Keeping the pump on while curing

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Keeping the pump on while curing

Author	Message
Jcookson	Jcookson posted 13 Years Ago HOT Topic Details
Group: Forum Members Posts: 5, Visits: 124	Hi I infused half of a hull this weekend and after it had infused I found the pressure started dropping my question is, can the vacuum pump be left on while the part is curing of will in suck the resin out the laminate or could in put and extra vac port in that doesn't come in to contact with the infusion mesh. Also does anyone know of and infusion mesh that is easy to use.
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Warren	Warren posted 13 Years Ago HOT Post Details
Group: Administrators Posts: 214, Visits: 782	Depends on your layup. If youve got a physical gap between the fabric and the vacuum area then usually you can get away with it as long as there is no resin flow up the vacuum line. The biggest problem with leaving the pump on is the risk of sucking out too much resin. The other problem is you may well get pinholes if the pressure is dropping a bit as any air in the resin will expand as the pressure drops.
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Jcookson	Jcookson posted 13 Years Ago HOT Post Details
Group: Forum Members Posts: 5, Visits: 124	Thanks I think it will be ok as I put the mould in one big bag as it is not possible to go of the flanges and pleat the bag so I'm thinking on the underneath of the mould put a couple of layers of breather and place an extra vac port as it hard to get a perfectly sealed bag
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andygtt	andygtt posted 13 Years Ago HOT Post Details
Group: Forum Members Posts: 157, Visits: 1.2K	I regularly leave the pump running while the part is curing.... I usually do this when i've had a leak (with my complex shapes this happens a lot unfortunatelly). doing this has helped me save some massive parts that developed leaks and would have been scrap otherwise. basically if the bag has any kind of leak you WONT get an absolutely perfect pinhole finish anyhow so its worth doing... you wont suck too much resin out of the part, what will happen though is that you MAY fill the vacume pot with resin and get issues here so keep an eye on it and empty as required. Remember you technically only need enough resin to wet the cloth out... if its been wetted I dont think you can suck resin out and 'unwet' it so the part will just be lighter and yet just as strong... the drawback is finish.... certainly this is my experience. If the part is being laquered or painted there is no drawback of leaving the pump on in my experience.... Yes I have just had to replace my vacume pot this month due to resin damage while leaving the pump running, but that is a lot less money than the many thousands I would have lost in materials (not including many days of time) if I hadnt left the pump running. I've considered using the MITI hose, but i'm worried it will block once resin reaches it and stop air being pulled thus my part would loose vacume... be interested in knowing if this is others experience.
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Jcookson	Jcookson posted 13 Years Ago HOT Post Details
Group: Forum Members Posts: 5, Visits: 124	interesting but thre way i want to try is putting an extra vac point on the underside on the mould so no resin can be sucked through.
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Warren	Warren posted 13 Years Ago HOT Post Details
Group: Administrators Posts: 214, Visits: 782	andygtt (11/12/2012) you wont suck too much resin out of the part, what will happen though is that you MAY fill the vacume pot with resin and get issues here so keep an eye on it and empty as required. Remember you technically only need enough resin to wet the cloth out... if its been wetted I dont think you can suck resin out and 'unwet' it so the part will just be lighter and yet just as strong... the drawback is finish.... certainly this is my experience. yes you cant make it 100% dry, but you can suck out enough resin to make the surface 100% pinholed on the vacuum end of the part. Ive done that before. Sure its still strong and is as light as it can be but highly cosmetically flawed obviously.
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andygtt	andygtt posted 13 Years Ago HOT Post Details
Group: Forum Members Posts: 157, Visits: 1.2K	i agree its going to be cosmetically flawed if pump is left on... but not as badly as if it was off. The only reason I've left the pump on is when the bag has a leak i cant find/resolve.... almost all my parts need painting due to them being exposed to sun.
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