SUKIMA SANGYO

[Random note] Surface treatment methods and tips for 3D printer output product kits from a painter

Added 2022-10-16 08:08:36 +0000 UTC

The term "garage kit" generally refers to a cast kit made of polyurethane resin, but recently (especially in the past 1-2 years), it has become easier to obtain resin for 3D printers and optical modeling. And there are some sculptors who sell output kits instead of polyurethane resin cast kits on BOOTH.

However, there are some cases where the surface treatment and painting methods that can be done with resin casting cannot be done with output kits, or are not allowed to be done with output kits.

It would be a shame to damage a kit that was purchased at an event due to carelessness, and I think it would be a good idea to regularly provide this kind of information, so this time I would like to share how to handle output products from a general consumer perspective (people who only do painting and assembly).

The other thing I'd like to share is a tip on how to polish 3D printer output products, which I received a question about in the comments section of the Youtube community.

Although there are no seam line like a typical cast kit, there may be some things that you are not familiar with, such as removing layer marks and support marks, so I hope to convey this from the perspective of someone who is always tinkering with resin. (Actually, this is the main one.)

If there are any mistakes, please point them out to me and I will correct them (it will be better for the readers).

■The minimum you need to know to paint and assemble a 3D printer output product kit.

First of all, let's review what you need to know.

You may be thinking, "Well, with a regular resin kit, I don't have a problem..." But beware, doing it with an output kit can cause cracking or shattering that can make it unrepairable!

┃What not to do with 3D printer output kits

・ Prolonged exposure to hot air

Spot heat source forced drying with an embossing heater, etc. and bending are not acceptable.

There is no problem if it is left in a Yamazen dry booth (around 40°C) for 1 to 2 hours or something like that.

・Soaking in water for a long time

If it is just a quick wash of polished powder in water, it is perfectly fine. Soaking in water is x. It may be possible to use waterproof sand paper or a waterproof sand sponge file to polish with water, but we do not recommend it.

・Boiling in hot water

This is a common mistake. (In some cases, it is better to use hot water to correct distortion of the parts, but there is no need to boil them except for that.)　Boiling output parts is likely to cause them to disintegrate after cracking.

・Prolonged soaking in organic solvents

As with polyurethane resin casting, prolonged soaking in solvents is a no-no. Soaking for 3 to 5 minutes to remove the paint will not affect it, but 10 minutes or more is not recommended.

When I repaint, I use a small amount of solvent and wash it off with a brush or wipe it off with a Kimwipe. If you do it quickly in a short time, there is no problem.

・Drilling holes for pins, thin or thin parts made from fragile output resin.

Unlike resin casting, the main reason why output parts seem brittle may be because they are hardened to a crisp.

I think this is because the parts are hardened to a hardened state. This depends on the type of resin used (hard or soft, etc.), so it is difficult to make a general statement.

My personal feeling is that hard resin feels smooth to the touch (similar to polyurethane resin casting) but is brittle. It is easy to crack when a little force is applied or a hole is drilled in the shaft. (It is said that many inexpensive resins are hard and brittle like this.)

On the other hand, soft resin is slightly sticky to the touch, but does not break with a slight impact and has elasticity similar to resin casts. The stickiness disappears with sanding, so there is no particular disadvantage.

Therefore, I think it is better to assume that axis hammering on hard, thin or thin output parts will break. It is easier to work with the expectation that it will break. Even if it breaks, you can use cyanon or something else to attach it.

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The reason why these treatments are not possible for output parts, unlike polyurethane resins, is that they increase the likelihood of cracking and breakage. Some of them are made with special optical modeling resins, which are resistant to water washing, heat, and impact. Excluding those exceptions, it is safe to avoid the above items.

Also, if the kit is around 1/7 scale and hollow, it may not be strong enough to be painted and assembled, so it may be better to give up or assume that the kit will break if it is complicated, stands on one leg, or has parts that are heavily loaded. (I don't think this is possible, but...)

I have written at length, but even a 3D printer output kit can be painted and assembled just like a resin cast kit, except for the above mentioned points. To be frank, you can see that when you paint or assemble a few kits, you don't have to be so nervous.

Nowadays, there are many people who sell original output kits on BOOTH, so if you are prejudiced against output kits, it would be better to practice with such kits. I used to think, "I wish they would all be replaced with polyurethane resin," but I have changed my mind.

I was impressed by the fact that it can be painted and assembled. I have a feeling that it is a bit more brittle than regular resin cast, but I can paint it if I apply surface treatment and paint it.

I recommend you to put aside your prejudices and assumptions for now and try to assemble a few pieces. You can paint with lacquer, enamel, or repaint as you normally would.

■Using the right tool in the right place is the basis of surface preparation for output product kits.

After a too long preamble, I would like to share some tips for surface preparation of output product kits that have been requested.

In the case of kits for sale, it is assumed that almost all of them have already been cleaned and secondarily cured. Therefore, the necessary treatments are as follows.

・Removal of supports and rafts

Supports and rafts are these kinds of things.

The board on the underside is the raft. The bar growing out of it is the support. Some time sculpter have already removed both the support and the raft, so there is no need to do anything.

・Removal of support and layer (sanding)

When these supports are removed, the surface becomes bumpy. The basic surface preparation for those who purchase output kits is to remove the layer by using a sponge file or sanding tool.

↑These are layer. The entire kit has these layer, so the entire surface needs to be sanded along with the support marks.

If you do not mind the layer you can paint the kit as it is, but it would be better to treat the surface because it will change the appearance of the kit after painting.

As mentioned above, it is unlikely that rafts or supports will remain. Nippers specialized for removing supports from output products are available, but there is no need to buy them.

There are two tips for processing stacking marks: don't worry too much about the details, and use the right tool in the right place.

The other is patience... polish, sandpaper, and if it bothers you, polish and sandpaper again... repeat... even if it is tedious, there seems to be no other way but to take the time and patience to sanding.

It is quite difficult to completely remove all of the layer since they are on almost all surfaces, and it is easy to overlook the parts that are deep inside. However, if it is not a skin part or a clear part, it will disappear if it is treated with a buff.

Therefore, you should not think of sanding all of them, but only the visible parts and skin parts.

│Spiral wheels that can be used for surface treatment of output parts to make progress

Basically, if you have the same surface preparation as for ordinary resin casting kits, there is no need to worry about anything. Simply sand the entire surface with Artima 7, AT, or a sponge file.

If I were to add one more thing, it would be spiral wheels.

This is recommended because it makes it easier to remove only layer without destroying details.

Even a slightly complicated part like this can be sanded rather easily with a spiral wheel.

↓

Changing the direction and angle of the spiral wheel depending on the location will improve work efficiency.

The image shows two layers of #400, but for large surfaces, three layers of #600 will be more stable and easier to polish. Two pieces of #600 may be better when sanding a deep part.