Do you post-cure a part inside the mold, or outside (once demolded) ?

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Do you post-cure a part inside the mold, or outside (once demolded) ?

Author	Message
Jess8bit	Jess8bit posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 133, Visits: 566	ok
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wozza	wozza posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 688, Visits: 5.4K	The bag will become a bit brittle but not a problem as that is what it was designed for. Anything above 65- 70 and you will need silicone hose. Also be careful where you clamp of the lines as when the gum tape goes soft the weight of the clamps can pull the hose out of the connector Keep the clamps as close to the connectors as you can. Warren Carbon Copies Ltd Edited 12 Years Ago by wozza
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Jess8bit	Jess8bit posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 133, Visits: 566	that's great. I was wondering how the bagging materials react when heated.
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Warren (Staff)	Warren (Staff) posted 12 Years Ago HOT Post Details
Group: Administrators Posts: 2.5K, Visits: 8.5K	Yep leave it in the bag all sealed off with 2 line clamps when you chuck it in the oven. No stink issues then!! Warren Penalver Easy Composites / Carbon Mods - Technical Support Assistant
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Jess8bit	Jess8bit posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 133, Visits: 566	..oh and, do you keep the bagging materials while post curing ?
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Jess8bit	Jess8bit posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 133, Visits: 566	thank you Warren
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wozza	wozza posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 688, Visits: 5.4K	The Uni-Mould system is good for 90 Degrees C. Ideally put the mould through a couple of heat cycles before you pull a part from it. ( too late for that now ) You only really need to post cure parts at a temperature slightly higher than what you expect the part to be exposed to when in use. And yes if the mould will fit inside then your domestic even is good enough. As said fumes can be an issue so just envelope bag the mould before putting it in the oven. Warren Carbon Copies Ltd Edited 12 Years Ago by wozza
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Jess8bit	Jess8bit posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 133, Visits: 566	Thank you so much for having taken the time to post a detailed explanation, CC ! I use EC Uni Mould system o build my tools, and EC IN2 Epoxy resin (+GC50 sprayed gel coat) to make the parts. As I had bad results recently when demolding (surface defaults), I decided to let my last part cure for 2-daays before demolding. Now it's time to demold, I wonder whether I should post cure it to strengthen both the mold and the part. A bit paranoïd I guess ^^ It's my kitchen oven, yes, as I only do infusion and not prepreg (I'dlike to but lack a freezer to store the rolls, and a bigger oven as well).
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carboncactus	carboncactus posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 243, Visits: 1K	Depends on the HDT of the resins in your mould and in the part. Not to mention the release agents used. Data sheets of the resins you used should mention post cure cycles. Due to shrinkage, I always post cure with the part inside as much as the part will take. Even with "zero shrinkage" resins, there is always shrinkage. Although your part fits in a domestic oven, so no significant shrinkage will occur. Another reason to post cure with the part inside is less chance of damaging the mould when you pull, as the mould will be much stronger. For example, I recently made a mould off a fibreglass wing. Lowest HDT of my resins used was 100C for the tooling resin. So I started at 45 and ramped to 65, left it for 4 hours. As the part inside was fibreglass of unknown resins, I didn't want to take it any higher. So at this point I took the part out and continued with the post cure. Ramped to 80 for 4 hours, ramped to 90 for 4 hours then ramped to 100 for 4 hours. Shut the oven off and let it cool down by itself. If this was a carbon part I was moulding off, I would have left it inside all the way up to 100. Ramps should be at 2 degrees per minute. In large ovens its not much to think about since the larger the oven, the slower it heats up. But in smaller ovens, it's something to keep track of. Also mind the fumes that are going to be released, is this your kitchen oven?
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Jess8bit	Jess8bit posted 12 Years Ago HOT Topic Details
Group: Forum Members Posts: 133, Visits: 566	Yeah, again a silly n00b question of mine And how do you heat it ? simply by placing it in a domestic oven, @60° for some hours ? thanks guys !!
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