+x

 

quinn - 1/27/2019 12:13:49 AM

First part out of the mold.  Still waiting on stuff to show up for bladder so did this one with vacuum. Came out good but has some pinholes in the surface. I assume it should be easier to avoid those with the bladder and plenty of pressure. 

+x

 

Lester Populaire - 1/27/2019 12:12:47 PM

+x

 

quinn - 1/27/2019 12:13:49 AM

First part out of the mold.  Still waiting on stuff to show up for bladder so did this one with vacuum. Came out good but has some pinholes in the surface. I assume it should be easier to avoid those with the bladder and plenty of pressure. 

Looks mint!

+x

 

quinn - 1/27/2019 7:19:35 PM

+x

 

Lester Populaire - 1/27/2019 12:12:47 PM

+x

 

quinn - 1/27/2019 12:13:49 AM

First part out of the mold.  Still waiting on stuff to show up for bladder so did this one with vacuum. Came out good but has some pinholes in the surface. I assume it should be easier to avoid those with the bladder and plenty of pressure. 

Looks mint!

Looks pretty good from a couple feet away, but there's some pinholes. Hoping the higher pressure of bladder will fix that. One thing I'm trying to wrap my head around though, with vacuum bagging, any tiny voids in the laminate are at full vacuum so as the resin heats and starts flowing, the voids should mostly collapse on themselves and dissapear. How does this work with bladder molding? The bladder pushes on the laminate with a lot more pressure, but any tiny voids in the laminate will be at atmospheric pressure, so won't they just stay there? How do they work their way out? With an autoclave, the voids have vacuum on them and the positive pressure assists with extra pressure so that makes sense, but I can't picture how this works with just positive pressure from bladder and no vacuum on the laminate. How do small pockets of air escape the laminate?  I guess somehow it works since it's a common method, just trying to understand how

+x

 

Lester Populaire - 1/27/2019 8:29:00 PM

+x

 

quinn - 1/27/2019 7:19:35 PM

+x

 

Lester Populaire - 1/27/2019 12:12:47 PM

+x

 

quinn - 1/27/2019 12:13:49 AM

First part out of the mold.  Still waiting on stuff to show up for bladder so did this one with vacuum. Came out good but has some pinholes in the surface. I assume it should be easier to avoid those with the bladder and plenty of pressure. 

Looks mint!

Looks pretty good from a couple feet away, but there's some pinholes. Hoping the higher pressure of bladder will fix that. One thing I'm trying to wrap my head around though, with vacuum bagging, any tiny voids in the laminate are at full vacuum so as the resin heats and starts flowing, the voids should mostly collapse on themselves and dissapear. How does this work with bladder molding? The bladder pushes on the laminate with a lot more pressure, but any tiny voids in the laminate will be at atmospheric pressure, so won't they just stay there? How do they work their way out? With an autoclave, the voids have vacuum on them and the positive pressure assists with extra pressure so that makes sense, but I can't picture how this works with just positive pressure from bladder and no vacuum on the laminate. How do small pockets of air escape the laminate?  I guess somehow it works since it's a common method, just trying to understand how

You basically just increase pressure so bubbles become so small you cannot see them anymore. Furthermore air can still eacape through mold seams realistically. On moulds where i cannot apply too much pressure i usually pack the whole shabam into an envelope bag as well.

+x

 

quinn - 1/27/2019 9:07:54 PM

+x

 

Lester Populaire - 1/27/2019 8:29:00 PM

+x

 

quinn - 1/27/2019 7:19:35 PM

+x

 

Lester Populaire - 1/27/2019 12:12:47 PM

+x

 

quinn - 1/27/2019 12:13:49 AM

First part out of the mold.  Still waiting on stuff to show up for bladder so did this one with vacuum. Came out good but has some pinholes in the surface. I assume it should be easier to avoid those with the bladder and plenty of pressure. 

Looks mint!

Looks pretty good from a couple feet away, but there's some pinholes. Hoping the higher pressure of bladder will fix that. One thing I'm trying to wrap my head around though, with vacuum bagging, any tiny voids in the laminate are at full vacuum so as the resin heats and starts flowing, the voids should mostly collapse on themselves and dissapear. How does this work with bladder molding? The bladder pushes on the laminate with a lot more pressure, but any tiny voids in the laminate will be at atmospheric pressure, so won't they just stay there? How do they work their way out? With an autoclave, the voids have vacuum on them and the positive pressure assists with extra pressure so that makes sense, but I can't picture how this works with just positive pressure from bladder and no vacuum on the laminate. How do small pockets of air escape the laminate?  I guess somehow it works since it's a common method, just trying to understand how

You basically just increase pressure so bubbles become so small you cannot see them anymore. Furthermore air can still eacape through mold seams realistically. On moulds where i cannot apply too much pressure i usually pack the whole shabam into an envelope bag as well.

Ok, that makes senss. A tiny void at atmospheric pressure will become almost nothing at all when compressed to much higher pressure. I imagine it also might be slightly beneficial to orient the mold so seams are vertical, one seam at top and one at bottom so bubbles moving around will have an escape at the high point. As for pressure, with this mold I imagine I could go as high as I wanted. Would probably take 1000 psi to split this mold apart. Although at some point the m6 bolts will start to stretch a bit and open the seam slightly. I'll probably go with 100psi or so. Is there any benefit to varying pressure throughout the cure? Like maybe lower pressure at first so bubbles can move around easier while resin is liquid, then ramp up the pressure right before going to final cure temp? Or just give it full pressure in the first place and keep it there?