Starting a restoration project Options

[JCHinCT]

I am starting restoration work on the first car I owned, a 1975 2.0L that I bought in 1979. Though it hasn't run since the mid 1980s. I finally got the car on a rotisserie, and I've just started a long slog to get the undercoating and seam sealer off.

I would appreciate some advice re metal prep. My plan is to eventually have the car media blasted prior to priming and finish paint. But in the near term I plan to attack each structural rust patch, and one-by-one weld in new metal, then hit each with some kind of primer. The goal is to protect each fixed patch temporarily while I go on to the next one. And since this process might take a long time, many months, I need to protect against encouraging rust on the newly patched zones. Only after I think I've got all the patch welds done will I take it for media blasting down to bare metal all over, prior to finish painting.

So here are a few questions:
- is there any concern about the type of temporary primer I use while the car is piecemeal patch welded? Or is it better to use some zinc or phosphate coating instead of temporary primer?
- I do not have a paint shop lined up yet. Is it advisable to find a shop that wants the job, and ensure I'm using a suface prep that is agreeable to the planned paint system? Or can that be dialed in just before media blasting? (I’m worried a reputable paint shop won’t want to deal with a car that they haven’t controlled through the media blasting phase.)
- any advice on getting inside the longitudinals to try to remove interior surface rust, and treat it, without actually cutting and opening the longs up? (I think a dumb question but thought I'd throw it out there anyway)
- similar question: after 15 minutes of shop-vacuuming, I think I see mild surface rust under the headlight buckets ... how do you get in there and deal with it properly?
- regarding sheet metal for the weld patches: I plan on 18 gage for structural areas, and 16 for non-structural ... but plain old low carbon steel? or should one aim for something with a rust-preventative coating on it - even though it needs to be MIG welded?
- I found some horrible rust in the front trunk compartment, under the seam sealer on the driver's side. Rusted through, with a couple of index-finger-sized holes. Obviously, this needs to be totally removed and creative weld-in patches made. However, in other places the seam sealer looks really solid with no sign of the "rust-crunch" sound underneath. Option 1: just leave the “good” seam sealer, and later media blast it and paint over it. Option 2: dig it out even though its probably fine, assess the metal underneath, and then later apply more seam sealer over it before painting? What do you think? This is especially a question at the rear shock towers, that seem almost like they're new and almost certainly rust free (though, how really can one tell without digging in?)

Thx in advance.

[Dlee6205]

"is there any concern about the type of temporary primer I use while the car is piecemeal patch welded? Or is it better to use some zinc or phosphate coating instead of temporary primer?"

-I would use cheap rattle can primer for any surface that will be blasted. For any areas that will be covered up, I like to epoxy primer before welding. Under the battery tray and mount is one area I like to prime before welding those on. Anytime I have the long open, I try to clean up as much surface rust as I can and hit it with epoxy. primer.

"I do not have a paint shop lined up yet. Is it advisable to find a shop that wants the job, and ensure I'm using a suface prep that is agreeable to the planned paint system? Or can that be dialed in just before media blasting? (I’m worried a reputable paint shop won’t want to deal with a car that they haven’t controlled through the media blasting phase.)"

-Anytime I've had cars blasted, it's been at the body shop so it can be controlled by them. i.e. as soon as it gets blasted, they can roll it in and prime. Some shops are comfortable (with their paint system) priming over a blasted surface, some prefer to knock down the texture of the blasted surface before priming. Some shops still do their filler work before priming, some will epoxy prime the whole car and then begin the filler work.

"any advice on getting inside the longitudinals to try to remove interior surface rust, and treat it, without actually cutting and opening the longs up? (I think a dumb question but thought I'd throw it out there anyway)"

-I've used products like Ospho with some success to try to convert the rust inside of the long if I don't have full access. If I have a small section of the long open for repairs, I can spray some in there followed by a cavity coating like Eastwood's Internal frame coating or a cavity wax. Even if I don't use an acid to convert the rust, I still use the cavity coatings on all my repairs.

"similar question: after 15 minutes of shop-vacuuming, I think I see mild surface rust under the headlight buckets ... how do you get in there and deal with it properly?"

-Seems like blasting will take care of most of that?

"regarding sheet metal for the weld patches: I plan on 18 gage for structural areas, and 16 for non-structural ... but plain old low carbon steel? or should one aim for something with a rust-preventative coating on it - even though it needs to be MIG welded?"

-You meant 16ga for structural and 18ga for non-structural, right? You can use plain carbon steel or try to find galvanneal panels for repairs. As always though, do you research and weld in a well ventilated area. A lot of repair panels available are galvanneal and are more resistant to rusting.

"I found some horrible rust in the front trunk compartment, under the seam sealer on the driver's side. Rusted through, with a couple of index-finger-sized holes. Obviously, this needs to be totally removed and creative weld-in patches made. However, in other places the seam sealer looks really solid with no sign of the "rust-crunch" sound underneath. Option 1: just leave the “good” seam sealer, and later media blast it and paint over it. Option 2: dig it out even though it's probably fine, assess the metal underneath, and then later apply more seam sealer over it before painting? What do you think? This is especially a question at the rear shock towers, that seem almost like they're new and almost certainly rust free (though, how really can one tell without digging in?)"

-Rust is very common under the seam sealer but it's not under all the seam sealer. I suggest removing any questionable areas until no rust is found and stop. Rear shock towers are a great example, very rarely will there by rust under there so not really a need to remove ALL seam sealer unless you're just adamant. BTW I like to use a textured seam sealer to match the factory stuff for any spot repairs.