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Can I use normal car primer on my model?

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I have run out of my Tamiya primer, and was wondering if it is any harm to use standard automotive primer. Im very new to this hobby so please don't kill me.

 

Thanks

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Yes you can but go light on the first few coats or it will craze the plastic.

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I've used duplicolor primer with no issues.Wash yer parts in dawn before applying the primer.

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The answer is maybe. You really want to test your primer on some of the sprue to see if it will craze otherwise you could have an issue. There have been several posts recently that the newer kits and the current primers don't always play together. Better to test than to ruin a kit.

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Dupli-color or if you can find Plasti-kote primer. As Willie said  wash the parts with original blue Dawn before priming.

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4 hours ago, willieman said:

I've used duplicolor primer with no issues.Wash yer parts in dawn before applying the primer.

 

29 minutes ago, Bobdude said:

Dupli-color or if you can find Plasti-kote primer. As Willie said  wash the parts with original blue Dawn before priming.

Here's a thread addressing using Duplicolor over current kit plastics.

As far as Dawn goes, well, it's OK I guess.

But for MAXIMUM adhesion, scrub the parts with an abrasive cleanser like Comet, a toothbrush, and plenty of hot water.

Not only does this remove mold-release agents and lubricants from the parts, it also uniformly scuffs them, including down in nooks and crannies where sandpaper and ScotchBrite pads can't go.

Parts that are NOT scuffed often exhibit paint pulling away from edges and panel lines, and scuffing with sandpaper can obliterate fine details.

For extra insurance against fisheyes, wash your parts with CLEAN paper towels and 70% isopropyl alcohol (available in any drug department).

image.jpeg.b13b11a5ee839df99e7c95d49cb81564.jpeg   image.jpeg.79ed3a1dfbde90a855bf36e3df6b2835.jpeg   image.jpeg.a948876e9a40dd4f103a44cb8acb42a1.jpeg

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I use Duplicolor sandable primers, (all colors) and, or Duplicolor "primer-sealer" for every build.

It has it's advantages & disadvantages.

Some advantages are:

                                            It's much cheaper than Tamiya.

                                            It sprays very thin coats & levels extremely well,

                                           The fan spray nozzle is an absolute joy to use versus the round spray nozzle of most hobby sprays.

                                            If applied correctly, it's a superb barrier for hot lacquer paints.

Disadvantages are:

                                           It's a hotter primer & can craze the plastic if shot too heavily.

                                           Coverage is not the best, so it can require several coats to cover.

 

I will usually start with a coat of something that covers a little better like Testors primer.

This will not only afford coverage over body work, etc, but it will give you a bit of a barrier from the hotter Duplicolor primer.

Then I will shoot up to 5 coats of Duplicolor primer, starting with very light coats & getting progressively heavier with each coat.

This will guard against any crazing when using automotive lacquers.

Don't worry, Duplicolor primer goes on so thin & levels so nicely that multiple coats will not hide any detail.

Of course, the number of coats can be reduced significantly if you will be using enamel or acrylic.

 

Steve

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One point of clarification- if you've already sprayed the model with Tamiya primer, I wouldn't suggest shooting coats of a hotter automotive primer over top of it. 

If you are starting with a bare body, yes you can use automotive primers. I would do mist coats with ample time for the coats to dry/gas out before doing any heavier wet coats to avoid etching the body or lifting the mist coats. I've used Plasticote and Duplicolor primers for years, with the newer plastic being more sensitive to the solvents than kits of old. I've also used Tamiya's grey primer, grey and white fine primer. While it doesn't have the same cost effectiveness of automotive primers, it can give really good results...great (but expensive) stuff for use underneath typical hobby spray paint.

I haven't tried Tamiya primers under hotter automotive lacquers however, and if I was going to do color coats with an automotive product on a model, I would do so over automotive primers that were built up in thin mist layers with ample curing time before color coats.

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Been using automotive primers on models since forever because I use automotive paints .  The primers work well, however I have replaced them with Tamiya primer because I like the very fine grain of it when it is dry.   Primary difference between the two is the size of the pigments. Auto primers are mostly meant to do some filling so they are generally denser and thicker.  Therefore they will bury details if you are not careful.  Because of the density you need a large nozzle if you are going to spray them with an air brush.  You also need to thin the heck out of them or you model will look like a primer lump.

