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Underbody cleaning question.
Posted by: lostbooger ()
Date: April 19, 2010 01:06AM

So Im under my sedan today trying to figure out how the best way to remove years of oil dirt and undercoating. I have plans to eventually coat everything not directly visable with POR 15 since I plan on moving back to Montana someday. I know you need a clean oiless surface for that stuff to stick. While the motor and suspension is out I want to get the area above the transmission and blower taken care of.

So my question is this. Is it best to sandblast or pressure wash? Also when I do get it all clean I was planning on using that POR 15 gel to seal all the smaller sheet metal gaps. Is that a good idea?

Also Im posting a picture of my fuel line. Think I need a new line? lol

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Re: Underbody cleaning question.
Posted by: parihaka2 ()
Date: April 19, 2010 03:38AM

it's a question that I need answered as well so if someone PM's you the answer, will you forward it on to me?

good luck with your car.

Temecula California
64 Monza Coupe

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Re: Underbody cleaning question.
Posted by: lostbooger ()
Date: April 19, 2010 03:48AM

No no PM's yet sad smiley

Damian

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Re: Underbody cleaning question.
Posted by: upnorth1 ()
Date: April 19, 2010 04:01AM

heres 50 pics of what I did on my truck. Sandblasted followed by repair, then epoxy primer, then red oxide followed by undercoating. Tried pressure washing first, didn't cut it.

me truk resto

don't make the mistake I did using rust converting paint, had to blast it a second time.

POR is for rusty surfaces, not blasted clean ones. If you plan a complete resto in the future, blast it. Otherwise I would rent a very high power washer, use degreaser a few times. the BLUE LABEL EZ OFF oven cleaner works great on grease, NO LYE to eat the metal. then follow with por for a next to forever finish.

Enjoy!

bob

Chaplain Bob
135 miles from Canada

AT THE TIP OF LAKE SUPERIOR
1961 Loadside 110 140 4 speed, 30 over. 4 speed
1966 Corsa clone
1966 4 door 110 pg

DON'T mess with Old Men, we didn't get old by being, STUPID!!!

\/ this is a mile from my house... \/

Click for Hermantown, Minnesota Forecast

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Re: Underbody cleaning question.
Posted by: lostbooger ()
Date: April 19, 2010 04:52AM

Great pics thank you! I was playing with the aircraft stripper today and it took everything right off! However the scraper wasnt cutting it. I figured that plus the pressure washer would do it. Can the POR be used on blasted surfaces if you use the metal ready acid stuff?

Thank you
Damian

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Re: Underbody cleaning question.
Posted by: lgoodwin ()
Date: April 19, 2010 05:58AM

Seems like a good steam cleaning would be the best first step to remove all the grease, then blast what's left. Are there any shops left that still do steam cleaning, or did the environmental laws shut them all down for good? Haven't seen one since the 70's...

1962 Corvair 900 sedan1967 Corvair Monza 140/4-speed1968 Corvair 500 coupe1983 Mexican Mustang 5.0
1962 900 sedan needs a home1967 Monza 140/4-spd1968 500 coupe (now my son's)1983 Mexican Mustang 5.0

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Re: Underbody cleaning question.
Posted by: Darrin ()
Date: April 19, 2010 10:17AM

POR can be used on clean (including blasted) metal, but it must be etched with acid as noted to create some "teeth" for it to bond to. I have blasted and etched and had it stick well..I have also applied over rust after wire wheel and etchings...and had it stick well. Comes off in sheets from clean, smooth metal though.

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Re: Underbody cleaning question.
Posted by: gnvair ()
Date: April 19, 2010 12:03PM

Best thing IMHO is to get the vehicle as high off the ground as possible. Pressure wash. Then use heat to remove under coating. I have found brake clean/solvent works excellent for removing the remaining residue or oil. Blast any rust as POR 15 is not an end all be all. The current formulas are not what they were back in the 80's. As such, if it gets nicked or scratched it will peel off in sheets.
I personally prefer self etching primers and then paint.

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Re: Underbody cleaning question.
Posted by: richard1 ()
Date: April 19, 2010 12:07PM

After replacing various panels with donor car panels (not Corvairs) I suggested blasting, but my body man insisted that nothing is as good as hand sanding, so that is what he did.


Restoration in Bolivia
Richard's Mini Pickup
Richard's Corvair
Richard's Renault Dauphine

Selection of the Right Motor Oil for the Corvair
Selection of the right transmission oil for the corvair
How to polish and restore stainless and aluminum trim

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Re: Underbody cleaning question.
Posted by: lostbooger ()
Date: April 19, 2010 07:35PM

When Im done with this car I plan on making it my daily driver. Montana roads are harsh and there is lots of gravel. I really want to do whats best especially in places around where the drivetrain goes that I cannot easily get to while its installed. I plan on doing the same thing to the gas tank and front suspension area when I yank it out soon. So knowing that what do you good gentlemen reccomend? Im open to anything that doesnt involve me moving the car out of my small garage lol. It has no wheels or suspension installed and is up on jack-stands. I have access to a small sand blaster and maybe a small pressure washer. Whatever I put up there needs to be very corrosion ressistant. I know Im beating a topic thats been discussed before but I really cant afford to do this twice.

Thank you
Damian

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Re: Underbody cleaning question.
Posted by: lgoodwin ()
Date: April 19, 2010 08:19PM

lostbooger Wrote:
-------------------------------------------------------
> When Im done with this car I plan on making it my daily driver.
> Montana roads are harsh and there is lots of gravel.
Damian, have you considered installing skid plates after treating the undercarriage?
POR 15 is prone to peeling. It would be a shame if it all peeled off one day...

