body and interior Rust prevention

[phano]

I've finally purchased a welder and have been getting some practice. I'll be replacing the rockers, quarter panel, and both fenders as well as patching some holes in the floor pan & in one of the shock towers. Paint isn't happening for a very long time and I'm concerned about rust prevention on everything old and new. The questions are below. Thanks in advance. 

 

I've read quite a bit about the use of POR-15 for rust prevention and think I understand that well enough. It either goes onto super rusty metal OR clean metal that has been treated with their metal prep, that's it right?

Is seam sealer needed on the the patch welds if I plan on covering them with POR15?

How should I proceed to treat the seams/welds on the rocker and quarter panel? The new rockers (inner/outer) and fender come primed already. At least I think it's primer. Can I weld these items or will I have to grind it off prior to welding? How do I protect my work? Any product endorsements welcome!

 

Oh, what kind of weld do you suggest to secure the new rockers? 

['76mintgrün'02]

Oooh, you are going to have so much fun!

I hope you'll share photos.

 

As for the Por 15 question, I don't think it works well on "super rusty metal".

You want to make sure there is no rust scale.  Air/moisture get trapped under there and spread under the paint and it will peel off like a thin sheet of plastic.  I believe in rust removal prior to their etching treatment/paint.

[cwlo]

The most durable work is getting it clean via blasting, wire wheel, or other means and then 2-3 coats of  a good epoxy primer.   Also, any metal prep or acid type treatment will need to be neutralized prior to epoxy.

 

Any welding will require the metal to be cleaned of rust, paint etc.. Also, sheet metal welding requires different techniques than heavier metal, as its very prone to warping.  Welding short dots, planishing, and then continuing is the preferred method to limit warping with a mig.  Tig isn't much different, and oxy/acetylene somewhat.  There's lots of info on the web.

 

Good luck,

 

Chris

 

 

[adawil2002]

Sounds like you're building a new car with all the panels, why not find a clean shell? Does this 2002 have sentimental value? 

[Saintz]

A fantastic alternative to POR-15 is KBS coatings. I have used KBS and the finish is more like ceramic than paint (stick to the instructions and use the two prep products). POR or KBS first then seam sealer over that, then paint over the seam sealer. As for welding, I went down your path 2 years ago. Don't weld on the car until you have had literally hours of practice on similar thickness scrap steel. Use the rust free areas of cast off pieces of the car, joining to new steel as practice pieces.

[phano]

2 hours ago, adawil2002 said:

Sounds like you're building a new car with all the panels, why not find a clean shell? Does this 2002 have sentimental value? 

This has absolutely no sentimental value. It probably wasn't the wisest of purchases but I saw it as a running project that I'd at least be able to drive here and there. I'm in NYC and clean shells are a little difficult to come by. That, coupled with minimal knowledge and the lack of garage space to take on such an endeavor, makes the idea of swapping for a clean shell seem impossible to me right now. 

 

2 hours ago, cwlo said:

The most durable work is getting it clean via blasting, wire wheel, or other means and then 2-3 coats of  a good epoxy primer.   Also, any metal prep or acid type treatment will need to be neutralized prior to epoxy.

 

Any welding will require the metal to be cleaned of rust, paint etc.. Also, sheet metal welding requires different techniques than heavier metal, as its very prone to warping.  Welding short dots, planishing, and then continuing is the preferred method to limit warping with a mig.  Tig isn't much different, and oxy/acetylene somewhat.  There's lots of info on the web.

 

Good luck,

 

Chris

 

 

How would you recommend going about stripping a brand new rocker panel for welding and protecting it after welding is done?

 

3 hours ago, '76Mintgrun'02 said:

Oooh, you are going to have so much fun!

I hope you'll share photos.

 

 

I will definitely share photos of my progress.

 

Thank you all for your answers.

[adawil2002]

http://losangeles.craigslist.org/sgv/cto/5811723405.html

[Neildo11]

I'm getting ready to tackle a bunch of sheetmetal repairs and filling unwanted trim holes. I'm going to use eastwoods 2 part epoxy primer in an aerosol can to seal prime all the bare metal, I've read that you can throw the can in the freezer to stop the catalyst process so you can do a little at a time... We'll see how that goes, I hope it works. 

