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Question about patching rust on bottom of EM doors
Posted by: lgoodwin ()
Date: September 05, 2011 10:28PM

The 62 Monza sedan I'm fixing up has small rust patches at the bottom corners of the doors. I ground down to the metal tonight, but will have to eyeball them in broad daylight to see exactly what I have. It looked like there were a couple of spots that had narrow cracks, and the rest was just a smattering of tiny rust holes here and there.

I'd like to know what my chances are of welding these holes shut using my wirefeed welder (NOT TIG)? It works fine for welding a patch that is not exposed, but this is another thing entirely. I'd like to fill the rust holes and grind the welds down, then treat them with Rust Bullet, add a tiny amount of body filler to fill them in. Is this plan realistic?

Also, what else do I need to know about welding these areas? I know there is some kind of undercoating type material that looks like tar on the insides. What should I do to protect the INSIDES from rusting out from inside all over again?

Thanks!

<table align='center' width='0'>
<tr>
<td><img src='[www.automation-scs.com]; alt='1962 Corvair 900 sedan' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1967 Corvair Monza 140/4-speed' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1968 Corvair 500 coupe' width='190' /></td>
<td><img src='[www.automation-scs.com]; alt='1983 Mexican Mustang 5.0' width='190' /></td>
<td><a href='[www.automation-scs.com&]; target='_blank'></a></td>
</tr>
<tr>
<td align='center'><font size='1'>1962 900 sedan needs a home</font></td>
<td align='center'><font size='1'>1967 Monza 140/4-spd</font></td>
<td align='center'><font size='1'>1968 500 coupe (now my son's)</font></td>
<td align='center'><font size='1'>1983 Mexican Mustang 5.0</font></td>
</tr>
</table>

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Re: Question about patching rust on bottom of EM doors
Posted by: MattNall ()
Date: September 05, 2011 10:34PM

It's perfect for the job... not much heat / amperage...won't burn thru..

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

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Re: Question about patching rust on bottom of EM doors
Posted by: lgoodwin ()
Date: September 06, 2011 12:47AM

MattNall Wrote:
-------------------------------------------------------
> It's perfect for the job... not much heat / amperage...won't burn thru..
Have you ever done it?

The patching I've done so far did not require grinding the welds flush. Not sure if they will grind down smooth enough and have enough strength to last. I wonder it it would be better to EPOXY metal patches on the inside, and just fill the cracks/holes with body filler?

Also thinking I will need to remove the tarlike sound deadener from the areas inside that require welding so I can place some backing material behind the holes to prevent blowouts.

<table align='center' width='0'>
<tr>
<td><img src='[www.automation-scs.com]; alt='1962 Corvair 900 sedan' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1967 Corvair Monza 140/4-speed' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1968 Corvair 500 coupe' width='190' /></td>
<td><img src='[www.automation-scs.com]; alt='1983 Mexican Mustang 5.0' width='190' /></td>
<td><a href='[www.automation-scs.com&]; target='_blank'></a></td>
</tr>
<tr>
<td align='center'><font size='1'>1962 900 sedan needs a home</font></td>
<td align='center'><font size='1'>1967 Monza 140/4-spd</font></td>
<td align='center'><font size='1'>1968 500 coupe (now my son's)</font></td>
<td align='center'><font size='1'>1983 Mexican Mustang 5.0</font></td>
</tr>
</table>

Options: ReplyQuote
Re: Question about patching rust on bottom of EM doors
Posted by: richard1 ()
Date: September 06, 2011 03:52AM


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Re: Question about patching rust on bottom of EM doors
Posted by: aircooled ()
Date: September 06, 2011 08:50AM

I recently did the same repairs on my early door. They rust there because there are two layers of metal very close, the area is easy to clog and does not drain well.

The best way to do it is to cut the rusted areas out. Make sure to cut wide around the rust. If it is rusted through in an area, you can be SURE it is VERY thin near those holes. Thin is not only bad because it is rusted, but it makes welding very hard to do (lots of burn throughs).

That area is fairly flat, and if the rust through is only on the outside (most likely) you can use flat steel and just give it a bit of a bend (hammer or hand). Take a sheet of paper, place it over the hole, rub the edges with a pencil, cut that outline, then transfer that to the sheet metal, trim as needed.

