Thinnest viscosity casting resin

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frank123

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I have limited experience with different resins but have a potential experiment I'm thinking of involving molding completed fountain pen bodies and caps that only need final fitting and finishing and am wondering if anyone knows which casting resin has the thinnest consistency and also maybe which of the resins produce the least heat when curing.

It's a 3D printing mold making from CAD designed parts if anyone is wondering what it may be used for.
 
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Well over here (Uk)

glass cast 50:10 is thin but I would anticipate maybe issues with air bubbles , although it does seem to de gas itself fairly well due to long curing time.
 
Although I have not used it myself, I have heard that Liquid Diamonds has a very low viscosity, low enough that it remains relatively bubble free even without using a pressure pot. I'm sure there must be others on the forum that have much more experience with the resins than I do though. - Dave
 
I've used Liquid Diamonds snd it's a very thin resin. I tried without pressure and there were still bubbles. You need a magnifying glass or bright light to see them but they were there. My problem was that it always yellowed. There are better resins for what your doing you just need to be careful handling the bubble issues.
 
You're venturing into the realm of real plastics manufacturing. Injection molding to be precise... Which pretty much rules out any of the standard hobby resins. I mean, you can fiddle with making a mold and playing with the available stuff but I don't think epoxy is going to be a good option at all for a number of reasons. Pretty much all of the hobby ones have VERY low heat deflection and a pen left in a car in summer would wilt as an example.

I can think of a few ways to do it but none of them are ideal. What is the maximum temp your 3d printed mold can handle? Viscosity shouldn't be much of an issue with any retail level resin... you SHOULD be using pressure if you don't want voids and most of them flow fine for shapes like this.
 
McKenzie Penworks said:
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I can think of a few ways to do it but none of them are ideal. What is the maximum temp your 3d printed mold can handle? Viscosity shouldn't be much of an issue with any retail level resin... you SHOULD be using pressure if you don't want voids and most of them flow fine for shapes like this.
Click to expand...

I'm planning to try HIPS filament for the mold and think I should be able to get away with around 360F without any problem. I could probably cool or support the mold if needed to raise that temp easily enough, there are other filaments I could use but I lean toward HIPS because it is cheap and can be dissolved to remove the mold from the part. The actual making of the mold using a 3D printer is the easy part, probably the easiest way possible to make any kind of detailed mold.

Post treating the part by salt fusing would be desirable as either a finishing or pre finishing step if the resin is not heat resistant to any degree but that's just an idea I'm toying with. I generally think about a project for a fair amount of time before I try it but I usually end up making three of everything I make from an original concept anyway, the alpha, the beta, and the one that works.
 
360 is way up there as far as exotherm, nearly any off the shelf resin will be just fine. Off the top of my head one of the highest heat cure resins you can buy commercially is heat cured at just over 200 F so you've got all kinds of options there. As far as the cured part goes, your epoxy resins will average close to 100F for heat deflection but there are some out there with considerably higher tolerances. The problem becomes color... Most of the truly heat resistant stuff will be tinted vs clear if that matters. Not to say you can't color it but it'll be regular plastic looking vs sparkly resin like so many pen blanks (including my own..) I think anything in the 140F range is probably safe from a heat deflection property. You'll want something near 80D hardness so it takes a polish. In theory you could rough finish with a simple tumbler... you'll still be looking at hand sanding and polishing but that might shorten the manual process a bit.

I'm a big fan of urethane... though unless you're truly injection molding you will typically want the part to be under pressure.
 
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