FORM 2 PDMS LAYER RESTORATION .pdf

FORM 2 PDMS LAYER RESTORATION
Well, I've been doing this for awhile to make sure everything was working. I've done this on my Moai
and also on my Form2. With surgical guides, the silicone layer (PDMS layer) will start to cloud and
wear out. Form has stated that you would only get a couple liters of resin through one resin tank
(aka Vat). The PDMS layer can also pull away due to suction forcess. It can tear from either a print
failing and the build plate smashing it, a print failing and curing to the PDMS layer, or we tear it while
cleaning it.
A new resin tank is 59 dollars. The new silicone is 45 dollars that can restore 5-6 vats. In essence
you could save about a little more than 300 dollars. It's not hard and only takes a few mins.

David W Honey DMD

First you will need to remove the old PDMS layer. You can get a spatula and pry up on the PDMS
from a corner. Be careul not to pry to hard to crack or scratch the acrylic. Seen in pic #2 and #3

David W Honey DMD

David W Honey DMD

You should be able to peel the PDMS layer all as one piece like in pic #4, #5.

David W Honey DMD

David W Honey DMD

Then measure the old PDMS layer. Pic #7 and #8
David W Honey DMD

David W Honey DMD

Also clean the sensor as seen pin picture #9 and #11
David W Honey DMD

David W Honey DMD

Clean out the old resin in the tank with IPA if needed. Do not leave the IPA in the vat for long as it
can start to break down the silicone holding the acrylic together. Pic #12 (this is a Moai tank)

David W Honey DMD

If there are any scratches that are deep, you will need to polish those out. I used the novus polish
(#13) and cleaner along with a 3M headlight polish pad that fits to a drill (#14).

David W Honey DMD

novus polish amazon link:
https://www.amazon.com/…/B00…/ref=oh_aui_detailpage_o00_s00…

3M headlight polish pad:
https://www.amazon.com/3M-39008-Headlight-Res…/…/ref=sr_1_2…
In pic #15 you can see the scratch slightly to the left of the middle. Resin had gotten underneath the
PDMS layer and cured. When flaking it off I scratched the area. IF a heavy scratch use a good
amount of 3 on the pad and polish the heck out of that acrylic area. Then go to two, and then the
cleaner 1.

David W Honey DMD

It should look like clear like in pic #16

David W Honey DMD

What we need is called sylgard 184 (pic #17). The stuff from Dow Corning is very expensive and
always on backorder. This stuff is the same stuff they coat solar panels with. I tried this stuff from
another vender and it works really well that Paul Yanzick had found. I've done about 20 recoats and
havent had problems with it. It can be found here:
http://www.ebay.com/…/Cell-Guard-PDMS-Materia…/172542720937…
https://www.amazon.com/Solar-Encapsulation-Ma…/…/ref=sr_1_1…

David W Honey DMD

This stuff is mixed at a 10:1 ratio of silicone to activator
Remember how you measured your old PDMS layers. They are all typically around the 100mg mark
and we want to match that as close as possible. So this stuff is 1mL = 1mg

I measured 100mg or 100mL (If this is your fist time measure out 110mg or 110mL) pic #18
David W Honey DMD

Then measure out 1/10 of the amount of silicone you used of activator. Example: You use 110mL of
silicone, then use 11mL of activator. (Pic #19)
David W Honey DMD

Mix the two together in a disposable cup. Mix this up really well for a couple of mins. There will be
lots of air bubbles. Do not worry about the bubbles. They will self pop. (Pic #20)
David W Honey DMD

Put your clean resin tank on top of a scale. Then pour in the same amount of material in weight as
what your old pdms layers is. Slowly pour it in and try to get the whole bottom coated. It will also
level out. Pic #21

David W Honey DMD

After pouring it you will need to find a fairly level place to put it and get a level and make sure it is
level front to back and side to side Pic #23, #24
David W Honey DMD

David W Honey DMD

Again do not worry about the bubbles. They self pop. Pic #26, #27.

David W Honey DMD

David W Honey DMD

Put the cover that comes with the resin tank from form on to keep dust out. This will need to set for
minimum 2 days.
Pic #28

David W Honey DMD

Pic #29 shows what it looks like after 2 hours
David W Honey DMD

Pic #30 shows what it looks like after 2 days. No air bubbles.
David W Honey DMD

Now for the true test. Will it work!!!
I first tried model resin. You will want to test the wiper, but DO NOT TEST WITHOUT resin in the
tank. This helps lubricate the wiper so it will glide across. IF not it will rub against the PDMS layer
hard. (pic 31b)
David W Honey DMD

You will get prompted that the tank had a different resin type. Just hit ignore. (pic #34) Then it will tell
you that it will change the tank resin type. Just hit continue print. (pic#34b)

David W Honey DMD

David W Honey DMD

The models have been printing well (pic#35)
David W Honey DMD

I have also tested this on surgical guide resin from Form as well. This resin tears up the PDMS layer
the easiest. But its working great! (Pic #36)
David W Honey DMD