With the hole still open, make sure to clean the rust out of the inner area as much as possible. Acid base rust stop, then POR-15 (or equivalent) is about a good as you can do with out de-skinning the door.

One more rust proofing tip. I diluted some POR-15, poured it into the door then swished it around in the door to cover the bottom area of the door (obviously the door was off). Obviously, making sure the inner door is as clean as possible and using some rust stop in it before the POR is essential.

Another thing I did was cut a small hole at the front bottom of the door and another slot near the rear bottom. This should allow me to use a air want to blow stuff out the back of the door. The early doors do NOT have a very good drainage setup and are almost impossible to clean properly (thus all the rusting).

Tim
Southern California - Where the stars are on the ground and dirt is in the sky

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Re: Question about patching rust on bottom of EM doors
Posted by: lgoodwin ()
Date: September 06, 2011 10:24AM

Richard, I hope I don't have to go to such extremes! eye popping smiley

This car will be parked on gravel with a weather break (evergreen bushes) on the south side, and a carport on the left. Not ideal, but better than where it has been for the last two years. I also plan to install new fuzzies OR beltline trim that actually seals out the water (what GM should have done, IMO).

Tim, thanks for the tips. I know you're right about the rust spots. I've run into that problem plenty with floor patching. Even when the adjacent metal looks good, you run into thin spots. Is there an "ideal" shape to cut the patch (e.g., square)? I was going to cut the patch, lay it over the area, scribe an outline, and cut the hole, then file the edges back enough to make a thin gap for the welds. This is how I did the last two patches. I'd rather not cut/weld, though...

What if I grind off the rust, cut two pieces of galvanized steel, paint them with Rust Bullet and epoxy them onto the inside (after cleaning inside of door of course!)? Then I could use Rust Bullet on the outside go over it with either epoxy or body filler.

Drilling a couple of good drain holes makes good sense. The right-rear door panel was dripping water the other day when it rained a bit. The backer material is curled up from getting wet so many times. I assume the slots in the bottoms of the doors were to permit fresh air to circulate behind the door panels. I'll seal them off using plastic instead of tar paper.

<table align='center' width='0'>
<tr>
<td><img src='[www.automation-scs.com]; alt='1962 Corvair 900 sedan' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1967 Corvair Monza 140/4-speed' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1968 Corvair 500 coupe' width='190' /></td>
<td><img src='[www.automation-scs.com]; alt='1983 Mexican Mustang 5.0' width='190' /></td>
<td><a href='[www.automation-scs.com&]; target='_blank'></a></td>
</tr>
<tr>
<td align='center'><font size='1'>1962 900 sedan needs a home</font></td>
<td align='center'><font size='1'>1967 Monza 140/4-spd</font></td>
<td align='center'><font size='1'>1968 500 coupe (now my son's)</font></td>
<td align='center'><font size='1'>1983 Mexican Mustang 5.0</font></td>
</tr>
</table>

Options: ReplyQuote
Re: Question about patching rust on bottom of EM doors
Posted by: aircooled ()
Date: September 06, 2011 10:43AM

The epoxy idea might work, but if you are talking about the lower corners of early doors, there is likely no way to get behind the skin. As I mentioned, the structure behind the skin there is very close to the skin, the primary reason it rusted in the first place. Cutting the patch then cutting the door to match is a good idea though, it should be faster.

One thing you might try, if you really don't want to weld, is go get one of those HF flangers (assuming you have a compressor). The you can cut your hole, flange the edges (you will have to figure something out for the corners), then just lay and glue the patch into the flange. The bottom edges might be trickier. One note: you really don't want any body filler exposed to water, it tends to absorb it (so I read) and that would be bad.

Those drain holes on the bottom are pretty silly, they aren't even at the low point of the door! The low point is the pinch weld next to the holes, the last place you want water to sit, argh!

If I remember, will try and post some pics of my repair, so you can see the structure behind those areas.

Tim
Southern California - Where the stars are on the ground and dirt is in the sky

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Re: Question about patching rust on bottom of EM doors
Posted by: Dennis D ()
Date: September 06, 2011 10:48AM

Some photos to illustrate the process.

Dennis D.

