MGB Repaint

austincooper

Promoted Users
Hello: I am restoring a 1976 MGB. Rust-free dent free example (surface rust on floor). Engine out. Body work is starting in May. Plan to use SPI epoxy primer as much as possible for blocking and use G2 where needed but not everywhere, Seal in SPI epoxy primer and then finally single stage urethane. Before that can happen, I am at a decision point regarding paint removal. The original weird yellow looks to be very much intact, but the red respray is chipping and cracking. Options are to media blast the car to bare metal, or to try to mechanically or chemically remove the red layer. I see advantages to leaving the original base coat in place if possible. Any thoughts as to methods to try to remove the inferior red layer without taking out the quality original base layer? Thank you.
 

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If that’s the original yellow it’s going to be the 70s era single stage paint like enamel or lacquer. That’s not what you want as the base layer under new paint and might be part of the reason the red isn’t holding up. If you use a DA like Barry recommended it would only take a little more time to sand down to bare metal.
 
I've used these on several cars. They last a long time.

Stay away from the harbor freight ones. They are junk.
 
Typically if this is done as time permits, is it better to properly epoxy prime each panel as you go, or put on a temp rattle can coating?
 
Typically if this is done as time permits, is it better to properly epoxy prime each panel as you go, or put on a temp rattle can coating?
I wouldn't rattle can them. You'll just have to sand if off. You don't want that paint on your car.
As long as the car is inside a garage or shop, you can wait and do it all at once.

Mixing epoxy for a panel or two at a time ends up wasting more material. Plus time to induce, clean the gun etc.

It can be helpful to think 2 or 3 steps down the road.

What is after the epoxy? 2K, filler, etc ?

Knowing that can help with timing.
For example, if 2K is next, after you shoot epoxy, you have 7 days to shoot the 2K, without having to scuff with 180. Saves a couple hours.
 
I wouldn't rattle can them. You'll just have to sand if off. You don't want that paint on your car.
As long as the car is inside a garage or shop, you can wait and do it all at once.

Mixing epoxy for a panel or two at a time ends up wasting more material. Plus time to induce, clean the gun etc.

It can be helpful to think 2 or 3 steps down the road.

What is after the epoxy? 2K, filler, etc ?

Knowing that can help with timing.
For example, if 2K is next, after you shoot epoxy, you have 7 days to shoot the 2K, without having to scuff with 180. Saves a couple hours.
Thanks Dean:
I may change the plan after seeing bare metal, but since the body work seems minimal (no dents, no rust, and I don't "hear" any bondo under the existing paint), and I'd like to avoid iso's until the color step, I am planning blocking and building using SPI epoxy (no 2K primer) and use G2 or Slick sand where needed, sealing with reduced epoxy primer, then on to single-stage British Racing Green. I have read about some experienced painters on this forum blocking with epoxy primer, so I'd like to go down that path if possible. Does sound reasonable to you?

I want to get a process down that I can use beyond this car as I have a number of autos I have accumulated over the years that I have held onto until I have time.... a 1960 Mercedes Benz 190SL that I bought from a used car lot in 1975 for $225.00 when I was 20 (I'm 67), and has been dry stored ever since. Also 1 1984 Jeep CJ7 that came off the road in 1997 and is all stock-original.
 
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Here is another tip. Write down how much material you mix and use on each panel and this way you know how much to mix next time. If say you use 4 ounces on driver door per coat then you will know about same amount for other side. Saves material for something else.
 
Thanks Dean:
I may change the plan after seeing bare metal, but since the body work seems minimal (no dents, no rust, and I don't "hear" any bondo under the existing paint), and I'd like to avoid iso's until the color step, I am planning blocking and building using SPI epoxy (no 2K primer) and use G2 or Slick sand where needed, sealing with reduced epoxy primer, then on to single-stage British Racing Green. I have read about some experienced painters on this forum blocking with epoxy primer, so I'd like to go down that path if possible. Does sound reasonable to you?
Very reasonable to only use epoxy for blocking. Many do that.
If the car is in good shape, why G2 or Slick sand? It is intended for panels that need a lot of leveling.
If there are just some spots that need work, I would use a quality filler like Rage Ultra.
 
Very reasonable to only use epoxy for blocking. Many do that.
If the car is in good shape, why G2 or Slick sand? It is intended for panels that need a lot of leveling.
If there are just some spots that need work, I would use a quality filler like Rage Ultra.
Dean you are right. I was referring to a panel that was problematic overall (which I don't expect). Yes, I expect to use rage filler for spots. Thanks again.
 
Thanks for the guidance. I am going with Barry/Chris' DA/grind approach. I was going to have the removable panels sent out for media blast and sand the rest of the car to bare metal. Now I intend to DA/grind the whole car. One area I haven't figured out: What would you do about the inside of the doors (attached pic), which still have the original factory paint on them. I don't know how I can get to bare metal there, especially on the back side of the panel. Being a heavily modified MGB I'm not worried about doing it "correctly". I just want good adhesion and corrosion prevention. What do you all recommend?
 

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The fastest way is to media blast. The slow way is to use 3m cookie disc's on a die grinder, an assortment of wire brushes on a drill or die grinder etc. Hand sanding in places as well.. Slow and labor intensive.
 
What would you do about the inside of the doors (attached pic), which still have the original factory paint on them. I don't know how I can get to bare metal there, especially on the back side of the panel. Being a heavily modified MGB I'm not worried about doing it "correctly". I just want good adhesion and corrosion prevention. What do you all recommend?
Makes sense to get to bare metal for everything that is getting repainted, all the visible surfaces.

In your initial post you described the car as rust free. If the inside of the door panels (not visible) are truly rust free after 46 years, I would just leave them alone.
 
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