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Just my observation, but if you get a booger with auto primer you have a booger. If your using tamiya, don't panic and leave it sit and when you come back the next day it will be smooth as silk no blemish at all. More costly yes but a very good product. I used to use plasti-coat t-235 but they have had to of changed the formula. It seems way thicker and squirts alot more no matter which nozzle you use. Longer dry times it just seems like a different product. I only know of 2 places that still carry it around here  everyone else switched. Never had a problem going back or forth between auto and tamiya maybe ive been lucky.

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I use a whole bunch of different primers but be careful what you use.Duplicolor sandable primers and plastikote work well.I love tamiya primers but can be costly.

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11 hours ago, Ace-Garageguy said:

 

Here's a thread addressing using Duplicolor over current kit plastics.

 

      

Bill.. two years later what is working for you now?  I read the thread and it didn't seem like you had found a solution.

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On 7/6/2018 at 8:59 AM, jchrisf said:

Bill.. two years later what is working for you now?  I read the thread and it didn't seem like you had found a solution.

One of the main reasons I've stopped building...last Revell '29 Ford body I shot with Duplicolor red "sandable" primer right out of the can crazed so bad, it looked like HEAVY surface rust...and that was NOT the look I was going for.

In years past, I learned to shoot my primer slick (which means "wet") so I wouldn't have to do much sanding, and wouldn't have to use a lot of detail-filling coats. I don't like the surface texture, dusty orange peel, if you shoot "mist" coats from a spraycan either.

It's shooting my primer wet, after scuffing the surface very thoroughly, that's causing the problem...but ONLY ON THE SOFT STYRENE that most kits are made from these days.

I can use my old tried-and-true method on most early Johan, Revell and AMT kits with no ill effects. The '61 Dodge below was shot with SEM self-etching primer (black), one of the "hottest" primers out there. Shot WET. Slick and smooth as a baby's backside. No crazing, no problem.

DSCN7592.jpg

The older 1/8 scale '32 Ford from Revellogram, below, was shot WET with Duplicolor red "sandable". Again, hard plastic, much harder than today's kits, no crazing problem.

DSCN0535_zpsfdi6ddec.jpg

To answer your question, I have no answer as yet. I'll be experimenting with Steve Guthmiller's recommendations (and variants) as soon as I have the time to invest in a potentially maddening and frustrating series of tests.

 

Edited by Ace-Garageguy

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20 hours ago, crazyjim said:

I've bee using Duplicolor primers for years with no ill effects.

x2

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19 hours ago, Ace-Garageguy said:

To answer your question, I have no answer as yet. I'll be experimenting with Steve Guthmiller's recommendations (and variants) as soon as I have the time to invest in a potentially madding and frustrating series of tests.

 

The two times I have used Duplicolor primer it has crazed my plastic.  It was my fault probably because I put it on too thick and too fast.  The stuff goes on so nice and dries so fast I basically just kept spraying it.  Too bad the plastic crazes this way because it is so quick and simple to do.  I didn't notice the crazing until I put the color coat on.. looked like deep scratches in the plastic in those areas and I couldn't figure out where they came from.

This next time I am going to do it the way Dave Thibodeau does it in his Gravity Colors videos.  He says that the paint will craze the plastic if you don't feather it on and build it up... this may be what Art was talking about in his replies in your original thread.  I queued it up where he starts painting the primer and the second video on where he explains the crazing (it's all the same video though)

I am going to decant the  Duplicolor and try this. If it doesn't work then I will move on to Tamiya primer.

 

Edited by jchrisf

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On 7/6/2018 at 11:38 AM, Daddyfink said:

Go buy another can of Tamiya and avoid any possible disasters

I agree, why risk what you've got started already - just keep it the same for now. Try the auto primer next time.

Also, regardless of what primer you use, you'll want to block sand it before paint, as primers leave a small amount of texture that WILL show up under the final color. Real car builders block sand the primers before painting for the best finish - why shouldn't we?

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