Attachments:


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Re: Question about patching rust on bottom of EM doors
Posted by: corventure Dave ()
Date: September 06, 2011 11:45AM

This is what works for me...
I have found replacing metal with metal is the only way to go. Yes we deal with rust in Southers California!! Fillers will give out. Rust has to be cut and or sand blasted away.
Not having a wire feed welder, I have done many rust and panel repairs with a Oxy-Acetylene brazing torch. Have to be careful of heat load and practice stitch welding techniques, Use the smallest tip, but it works with the thick body panels on Corvairs. I do some grinding after welds but when possible... I primarely try to dimple the weld repair inwards. This makes a thicker stronger weld as opposed to grinding it flat. From there it is easy to fill and smooth the surface. Also dimpling the weld makes it impossible to have the welded area surface when doing final filling and smoothing.... always a pain when that happens.
The back area of the panel has to be cleaned after welding. I final wash it with a rust converter material and finally heavy coat with "Rust Destroyer" red oxide primer paint. I have had new rust spots appear but have never had one come back after this kind of repair. As for my Greenbrier... that has been 33 years.


Corventure Dave



Edited 1 time(s). Last edit at 09/06/2011 11:48AM by corventure Dave.

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Re: Question about patching rust on bottom of EM doors
Posted by: lgoodwin ()
Date: September 06, 2011 12:49PM

Great advice, guys! Thanks for the pics, Dennis. I now see what I will be dealing with. Tim, yes, please post pics--the more the better!

Dave, how the heck do you "dimple" a weld (with a wire-feed welder)??? I'd love to do that, but no idea HOW! Getting good current flow through both pieces can be quite a challenge. On the last job, I used a rail car lynch pin to help get good contact, nothing good to clamp to, as seat bolts were too too far away from work area and pretty rusty.

Making a seam sounds great, just not sure how I'd do that for these areas, with the material right behind the skin--looks like the gap is about one thickness, too little to get the seaming tool in place?

Since I'll be using Rust Bullet inside and outside, should I apply Rust Mort over the bare spots FIRST, or just apply the Rust Bullet directly onto the metal?
Have read claims that rust converters do not work. I've only used the Rust Mort for one project (battery support in my truck), not sure if it helped.

<table align='center' width='0'>
<tr>
<td><img src='[www.automation-scs.com]; alt='1962 Corvair 900 sedan' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1967 Corvair Monza 140/4-speed' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1968 Corvair 500 coupe' width='190' /></td>
<td><img src='[www.automation-scs.com]; alt='1983 Mexican Mustang 5.0' width='190' /></td>
<td><a href='[www.automation-scs.com&]; target='_blank'></a></td>
</tr>
<tr>
<td align='center'><font size='1'>1962 900 sedan needs a home</font></td>
<td align='center'><font size='1'>1967 Monza 140/4-spd</font></td>
<td align='center'><font size='1'>1968 500 coupe (now my son's)</font></td>
<td align='center'><font size='1'>1983 Mexican Mustang 5.0</font></td>
</tr>
</table>

Options: ReplyQuote
Re: Question about patching rust on bottom of EM doors
Posted by: aircooled ()
Date: September 06, 2011 01:15PM

You want to use the rust converter (diluted phosphoric acid I believe) to try to neutralize as much rust as possible, then put the POR type paint on. The POR type paints don't really kill the rust, they just cover it to keep it from spreading, so having the rust "killed" already is best.

Tim
Southern California - Where the stars are on the ground and dirt is in the sky

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Re: Question about patching rust on bottom of EM doors
Posted by: lgoodwin ()
Date: September 06, 2011 01:37PM

OK, I'll use the Rust Mort first. Thanks!

