Sanding down TS primer.

[D.Pack]

Hi.

I need to ask if i'm actually treating Tamiya TS primer correctly.

This is the white primer wet sanded, with some orange peel (pin holes) that's only visible after sanding.

Should I just not sand the primer and retain it's uniform all over semi- matt finish?

It had just slight uniform orange peel, nothing like the divots you can see in the close up of the now sanded surface.

[jaymcminn]

Huh. Tamiya TS primers are pretty soft and I'm wondering if there might have been some loose grit in the sandpaper, especially if you started off with a fairly coarse grit, that caused this. I generally don't sand them, even if I've had to do corrections after a first primer coat I'll hit it with another coat and leave it alone. 

[Bainford]

Pin holes in the paint is often an indication that the paint or primer was applied too heavily in one go. 

[Zoom Zoom]

2 hours ago, Bainford said:

Pin holes in the paint is often an indication that the paint or primer was applied too heavily in one go. 

Tamiya rattle cans will do this, sometimes worse, if you shoot too close to the surface in too wet of a coat. Those tiny pinholes are likely trapped solvent bubbles that appeared after sanding.

[Exotics_Builder]

56 minutes ago, Zoom Zoom said:

Tamiya rattle cans will do this, sometimes worse, if you shoot too close to the surface in too wet of a coat. Those tiny pinholes are likely trapped solvent bubbles that appeared after sanding.

I'll second that!!!

 

[D.Pack]

Thanks for the replies.

When also using auto acrylic primer (here in UK) I don't have this problem.

This rattlecan paint is supposedly not as 'hot' as TS primer, so less solvent means no solvent popping?

I've just recoated with it. Will see how it levels off.

[peteski]

24 minutes ago, D.Pack said:

This rattlecan paint is supposedly not as 'hot' as TS primer, so less solvent means no solvent popping?

The "hotness" of the paint has nothing to to with amount of solvent present in it.  It is the chemical composition of the solvent itself. Solvents can be substances like naphtha, alcohols, acetone, and many others.  They are usually blended using multiple ingredients, and depending on the blend, some are "hotter" than others.

[Matt Bacon]

Make sure it’s clean, and just hit it with 2-3 light coats of Tamiya Fine Surface Primer 5 minutes apart from 20-30 cm away, and keep it away from dust. You shouldn’t have to sand the primer at all. Keep the can moving, and build up by doing several light coats rather than trying to get full solid coverage in one. You don’t want a “wet coat” in primer…

best,

M.

[1972coronet]

I wet sanded a final coat of Tamiya aerosol primer exactly one time. 

That was a mistake.

Not that there any paint (colour coat) application issues, but the colour coat dried with virtually no gloss. 

Since that one instance, I've stopped sanding - wet or dry - the final coat of Tamiya primer. It made a positive difference. 

[D.Pack]

4 hours ago, Matt Bacon said:

Make sure it’s clean, and just hit it with 2-3 light coats of Tamiya Fine Surface Primer 5 minutes apart from 20-30 cm away, and keep it away from dust. You shouldn’t have to sand the primer at all. Keep the can moving, and build up by doing several light coats rather than trying to get full solid coverage in one. You don’t want a “wet coat” in primer…

best,

M.

Will definitely try this for next paint session.👍.

[Matt Bacon]

44 minutes ago, D.Pack said:

Will definitely try this for next paint session.👍.

If you want the whole nine yards...

https://www.britmodeller.com/forums/index.php?/topic/234956647-matts-tips-for-painting-cars/

best,

M.

[Bugatti Fan]

Matt's painting guide over on the Britmodeller forum is a very good one with plenty of good information within.I

He has put the link up.

Edited December 3, 2024 by Bugatti Fan

[Andrew McD]

Sometimes when using rattle cans I will be too close to what I'm painting and end up with a thick wet coat that has areas of bubbling.  I've had this occur with both Tamiya and Testors rattle cans.  I believe the bubbling is propellant still dissolved in the paint that is rapidly evaporating (gassing off) and forms bubbles and pits in the paint.  I now decant my rattle can paint, let it gas off, and then apply it with the airbrush.  I haven't experienced the bubbling when the paint is applied with the airbrush even when I put it on too wet; then it just runs but that's another issue! 

[Greasefinger]

On 12/1/2024 at 6:50 PM, 1972coronet said:

I wet sanded a final coat of Tamiya aerosol primer exactly one time. 

That was a mistake.

Not that there any paint (colour coat) application issues, but the colour coat dried with virtually no gloss. 

Since that one instance, I've stopped sanding - wet or dry - the final coat of Tamiya primer. It made a positive difference. 

That’s interesting. One would think quite the opposite would happen. Any idea what causes loss of gloss with sanded primer? 

[1972coronet]

2 hours ago, Greasefinger said:

That’s interesting. One would think quite the opposite would happen. Any idea what causes loss of gloss with sanded primer? 

I wish that I knew , that I had an answer here. I just chalked it up to that primer being a final, no sanding 'sealer' under the colour coats.