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General discussions about modeling topics.
horrible pigment clumps to airbrush
Mrclark7
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Posted: Tuesday, September 01, 2020 - 05:43 AM UTC
Wanted to post this as a FYI mainly. I dont want to slam the brand as maybe this is a an issue from somewhere in the supply chain. This is happening to a major portion of my 17ml and 200ml size bottles. I have well over 125 bottles all bought from the same store of the last two years. Bottles purchased in the last month are also having this issue. I would say over 50% of my paints have this issue.

Long story short, I would highly recommend straining your paints even if just using a small amount in the airbrush. I drove myself nuts for months wondering why my brush was acting so different many times.





Scarred
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Posted: Tuesday, September 01, 2020 - 06:36 AM UTC
Are you shaking or agitating your paint?
Mrclark7
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Posted: Tuesday, September 01, 2020 - 01:22 PM UTC

Quoted Text

Are you shaking or agitating your paint?



yes, done with using a shaker. The clumps are dried paint, and are in new and old stock from the hobby store. Straining works, but might switch to a different brand every time I run out of a color. I have a brand I will switch to. But I dont want this to be about being pro or con on any brand.
Scarred
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Posted: Tuesday, September 01, 2020 - 04:06 PM UTC

Quoted Text


Quoted Text

Are you shaking or agitating your paint?



yes, done with using a shaker. The clumps are dried paint, and are in new and old stock from the hobby store. Straining works, but might switch to a different brand every time I run out of a color. I have a brand I will switch to. But I dont want this to be about being pro or con on any brand.



Everyone has different opinions about different brands. What brand are you see this issues with? I use Vallejo, Ammo, some Tamiya.

I also put agitators in my bottles. Stainless steel balls, little tiny rocks in a pinch (don't laugh it works and they're free). I'm down to my last strap for my shaker I've got to order some new ones. The last batch I got were old and you could feel they were dry and cracked.
Kevlar06
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Posted: Wednesday, September 02, 2020 - 05:28 AM UTC
Kelly—It’s almost impossible to diagnose a problem without knowing a brand, and the conditions under which it was stored, wether carrier was added, etc. Almost every brand of paint has suffered from bad batches occasionally, but it could also be because of the way it was stored. Temperature could have something to do with it, as well as length of time from manufacture to use. Unfortunately, paint is not an item that gets better over time.

Patrick— if you’re talking about the rubber band with holes in it that comes with the Robart paint shaker, I dispensed with mine years ago. Instead I use a wide rubber band tied with a knot at the appropriate place which works beautifully, is almost unlimited in supply— and much cheaper.
VR, Russ
Scarred
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Posted: Wednesday, September 02, 2020 - 06:58 AM UTC
Good idea. Don't know why I didn't think of that. My first Robarts I got decades ago, DC powered but I never replaced a strap. Sadly it didn't survive the house fire of 07 so I had to replace it. The new one seems a bit flimsy compared to the old DC version.
Mrclark7
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Posted: Wednesday, September 02, 2020 - 08:06 AM UTC
I reread my original post and probably should have said airbrush instead of just brush when talking about the caused issue.

To be more precise, I use a modified saws all with a blade attached to a pill bottle to do my paint shaking. I had a winter with the paint stored in the garage the first year. But I have had the same issue with bottle bought after that time. I used daisy 3/8 slingshot ammo the first year. So I thought maybe the type of steel was an issue? The paint would clump to the ball bad. But again, stopped using them a year ago and still happening. The little fragments in some bottle were so small in some paints that without straining I would never had known. however this caused me so much airbrush frustration that I was changing compressors, airbrushes, filters. Until I started straining.

So about 90% of my paint is Vallejo air. But this happens really bad with Vallejo primer paints the most. From this source. Both black and white have been extremely bad. The pics are Vallejo black primer 200ml. Not having this issue with Vallejo model color from hobby lobby. I might switch over to Mission models. But my paint racks fit 17ml bottles. I also have some tamiya and have had no issues.

None of my bottle are more than 3 years old. All are stored in home temperature controlled now.

Anyway, where I went wrong is just assuming all purchased paint is good and ready to go in the airbrush. Just saying, strain it and you might be surprised.
Kevlar06
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Posted: Wednesday, September 02, 2020 - 09:22 AM UTC
Kelly,
Temperature, age, and a bad paint lot are usually to blame for paint failures like you are experiencing. However, there are other factors, and primarily it’s what we add to the paint that changes the chemical balance in it. Normally, we modelers think nothing of dropping a few bb’s into paint as an agitator. However, not all bb’s or ball bearings are equal. There was a thread here at Kitmaker about this a few months ago, I can’t remember where now. Unless you’re using stainless ball bearings, the chemical leaching of copper, lead, or zinc can indeed interfere with the properties of the paint. Not saying that’s the problem here, just commenting that it could be.

I don’t use any agitators in water based paints, and use only a few in hydrocarbon based paint. In fact, the only place I use stainless ball bearings is in Alclad primer. For years, I’ve used a stir stick and a Robart paint shaker, and that’s all to agitate my paints. I have paint going back 25 years that’s still good, but on the other hand I have paint that’s only a few years old that’s solidified at the bottom of the jar (Testors Model Master mainly, but also some Humbrol). My Vallejo, Tamiya and Mr. Hobby have held up well over several years as long as all the lids are cleaned and sealed properly, otherwise, I’ve had a few issues with dried out paint jars.

