StressedOut
Well Known Member
While I wait for some parts to be delivered, I'm tinkering with a mold for some sealant to see if I can replicate cap seals like they use in building larger airplanes. This is also a good opportunity to sharpen up my Solidworks skills that have eroded since I took a class in 2017.
If you're not familiar with pre-manufactured cap seals, you fill the inside with some sealant and push them over the shop head. The sealant squeezes out the bottom to form a nice, clean seal around the shop head. It's less prone to leaks and much, much cleaner to use than smearing around a gob of sealant with a Popsicle stick.
I'm new to mold creation, so I thought I'd ping the community for your thoughts. I'm planning on using fuel tank sealant, like 3M AC-350. I can't seem to find AC-236 anymore except from Vans, but they don't have Class A. Class A is less viscous which makes it a better candidate for injecting into a mold, so I'll start with that and see how it goes.
I've already designed a prototype mold and my friend is going to fabricate it for me. (BTW, it really helps to have a friend who just happens to be a master machinist with his own milling machine.) It's a pretty basic design that will fit over the shop head of a #3 rivet.
Since sealant was originally designed as an adhesive, I want to make sure to use some mold release so I can pry apart the mold after cure without damaging the cured part. There are several types of mold release products out there, but I'm concerned about the release agent having some adverse effects on the sealant during cure.
What might be a good choice for mold release? Wax, silicone, crisco, or something else? It has to be something that won't react to a poly sulfide sealant.
If you're not familiar with pre-manufactured cap seals, you fill the inside with some sealant and push them over the shop head. The sealant squeezes out the bottom to form a nice, clean seal around the shop head. It's less prone to leaks and much, much cleaner to use than smearing around a gob of sealant with a Popsicle stick.
I'm new to mold creation, so I thought I'd ping the community for your thoughts. I'm planning on using fuel tank sealant, like 3M AC-350. I can't seem to find AC-236 anymore except from Vans, but they don't have Class A. Class A is less viscous which makes it a better candidate for injecting into a mold, so I'll start with that and see how it goes.
I've already designed a prototype mold and my friend is going to fabricate it for me. (BTW, it really helps to have a friend who just happens to be a master machinist with his own milling machine.) It's a pretty basic design that will fit over the shop head of a #3 rivet.
Since sealant was originally designed as an adhesive, I want to make sure to use some mold release so I can pry apart the mold after cure without damaging the cured part. There are several types of mold release products out there, but I'm concerned about the release agent having some adverse effects on the sealant during cure.
What might be a good choice for mold release? Wax, silicone, crisco, or something else? It has to be something that won't react to a poly sulfide sealant.