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.

[JCHinCT]

Thanks for all the responses and the links to key threads. Some I had seen but others were new to me and exceedingly helpful. I really appreciate folks taking time to respond and provide advice.

I had removed the rear floor pan many years ago and thought my main focus would be installing a new back half, plus patching a couple of holes in the longs and the front trunk. This fall I was really focused on getting an old rotisserie up to snuff so I could mount the car and really go after the undercoating. I have become a bit discouraged in the past few days because on removing more undercoating, what I thought was surface rust has turned out to be rusted through holes. I think undercoating may be hiding a lot of ugliness. So I guess my job is going to be bigger than I thought. On the other hand, reading these "rustoration" threads suggests that with time and patience I'm going to be able to do this no matter how bad it is.

Chris - yes I picked up your door braces at your shop a couple weeks ago ... they look really solid. This coming week I'm lowering the car back on to jack stands to level it, put the doors back long enough to take key measurements, and then install the braces. I am absolutely determined to not only deal with the rust but to have a straight chassis when its done.