Not to suggest any of this is your issue with Vallejo paint, but generally speaking, it might be a combination of any of these things.
VR, Russ
Vicious
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Posted: Wednesday, September 02, 2020 - 01:37 PM UTC
about the "agitators" not all stainless steel is equal,i buy only 316 Marine grade Stainless steel,it is resistant to sea salt but also to various Acid and other corrosive agents unlike other lower grades,some stainless steel corrode after some time in the Acrylics like Vallejo...dont ask me how i know that...

Probably the best is Glass marble like Mission Models and Createx use in there paints,Glass is always the most stable material...
Scarred
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Posted: Wednesday, September 02, 2020 - 11:03 PM UTC
Ammo is putting agitators in some of their paints at the factory. On their site they sell stainless steel agitators: https://www.migjimenez.com/en/accessories/347-stainless-steel-paint-mixers.html

Don't use BB's and if in doubt put the bearing or what ever you are using in a bit of salt water for a few days. If it doesn't rust or come apart you're good to go. So soak your slingshot ammo in some salt water to test it. I have a feeling that they'll rust.

I've read, and I've been trying to find the article, that acrylics that got too cold could suffer issues like you are having. Perhaps your paint froze in the garage or while they were being warehouse after manufacturing. Some things are shipped by air in unheated holds.

Also your paint could be old. Old stock shouldn't be sold but there are a lot of unscrupulous retailers out there.

Don't laugh but I've used small rocks and aquarium glass and gravel in a pinch as agitators. I just washed them really good and let them dry thoroughly by putting them in the oven for about 10-20 minutes at 200 degrees.
SSGToms
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Posted: Thursday, September 03, 2020 - 03:09 AM UTC
If a true acrylic (water based) gets below 35 degrees F., it's FUBAR. Dead. Unusable and not coming back. Throw it out. If you open a bottle and it has clumping or rubbery texture and will not mix, somewhere along the line to you it was subjected to sub-35F temperatures.
varanusk
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ARMORAMA
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Posted: Thursday, September 03, 2020 - 07:40 AM UTC
I agree about the agitators must be 316 Marine grade Stainless steel, easy to get on eBay or Aliexpress, otherwise they may rust.
Also have heard about very low temperatures affecting the paint.

I have some Model Air bottles well over 10 years (and others from last month) and all work fine.
Vicious
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Posted: Thursday, September 03, 2020 - 09:05 AM UTC
the paint no,but the Mission Model Poly also high temperature turn the stuff in to something like PVA glue
SSGToms
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Posted: Thursday, September 03, 2020 - 11:52 PM UTC

Quoted Text

the paint no,but the Mission Model Poly also high temperature turn the stuff in to something like PVA glue


A guy just posted on the Painting Forum with this exact problem. Temperatures in the back of a UPS truck or on a front doorstep can easily reach over 100F...
Vicious
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Posted: Friday, September 04, 2020 - 10:11 AM UTC

Quoted Text


Quoted Text

the paint no,but the Mission Model Poly also high temperature turn the stuff in to something like PVA glue


A guy just posted on the Painting Forum with this exact problem. Temperatures in the back of a UPS truck or on a front doorstep can easily reach over 100F...



Yep...i love MMP,the paint and the mathematical system to mix it,but the poly is very susceptible to light and both high and low temperatures.

Because is the same thing of Createx 4030 balancing clear,Createx have a sheet of Technical data and say to store in dry place between 40-80°F (4.5-26.5°C) and away from light...i live at the Tropics,nice hot and humid,now i store it in the beer fridge at 45.5°F (7.5°C) and see if hold or goes pear shapes again
Mrclark7
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Posted: Friday, September 04, 2020 - 01:22 PM UTC
wow, okay lots of good info going on here.

i do want to say I am not trying to slam vallejo. I still use and will use all of what I have from them. Although I have thrown some away because of to much decay going on in them from the ball bearing issue.

Obviously most paint booth guys filter all the paints they use before shooting. not sure why I took it for granted and assumed I didnt have to. Looking back, just the way the paint drys around the tip of the 17ml bottles just screams future clog issues, but my bad.

This issue killed three iwata neo brushes for me. Again my bad. But if you ever have had this happen to you you know how seriously small the tiny little rubber balls get. They are smaller than the screen in the pics alot of the time. man this really made me dread paint time. It was sucking all the enjoyment out of the hobby. Now that its figured out, I am building like crazy.

Russ- I will be looking into getting that paint shaker soon.

Vicious-after this issue I am afraid of any ball because of the wondering of paint clinging to it.

Patrick- I wouldnt be surprised if I did kill off some of them when they were in the garage. There might have been one or two days below freezing overnight.

Matthew- all of what you said I agree with also.
Vicious
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Posted: Friday, September 04, 2020 - 02:03 PM UTC
There’s filters a lot better then that one ,you can find them in shops for professional airbrush ,they are pretty cheap,Vallejo over time they tend to sediment like sludge/mud of pigment on the bottom I put bearings ball in all my paints but at the meantime I use a electric stirrer,the ball just help the stirrer or shaker do the job...clearly works also without
Scarred
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Posted: Friday, September 04, 2020 - 02:28 PM UTC
One other thing. Regarding the paints and additives. Over the years I learned that paint manufacturers started to make their paints proprietary. You used to be able to thing Testors with any paint thinner. But when model masters came out I started having issues doing that. Plus I was overseas and getting thinners from different countries. Some of those thinners were hot and melted the plastic of the kit, caused the pigment in the paint to separate from the carrier liquid. Or the thinners went the other way and weren't strong enough to thin the pain and it caused the pigment to turn into a blob.

Acrylics seem to be more temperamental. I use Vallejo paints with Vallejo additives and thinners. Same with Ammo of Mig and AK. I don't mix products as it has cause problems. I like to remove any variable that could cause problems.