Picture of How to Polish Resin
Polishing resin is a relatively simple process that just takes a little patience and effort.  This Instructable will address how to polish resin to a high gloss, focusing specifically on how to polish a resin part made from a 3D printer.  The same methods I will address in this how-to, apply to all cast resin polishing, and can be used to polish virtually any type of resin be it polyester or epoxy based.

The method first starts with some good old fashioned detail sanding working up through the grits, from very rough, to a very fine wet sanding.  Then we move into two different grits of polishing compounds, and finally finish everything off at the buffing wheel using two very fine polishing abrasives, and finally, a carnuba wax polish to buff everything to a bright shine.

When done correctly, well polished resin casts and parts look absolutely amazing, and are works of art, ready for display, jewelry and enjoyment in and of themselves.

Before I get too far into things, let me just tell you a little bit about the part that we'll be polishing.  A few of us at Instructables have been working with a lab at UC Davis to do some test prints of 3D models that they've been developing to better understand how and why race horses break their bones.  This Instructable focuses only on how to polish these kinds of models.  There will be a much larger Instructable about the entire research project coming along soon.  

The particular model featured in the photos in this Instructable is a horse's leg muscle that's been scanned and modeled to show how tendon attaches to the end of a horses muscle.  Tendons are modeled in white, while muscle tissue is represented in clear.  While casting a resin part like this would be extremely difficult, and realistically speaking, virtually impossible, our Object 3D printers can produce a resin print like this a matter of hours.  

I've been excited to work with the researchers at UC Davis because I find this kind of 3D printing really compelling when it comes to showing off the kind of work that we're capable of producing with this new technology.  There's obviously a whole lot to be explored with 3D printing, but representing complex biological models to advance medical research is one of the more compelling applications.  

In any case, if you've ever wondered how to make resin shiny, read on.
Corinbw7 months ago

I just used a two part epoxy to make a giant clothespin and I was wondering if this method would work for that kind of resin casting also. Great ible and hopefully I can achieve that kind of shine.

Would other waxes work because I only have candle wax.

LesB11 months ago

Awesome casting. I am in the middle of a casting. I followed directions from other I'bles and things are not working out as described, so I decided to check more on Instructables and found your posting, which I would call "The Ultimate Casting Guide".

I am at the P1200 sanding point, and according to 3 other I'bles I checked, I should be able to get a high gloss finish now with using scratch sealer and polish.

No such. The casting looks like I'm definitely getting there, but there's still a haze. These other castings have a nice high-gloss finish, so I'm thinking they it might be due to a different resin. I am using Environmental
Technology Polyester Casting Resin.

Hopefully I won't have to go the full route you did, as it gets a little pricey. I am going to start from here with a "4 Piece Buffing Kit" on sale for 4 bucks at Harbor Freight.

For the P600 and P1200 paper I used a orbital sander with water. I know I risk being treated to electroconvulsive therapy, but the sanding end is below the electric parts so I should be ok with some care.

I am writing my I'ble while I do the project and will post upon completion. And I will be referencing your project in the polishing part.

So thanks for sharing this beautiful object. I was going nutz for not being able to get a high-sheen finish with at this point.

Here's my casting out of the mold:

Wrinkles 0 Cropped.jpg
mrlunna132 years ago
I know that I am almost 6 months late, but I wanted to say that it looks awesome as the finished product! May I ask what it is? Is it just an abstract creation? Or, something else?
Thank you,
Jesse M.
this looks great noah! excited to see how these other techniques work out
marhar2 years ago
That's an amazing look! Hope to see more of your results, especially with the vibrating polisher.
dreiduke2 years ago
looks like a muscle
Denger2 years ago
Will this process work for "five minute" epoxy or other epoxies, 'JB Weld', etc?
It looks just like glass at the end! Beautiful job. I've done some sanding on polymer clay, but only took it to the 1000 grit level. Molding both acrylic and polymer clay in silicone molds tends to leave a fairly smooth surface (depending on the mold, of course) so I started with 180 grit or even 220 in some cases. I wish that someone would work on bringing the 3D printers down to the "common man" price level! I'd love to get the chance to play with them! Very nice Instructable and a beautiful finished product. You've done well.
Hi Noahw thanks for posting. Just out of curiosity how was the mussel scanned? Cant wait to see the "hands off" version. Just noticed the way you have your drill clamped to the table, have a look at this, I hope it helps

noahw (author)  liquidhandwash2 years ago
The muscle was scanned with a microCT system I believe. Thanks for the suggestion on the drill conversion - what a smart idea to use the 2nd hand handle on a hammer drill as an anchor point - I like it.
I was wondering, are you 3d printing epoxy? I also had to comment because I live in Davis.
noahw (author)  snowluck23452 years ago
We are 3D printing epoxy, the future is here! Davis - small world - I live in Oakland. Maybe I'll see you at the next Picnic Day.
fretted2 years ago
love this company i've worked with them a long time you can shine or dull anything with their machines ...