Dry Ice, the good and the bad

[MEZZZ]

Well, I finally have a week off from work and some time to work on the '77 I bought back in September. I had gutted the interior and have all the parts to put it back together, most coming in the past week.

I figured I would do it right and do the POR 15 treatment on the interior and use Dynamat before laying in the new carpet. That required removal of the nasty stock sound deadener.

The good....

I used the dry ice method I found here and my sincere thanks go out to whomever figured this out because it worked fantastic. I got about 10 lbs of it from my work yesterday and laid it in. Came back 5 minutes later with a hammer and small chisel and just tapped it and the pieces just popped cleanly in fairly big chunks. Highly recommend to anyone wanting to do this, I worked about an hour and it was done.

The bad....

The driver side went quick and the floor was VERY clean...no surface rust, nothing. I get almost finished with the passenger side, get close to the firewall, hit the chisel with the hammer and...it goes right through the floorboard! I carefully scrape off the deadener and there are 3 little holes, about 1/8 inch. I move up to the firewall and open up about a 2 inch rust hole. I'll post some pics once my wife wakes up and she tells me where her camera is I am going to need some advice on how to handle this..

[Six_Shooter]

Cut out the bad, and weld in new metal.

[ktm]

MEZZZ, post the pictures and then we can better assess the damage and make the appropriate recommendation. If the holes are small, you do not need to weld in new metal.

[FluffyBunnyFeet]

well if by what he is saying, if he was able to put the chisel through it the cancer already got a good peice.

in most casses its best to take a small bit of good steel around any rust and just replace it with a new peice to be sure it doesnt come back

[MEZZZ]

Ok, found the camera and took some pics, I took them in VGA mode so that they were not huge in size.

Let me know what you guys think. I did a search earlier today and someone wrote of riveting a piece in place after cutting out the bad. It looks to me that the piece. I dont want to half-arse this but have no MIG welder. If welding is the only way (I am sure it is the best way) then I will have to pony up the bucks and get it done.

I appreciate all the comments.

Driver side...it looked great

passenger side..it looked good until I got towards the firewall

closer shot of the rust.

[Z train]

First things first-POR will not stick to any painted surface.It must be rust,blasted or sanded first.

With regards to the rust-is the car undercoated?If so it(undercoating) would have to be stripped form the area.The rust is very borderline between needing a new piece welded in and being able to fix it with POR & fiberglass cloth.

[MEZZZ]

First things first-POR will not stick to any painted surface.It must be rust,blasted or sanded first.

With regards to the rust-is the car undercoated?If so it(undercoating) would have to be stripped form the area.The rust is very borderline between needing a new piece welded in and being able to fix it with POR & fiberglass cloth.

Thanks ZTrain, I planned on sanding it down before using the POR-15.

Yes, the car is undercoated...would a closer shot help?

I thought of the POR-15 floorboard kit too, didnt know if this would be a good candidate or not.

[Z train]

I'm un-familiar with the "Floorboard kit".What's in it?

If you can,get a really well lit shot of the underside AFTER the undercoating is stripped.

[MikeW]

Thanks ZTrain, I planned on sanding it down before using the POR-15.

I recall trying a bunch of different abrasive disks on an electric drill for this same job as there are a lot of bends and hard to get to places like under the seat support. Some of them worked quite well; here's an example:

http://www.acehardware.com/product/index.jsp?productId=1287722&cp&kw=2004919&origkw=2004919&sr=1

[geezer]

You can cut out any bad/perforated metal and remove all rust by whatever means you decide on and cut your own patch pieces. Then find someone with a portable 110V MIG welder that will come weld it up for you. Make sure you disconnect the (-) battery cable to prevent electrical wiring/component damage while welding. Although the rust damage does not appear to be that extensive, I would investigate further. I would remove the cowl screen and get a good look at the hidden areas higher up the cowl. Look it over real good behind the dash also. Try to find where water has possibly entered. It is actually not too bad and you have the foresight and means to nip it in the bud. If you find yourself on this side of the lake I'll give you my old MIG welder. Good Luck

[EScanlon]

The Good:

It's repairable.

