What resin setting and thickness setting were you using?
Mostly .1 with the odd .5 in black resin. When I had my first printer before the upgrade, i made the mistake of printing at .25 all the time and killed PDMS sections very rapidly printing in grey.
In response to the zero position they have an optical switch at the top of the right side of the column which houses the threaded rod that drives the platform. They also have what I assume is the zero position switch taped to the right side of the column near the bottom. With this second switch I’m not sure what type of switch it might be.
So I figured out how the zero position is found. There is only one sensor. It is an optical endstop at the inside top right of the column that the carriage the platform is mounted to moves up and down in, there is also a flag on the back right hand side of the carriage that triggers the endstop. When a print starts if the flag is not in the endstop the carriage is moved up until the flag is detected in the endstop. Now the carriage is moved down until the flag exits the endstop. This is the 165mm position. The carriage is then moved down 165mm to the zero position and the print then begins.
The takeaway from this is that when replacing the PDMS layer with new PDMS or alternate materials getting the thickness correct is important as the zero position is a fixed location you can adjust it ±1mm but that is it, so you have to be close or you risk the tray not working.
@Leefields and others on this side of the pond - I found a cheaper optically clear silicone that works just as well. It’s called Electrolube SC3001 - and it’s £18 for 250gms on Amazon (free delivery on Prime).
I’ve tested it with about 2000 layers of parts in FL and MS resin, parts printed just the same - and it seems to cloud at about the same rate as the Sylgard 184. Which is to say at about 1000 layers 50m in Madesolid kickstarter white, and no clouding at all after 2000 layers of FL resins at 50m.
Note the product image on amazon is borked - this is what it actually looks like -
The downside is that it’s condensation cure and comes in evacuated resin packs, which are designed to be mixed in the pack and used in one go - and because it’s condensation cure and is sensitive to normal humidity ranges (hence why it comes in no-air sealed packs)- you pretty much have to.
So - it’s about right for resurfacing 3 of the old style tanks at once which take approx 80/85ml of silicone, but it’s awkward for the new style resin tanks which take about 65ml. You might be able to eke it out to resurface 4 of the new style tanks in one go - if you carefully squeezed out every drop - but that’s a lot of tanks to do at once.
If you’ve only got 1 or 2 tanks to do, it’s probably not cheaper…
The weight of PDMS has been measure by stripping out a failed layer whole and weighing it.
The weight of cured PDMS is 63g +/- 1g
There is a nice little business for somebody in the UK recycling the old trays.
I believe orange oil based solvents are safe with acrylics but cna not confirm if the material the trays are made of will with stand it.
The Sylgard 184 is available in America on ebay . I think it may require vacuum degassing after mixing the catalyst to the bulk but not a difficult task. The mixed silicone could be dispensed to a cleaned print tray using digital scales as the control of thickness assuming the top of the scales was ensured to be level.
I may have a go for myself as it is more economic than buying new ones especially if a suitable supplier of an alternative resin could provide the service as a single source.
Hello there,
we followed this discussion back then, when we had these issues by our selfs. It’s quite hard to maintain a profitable printing service with a F1 if you have to buy every liter or so a new resin vat.
We used the manual process described here and elsewhere to refurbish our old tanks. But if you are not based in the US (i.e. europe) it’s quite hard to get Sylgard or similar silicone.
During the last year we developed a somewhat convenient process for renewing a vats silcone layer. Last week we started a Kickstarter campaign, to get our process available for everyone which is willing to reuse their vats. We thought, it could be of interest for you: https://www.kickstarter.com/projects/257551006/druckwege-recoat
OK, here is my first attempt to recoat the PDMS layers on some tanks. I have a Zvats a Form 2 and two Form 1+ tanks. Everything seemed to go well, the weight scale is a must have to be accurate. The heat gun to remove the air bubbles was amazingly quick. They are now covered and ready for 48 hours of curing.
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Looks great Mlabird, good on you for taking the time to be efficient and resourceful. I had a couple thoughts given your setup and notes, if I may-
-I see you’re using a glass plate for. That’s an excellent choice for a level surface, it’s what I use too. Just make sure it’s thick enough given the length and width so that it won’t bow at all. Mine is super rigid at 3/8", for what it’s worth.
-One thing that may make it easier in the future is to use three points of contact rather than four. It’s easier to level on three points because there is always one touching the surface (think of a 3-legged stool vs. a wobbly 4-legged table. And as a bonus, that way you can use one of those cans for some delicious red beans and rice while you wait for your PDMS to cure 
-You don’t need to use a heat gun, the bubbles rise and pop from the mix completely on their own after a short time. The heat gun probably won’t hurt things, but it won’t help them either and will save some trouble.
Cheers!
Zvat,
Thanks for the tips, my glass is very ridged no issues there, the leveling I needed to work on. the glass was level but it took me some time to get it there. I need some kind of printable jacking screws that I can put under the glass. I don’t plan to use the heat gun in the future. They all cured nicely and are ready for use.
I thought the cans were a great idea, LOL
Mike
Scout Design & MFG
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Did anybody ever tried Sylgard 182 instead of Sylgard 184? seems that it is a little bit harder… would like to hear your toughts.
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Hi friends,
I know this is four years old but I need some help after reading a lot here about.
I am recoating my Form2 orange tanks with success. I am using 110gr of PDMS on it. But I won a
Form 2 LT tank and saw that people are using less PDMS to coat it: 55gr and 63gr.
What’s the best number of grams for the LT Form 2 tank?
Thank you
Luis
That sounds really low.
I though it was around 102gr for LT. I have the numbers somewhere…
Yes, it seems really low. I think we will need ate least the same of the orange tray or even a few more grams.
If you find the magic number, please let me know, my dear friend!
Best regards,
Luis