<table align='center' width='0'>
<tr>
<td><img src='[www.automation-scs.com]; alt='1962 Corvair 900 sedan' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1967 Corvair Monza 140/4-speed' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1968 Corvair 500 coupe' width='190' /></td>
<td><img src='[www.automation-scs.com]; alt='1983 Mexican Mustang 5.0' width='190' /></td>
<td><a href='[www.automation-scs.com&]; target='_blank'></a></td>
</tr>
<tr>
<td align='center'><font size='1'>1962 900 sedan needs a home</font></td>
<td align='center'><font size='1'>1967 Monza 140/4-spd</font></td>
<td align='center'><font size='1'>1968 500 coupe (now my son's)</font></td>
<td align='center'><font size='1'>1983 Mexican Mustang 5.0</font></td>
</tr>
</table>

Options: ReplyQuote
Re: Question about patching rust on bottom of EM doors
Posted by: cnicol ()
Date: September 06, 2011 02:12PM

Here's a flanged patch I made for the Rampside. The flanges make welding and subsequent grinding much easier and stronger. They also help with warping but you still have to be religious about stitch welding and allowing lots of cooling (as in weld a couple of kernels and go away for a few minutes, the amount of weld sites depending on the size of the patch). With a bigger patch you can weld a few more kernels here and a few more there before the panels start getting hot and you have to stop and walk away before things warp.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
65 Canadian Monza 4dr 110/PG 40k
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

Attachments:


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Re: Question about patching rust on bottom of EM doors
Posted by: aircooled ()
Date: September 06, 2011 08:44PM

Here are a few shots of my "issues". They have obviously been sand blasted, but you can see how close the metal is behind the holes. In my case the rust has obviously gone all the way through.





Tim
Southern California - Where the stars are on the ground and dirt is in the sky

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Re: Question about patching rust on bottom of EM doors
Posted by: corventure Dave ()
Date: September 07, 2011 08:38AM

lgoodwin Wrote:
-------------------------------------------------------
> Great advice, guys! Thanks for the pics, Dennis. I
> now see what I will be dealing with. Tim, yes,
> please post pics--the more the better!
>
> Dave, how the heck do you "dimple" a weld (with a
> wire-feed welder)??? I'd love to do that, but no
> idea HOW! Getting good current flow through both
> pieces can be quite a challenge. On the last job,
> I used a rail car lynch pin to help get good
> contact, nothing good to clamp to, as seat bolts
> were too too far away from work area and pretty
> rusty.
>
> Making a seam sounds great, just not sure how I'd
> do that for these areas, with the material right
> behind the skin--looks like the gap is about one
> thickness, too little to get the seaming tool in
> place?
>
> Since I'll be using Rust Bullet inside and
> outside, should I apply Rust Mort over the bare
> spots FIRST, or just apply the Rust Bullet
> directly onto the metal?
> Have read claims that rust converters do not work.
> I've only used the Rust Mort for one project
> (battery support in my truck), not sure if it
> helped.

Dimpling a weld has little to do with what kind of welder I use. The weld joint is higher than the face metal. By dimpling... I mean to tap the weld inward with a small body hammer and push it just below the surface of the panel metal, making the actual weld lower than the surface. Body smoothing with filler is a lot easier, without grinding away the joined surface at the weld.
Hope this explains it. Wish I could post pictures from this location.
Corvanture Dave

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Re: Question about patching rust on bottom of EM doors
Posted by: cnicol ()
Date: September 07, 2011 10:01AM

Spot welding with a Mig welder...

Use a gun shield with extended legs (or make some legs - 1/8" or so and attach to shield. Example

Side by side panels - hold gun perpendicular to surface with nozzle touching surfaces and wire aligned to seam (but not through gap, if any) - pull trigger for "X" seconds (1-2)

Overlaid panels - drill 1/8" hole in top surface. hold gun perpendicular to surface with nozzle touching surfaces. Align wire to center of hole. pull trigger for "X" seconds (1-2)

You will have to experiment with current and time but generally it will be more current than a regular weld (cold start). You want the weld to form a blended-in button - edges flow low rather than stand proud.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
65 Canadian Monza 4dr 110/PG 40k
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

Options: ReplyQuote
Re: Question about patching rust on bottom of EM doors
Posted by: lgoodwin ()
Date: September 07, 2011 12:24PM

corventure Dave Wrote:
-------------------------------------------------------
> Dimpling a weld has little to do with what kind of
> welder I use. The weld joint is higher than the
> face metal. By dimpling... I mean to tap the weld
> inward with a small body hammer and push it just
> below the surface of the panel metal, making the
> actual weld lower than the surface. Body smoothing
> with filler is a lot easier, without grinding away
> the joined surface at the weld.
> Hope this explains it.
Thanks, Dave. That explains perfectly. I had assumed the dimpling was achieved by using a specific welding technique during welding, not via a separate method after welding.

