Sintering large objects

I’ve been trying to sinter larger objects than what I’ve seen so far on here. The largest of which is a “benchy” boat. I tried slowing the rate of temperature increase, but it obviously didn’t turn out well. Has anyone had success with larger objects? How did you do it?




How big is it? I recently did a copper mask that was about 3in x 4in

Here’s how I did it

Benchy is whatever size they usually are (2x2”?)+5%, but I’m looking to do much larger prints 2x4.5” and bigger). I guess what I’m asking is what rate of temp increase are you using for debinding and sintering, and does part orientation matter?

I’ll have to get a shot of my schedule, but in my experience part orientation is pretty important with my rule or thumb to lay the highest dimension flat (ie. If z is the highest position it flat in refractory not sticking straight up)

Also my rates might not match up totally with recommendations since I use a single fire to do both the debind and sinter.

Do you put the carbon on top before debinding and then run the whole sequence? Cuz I’ve thought about doing that. When you say flat, do you mean the longest axis should be horizontal?

Yeah carbon in for the whole process and horizontal is a better way to describe that :slightly_smiling_face:

I also cover with copper tape and sometimes aluminum foil (my other videos show this in a lot more detail)

This is the sintered mask that I mentioned

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Ah, ok. I’ve been using broken pieces of kiln shelving, but I did just get some crucibles with lids.

Lids are the way to go for sure. My smaller crucibles I made have a lid mould, but my bigger ones don’t so I need to get off my butt and make something that’ll fit. I may try to use tpu to print the lid mould… we’ll see

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I got 10 100ml crucibles for doing shotgun slugs. I haven’t seen much bigger though. I should make my own for larger prints, I just haven’t gotten to it yet.

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I perked up when I saw “shotgun”. What are you doing with your slugs and what are you printing with?

I call them la bomba slugs. It’s a similar idea to link’s heavy hitters, except mine are modeled after foster slugs and made of copper. I still have yet to test the copper ones, but the plastic prototypes fly great. I plan to sell them through my business, Gun Runners Arsenal LLC.


Cool :ok_hand:
You should send some over to taofledermaus to test. I enjoy watching them shoot things :grin:

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That’s the plan. I tried doing a batch doing the whole sequence, and they didn’t sinter. I’ll have to check the settings, but I threw them in again using only the sintering sequence, so​:crossed_fingers::crossed_fingers:I probably need to extend the time it’s at 900F. I got a pistol frame in bronze I still need to do, and a silencer in 17-4 when I get my licensing.

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Interested to see, good luck :+1:

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I’m holding off until I get really good at sintering. They take about a third of a roll to print.

Check out this case study. These are large copper prints - 600g +.
The ramp rates are super slow. This might give you some ideas for your process in addition to what’s already been discussed.
https://thevirtualfoundry.com/wp-content/uploads/2021/12/Filamet™-Case-Study-Large-Copper-Print.pdf

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Very interesting and a good use of the process.

Jim

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That’ll definitely be helpful when I sinter the pistol frame (bronze) and the suppressor (17-4).