Thank you for all the testing with FEP!
It’s because of people like yourself doing things like this that we end up with true improvements 
What did you find was the best method of putting down the FEP? How difficult was it to apply? Does it have a stick backing so it sits well with the PDMS? I am planning on applying a FEP layer to the whole of my resin tank to use with a custom resin as I have an incompatible resin that cannot come into contact with PDMS. Any information you can give me would be great, and I would be happy to share my findings with the community.
2 Likes
Yes, It is a adhesive back so you have to peel a carrier sheet off… That is the biggest issue. It so thin that it stretches when you try to get started. That’s why I am getting larger sheets and will start it on the side of the tank then work it down the PDMS layer from the wiper side to the opposite side… That way there is no edge for the wiper to catch. (Just a safety precaution)
A few other things I am playing with is using a Graffiti resistant laminate. In my main business (Signs) we have a laminate that is optically clear, adhesive backed, UV Coated and is 3mils thick. It acts like clear wax paper so it repels any paint so I want to do a test with this also. May be a much cheaper alternative as long as it sticks to the PDMS. Just not sure if the UV coating will cause an issue… Even though Form printers are not UV I am not sure if will restrict any wavelengths
The Graffiti Laminate… EPIC FAIL. Stuck to the PDMS fairly well… But I guess the coating and resin really like each other… They made a love connection and are permanently stuck together 
Chock it up to one more idea that doesn’t work.
2 Likes
I have some redundant tanks and looking to replace the PDMS layer. what silicone are you using and how do you go about putting the resin in without bubbles forming? Help appreciated
Silgard 184… Silicone really needs to be degassed with a vacuum chamber, but I have read many people are having good luck just mixing it and pouring it in a corner and let it self level… You can eliminate most surface bubbles by blowing over the top or you can use a propane torch and quickly pass over the top and that will pop the bubbles also. (This is the trick I use on paint also when rolling out enamels to level it off and give a glass smooth finish)
For others following, Sorry for the delay, Have been super busy in the shop and just haven’t had the time to mess around with the FEP as the printer has been running 24-7 for the last few weeks. I am having surgery on the 24th so will be closed for a couple months so once I am out and recovered a little bit I will have time to play/experiment with the FEP/PDMS combination.
Unfortunately I don’t think it will work with the FL resins as there is no way to adjust the laser settings (F2).
Was using the the Makerjuice Resins on some non critical parts in open mode with very good success by using one step lower settings. (Grey profile on Black, White on Grey) So my line of thinking since the FEP does restrict a little bit of Light (20% or so) that the standard settings for each color will end up being right on for the MJ resins.
If so hopefully FL will give us the ability to tweak the laser a bit to compensate for this and use their resins as the heater and wiper would be nice.
1 Like
I’m not sure if it will help, but when I cover my FDM printer’s heated aluminum build platform with Kapton tape, I put down a layer of warm water with a little bit of soap mixed in. Then I squeegee out the water. It would be practically impossible to get the wide roll completely flat/bubble-free without the soapy water…
Is it worth considering that since the Form2 printer has a leveling function, that IT might be a good place to pour the new Sylgard? In my mind you just level the printer, pop in the tray and pour. Granted, the printer is unusable until it dries, but if you didn’t have a spare tank anyway it would still be so. If the printer’s heater could be hotwired, cure time would be significantly reduced.
Also, am I correct that anything needing to be nonstick and optically clear/smooth/etc. in the tray need ONLY be so over the clear acrylic panel, and anything over the orange plastic wouldn’t affect printing?
1 Like
The guy in the group that does the breathtaking glasswork and makes glass-bottom F1+ trays might be able to set up a jig to cleanly produce these trays with the Sylgard and FEP. I would be curious about the laser spot diffusion when passing through the FEP+EPDM+Acrylic or Glass on an angle, except that your part looks pretty nice, considering the attenuation AND B9, and other competitors have already switched to FEP or water or? Only FL is major manufacturer with EPDM, but that could be because of the cool things they are doing to enhance resolution (that would take time to redo), and that might change soon, anyway.
1 Like
so no one knows if we can just order the silicone base as a sheet instead of pouring it? there isn’t a way to reverse engineer the silicone to know exactly what is needed?
There isn’t much work to be done here. Weigh the original PDMS and use that weight for your new material.
Level the tank, pour, get the bubbles out. Wait for it to cure. Done.
1 Like
The PDMS should be poured so it fits to the walls of the tank and blocks any resin from creeping below. Only other way is to make some sort of clamping system and at that point might as well use a flexvat.
As far as getting bubbles our you can build a degassing chamber fairly easy. I used a paint pressure can from Harbor Freight and was on sale for around $75. I used the tank for either pressure casting or with a pexi sheet and home made gasket and my old vacuum pump. Vacuum pumps are readily available on ebay and costs vary. A rotary vane is the best. You need 29 bars.
1 Like
FYI, you do not need to manually de-gas the PDMS after mixing. All bubbles will rise to the surface and extinguish themselves within about ten minutes, leaving a perfectly clear mix. This should save some money and labor on vacuum equipment.
That makes it easier.
Curious if anyone has tried pressure casting the PDMS and if so does it increase the durability?
Do we know how soon the FL F2 green long-life trays will become available? I am more inclined to use the more-challenging resins once I am sure the tray will last through a few cartridges. Seems like a great idea and great timing. Thank you.
For order now with 8+ week lead time.