Lens Aperture Exploded in Resin




Introduction: Lens Aperture Exploded in Resin

About: I'm a physics student. I like to build stuff and learn about electronics.

I travelled to New York the last Christmas and I enjoyed it as much as troubles me and my family had there. One of them was my sister's camera.  It lens got blocked; maybe because of the high changes of temperature (We live in Canary Islands, so we aren't used to control those things). The thing is that we couldn't take photos there with that camera. Now, I decided to take the piece that wasn't working (aperture) and sink it into resin, making a gift for my sister in order to remind her the good (and bad) times we had in New York.

This 'ible is an example of what can you do with transparent resin, so the following instructions can be taken for other ideas. The resin used is Transparent Polyester. I bought it on this store , very cheap by the way.

Step 1: Safety First

Resin can become an hazardous issue if you don't take the correspondent precautions. There are required some protections:
- Latex or nitrile gloves.
- A Mask for the fumes
- Acetone (is the best product for clean polyester resin).

Step 2: Tools and Materials

- Sandpaper:
  · Wet sandpaper 120
  · Wet sandpaper 360
  · Wet sandpaper 1000
- Sander (optional but recommended)
- A graduated cylinder (to measure the resin)
- syringe (to measure the catalyst)
- A stick
- Solder iron
- Hot melt glue gun
- Polish paste
- Cloth

- Polyester Transparent Resin
- A object to sink (in this case an lens aperture)
- A mold (I used a tetra brick pack, but I recommend crystal or plastic, you wont have to sand with them)
- 4 LED's
- Plug conector
- 12V transformer

Step 3: Dissasemble the Lens and Aperture

My first idea was to sink all the lens exploded, but I haven't so much resin.

Take apart the aperture and disassemble it as well.

Step 4: Make the Mold

My pattern was a 5x5 cm of base, even when the aperture has 3 cm of diameter. I did that so as to let a security space for any problem that can happen (at the end, I sanded the piece, letting it in 4x4.5 cm)

My mold was made on tetra brick, because I haven't anything better, but plastic and crystal containers are a better option. Silicone is the best option, but is a waste of money if you'll only use it one time.

I made two pieces. One for the base, which is illuminated by four LED's, and other for the aperture piece.

Step 5: Make the Base Light

Solder the four LED's in series to a 12V plug. Make a hole for the plug in the base mold. Stick them with hot melt glue, which will be easy to remove later.

Step 6: Prepare the Resin

After take all the security measures, it's time to mix the resin with the catalyst. Polyester resin is often sold with the catalyst, so don't get mad about it.

Catalyst quantity may vary depending on the temperature of the environment, but is always between 5 and 2% of the volume of the resin.
After mix them in a recipient, stir it with a stick drawing an eight. That will erase most of the bubbles that can appear.

Resin dries relatively quick(around 5 - 10 min.), so you'd better control your time.

Don't make a big amount of resin for this project in a time, because it will be poured by layers.

Step 7: Pouring the Resin

Right after mix the resin with the catalyst, pour it into the mold. Put the first aperture piece with care then.
To create the "exploded" effect, I put the resin by layers, each layer for one part of the aperture.

Wait around 30 minutes so as to let the resin dry well and prepare more resin mix for the next layer.

After make all the layers, let it dry 12 hour's.

Step 8: Extract the Resin Piece

After the resin dries completely, take it out of the mold. If you won't use the mold again, simply break it.

Step 9: Sand the Piece

So as to smooth out the bigger irregularities, use a sander with a wood sandpaper.

Afterwards, sand the piece first with the 120 sandpaper, then with the 360, and finish with the 1000.

I sanded the base only with the 120 and 360 sandpaper, giving it a semi-transparent look.

This is the hardest step so far. I spend at least 4 hour's sanding, just because my mold was very irregular, so take care about that.

Step 10: Polish the Piece

Blend the polish paste with a bit of water and moisten a cloth with it. Make circular movements with the wet cloth in the faces of the piece. After that, dry it with other cloth.

Step 11: Finished!

So this is the result of the hard work! I hope you enjoy this instructable.

Please, post your questions or examples of this technique bellow.



