Hello,

So I recently painted my MGA body and body parts. I used acrylic lacquer, single stage, no clear coat, like it was originally. My painting skills, if you can call then that, are amateur as I have not painted a car in 40 years, a little rusty. I put four coats of base on and ended-up with some orange peel but not too bad, only had two very small runs. I started to wet sand with 1000 grit and things were going well until I sanded through to the primer. This has occurred on all but one body part so far, in just one or two very small spots. So I will need to re-spray the base coat to complete the job. I have completed the wet sanding with 1500 grit and will wait until after the re-spray to complete the 2000 grit sanding. I am looking for advise on how to proceed with spraying these small spots? I would like to minimize over-spray to avoid the need for too much more sanding and more possible sand through. Do I mask off what has already been sanded or just try to minimize the area that I spray?

Thanks
Jack

I'm not a lacquer guy myself but 4 coats doesn't sound like enough to me.

Acrylic, which you call lacquer, is very forgiving, but also very low in solids. That means it needs more coats to get the Dry Film Thickness that is required.

I'd normally put on 4 coats with a 1.3mm or 1.4mm RP gun, then allow to dry and lightly sand - just to get the worst of the problems out. Even with 4 coats I'd be sanding quite gently and really watching my progress. I'd do that with P1200.

Then take back in the booth and spray another 3-4 coats. The number of coats depend on the quality of the paint - I use Axalta Cromax L400 and thin 1:1 for solid colours; 1:1.5 for metallics, but metallics get clear over the top so 2-3 coats, with no sanding, is sufficient. Each coat should be an even, medium wet coat and make sure you allow to flash well. Thinner should be the slowest you can get - I use retarder to slow even further.

Allow a few days at a minimum, even a couple of weeks, before wet sanding and, even then, go easy. I usually use P1500 wet, resorting to P1200 only for problem areas.

For your rub throughs, 3 coats just on the rubbed through area, extending out a little further on each coat. Allow to thoroughly dry and prep, as above, for your second major session.

The paint is actually acrylic lacquer, the original was nitrocellulose lacquer which is no longer available. The four coats is likely marginal as pointed out. I also believe my coats were thinner in some harder to reach areas, and having to sand the orange peel out does not help the situation. I do sand lightly and check my progress often. I start with a 1000 grit but now also move-on to 1500 sooner. I am now also going easier close to the edges. I only have a pint of paint remaining so I will not be doing a complete re-spray. The main body, painted separately, got five coats. So with more paint and a lot of sanding practice behind me I am hoping it will go better. All in all I am very happy so far. The body works looks very good, and with a little extra paint work it should look nice. I'll post a picture once complete and reassembled.

Thanks!
Jack

jackinvt wrote:Hello,

So I recently painted my MGA body and body parts. I used acrylic lacquer, single stage, no clear coat, like it was originally. My painting skills, if you can call then that, are amateur as I have not painted a car in 40 years, a little rusty. I put four coats of base on and ended-up with some orange peel but not too bad, only had two very small runs. I started to wet sand with 1000 grit and things were going well until I sanded through to the primer. This has occurred on all but one body part so far, in just one or two very small spots. So I will need to re-spray the base coat to complete the job. I have completed the wet sanding with 1500 grit and will wait until after the re-spray to complete the 2000 grit sanding. I am looking for advise on how to proceed with spraying these small spots? I would like to minimize over-spray to avoid the need for too much more sanding and more possible sand through. Do I mask off what has already been sanded or just try to minimize the area that I spray?

Thanks
Jack

When dealing with small spots that need to be resprayed, there are a few steps you can take to minimize overspray and avoid further sanding or potential sand-through. Here's a suggested approach:

Mask off the surrounding area: To minimize overspray, it's best to mask off the area around the spot that needs to be resprayed. You can use painter's tape and plastic sheeting to cover the rest of the body part and any adjacent surfaces you want to protect.

Feather the edges: Use a fine-grit sandpaper (such as 1500 or 2000 grit) to feather the edges around the spot where you sanded through to the primer. This will help create a smooth transition between the existing base coat and the resprayed area.

Clean the surface: Before applying the new base coat, make sure the surface is clean and free of dust or debris. Use a clean cloth and a suitable automotive surface cleaner or wax and grease remover to wipe down the area.

Apply the base coat: Shake the can or mix the base coat according to the manufacturer's instructions. Spray a light, even coat of base coat over the sanded-through area, making sure to blend it smoothly with the existing base coat. It's better to start with a lighter coat and apply additional coats as needed, rather than trying to cover the spot completely with one heavy coat.

Allow proper drying time: Follow the manufacturer's recommendations for drying time between coats. It's essential to give the base coat enough time to dry properly before proceeding with further sanding or applying additional coats.

Inspect and repeat if necessary: After the base coat has dried, inspect the resprayed area to see if it blends well with the rest of the body part. If necessary, you can repeat the process by applying another light coat of base coat to further blend the spot.

Lacquer is very different from modern paints, so there's a few things you need to know. 4 coats is not enough, esp. if you are going to sand and buff. 6-8 is what I used to do, minimally, often I would sand and put more on later, letting the paint shrink up.
Overspray should not be a problem with lacquer. Use a slower thinner, and you can even spray a light coat of slow thinner only over the repair area (or the edges of it, if it is large). It will melt in any overspray, that's one of the beauties of using lacquer. Easy to blend!
Just be sure you use the proper thinner for the temperature (except for the blending part), and don't spray it when it's humid or raining.

tip on sanding runs:
spread some lightweight filler over the run and out a bit. that way when sanding the run you will only be sanding on the run.