Looking for advise on sandable primer

[Oldmopars]

I have a few projects going right now that will be due for paint soon. It has been a long break for me and I had never used Acrylics before, but now I am. I need to find a good sandable primer that will allow me to spray Acrylics over the top. I have an Airbrush, but will use rattle can if I need to. 

Also, if there is a high fill and a low fill, that would be great to know also.

Thank you

[martinfan5]

If you wanted to stick with hobby products, Tamiya and Mr Hobby both have primers to fill your needs, both offer their products in cans and jars for A/B.

Duplicolor has a high build primer and regular primers that work really good.

Edited March 6, 2018 by martinfan5

[JollySipper]

I like the DupliColor products....... The tall can is the "sandable", The small Perfect Match cans are "scratch filler"........

You want to take a few coats to cover instead of trying to cover the plastic with wet coats, as it MIGHT craze the plastic a little. That's the only drawback of using the auto primers.

[Snake45]

Plastikote T235 is my go-to on the rare occasion when I need a high-build, sandable primer. It's gray. I think they have it in other colors under other part numbers. 

[Erik Smith]

I wouldn’t recommend the smaller Duplicolor Scratch filler primer. It sprays really well and, even as “filler” is relatively thin, but for some reason it does not adhere well to bare plastic. I had multiple occasions where Tamiya masking tape lifted it off. 

The big cans of sandable Duplicolor, however, are great. 

[Sledsel]

Duplicolor and Plastikote are both very good. Plastikote is tough to find now that they have ceased production.

As with any paint and primer, sand first for good adhesion 

 

[Snake45]

2 hours ago, Sledsel said:

 Plastikote is tough to find now that they have ceased production.

 

Really? They still have it listed on their website. 

http://www.plastikote.com/products/Primer/Sandable-Primer.html

Although you're right it is harder to find than it used to be. Not as good distribution as before. 

[espo]

I have used the Tamiya Primers for years and have found them to be the best overall. They offer the Gray that makes it easier to find any imperfections when working with most White Car Bodies. Their White Primer is a much finer finish and with a White Body is not ideal unless you're using it for a base coat for brighter Finish Colors. They also have a Dark Red Primer that is perfect for Chassis and under Body Primers. For a very fine finish you might try Mr. Surfacer Primers. They offer them with a rating system much like Sand Paper. I now use their 1200 but they offer others  and they are very smooth right out of the can. Nether of these products can be considered inexpensive, but they provide what I feel is the best solution for what you are trying to accomplish.  

[Oldmopars]

Thank you. I am working on a School Bus that I have done extensive work to (shortened 2in, new nose, moved door, etc) and there has been a lot of cutting and sanding, filling, etc. I want to be able to put some primer that will fill on it so I can make sure through all my sanding I find those imperfections and get them filled, or sanded out.

[Sledsel]

5 hours ago, Snake45 said:

Really? They still have it listed on their website. 

http://www.plastikote.com/products/Primer/Sandable-Primer.html

Although you're right it is harder to find than it used to be. Not as good distribution as before. 

Yes, the plant has been closed for awhile now. According to the local fire marshall because of the size the building cannot be "unoccupied" and all systems in service.  I am in there every week to inspect the fire suppression systems. 

 

[Ace-Garageguy]

6 hours ago, Snake45 said:

Really? They still have it listed on their website. 

http://www.plastikote.com/products/Primer/Sandable-Primer.html

Although you're right it is harder to find than it used to be. Not as good distribution as before. 

They were also the featured rattlecan brand for CarQuest, but when CQ got taken over by Advance, Duplicolor came in to all the stores.

Plastikote has been available on Amazon and other web sources, but there were also reported problems with an apparently cheapened and offshore-sourced product.

It's a shame, really, as Plastikote primer was the #1 go-to product for a lot of better modelers for years.

Edited March 6, 2018 by Ace-Garageguy

[Ace-Garageguy]

17 hours ago, martinfan5 said:

If you wanted to stick with hobby products, Tamiya and Mr Hobby both have primers to fill your needs, both offer their products in cans and jars for A/B.

Duplicolor has a high build primer and regular primers that work really good.

