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"Is self-etching primer the same as acid-etch primer?" Topic


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752 hits since 31 Mar 2018
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Baranovich31 Mar 2018 6:06 a.m. PST

Following up a thread about preparing metal miniatures for painting to ensure a good paint bond.

Thanks to Timmo UK I've got a good method to duplicate, utilizing a degreasing step followed by priming the metal with acid-etch primer.

My question is with regard to the primer itself. When I do a Google or Ebay search for acid-etch primer, I almost invariably get this product:

picture

But in the same search I also get "self-etching primers" like this one, which is decidedly less expensive:

picture

Do these both work in the same way? Or are they different products? All the self-etching primers I've seen online are all supposedly designed for priming metal. But I'm wondering about why the huge price differences. I don't want to go cheap with it, might as well get the right thing the first time around!

Winston Smith Supporting Member of TMP31 Mar 2018 6:17 a.m. PST

I have never gone to the bother to degrease metal miniatures. The manufacturing process itself uses no grease, so why bother?
And as for an etching primer, why?
I prime with cheap Walmart Flat Black or Flat White at $.99 USD per can. I've never had any problems.

Personal logo jeffreyw3 Supporting Member of TMP31 Mar 2018 6:29 a.m. PST

Agreed with Winston. I've been brush priming for the past few years, but cheap black spray paint does fine, and goes on thin, so detail obscuring is minimized.

MajorB31 Mar 2018 6:39 a.m. PST

Wash the figures with in hot water with a squirt of washing up liquid.
Dry using paper towels
Prime using Humbrol matt paint.

Been doing this for more years than I care to remember.

BrockLanders Supporting Member of TMP31 Mar 2018 6:59 a.m. PST

I've never washed any ever and my figs from 25 years ago look like the day I did them

princeman31 Mar 2018 7:10 a.m. PST

Same as BrockLanders except I have some over 40 years old. No problems other than my poor inexperienced paint job.

Winston Smith Supporting Member of TMP31 Mar 2018 7:24 a.m. PST

Greasy mold release is not used in modern metal miniatures manufacturing, so a prewash before priming is an unnecessary step.
But if it makes you feel more secure, go ahead and wash. grin

Garand31 Mar 2018 7:25 a.m. PST

The advantage of Wal Mart sprays is that, besides being dirt cheap, they're less pigmented so go on fairly thin!

Damon.

Darrell B D Day31 Mar 2018 8:01 a.m. PST

OK – everyone has told him what he's doing wrong. Now, can anyone answer his question?

DBDD

Baranovich31 Mar 2018 8:41 a.m. PST

@Darrell,

Lol, thank you… I noticed that as well.

Thing is, I've had mostly good results just washing metal minis. and using a basic primer like a GW or a Rustoleum primer. But I do notice that certain times the very highest areas of a mini, like the tip of a gun or hair or something where the mini. might be grabbed the paint will rub off showing the primer underneath.

Timmo UK seems to be taking the fool-proof, no-nonsense approach of ensuring that there's zero paint adhesion issues. That's why I took his method seriously. Doesn't seem that much harder to wash the minis. and then take one more step and buy a primer that's more designed to prime metal, which is what acid-etch primer is meant to do.

But indeed, back to the original question! Is self-etching Rustoleum primer the same thing as acid-etch primer? Both claim to be designed for metal and I assume both are used for automotive purposes primarily.

whitphoto31 Mar 2018 8:47 a.m. PST

I've never had a problem with that rustoleum and have always assumed that ‘self etching' is the same as acid etching. FWIW I've had sporadic issues with various cheap spray paint as primers, not limited to adhesion. Sometimes the nozzle clogs quickly, uneven coats, the spray paint being too glossy and not holding paint well, etc… that same can of rustoleum primer is what I recommend and use regularly and I think it's worth the higher price. Around here it's about $3.50 USD I think as compared to $1 USD for the Walmart spray. Plus I like grey better.

For me what I lack is time to paint, anything that makes me redo a step in the painting process is more of a waste then the money. It's the same reason I buy dedicated miniature carry cases instead of making something myself. Yes I COULD make a case, but that's less minis I'm painting. Plus I found myself spending too much time touching up mi is from them bouncing around in pistol cases and magnetic storage cases.

whitphoto31 Mar 2018 8:51 a.m. PST

The only other primer I've never had an issue with is Gesso brush on primer. It's dirt cheap, lasts forever, goes on everything, holds paint fantastically and is easy to clean up. But compared to the Rustoleum it takes forever… with my time being the scarce commodity I only use it on MDF terrain these days since I like the result bette than other primers.


Ps: I've never washed metals…

Winston Smith Supporting Member of TMP31 Mar 2018 8:59 a.m. PST

One more attempt… grin
Rustoleum and other "etching" primers are designed to prime iron or steel.
The oxidation process for ferrous metal is different than for the metal used in casting miniatures.
I don't think it's needed, whether it's acid etched or just plain etched.
In fact, it might even be detrimental. We don't see it much anymore, but remember "lead rot"? That was primarily caused by storing the miniature in an acidic environment.

So, I once again a cheap Flat Black or Flat White, and skipping the unneeded wash.
It's worked for me for years, with no issues. As for paint rubbing off a hat or elbow, no primer can prevent that. That's entirely due to handling.

