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Steve Broad - 8/8/2018 8:30:07 PM

+x

 

quinn - 8/8/2018 3:08:45 PM

+x

 

Lester Populaire - 8/8/2018 2:38:41 PM

+x

 

quinn - 8/8/2018 2:08:36 PM

Another question, after I'm done with the part and it's removed from the mold, how am I gonna want to finish it? I've heard pva can leave a less that perfect finish. Is a clear coat pretty much inevitable? Also am I gonna be able to sand the seam line from the split mold? I would imagine since I'm not laying any kind of gel coat first or anything like that, the fabric is gonna be right at the surface. Since I'm using infusion, I don't really have the option of building up a layer of epoxy at the joint before lay up right?

I would use a chemical mold release. PVA does a really good job at releasing, but when working with spray tack you often time rip off the PVA film when repositioning the fabric which is no bueno. And as you said the surface finish of your part is only as good as the application of the PVA, so realistically you will have brush marks.
If your molds line up perfectly then you don't need any gel coat or anything. Just sand the Burr with the same grid sandpaper as the mold, or a little finer, and you will hardly see it.

Ok, what would you recommend as a chemical release? Preferably something affordable in very small quantity. The canopy surface is about square 0.2 meter and I'll only do a couple so no need to spend a bunch of money on expensive release that will expire. I imagine maybe I want to season my mold with a few runs using pva? I could just do a few single layer lay ups with fiberglass cloth just to help deactivate the mold surface before doing a canopy with no pva if that would help.

EasyComposites offers Easy-Lease at £6.80 for 100ml

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quinn - 8/8/2018 3:08:45 PM

+x

 

Lester Populaire - 8/8/2018 2:38:41 PM

+x

 

quinn - 8/8/2018 2:08:36 PM

Another question, after I'm done with the part and it's removed from the mold, how am I gonna want to finish it? I've heard pva can leave a less that perfect finish. Is a clear coat pretty much inevitable? Also am I gonna be able to sand the seam line from the split mold? I would imagine since I'm not laying any kind of gel coat first or anything like that, the fabric is gonna be right at the surface. Since I'm using infusion, I don't really have the option of building up a layer of epoxy at the joint before lay up right?

I would use a chemical mold release. PVA does a really good job at releasing, but when working with spray tack you often time rip off the PVA film when repositioning the fabric which is no bueno. And as you said the surface finish of your part is only as good as the application of the PVA, so realistically you will have brush marks.
If your molds line up perfectly then you don't need any gel coat or anything. Just sand the Burr with the same grid sandpaper as the mold, or a little finer, and you will hardly see it.

Ok, what would you recommend as a chemical release? Preferably something affordable in very small quantity. The canopy surface is about square 0.2 meter and I'll only do a couple so no need to spend a bunch of money on expensive release that will expire. I imagine maybe I want to season my mold with a few runs using pva? I could just do a few single layer lay ups with fiberglass cloth just to help deactivate the mold surface before doing a canopy with no pva if that would help.

+x

 

Lester Populaire - 8/8/2018 2:38:41 PM

+x

 

quinn - 8/8/2018 2:08:36 PM

Another question, after I'm done with the part and it's removed from the mold, how am I gonna want to finish it? I've heard pva can leave a less that perfect finish. Is a clear coat pretty much inevitable? Also am I gonna be able to sand the seam line from the split mold? I would imagine since I'm not laying any kind of gel coat first or anything like that, the fabric is gonna be right at the surface. Since I'm using infusion, I don't really have the option of building up a layer of epoxy at the joint before lay up right?

I would use a chemical mold release. PVA does a really good job at releasing, but when working with spray tack you often time rip off the PVA film when repositioning the fabric which is no bueno. And as you said the surface finish of your part is only as good as the application of the PVA, so realistically you will have brush marks.
If your molds line up perfectly then you don't need any gel coat or anything. Just sand the Burr with the same grid sandpaper as the mold, or a little finer, and you will hardly see it.

+x

 

quinn - 8/8/2018 2:08:36 PM

Another question, after I'm done with the part and it's removed from the mold, how am I gonna want to finish it? I've heard pva can leave a less that perfect finish. Is a clear coat pretty much inevitable? Also am I gonna be able to sand the seam line from the split mold? I would imagine since I'm not laying any kind of gel coat first or anything like that, the fabric is gonna be right at the surface. Since I'm using infusion, I don't really have the option of building up a layer of epoxy at the joint before lay up right?

+x

 

Steve Broad - 8/8/2018 1:35:04 PM

+x

 

quinn - 8/8/2018 1:17:39 PM

+x

 

Hanaldo - 8/8/2018 6:07:49 AM

I wouldn't trust a jar to hold full vacuum. I've collapsed steel cylinders before, and only managed about half vacuum before they let go. They need to be pretty robust things to handle the vacuum well.

In all honesty, it probably wouldn't be that dangerous - but I'd still take cover. There's a chance that the thing would implode, the energy of which would send shards flying. It's much more likely that it develops a crack first that destroys the vacuum and nothing else happens, but flying glass isn't something I'd be taking chances with.

Well they are definitely designed to handle vacuum since that's how you preserve food in them but I don't know for certain if they are 100% safe at full vacuum. I could probably make it safe by wrapping in fiber tape or something, but ill find a safer way. A chunk of capped off pvc would definitely be safe. If it can handle over 100 psi inside, I'm sure it can handle 14.7 outside.

Maybe over the top, but interesting none the less :-)

https://www.youtube.com/watch?v=2bWxgrtOKz8

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quinn - 8/8/2018 1:17:39 PM

+x

 

Hanaldo - 8/8/2018 6:07:49 AM

I wouldn't trust a jar to hold full vacuum. I've collapsed steel cylinders before, and only managed about half vacuum before they let go. They need to be pretty robust things to handle the vacuum well.

In all honesty, it probably wouldn't be that dangerous - but I'd still take cover. There's a chance that the thing would implode, the energy of which would send shards flying. It's much more likely that it develops a crack first that destroys the vacuum and nothing else happens, but flying glass isn't something I'd be taking chances with.

Well they are definitely designed to handle vacuum since that's how you preserve food in them but I don't know for certain if they are 100% safe at full vacuum. I could probably make it safe by wrapping in fiber tape or something, but ill find a safer way. A chunk of capped off pvc would definitely be safe. If it can handle over 100 psi inside, I'm sure it can handle 14.7 outside.

+x

 

Hanaldo - 8/8/2018 6:07:49 AM

I wouldn't trust a jar to hold full vacuum. I've collapsed steel cylinders before, and only managed about half vacuum before they let go. They need to be pretty robust things to handle the vacuum well.

In all honesty, it probably wouldn't be that dangerous - but I'd still take cover. There's a chance that the thing would implode, the energy of which would send shards flying. It's much more likely that it develops a crack first that destroys the vacuum and nothing else happens, but flying glass isn't something I'd be taking chances with.