Several real-car body shop lines sell "sandable" as well as "high build" primers. SEM high-build is a high quality product , comes in multiple colors (black, white, rose, and gray)and fills very well.

Keep in mind a couple of things, however.

1) Some of the real-car primers have "hot" solvents that will attack and craze many of the softer polystyrene grades that kits are made from today. EXPERIMENT FIRST, ON THE ACTUAL MODEL YOU"RE WORKING ON (back sides of parts that won't ever show). Here's one thread that addresses the problem. 

 

2) "Sandable" primers are generally quite thin, and will only fill 400 grit sanding scratches, or finer. And some don't look like they're covering well, when in fact, they are. Duplicolor's white "sandable" takes several coate to achieve full-hiding, for instance.

"High-Build" or "scratch-filler" primers will usually fill up to about 180 grit sanding scratches.

3) There are also "self etching" primers that are generally even hotter than the others, and a good bit of experimentation is in order before you commit to using them on something you care about.

4) The adhesion issue mentioned above can usually be prevented by scrubbing your raw parts with hot water, Comet, and a toothbrush, rinsing very thoroughly, and wiping the model carefully with 70% isopropyl alcohol and CLEAN white paper towels.

 

 

[martinfan5]

44 minutes ago, Ace-Garageguy said:

Several real-car body shop lines sell "sandable" as well as "high build" primers. SEM high-build is a high quality product , comes in multiple colors (black, white, rose, and gray)and fills very well.

Keep in mind a couple of things, however.

1) Some of the real-car primers have "hot" solvents that will attack and craze many of the softer polystyrene grades that kits are made from today. EXPERIMENT FIRST, ON THE ACTUAL MODEL YOU"RE WORKING ON (back sides of parts that won't ever show). Here's one thread that addresses the problem. 

 

2) "Sandable" primers are generally quite thin, and will only fill 400 grit sanding scratches, or finer. And some don't look like they're covering well, when in fact, they are. Duplicolor's white "sandable" takes several coate to achieve full-hiding, for instance.

"High-Build" or "scratch-filler" primers will usually fill up to about 180 grit sanding scratches.

3) There are also "self etching" primers that are generally even hotter than the others, and a good bit of experimentation is in order before you commit to using them on something you care about.

4) The adhesion issue mentioned above can usually be prevented by scrubbing your raw parts with hot water, Comet, and a toothbrush, rinsing very thoroughly, and wiping the model carefully with 70% isopropyl alcohol and CLEAN white paper towels.

 

 

I was fully aware of all this, but thank you anyways , this should be helpful to other people that may not.

 

I personally dont use automotive primers because they are too hot for the Japanese plastic, its either Tamiya or Mr Hobby primers for me.

[Snake45]

Don't forget that a paint doesn't have to be marketed as "primer" to be a good primer. Try several kinds of rattlecan flat paints and see if you find one that sands well and works as a good primer for you. 

When airbrushing, my standard procedure is to prime a car body with the closest Model Master military flat paint I have to the final color I'll be shooting. 

[Ace-Garageguy]

5 hours ago, martinfan5 said:

I was fully aware of all this, but thank you anyways , this should be helpful to other people that may not.

I personally dont use automotive primers because they are too hot for the Japanese plastic, its either Tamiya or Mr Hobby primers for me.

Yes sir, I figured you probably knew this.

I just quoted you to add info on the same thought for anyone else who might be new to this stuff. 

[martinfan5]

Just now, Ace-Garageguy said:

Yes sir, I figured you probably knew this.

I just quoted you to add info on the same thought for anyone else who might be new to this stuff. 

There are many times  I feel I am new to this, so it could go either way

 

[Snake45]

And BTW, the worst primer I've ever used was Model Master Primer in the bottle. I cut it with lac thinner and shot it as normal, and when I went to sand it, it gummed up like nothing I've ever seen. Last time I ever used it and of course I'll never buy it again. But I use plenty of their other flat paints as primers with no problem at all. 

[89AKurt]

I'm learning stuff here, so keep up repeating yourselves!

As Richard said, Model Master gums up even when wet sanding, and takes forever to cure.