Dry areas appearing when using GC50

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Dry areas appearing when using GC50

Author	Message
MarkMK	MarkMK posted 9 Years Ago Post Details
Group: Forum Members Posts: 338, Visits: 2K	Doh! That'll teach me to pay closer attention. Thanks gents, glad I raised it now rather than just going round in circles looking for an solution
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Warren (Staff)	Warren (Staff) posted 9 Years Ago HOT Post Details
Group: Administrators Posts: 2.5K, Visits: 8K	Yes the formulation changed meaning acetone does not activate it in the same way as before. Acetone could well end up attacking any area that is not fully cured which would make things worse if you have holes in the gelcoat when it comes to infusion. Warren Penalver Easy Composites / Carbon Mods - Technical Support Assistant
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Brian_s	Brian_s posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 99, Visits: 2.5K	There is a note in that video that the formula for GC50 has been changed and acetone no longer works to make it tacky. Brian.
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MarkMK	MarkMK posted 9 Years Ago Post Details
Group: Forum Members Posts: 338, Visits: 2K	Sorry, no pics of set-up Chris, but will likely run another part this week. Stack was two plys of 200g twill backed with one of 450g. This was topped with peel-ply and EC mesh which, I believe, is medium flow. Everything was sealed quite soon after full vacuum was read on the guage and tone of the pump indicated no more air was being drawn. Warren - An interesting point regarding the acetone as I'm sure that one of Matt's tutorial videos shows him using it on the Fiat bonnet infusion. It does feel kind of logical, though, that this might have had a part to play in weaking the gelcoat surface, so I'll likely avoid it now.
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ChrisR	ChrisR posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 363, Visits: 3K	A bit more info may be required: What's the stack sequence? How long did you pull the vac before sealing for the drop test? How fast was the infusion mesh? Have you any pictures of the thing bagged up and ready to infuse?
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Warren (Staff)	Warren (Staff) posted 9 Years Ago HOT Post Details
Group: Administrators Posts: 2.5K, Visits: 8K	The picture looks like there are actual voids there not alligatoring. The voids are right through the gelcoat. We dont recommend spraying acetone onto the gc50 so its possible that eat through the gel leaving voids to trap air. Warren Penalver Easy Composites / Carbon Mods - Technical Support Assistant
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MarkMK	MarkMK posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 338, Visits: 2K	I can understand it had I been shutting off the resin feed prior to the vacuum line, as you explained, but I have been allowing the resin to continue flowing for a while after closing the vacuum which I hoped would help guard against possible dry areas. Thanks anyway
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Jacopo Carbonio	Jacopo Carbonio posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 43, Visits: 109	This also happened to me when I closed the entrance of the resin and after too much time the vacuum line, because the vacuum has sucked too much resin..so usually I wait the resin arrives in outlet pipe (vacuum tube) and so I close the line of the resin and after a very little time the vacuum line, to prevent the resin to be sucked from the gaps of the tube or of the spiral. You can try, or describe better how you did your work, no problems for the spray glue if you don't use too much
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MarkMK	MarkMK posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 338, Visits: 2K	I agree, it does, but the imperfections have also broken the outer gelcoat when previously I'd only ever witnessed this appearing underneath (which is worse as you can't get to them in order to try and rectify). The part wasn't overly large and ambient temps have been around 20° of late. I've also been careful to leave the resin feed open for 15 seconds or so following closure of the vac line.
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ChrisR	ChrisR posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 363, Visits: 3K	It looks like dry spots from the infusion rather than a surface problem
	Reply Like 4