Fixing holes in SLS

[samantha.scott]

We have a Fuse 1 30+ Nylon 12 and sometimes there is only a small defect in a large part. Its a cosmetic issue for sure and we want to be able to fix it!

I was hoping to fill it with an epoxy mixed with some of the powder, has anyone tried this? any help would be appreciated!

[DL_Jon]

That looks like you have contamination issues in your hopper. If you have not already, I recommend that you cover the hopper opening with a lint-free cloth or a 150 sieve mesh. I am using the latter on my hopper secured with magnets.

As it happens however, I am trying this proposed fix today to try and recover from another print defect. I have simulated your defect to test this proposed fix. I will have the results in the morning when the epoxy cures.

I am using Loctite 2 part epoxy and Nylon 12 from my Fuse Blast Waste Hopper.

[samantha.scott]

Thank you so much for the advice! I will definitely try a mesh sieve, did you buy one and cut it to size? or does formlabs sell one?

[DL_Jon]

I acquired this one from McMaster-Carr 9319T185 and cut it in half as it matches the specifications of the Fuse Sift mesh. I shared a picture this on this thread

[DL_Jon]

Good news! The fix works. It appears to work better on my simulated defect where I sliced into the part with a knife to recreate your defect. It also appears to work with the “Orange Peel” defect though multiple coats appear to be required.
Here is a before photo, showing the mild “orange peel” and a simulated contamination defect.

Here is an after photo. You can see that the fix does a good job at masking the defect, particularly the simulated defect. I did not have ideal lighting for the photo, in person the defect is mostly invisible, I would be satisfied with releasing this part to production.

I am waiting on a second coat to cure so see if it is worth the additional effort for the “orange peel” defect.

For the epoxy mix, I simply added spent nylon 12 powder to the 2-part epoxy until it looked mildly grainy. The nylon 12 is from the waste hopper of the Fuse Blast so it would have a small amount of spent glass bead powder.

[samantha.scott]

That looks great! I have some epoxy here and going to give it a try! Will post results when I get them!

[DL_Jon]

A second coat helps. And after Dyeing and Clear Coating the part, I would be hard-pressed to locate the defects if I did not already know they were there.
Here is a picture of the part before any post-processing.

And here is a picture after Dyeing and Clear Coating the part.

As you can see, this is a viable fix should one be willing to spend the time recovering their defective parts.
One thing to note however is this appears to not be as viable for especially bad ‘orange peel’ defects as it appears to be more difficult to apply the modified epoxy evenly to a larger and deeply pitted area.
Here is a picture showcasing this example. The photo doe not do it justice as in person the part has an extra shine in the fixed area that I was not able to remove with my clear coat.

Here is a picture showcasing a moderate orange peel and this one is better, I would allow it as a “factory second” in a pinch.

The 2-part epoxy I am using clearly does not accept dye or clear coat in a manner that meets the same standards as the dyed nylon.

[Mario_Martinez]

I have another solution, use a putty filler, sand it until the defect dissapears and lightly sand the whole part. Apply this Würth product 0892 075 012

Then use a brass brush all over it, you will get an even dark surface.

[Mario_Martinez]

Amazing solution.

[samantha.scott]

I may not have added enough powder, but like DL_Jon said, the epoxy doesn’t quite dye as good. I definitely did a rush job, but it wasn’t a great fix for me. I will try adding more powder next time and sanding the entire part.

I think I will also try the putty filler that Mario tried. Fingers crossed!