Which type of body hammer head do you use, pointy OR thin/square/flat (OR?), and do you back it up with anything?

I have the cheapo Harbor Freight body hammer set...

<table align='center' width='0'>
<tr>
<td><img src='[www.automation-scs.com]; alt='1962 Corvair 900 sedan' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1967 Corvair Monza 140/4-speed' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1968 Corvair 500 coupe' width='190' /></td>
<td><img src='[www.automation-scs.com]; alt='1983 Mexican Mustang 5.0' width='190' /></td>
<td><a href='[www.automation-scs.com&]; target='_blank'></a></td>
</tr>
<tr>
<td align='center'><font size='1'>1962 900 sedan needs a home</font></td>
<td align='center'><font size='1'>1967 Monza 140/4-spd</font></td>
<td align='center'><font size='1'>1968 500 coupe (now my son's)</font></td>
<td align='center'><font size='1'>1983 Mexican Mustang 5.0</font></td>
</tr>
</table>

Options: ReplyQuote
Re: Question about patching rust on bottom of EM doors
Posted by: lgoodwin ()
Date: September 07, 2011 12:48PM

Great job on the flanged patch, Craig! It's clear that the flanges increase rigidity. What brand/model tool did you use to make the flanges? I guess you do a very small section at a time to prevent warping the piece?

Seems like flanges have one down-side when you can't access the back of the work.
On the INSIDE of the repair, won't the exposed edges of the patch metal trap dirt and moisture? On the other hand, with a butt weld, there will be a rough surface on the back of the weld (in the form of beads and slag) anyway, so I guess it's a wash!

I looked into the door last night, and saw that the area to be repaired is not visible or very accessible from the inside without resorting to cutting the inside open. Any tips on this?

<table align='center' width='0'>
<tr>
<td><img src='[www.automation-scs.com]; alt='1962 Corvair 900 sedan' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1967 Corvair Monza 140/4-speed' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1968 Corvair 500 coupe' width='190' /></td>
<td><img src='[www.automation-scs.com]; alt='1983 Mexican Mustang 5.0' width='190' /></td>
<td><a href='[www.automation-scs.com&]; target='_blank'></a></td>
</tr>
<tr>
<td align='center'><font size='1'>1962 900 sedan needs a home</font></td>
<td align='center'><font size='1'>1967 Monza 140/4-spd</font></td>
<td align='center'><font size='1'>1968 500 coupe (now my son's)</font></td>
<td align='center'><font size='1'>1983 Mexican Mustang 5.0</font></td>
</tr>
</table>

Options: ReplyQuote
Re: Question about patching rust on bottom of EM doors
Posted by: lgoodwin ()
Date: September 07, 2011 12:54PM

Craig, do you have any pictures that show the welds you made and how you made them?
Did you spot weld using a MIG welder with a gun shield on it? Did you follow up by stitch welding the seams after securing the panel with the spot welds?

<table align='center' width='0'>
<tr>
<td><img src='[www.automation-scs.com]; alt='1962 Corvair 900 sedan' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1967 Corvair Monza 140/4-speed' width='190' /></td>
<td><img src='[corvaircenter.com]; alt='1968 Corvair 500 coupe' width='190' /></td>
<td><img src='[www.automation-scs.com]; alt='1983 Mexican Mustang 5.0' width='190' /></td>
<td><a href='[www.automation-scs.com&]; target='_blank'></a></td>
</tr>
<tr>
<td align='center'><font size='1'>1962 900 sedan needs a home</font></td>
<td align='center'><font size='1'>1967 Monza 140/4-spd</font></td>
<td align='center'><font size='1'>1968 500 coupe (now my son's)</font></td>
<td align='center'><font size='1'>1983 Mexican Mustang 5.0</font></td>
</tr>
</table>

Options: ReplyQuote
Re: Question about patching rust on bottom of EM doors
Posted by: richard1 ()
Date: September 07, 2011 04:06PM

Quote
I looked into the door last night, and saw that the area to be repaired is not visible or very accessible from the inside without resorting to cutting the inside open. Any tips on this?

That is why you can see the whole corner cut off mine, then patched and put back.

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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