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    55 Discussions

    I like to undercatalyze polyester resin to reduce the exotherm, and reduce the risk of cracking. That increases the setting time, of course. I also often use styrene monomer as a "float layer" to wet the object so bubbles don't stick to it. I then pour the catalyzed resin into the liquid monomer layer. Looks like your project turned out very well without those precautions, but they might help someone doing a thicker project or one with a surface more likely to trap air.

    4 replies

    How far do you think I should undercatalize?

    That's a difficult question, depending on the resin type and composition. I suggest to make a small test first and see it for yourself, but usually the one who sells it knows the product well, I asked the same thing on the store and gave me the proportions they saw fit.

    So much thanks for your comment, It's my first time working with resin, so I didn't known anything about that. Would polyvinyl alcohol work to avoid bubbles on the object too?

    I don't know for sure. I'm not very familiar with polyvinyl alcohol I thought it was used as a mold release, so my guess is that if you painted it on and let it dry, it might separate the object from the resin. That would probably not be what you want. The thing about styrene monomer is that it wets the surface and is compatible with the resin as the resin cures. So, for example, if you have a complicated porous object such as a dry piece of bark, you can anchor it with a thin resin layer. Then you can pour a layer of styrene monomer over it. It will wet the bark. Then you can pour the next layer of resin right into the monomer, and continue. Styrene monomer is available from Industrial Arts Supply Company in Minnesota.. I haven't looked into other sources.

    I have a question, I'm thinking of casting my diecast car into resin, the same thing to do, but I use the car's acrylic case as the mold, so do you think the final result will still be clear? and does the resin harm the acrylic case? also does resin shrink or expand when it cures?

    7 replies

    I would assume you'll have no problems at all if the inner surface of the acrylic case is not scratched. Normally the best molds are plastic ones, because they are usually perfectly smooth thanks to injection molding. If you use a spray mold release, I'm quite sure you won't harm the acrylic.

    The only thing you need to be concerned about (expansion is almost impossible to percieve) is heat, but the acrylic won't suffer at this range of temperatures.

    In any case, I suggest you make a small test with a corner of the case or something and see how it goes.

    thanks for your fast reply.
    This is what I want to work with. What I meant is more like I'll fill case with resin and embed the dismantled car into it. Do you think the surface between resin and the inner wall will be clear or blur? Also I'm curious about expanding/shrinking because I'll keep the base too so I want to make sure there'll be no air inside :)


    I'm sure it will look awesome! The resin will fill all the gaps it
    can get into and if the surface is smooth and well polished, then it
    will be crystal clear. As I said, plastic surfaces are really smooth
    because of injection, so I don't see why it shouldn't result in a great
    casting. Regarding the expansion, is so small the material won't even
    notice in terms of tension, it just expands a little when it heats up
    and then recover the same size, but as I said, you won't be able to
    notice it. In practice, it doesn't expand at all.

    The stuff you should be worried about are the mixing
    (depending on how well you make it, you might get no bubbles at all),
    the surface state (watch out for scratches on the case), water (you need
    to dry the object and case so as to avoid water drops, which would
    create bubbles!) and dust. Remember to pour the resin slowly so as to
    fill all the gaps.

    Good luck with it! Post a picture here when you its done!

    About settling time, say, the resin sets in 24 hours, if I pour the new layer after that timeframe has pass, will I still able to get a consistent result or there'll be a visible wall between them?

    Also check styrene monomer as suggested by eyrops, maybe that way you avoid interface problems.

    Also check styrene monomer as suggested by eyrops, maybe that way you avoid interface problems.

    I'm quite positive a wall will appear. I only took a few minutes/hours between layers and even then I got perceivable walls. I protected the mold with cloth, so I don't think it was a matter of dust, but of curing. Maybe using less catalyst is the key, but I don't think 24 hours is a reasonable time frame.

    If you don't want to invest in polish paste or a special cloth for this purpose, I have had good success with toothpaste and a sock.

    2 replies

    Do you think this would work for insects too? I found a huge cockroach in my room while visiting a friend in Venezuela. I want to put it in some resin like this.

    2 replies

    Yes, it works very well because I watched some examples on the net. The only precaution you may do is the exotherm effect, which make the resin rises over 60 ºC. However, it shouldn't affect the result in this case.

    Insects work well, but you need to make sure they are dried out first. Trapped moisture will want to expand when the resin heats up.

    wow amazing i wonder if i could do something like this with a old camera i have on my shelf