Now using clear gelcoat, finding new problems, advice??

Talk Composites - The Forum for Advanced Composites

Back

Home
»
Advanced Composites Forum
»
Resin Infusion
»
Now using clear gelcoat, finding new problems, advice??

Now using clear gelcoat, finding new problems, advice??

Author	Message
brettalloy	brettalloy posted 11 Years Ago HOT Topic Details
Group: Forum Members Posts: 23, Visits: 69	Hello. So got set up to spray and ordered in easycomposite clear gelcoat. No problems spraying this and getting a good even coat down. However my problems are coming with the infusion. So previously i had infused with epoxy, took a while but i got the process id say about 99%, very few pinholes in laminate. Most parts were bodywork and these were came up great after clearcoating. Please see attached pics, Im getting air pockets and some in really random spots. I dont know how i can get a relatively perfect looking part and then an air spot. Some instances where i have sharper geometry/edges i can understand a little bridge maybe, looking at the reverse side of the part its flawless. Surely the resin will pool in and fill even if the fabric is slightly back?? Attachments Void 1.JPG (592 views, 105.00 KB) Void 2.JPG (618 views, 108.00 KB)
	Reply Like 3
brettalloy	brettalloy posted 11 Years Ago HOT Post Details
Group: Forum Members Posts: 23, Visits: 69	More pics Attachments Reverse.JPG (615 views, 1.00 MB) Dry spots.JPG (469 views, 141.00 KB) Routed.JPG (488 views, 148.00 KB)
	Reply Like 2
FLD	FLD posted 11 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 2.7K	I've had similar. Looks like pin-holes under the gelcoat. Usual cause is too mcuh vacuum / not enough resin let in after vacuum close off. Thats what my problem was anyway.
	Reply Like 2
brettalloy	brettalloy posted 11 Years Ago HOT Post Details
Group: Forum Members Posts: 23, Visits: 69	So full vaccuum might be restricting resin flow? Didnt have such a problem without the gelcoat. Does this mean as the fibre is being pulled tight under full vac that it struggles to get between the gelcoat and the first layer. If my vaccuum is set on full how do i reduce it slightly to help the infusion? Im running the standard easycomp pump and catch pot. The idea being less vac more slack for resin to penetrate, then when you have it infused you crank the vac back up to full to get best consolidation?
	Reply Like 2
brettalloy	brettalloy posted 11 Years Ago HOT Post Details
Group: Forum Members Posts: 23, Visits: 69	Sorry when you mean vaccuum close off do you mean after the part has infused close the vac outlet offbut contiue to pump more resin in through feed. One thing i will say is that as soon as everything has wetted out i am stopping the resin feed, eg not pumping more in. Do i need extra resin fed in to ensure the that i get all the spots in. The problem i see is spot areas in amongst a decent full infusion, rather than a lack of resin
	Reply Like 3
FLD	FLD posted 11 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 2.7K	Sorry should have been clearer. Yes let more resin in after the vac line has been closed. I find with the gel coat in place it infuses just fine but if you dont let the resin flow for a few seconds after the vac has been closed off you get little pockets like this. An extra 10 sec makes a big difference in my hands.
	Reply Like 2
brettalloy	brettalloy posted 11 Years Ago HOT Post Details
Group: Forum Members Posts: 23, Visits: 69	Thanks! So I will make sure i have abit more resin mixed, once full wet out achieved will close off vac outlet and keep resin feed going for abit longer.
	Reply Like 3
fgayford	fgayford posted 11 Years Ago HOT Post Details
Group: Forum Members Posts: 433, Visits: 1.2K	Hi I always close off the vacuum side and wait 10 seconds before I close off the resin in line. I would also stress, make SURE your resin and mold are warm. I actually pre-warm my mold in the oven to 85 f before I infuse. Hope this helps. Fred brettalloy (10/08/2014) Thanks! So I will make sure i have abit more resin mixed, once full wet out achieved will close off vac outlet and keep resin feed going for abit longer.
	Reply Like 3
brettalloy	brettalloy posted 11 Years Ago HOT Post Details
Group: Forum Members Posts: 23, Visits: 69	Just an update, as although I have improved things a fair bit im still having a small amount of trapped air. I had a good wet out, and closed off the feed line after the vac line to allow for more resin into the part. Im wondering if the bubbles that have trapped in the laminate, are caused by air getting into the job via the feed line, before resin is introduced. I must stress that the laminate is 95% there, no dry spots, just a few random air pockets. There is no reason to believe the resin would not fill these areas, it must be because of trapped air in the job. Any pointers here greatly recieved. How do you ensure the feed line from the clamp to the feed pot does not take in air, or at least kept to a minimum? Cant see how else the job is failing. Cheers
	Reply Like 3
FLD	FLD posted 11 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 2.7K	Do you degas your resin fully before infusing?
	Reply Like 2