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Refurbishing Hard Vat - FEP Adhesion Problem


#1

I’m trying to replace the silicone and FEP layers in my v2 hard vat. I poured QSil 216 silicone and it came out crystal clear overnight. It was easy to do.

But I’m having problems adhering an FEP layer.

First, I cut a piece of mUVe FEP sheet to fit and used light soapy water and a roller to suction it onto the silicone. Then let it sit overnight. But this pulled up easily on the first print’s base layer.

Second, I scuffed the FEP bottom surface with 600 grit (300 seemed way too coarse). But it was very cloudy after adhered, and it pulled up easily too.

Third, I sandwiched a piece of 3M 467MP double-sided adhesive between the mUVe FEP and silicone. This stuff is very cloudy and did not clear up when applied with light soapy water. And it was a bear to apply. It did have excellent adhesion. But I don’t want to use it because its not optically clear.

Anybody have experience getting FEP to stick? I’m at a loss. I’m not sure how Kudo is doing it. mUVe FEP is a little thicker than the Kudo film. I’m wondering if perhaps I should seal the mUVe FEP edges with silicone to keep a vacuum under the film?

thanks,
-Robert


#2

If you are refurbishing a hard vat by pouring new silicone, you will probably need to lay down the FEP film while the silicone is still wet (think how silicone caulk will adhere stuff very strongly when still liquid, but is non-stick when cured).

Once the silicone is fully cured, you probably have no way of getting good adhesion unless you use adhesive.

It is possible that you could save your work by using something like sil-poxy, which is supposedly clear, and applying a thin layer across the surface of the FEP film, squeegee-ing out any excess, However, I’ve never done this before.


#3

@jkao thanks for the idea. I gave a clear silicone adhesive a try. Unfortunately, the result was wavy like bottle glass windows. I think the adhesive needed to be thinned down quite a bit with mineral spirits so the sheet would roll out flat with a brayer.

I’m curious. You’ve found that peeling up the Kudo FEP and reapplying is a workable solution for waviness. So in that case, there wouldn’t be adhesion due to anything but vacuum forces. The difference from what I’m doing must be the QSil, or the mUVe FEP sheet. The mUVe sheet is thicker and not as glossy, so perhaps that is contributing to the air bubbles forming underneath?


#4

The peel-and-replace procedure only works for the soft vat, which has a tacky surface. It won’t work for the hard vat.


#5

My guess is that if you apply while the QSil is still wet (uncured), you can probably use a similar procedure as I did for the soft vat.


#6

Hi Everyone,

I’m new to the forum so excuse me if this has been answered before but I have just purchase some new hard vats after learning a lot with one old hard vat (30 prints or so) and only 2 prints from the soft before it became wavy and unusable for me.

Anyway I have the new vats and was wondering if anyone has considered putting a extra layer of silicon around the outside of the vat so that bonds to the existing silicon and just goes over the FEP layer while not touching any area that is used by the build platform. This would give it a little more protection from the resin getting under the FEP layer and potentially extending the life of the vat.

Dordy


#7

If using hard vat, it is better not to leave the resin in the vat after printing as the resin may attack the adhesive between the film and the silicone. You don’t need to clean the vat unless you are not going to use it for a long time. Just store the vat in the original box should be fine. Make sure the outside bottom of the vat is clean.

If using soft vat, do not print large cross sectional models. There are more stretching on the film but the separation is smoother and faster. If precision is required, do not use the soft vat.


#8

hi, i’m just purchased new hard vat. after only using 1st time my vat becomes wavy and bubble create between vat and teflon film. i’m also try to replace teflon film on new hard vat. but it doesn’t work. bubbles are generated into new teflon film. please help me to repair or how to i reuse my hard vat.

!