Painting a bio disaster

[MeanGene]

We all learn.

Sometimes from others.

Sometimes the hard way.

 

Today I learned the hard way.

I got this P1 with plans to make I a movie accurate version. 

Story goes as follows.

1. Months ago, primed it with Rust-Oleum automotive primer.

Primer dried. But the primer cracked horrifically. Like a dry lake bed.

I blamed my prep work and body filler.

The cracking was frustrating so the project sat on the healing bench till this week. Wanted to get it on my wall.

 

2. Took the helmet off the shelf.

Sanded ALL the cracking away. Got it smooth. Ready for paint.

3. Painted with the same primer.

Got the same result. River bed cracking! Ffs.

 

Friends informed me that old cans of primer can gas off the solvent. When the solvent is reduced in the van the paint dries too fast. Making cracks.

So... The lesson learned.

Check the date on your cans before using them. Mine was 2019.

Cracked primer. FML

 

all the sanding done prior to paint.

 

 

[NeoKazama]

Great info Gene. I would add up that using an adhesion promoter after the primer would help the paint stick to the surface.

[MeanGene]

 

This was mentioned to me. 

[PredatoRob]

With the helmets I've painted in the past, I've used some form of automotive bonding primer. I've never heard of a reduced solvent aerosol, or how having reduced solvents would make the paint itself dry faster (that's why the solvents are there - to speed up the dry time) - apparently at a Superman rate. I've never used an adhesion promoter when painting a helmet - just primer and the basecoat. Is your shop too cold? Low temperatures will cause paint to kind of shrink up and recede - resulting in wrinkles and cracks in the finish. You know, kind of like your balls on a cold day... without the cracking part.  Also, storage of the cans is a factor. I keep mine indoors instead of the garage which can get down to freezing temps.

Edited November 23, 2022 by PredatoRob

[MeanGene]

Thanks Rob.

My site conditions were the following. Warm summer. Normal humidity levels. Cans stored inside.

Best I can tell the paint was just super old.

 

Only other thing that may have caused issue was using some wood filler as pictured below.

 

[PredatoRob]

The wood filler could play a part in this and I wouldn't write it off. Or, like you said, the aerosols were just old - and old spray paint can do goofy and most unwanted things. I've got a "test" bio that I used to test out different colors and such, and I used 3M Spot Putty (basically a not-as-toxic bondo) and some plumbers epoxy along with other sculptable, hobby epoxies (milliput, etc) and I never had a problem with contamination. I have a hundred different reasons why that happened running through my head right now, and I can't focus on just one. 

How did you clean it before you shot the primer?

[MeanGene]

I cleaned it with rubbing alcohol and paper towels.

[Blue Scorpion]

Personally, I think the cracking is pretty effective and I can confirm that wood filler will cause it to crack as I did the same on mine, I used a watery wood filler mix to cover the top of my helm and left it outside in the sun to dry, when I came back it was cracked to hell.  When I started to rub it down the natural cracks looked pretty good.

The cracks are natural and trying to create such natural cracks on purpose would be really tricky so I decided to keep them.

[MeanGene]

Thanks for confirming what I experienced. It was maddening.

Lesson learned.

But also a positive.. if I want a cracked earth bio "look" all I have to do is use that filler.

Next time. Gonna use traditional Bondo. Just hate the stink of it.

Do you have pics of the cracking on your bio?

[Chopperf]

Same happened to me on some Halo armor for my son. It was indeed from old paint. I resanded it down and resprayed with same brand and all was good.