1962 Corvair 900 sedan1967 Corvair Monza 140/4-speed1968 Corvair 500 coupe1983 Mexican Mustang 5.0
1962 900 sedan needs a home1967 Monza 140/4-spd1968 500 coupe (now my son's)1983 Mexican Mustang 5.0

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Re: Underbody cleaning question.
Posted by: richard1 ()
Date: April 19, 2010 09:23PM

After the primer I put 3 coats of a waterbased undercoating. First two were when it was vertical like above. then once I had it on the table ready to put the suspension in I hit it again from all angles.



Restoration in Bolivia
Richard's Mini Pickup
Richard's Corvair
Richard's Renault Dauphine

Selection of the Right Motor Oil for the Corvair
Selection of the right transmission oil for the corvair
How to polish and restore stainless and aluminum trim

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Re: Underbody cleaning question.
Posted by: lostbooger ()
Date: April 20, 2010 01:51AM

Now Ive heard that undercoating holds in moisture. It seems to work fine to me especially since the car already has a ton of it and it is rock solid. Very little rust under it. Im all for using it though cause its cheap and easily applied. However I read that long term it is not the best way to go. Any thoughts on that? Are there different types of undercoating?

Thank you
Damian

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Re: Underbody cleaning question.
Posted by: kenFL ()
Date: April 20, 2010 12:29PM

In my shop if the customer does not want to do a "body off frame" restoration, we will usually put the car up and pressure wash the heck out of it. This not only cleans the surface but it also tends to reveal all the loose areas of OEM undercoat that needs to come off anyway.

Once clean we will (as Richard did) spray the underside with the Wurth SKS texture coat product. It is a water soluble product that sticks like crazy and dries hard as nails. An added advantage is you can paint right over it if you like. Plus since it's a water based product you wont need to worry about if the car's underside is completely dry before you apply it.

I don't know if there is any advantage to removing all the OEM undercoat that is still stuck on the car really good (as you stated with your car)-- only remove the areas that have started to come loose. Follow by brushing on a little POR 15 on the exposed rusted areas-- the Wurth will stick to it nicely.

PS: you can rent a small pressure washer for the day relatively cheap if you have a place to do it yourself.

I have had cars we have done with the Wurth product that my customers have had for years that still look terrific underneath!

Pressure washing the underside is messy but if you get yourself a cheap Tyvec suit like those worn by fiberglass guys, it's not too bad. Do it on a hot day--- kind of refresing then!! LOL



Edited 1 time(s). Last edit at 04/20/2010 12:30PM by kenFL.

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Re: Underbody cleaning question.
Posted by: lostbooger ()
Date: April 20, 2010 05:04PM

Thank you Ken! The undercoating the car already has, I cant tell if its factory or not. Its up to 1/2" thick in some spots! The only rust the car has underneath it however is where the undercoating was either scraped off or where it wasnt applied. So I guess that means its doing its job just fine. I just heard bad things about undercoating so I guess I got a little acared about relying on it.

Damian

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Re: Underbody cleaning question.
Posted by: wagbear ()
Date: April 22, 2010 12:10AM

Great posts!!!! Guess I'll have to get under the wagon and clean all the cobwebs....light crud..... and maybe a few random boogers....

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Re: Underbody cleaning question.
Posted by: richard1 ()
Date: April 22, 2010 12:19AM

A disposable poncho also works. I sandblasted in a cheap bee-keepers poncho. This pic was the day I learned I should use gloves.



Restoration in Bolivia
Richard's Mini Pickup
Richard's Corvair
Richard's Renault Dauphine

Selection of the Right Motor Oil for the Corvair
Selection of the right transmission oil for the corvair
How to polish and restore stainless and aluminum trim

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Re: Underbody cleaning question.
Posted by: mrtrimmier ()
Date: August 24, 2010 11:15AM

If you can get ahold of a steam cleaner they work really well to remove most of the ick. Any undercoating that stays after that is part of the car IMHO!!!

Regards,
Mike T
Lady's Island S.C.

Black '65 CORSA "parts" car ("RatVair") '65 CORSA Weber/180 ("Whitey") '60 500 Sedan ("Smurf Surf Sedan")


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Re: Underbody cleaning question.
Posted by: cfmann ()
Date: August 24, 2010 12:52PM

sandblast or pressure wash?
-i removed a front crossmember from a LM and used my cold water pressure washer (2400psi) to "clean it" with the intent to paint and reinstall it on another car.
But even so, it did not get all the crud and grease out of the cracks and crevasses. If you pursue this method, I would look into the the steam or hot water pressure washers, as others have stated. I would imagine you could rent one, but don't have any personal experience using one.
-by abrasive blasting, this is more of a mechanical process. Crud, grease, grime, small stones, 45 year old dried-out undercoating, are easily removed with this method. As you can see from earlier posts, using a rotisserie can be really convenient tool to have in the shop. The trailer in the Picasa pics posted by Chaplain Bob is a diesel powered air compressor and those I know are available from a well supplied rental agency. Sandblasting can be a tiresome and tedious process. Your hands get sore from holding the gun and your back might ache a day or so afterward. But Abrasive blasting is a very effective way of getting to bare metal quickly, including those hard to get to areas.
As far as finishes are concerned, personal preference will prevail. You'll have some guys say POR15, others will say primer and paint works fine. POR is a great product, but with the steps involved, and the extra chemicals (etching) you may reconsider for the primer and paint routine. I have used POR for inside a gas tank but never out in the open. Cosmetically speaking, POR looks very much like undercoating in my opinion. All in all, whatever you do, you will certainly lease a new life on the underbody of your Corvair.

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