Both by using POR-15 with their Power Mesh product, and by cutting and replacing the metal.

The Bad:

The hole opens up directly into the Frame Rail Support. The rusted metal you see in the background of the hole, is the INSIDE of the rail. As rusted as it looks, you may have to examine the whole frame rail to determine if it needs repairs or replacement. There are replacement pieces available for it, or you can have a piece cut to shape to patch.

As far as a paint removal, the product that MikeW recommends works very nicely and quickly. My only gripe about it is that it does NOT like edges of any sort and will quickly and suddenly grab and literally tear it and the edge to shreds. It is excellent for the bulk of the flat areas though. Just watch out for flying bits and pieces...it shoots them out like a Gatling gun. It is VERY abrasive, so keep your fingers and skin well away from it, it WILL give you a scrape like your first skateboard asphalt rash in nothing flat.

Here are 3 other links for two products by 3M which I've used and really liked. They will help you get into the tiny corners and will help you remove paint and some corrosion quickly without literally grinding the metal:

The first one is the 3m Roloc Bristle Disk:

http://solutions.3m.com/wps/portal/3M/en_US/3MAutomotive/Aftermarket/Products/Product-Catalog/?PC_7_RJH9U5230GE3E02LECFTDQCEK3_nid=TX88WPL3PGbeRP70999582gl

It's biggest advantage is that it will clean up a large area before it even starts to wear down, and will continue working until all you have left are tiny bumps on the pad. It will require an adapter for your drill or angle grinder. The adapter for it is the same as for the conditioning disks below. It's very inexpensive for the amount of work it will do.

Second product is the Surface Conditioning Disk, which comes in 3 (or possibly more) grades. Here's a link to the "Try" kit, and the link that follows is for the bulk packs.

http://solutions.3m.com/wps/portal/3M/en_US/Manufacturing/Industry/Product-Catalog/Online-Catalog/?PC_7_RJH9U5230GE3E02LECFTDQGLE0_o=HTML&PC_7_RJH9U5230GE3E02LECFTDQGLE0_nid=JZ2VXJ4Q27beSQSFJR0R56gl

http://solutions.3m.com/wps/portal/3M/en_US/3MAutomotive/Aftermarket/Products/Product-Catalog/?PC_7_RJH9U5230GE3E02LECFTDQCEK3_nid=GSD8DBBXPPbeGS66HQKGFZgl

The biggest advantage to these is that it will very quickly remove JUST the paint and light rust. They also require an adapter, but whether you size the adapter to the size of the disk or undersize it, they'll do a great job. I intentionally undersize the adapter when I'm cleaning up grooves or deep crevices. If you are careful, you can even use the softer one to give your piece the beginnings of a "polish" before you actually polish.

The repair by metal replacement or the POR/ Power Mesh repair has been referenced before, so I won't re-iterate it here unless it can't be found. But do take note that that frame rail has decideldy been compromised, that amount of rust INSIDE means it's been weakened, and just shooting a bunch of POR inside there will not restore it's strength. (If you need info on spraying POR, there's been info before although the air blower syphon is no longer carried by Harbor Freight.)

HTH

E

[ktm]

The Good:

It's repairable.

The Bad:

The hole opens up directly into the Frame Rail Support. The rusted metal you see in the background of the hole, is the INSIDE of the rail. As rusted as it looks, you may have to examine the whole frame rail to determine if it needs repairs or replacement. There are replacement pieces available for it, or you can have a piece cut to shape to patch.

But do take note that that frame rail has decideldy been compromised, that amount of rust INSIDE means it's been weakened, and just shooting a bunch of POR inside there will not restore it's strength. (If you need info on spraying POR, there's been info before although the air blower syphon is no longer carried by Harbor Freight.)

HTH

E

EScanlon beat me to the punch.