Aluminum mold for prepreg

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Aluminum mold for prepreg

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quinn	q quinn posted 6 Years Ago HOT Topic Details
q Group: Forum Members Posts: 155, Visits: 992	I'm about to start machining my mold but I have a few concerns. The composite part is an 800m long tapered tube. 46mm diameter at one end, 30mm at other end. The closed mold is 75mm square by 800mm long. This means the mold walls will be as thin as 15mm at one end and as thick as 22mm at other end. One concern is the time it takes for this big chunk of aluminum to heat up, the other concern is uneven heating, thinner walled end heating up first. How should I approach this with my ramp cycles? Just go slower in general? Hold temps longer? I'm really not sure what to expect for how long it's gonna take for it to heat up. If the varying wall thickness is gonna be a big problem, I can do some machining on the outside to even it out, but would rather not if it isn't needed. First few parts will be done with vacuum bag so the laminate will be exposed to the heated air but later on I'll be trying silicone expanding plug so I'm sure that will change things as far as heating. Any advice on how to approach this? Thanks
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Steve Broad	Steve Broad posted 6 Years Ago HOT Post Details
Group: Forum Members Posts: 408, Visits: 4.1K	+x quinn - 1/29/2019 4:35:57 PM Been doing a little more reading and feeling a bit less confident about the latex bladder. Seems that latex isn't all that resistant to heat and deteriorates pretty quickly. I already have some wax sheets that I ordered a while ago when I was planning on making my own bladder, so I went ahead and ordered some silicone too so I'll also have that option. The thick sausage type party balloons survived 120 deg C with no issues.
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quinn	q quinn posted 6 Years Ago HOT Post Details
q Group: Forum Members Posts: 155, Visits: 992	+x Steve Broad - 1/29/2019 6:18:46 PM +x quinn - 1/29/2019 4:35:57 PM Been doing a little more reading and feeling a bit less confident about the latex bladder. Seems that latex isn't all that resistant to heat and deteriorates pretty quickly. I already have some wax sheets that I ordered a while ago when I was planning on making my own bladder, so I went ahead and ordered some silicone too so I'll also have that option. The thick sausage type party balloons survived 120 deg C with no issues. Ok good to know. It sounds like latex can work well, but maybe not for that many repeated cycles if using a more permanent reusable one. I guess even if I use the latex bike inner tube, it's still only a few bucks for each one. Maybe use it a couple times or even use a new one each time. Not a big deal. Having a hard time finding balloons that are long enough and expand enough at the large end. I ordered some "rocket balloons" on Amazon and they inflate enough to fill the cavity, but they are just about at their limit at the large end and they aren't very durable. Large end is 40mm×46mm. Edited 6 Years Ago by quinn
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Steve Broad	Steve Broad posted 6 Years Ago HOT Post Details
Group: Forum Members Posts: 408, Visits: 4.1K	+x quinn - 1/29/2019 6:25:37 PM +x Steve Broad - 1/29/2019 6:18:46 PM +x quinn - 1/29/2019 4:35:57 PM Been doing a little more reading and feeling a bit less confident about the latex bladder. Seems that latex isn't all that resistant to heat and deteriorates pretty quickly. I already have some wax sheets that I ordered a while ago when I was planning on making my own bladder, so I went ahead and ordered some silicone too so I'll also have that option. The thick sausage type party balloons survived 120 deg C with no issues. Ok good to know. It sounds like latex can work well, but maybe not for that many repeated cycles if using a more permanent reusable one. I guess even if I use the latex bike inner tube, it's still only a few bucks for each one. Maybe use it a couple times or even use a new one each time. Not a big deal. Having a hard time finding balloons that are long enough and expand enough at the large end. I ordered some "rocket balloons" on Amazon and they inflate enough to fill the cavity, but they are just about at their limit at the large end and they aren't very durable. Large end is 40mm×46mm. Look for something like these: https://www.ebay.co.uk/itm/Pack-of-10-Qualatex-Latex-Modelling-Balloons-160Q-260Q-350Q-646Q/142279076152?epid=1010298085&hash=item21207e6938:m:mEGch4FK9sgwAfjs6GsXwcg:rk:2:pf:0
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quinn	q quinn posted 6 Years Ago HOT Post Details
q Group: Forum Members Posts: 155, Visits: 992	+x Steve Broad - 1/29/2019 11:36:55 PM +x quinn - 1/29/2019 6:25:37 PM +x Steve Broad - 1/29/2019 6:18:46 PM +x quinn - 1/29/2019 4:35:57 PM Been doing a little more reading and feeling a bit less confident about the latex bladder. Seems that latex isn't all that resistant to heat and deteriorates pretty quickly. I already have some wax sheets that I ordered a while ago when I was planning on making my own bladder, so I went ahead and ordered some silicone too so I'll also have that option. The thick sausage type party balloons survived 120 deg C with no issues. Ok good to know. It sounds like latex can work well, but maybe not for that many repeated cycles if using a more permanent reusable one. I guess even if I use the latex bike inner tube, it's still only a few bucks for each one. Maybe use it a couple times or even use a new one each time. Not a big deal. Having a hard time finding balloons that are long enough and expand enough at the large end. I ordered some "rocket balloons" on Amazon and they inflate enough to fill the cavity, but they are just about at their limit at the large end and they aren't very durable. Large end is 40mm×46mm. Look for something like these: https://www.ebay.co.uk/itm/Pack-of-10-Qualatex-Latex-Modelling-Balloons-160Q-260Q-350Q-646Q/142279076152?epid=1010298085&hash=item21207e6938:m:mEGch4FK9sgwAfjs6GsXwcg:rk:2:pf:0 Perfect, the 6 inch ones should should fill it nicely without thinning out too much. Was only able to find the standard size ones before. Now I know to search for 646q. Plenty on amazon
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