Machine Polishing Question

[DaddyJ]

Hi all - I have recently become obsessed with a perfect polished finish for my models ?

I have purchased a hobby rotary tool and follow the process below when it comes to polishing:

1. Sand with micromesh up 12000

2. Tamiya Polishing compound - Coarse, Fine, Finish (using polishing pads)

3. Mr Hobby ceramic compound (polishing cloth)

4. Final polish with rotary tool using Meguiar's carnauba wax

Its a process I learned from the fantastic "Scale Model Experiment" you tube channel (check it out he is great).   Unfortunately, when I complete the final polish with the rotatory tool it introduces scratches. Its very frustrating. Has anyone had an experience with this? I suspect its the head I am using, or is the tool too powerful? Can any one who has done this successfully recommend what type of heads to buy? I have attached a photo of the tool and head I use. FYI I am using Mr Hobby Super Clear as my clear coat (lacquer based)

 

Thanks in advance!

Andrew  

[JollySipper]

27 minutes ago, DaddyJ said:

when I complete the final polish with the rotatory tool it introduces scratches.

Hello! I have to ask, how does the finish look before polishing with the rotary tool? Is it acceptable as is? The reason I ask is maybe you could just skip this step........ Since there's no real reason to use a wax on model paint anyway. ( wax and polish are different things.... )

[DaddyJ]

Hello Jolly - yes we’ll it’s a good question. I’d say the finish looks pretty good but under light and at the right angle I can see some small scratches. My theory is the rotary would remove them faster than having to do more compound work. So the wax is the wrong material to try and remove those scratches perhaps? I thought it did a bit of polishing as well as enhancing etc. Maybe I just need to keep going with the compound until the scratches are gone ?

[Miatatom]

I've started sanding with 3600 and then finishing with Tamiya fine, all by hand. Looks like a mirror.

[Bugatti Fan]

Maybe using a rotary tool was a bit too fierce. Better perhaps to final polish by hand as you can actually feel what you are doing and have better control.

Sometimes people mistakenly interpret polish and wax as having similar properties. Polish in our terms means a product that has some abrasive qualities to take back the painted surface in minute amounts to a desired finish. Wax on the other hand is a material that adds another layer that can be buffed to a shine. It will not remove scratches, but just fill them.

[Dpate]

Well that clear is a soft clear as it’s not 2K. So you have to be careful, and use around 2-3K RPMs. I use these for polishing clear, the attachment part in the pic isn’t showing the 1/8 shank you’ll need for it to work with a dremel. Black pads can be use for wax as the black pads have no cut, and yellow is medium cut, and orange course cut. I use meguiers cleaner wax & ultimate compound for 2K.

 

Edited May 11, 2023 by Dpate

[ctruss53]

50 minutes ago, Dpate said:

Well that clear is a soft clear as it’s not 2K. So you have to be careful, and use around 2-3K RPMs. I use these for polishing clear, the attachment part in the pic isn’t showing the 1/8 shank you’ll need for it to work with a dremel. Black pads can be use for wax as the black pads have no cut, and yellow is medium cut, and orange course cut. I use meguiers cleaner wax & ultimate compound for 2K.

 

I use these foam pads on a electric toothbrush.

[DaddyJ]

1 hour ago, Dpate said:

Well that clear is a soft clear as it’s not 2K. So you have to be careful, and use around 2-3K RPMs. I use these for polishing clear, the attachment part in the pic isn’t showing the 1/8 shank you’ll need for it to work with a dremel. Black pads can be use for wax as the black pads have no cut, and yellow is medium cut, and orange course cut. I use meguiers cleaner wax & ultimate compound for 2K.

 

Nice thank you. I did suspect that the clear was “soft” (in my opinion it’s still a great clear though). I will look into getting those pads and keep experimenting. I have had a little bit more success since I posted this and suspect that the way I’m sanding may be a problem rather than the use of the rotary tool. Out of interest when sanding do you change direction after each grit? I sand in one direction the whole process…

[ctruss53]

8 hours ago, DaddyJ said:

Nice thank you. I did suspect that the clear was “soft” (in my opinion it’s still a great clear though). I will look into getting those pads and keep experimenting. I have had a little bit more success since I posted this and suspect that the way I’m sanding may be a problem rather than the use of the rotary tool. Out of interest when sanding do you change direction after each grit? I sand in one direction the whole process…

Soft isn't really the thing.

Yes, that buffing wheel on your rotary tool is designed for buffing and polishing. However, tools like that are actually designed more for buffing and polishing metals and jewelery. So they might be too harsh for these scale model clearcoats.

So just like these people that struggle to get quality paint jobs with Rustoleum and Krylon spray paints. You can polish your clearcoat with those buffing wheels, BUT you are going to have to develop a special technique to do it without damaging the finish. Because you are not using a tool designed for the job.

I read your original post, you are using a truly great clearcoat. I have an airbrush and I can spray any clearcoat I want. I still use Mr Super Glear spray cans. They are that good. There is something you need to do though in order for that clearcoat to polish out well.

Build it up in thin coats. Do like 3 very light mist coats with 5 minutes between each mist coat. Then do 1-2 heavier, wet coats. And wait 10 minutes in between those. But the thing that really helps the clearcoat polish out well, is after that last coat you need to let it cure for a while. Yes, it is dry and can be handled in a day. But if you let it sit for a week, it will be fully cured and will polish out better.

Any clearcoat should sit for a week or even more if possible to fully harden.

Here is an extreme case......

I know a scale modeler that always has the most amazing paint jobs.  He lays down the color coat, waits a week. Lays down the clear, waits a month. Then after he wet sands out the orange peel he lets it sit another month. Then he finally polishes it out. And his paint jobs are always flawless.

Edited May 11, 2023 by ctruss53

[SfanGoch]

Using a rotary polisher runs the risk of burning through and ruining the paint and clearcoat. Get a set of micro-mesh polishing pads. You have more control over how much pressure is applied.

Using paste waxes, such as Turtle wax or The Treatment, deepens the color of non-clearcoated finishes. They also have the tendency to remove the paint if rubbed too hard.

Edited May 11, 2023 by SfanGoch