doing some cleaning and some of the best clean places have been under some layers of tar that covered areas just right. It does not always happen that way, but it is clean and solid under that road tar of 60+/- years ago.

I bought a puny sand blaster years ago for a project on a horse trailer...that was a waste of money! It did nothing.

I really do not think that you will be getting much done laying underneath a body/frame in a suit and all kinds of protections. I would leave it to the pros, if that is the way you go.

You may need special sands for different materials. I do not know if it would cut through some of the tar stuff I am seeing on my recent work. It is not just beach sand.

It is too bad they have not figured out how to make a "wire brush DR" thingy! Or have they?

Slow progress is good....say it again!...Slow progess is good!

One thing that I have tried and is working for me...is a modified wire brush...I cut the handles off some of them and I use that type more often than the handle ones...it seems to work for me much better.

Your old truck is getting tickled when you are scraping down there...it enjoys it! You also get to know it much better and you become friends for a much longer period of time. Enjoy

Ramblings on a late, late saturday night.

rod
 
No sand

Bob

First do not use Sand. It contains silica which shatters when it hits something with force and gets in your lungs and causes silicosis of the lung. That will kill you. There are hundreds of lawsuits. I used coal slag on the frame with a cheap harbor freight 70# blast pot. It takes forever but can be done. If you are so inclined recover the slag sieve it through an old window screen and reuse. By the time I got to the body it was fine enough to use without tearing up the sheet iron. Make sure you have all ppe and use it! Old cloths, loud music, a big compressor and plenty of cold beverages are a must.

Papy
 
If you do media blast follow 51papy's advice: don't use sand. I use nickle slag, works great.

Media blasting is your best bet for quality end result, but I wouldn't blast it unless the truck is completely disassembled. The media will get into places you don't want, like bearings.

I would power wash it first. Then use an angle grinder with a twisted wire wheel. Then power wash it again.

In flat spots a Quick Strip Disc on the angle grinder will work great too.

Make sure to wear goggles, or better yet, a full face shield and goggles.

Hope that helps!

John
 
I'd like to add- there has been a lot written and promoted about soda blasting. Found a place and was about to use it for my truck when I learned (from the soda blaster coincidentally) it isn't recommended because paint manufacturers are having issues with the residuals from the baking soda.

Just thought I'd throw this in if anyone was considering it.

Haasman
 
The grease was hot when it went on, heat will help take it off. Use a propane bottle or heat gun to heat it up then scrape it off with a heavy paint scraper. Oven cleaner works very well for the final grease cleanup. carb and brake cleaner also work well.
 
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