Dynaman878931 Mar 2018 9:38 a.m. PST

> OK – everyone has told him what he's doing wrong. Now, can anyone answer his question?

I think they have – get the cheap stuff from Walmart. When I actually need to prime something that is what I use. Normally my "priming" step is a base coat of the predominant color of the miniature and I've had no problems except with some resin miniatures.

Personal logo Bobgnar Supporting Member of TMP31 Mar 2018 10:45 a.m. PST

I give my figures a little bath in vinegar which etches little bit. Then paint on the bare surface And finish with a polyurethane dip.

Darrell B D Day31 Mar 2018 12:26 p.m. PST

Dynaman8789 – no, they've told him what they do and that they think that's better than what he's planning, apart from whitphoto and he specifically says not The Walmart product. Otherwise, the original question has been largely ignored. That's all I'm saying.

DBDD

goragrad31 Mar 2018 12:30 p.m. PST

As i have purchased most of my figures second-hand, I always wash them.

Never know what has handled them or what they have been exposed too in the possibly 40 years since they were cast.

After that it is flat white – generally Wal-Mart – primer.

Then baked to set the primer.

jwebster31 Mar 2018 12:30 p.m. PST

I had some problems with adhesion on metal figures, so am now priming with the Rustoleum self-etching primer, and then the Badger primer (I like my figs white primed).

Have not done any experiments to see how much this helps but have not seen adhesion problem since.

The degrease step (I jus wash with some washing up liquid, I searched to find the most pH neutral) is not essential but will remove finger grease or whatever from when you prepped the figures

It's clear that most people simply don't have any issues with priming

John

Timmo uk31 Mar 2018 1:38 p.m. PST

Baranovich,

I think self etching primer is an acid etch primer – worth checking with the supplier.

There are etch primers that are designed specifically for 'difficult to prime metals' including brass, galvanised steel and white metal.

When I wash figures they become brighter and the water dirtier so something is coming off them. This 'production residue' and the natural oils from your hands are worth removing. YMMV.

Chris Wimbrow31 Mar 2018 1:39 p.m. PST

As a veteran of decades of getting fingerprints on my glasses, I'm going to wash anything. Mold release or my handling (during assembly), it may just be easing my mind.

But my mind needs massaging to relax. Then Liquitex gesso keeps it indoors with a brush on any metal or plastic.

YMMV, experiment. I air dry, with an old towel without lint to lay 'em on if they can't be stood up.

Nick Bowler31 Mar 2018 2:10 p.m. PST

I use the rustoleum self etching primer. It is, by far and away, the best primer I have found for metal figures.

1. Paint just sticks. I don't get paint rubbing off. And I don't bother varnishing -- because there is no need to. There is very little rubbing off of paint from elbows / hats compared to other primers I have used.
2. I have had no problems with lead rot. Granted I have only been doing this for 15 years. (Before that I used other primers)
3. I tried to get the 'speciality metal' primers but the paint store didn't have them, and the guy behind the counter didn't think it was needed -- he said etch primer works on just about all metals. Now, he was working in a paint store -- so he was no chemist. But it seems he is right so far!
4. For those that use Walmart primer with no problems, try the etch primer. its a few dollars more. Give it a go! You may be surprised.

As to the original question, no idea. But the rustoleum primer is certainly a primer that works, and it is available world wide I think. (In Australia it is Wattyl Super Etch Primer)

Oberlindes Sol LIC31 Mar 2018 3:51 p.m. PST

I have never heard of self-etching primer and acid-etch primer, (1) so thank you for the interesting information and (2) I assume, even when buying brand new figures, that someone's greasy fingers have been on them, so I always degrease with ordinary dish soap before painting.

Cerdic Supporting Member of TMP31 Mar 2018 5:20 p.m. PST

Well, this is what I have learned from many years bodging up old cars…

Etch primer is just etch primer. It is formulated to bond with the bare metal better than normal paint. Use this and it will help to prevent your paint coming off the figure if that is a concern to you.

If the can says 'high build primer' it is a paint intended to mask small indentations and produce a flat and even surface. Great for car panels. Not so good for wargames figures!

Personal logo StoneMtnMinis Supporting Member of TMP03 Sep 2018 7:22 a.m. PST

Back in the day(yes, I am that old), we would soak metal figures in vinegar for an hour or so, then wash with soap and water. The vinegar would micrscopically etch the metal so any primer used would have a better base to attach too. Never tried it on plastic(Airfix) figures. Some of the figures prepared this way(70's and 80's) still have pristine paint jobs.

Dave

von Schwartz17 Sep 2018 5:13 p.m. PST

Gotta agree with StoneMtnMinis soak in vinegar and wash with clean water. Only I soak them overnight. It's quick, easy, and CHEAP!! Why spend money on those pricey aerosol sprays? Doesn't matter what kind of vinegar, I've used both apple and clear. The vinegar is a mild acid and etches and cleans the metal just fine, then any decent quality flat white or light grey primer will do. Also, be frugal with the primer so you don't cover the detail on the figure. You don't need to thoroughly coat the figure, just a light dusting will do.

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