Dawing vacuum on my canoe mould

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Dawing vacuum on my canoe mould

Author	Message
rmaddock	rmaddock posted 8 Years Ago HOT Topic Details
Group: Forum Members Posts: 17, Visits: 1.5K	Having been kept away from my canoe project by such trivialities as working in lieu for the workshop rent, I got back to trying to get a good vacuum on my mould this morning. This is the first time that I've tried using the whole mould, having done a test on one end before now. I'm nearly there. I've bought a Sealey ultrasonic leak detector to try out. The result is that it's great for finding the gratuitous leaks that you need the pump running to find but isn't sensitive enough to find the last few little leaks. Next week is the half term for my boys so I'm going to take their younger ears along once the storms have stopped blowing and see if they can hear the hiss. So far, this is the vacuum drop over a five minute test with the pump off. Not good enough yet :-( I must make a canoe this week. I must!
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MarkMK	MarkMK posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 338, Visits: 2K	They are the worst kind of leaks, as it'd be very unlikely that you'd be able to hear the air ingress given the relatively small leak. If a thorough pressing down of the tape all around the bag doesn't fix things, it could be a tiny hole in the bag itself (which is usually very easy to pick up and fix once the infusion's running) but, on such a big part, I don't think I'd want to take a risk. Don't forget to try replacing the tape seal around your entry and exit lines, just in case that's the cause.
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rmaddock	rmaddock posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 17, Visits: 1.5K	+x MarkMK - 10/21/2017 12:25:54 PM They are the worst kind of leaks, as it'd be very unlikely that you'd be able to hear the air ingress given the relatively small leak. If a thorough pressing down of the tape all around the bag doesn't fix things, it could be a tiny hole in the bag itself (which is usually very easy to pick up and fix once the infusion's running) but, on such a big part, I don't think I'd want to take a risk. Don't forget to try replacing the tape seal around your entry and exit lines, just in case that's the cause. Cheers Mark. Yes, I've found from my own experience that the inlet and outlet connections can be one of the biggest problems.
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MarkMK	MarkMK posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 338, Visits: 2K	Not certain if you already employ the same, but I apply a small donut of tape to the top of each connector and seal the bag over it when I get to that point. This helps keep it positioned and helps to stop the bag wrinkling up when installing the entry/exit tubing. Very rarely do they seem to cause and issue since using this method.
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rmaddock	rmaddock posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 17, Visits: 1.5K	+x MarkMK - 10/21/2017 1:06:30 PM Not certain if you already employ the same, but I apply a small donut of tape to the top of each connector and seal the bag over it when I get to that point. This helps keep it positioned and helps to stop the bag wrinkling up when installing the entry/exit tubing. Very rarely do they seem to cause and issue since using this method. No, I do not do that, but I will be doing from no onwards. Thanks!
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Warren (Staff)	Warren (Staff) posted 8 Years Ago HOT Post Details
Group: Administrators Posts: 2.5K, Visits: 8.5K	Hi Maddock, Keep plugging with the bagging and i am sure you will get there in the end. Definitely not quite there yet on the leak test but ultimately thats why we do a leak test so it's better to find the problems now. Make sure your workplace is nicely sanitised and clean of anything that could puncture a bag or end up under the gum tape. Only takes a single strand from CSM to puncture a bag or a stray fibre to bridge the gum tape and it can be a pain to find! Its a shame there isn't some coloured gas you can spray around and watch for where it gets sucked in. Warren Penalver Easy Composites / Carbon Mods - Technical Support Assistant
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MarkMK	MarkMK posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 338, Visits: 2K	It's not been mentioned, but also make sure that you're isolating the vacuum end of your set-up when performing the leak test to eliminate the catch-pot as a possible leak source (this is not uncommon). Apologies if you are routinely clamping the vacuum line when beginning the leak test.
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