[cwlo]

A lot of the replacement metal is primed with an e-coat that comes right off with acetone.  On a rocker, you are mostly just plug welding, so you would really just need to sand a little off at the holes that are drilled before plug welding it.  That said, on a top quality restoration, the whole panel would be stripped, and then re-primed with an epoxy primer, as it is much more durable than the coating most metal comes with.  Then minimal stripping of primer where the plug welds will be.    Finally, once installed, you can flood the seam with some epoxy primer through the few holes on the inside. 

 

Bottom line, there are different levels of preparation and finishing.  Considering most 02's nowadays will never again see snow, salt, and little rain, even a more limited preparation will probably last quite a long time.  Chose the level of durability you want.

 

Chris

 

[TobyB]

Check your new panel.  Some are covered with a rust- retardant covering that comes right off.

Others are painted with a primer that scuffs right down to bare metal with 220 grit paper.

Others are nicely epoxy primed for your enjoyment.

 

My opinion, and it's just based on how I've done things that have worked-

remove ALL the rust- grind, sand, use the 3M strippy pads.  If you can spot-

blast with media, that's pretty much the ideal. 

Your welder will not weld through anything at all, so you need shiny metal for it.

You need an angle grinder with both grinding wheels and sanding discs, and a pneumatic slitting saw and about 100 wheels for it. 

You can buy both at Harbor Freight, Lowes, or The Sharper Image.  No, I lie about the third.  The Snap-On truck, then.  Or anywhere in- between.

Then line the panels up and start doing the bodywork to make them fit because

they will not fit right the first time.

They will not fit right the second time.

You may be happy with the first one you fit on the third pass,

but by the time you've fitted the last, you'll want to refit the first, because you can now see how to improve its fit.

 

So do all your cleaning, fit them up, tack them in place, and move on.

Then come back and make sure you agree.  And make sure you fit them to the doors, the hood, even the light bezels and grilles.

 

Seam sealer is for seams where 2 panels overlap.  So if you flange your repairs

(which I have personally had trouble with) yes, seal the back with it.

If you butt- weld, yeah, you CAN seal the back of it, but you don't have to.

What you DO have to do is coat the back of EVERYTHING you weld.  Epoxy primer works just fine.

As does Waxoyl or other (ewww) body cavity wax.  I used one by 3M, and 15 years later, nothing's perforated.

(yes, even inside the rockers.  They make long nozzles for that.  Yes, you have to use them)

 

As to surface finishes, make a friend at the least- hated autobody supply place

you can find, and buy your materials there.  Since this is your first time at it.

Yes, there are cheaper places closer to the border, but first time out, you need somewhere you

can walk in and say, "When I do this, this happens instead of what I wanted"  and while they may laugh at you,

they'll replace the jet in your gun, the hardener that's bad, or show you how to use the needle scaler that's not working.

Specifics- a phosphate- based etch wash, an epoxy primer over that.  It works, it works well, and it lasts

IF it's not exposed to sunlight.

 

After that, the paint of your choice, but for the first time, just give in, spend the money, and buy the same

system as the primer.  The supply store will upsell you- but you WILL get something that will work.

And personally, I just can't see saving $3-500 on paint after I've spend the thousands of dollars

and the hundreds of hours getting everything ELSE right.

 

hth,

 

t

 

Edited October 6, 2016 by TobyB

[vacca rabite]

17 hours ago, '76Mintgrun'02 said:

As for the Por 15 question, I don't think it works well on "super rusty metal".

You want to make sure there is no rust scale.  Air/moisture get trapped under there and spread under the paint and it will peel off like a thin sheet of plastic.  I believe in rust removal prior to their etching treatment/paint.

I have used POR15, and it mostly works.  But as '76 said, it DOES NOT work on rust scale.

In fact, you do have to get most of the rust off whatever you are coating.

I did an experiment a few years back with some POR15  and a rusty punched tin lantern I had.  I cleaned it, degreased it, and knocked off the scale but did not try to remove other rust.  I painted on the POR15 following their instructions and it was peeling off less then a year later.  

 

It works great on metal that used to be rusty, but has had the rust removed.  It works well on clean surface flash rust.  It works well on new steel that has been etched.  But it will fail on metal that has any rust scale or metal that has rust that is "toothy" enough for any small air pockets to exist after you lay down the POR15.

 

Zach