I'm getting ready to infuse my gunwales and since I hadn't done any infusing in a year or so I decided to warm up on a seat last night. Thought you might like to follow along.
Infusing is similar to vacuum bagging except that the bag is sealed up and the vacuum pulled with everything dry. Once you've got the bag sealed up and have achieved good vacuum you then suck the resin into the bag. I think it's a way better deal since not only do you not have to worry about the epoxy setting up while you're struggling to seal a bag but you're also not dealing with resin getting smeared all over everything in the process. You do need a very thin resin though so I've been using vinylester instead of epoxy. Another benefit to infusion is the lack of stink from the vinylester since it's sucked into a sealed bag with no open layup.
First put a ring of tacky tape around the edge of the mold flange and coat it with PVA. This hopefully keeps the part from sticking to the mold. The tacky tape needs to go down first or else it will just peel the PVA off:
20161117_001 by Alan, on Flickr
Lay out the cloth. Two layers of 20oz. carbon seems to be about right.
20161117_002 by Alan, on Flickr
Then peel ply. This keeps the seat from sticking to the layers yet to come:
20161117_003 by Alan, on Flickr
As you can imagine it's hard for a liquid to flow through a plastic bag that's smushed flat by a vacuum pump. So on top of the peel ply you put the flow media. This is a semi-thin piece of "woven" plastic that lets the resin flow through the sandwich:
20161117_004 by Alan, on Flickr
20161117_005 by Alan, on Flickr
Now spiral tubing with a vacuum tee. One side connects to the vacuum pump and the other to the resin cup:
20161117_006 by Alan, on Flickr
20161117_007 by Alan, on Flickr
If I can remember I put tacky tape around the fitting before the final bag goes over the top:
20161117_008 by Alan, on Flickr
I stop the flow media short of the vacuum side and put a piece of peel ply down to bridge the gap. This still lets the resin flow but slows it down considerably once it leaves the flow media and hits the peel ply. Some of the resin will short circuit around the edges of the seat (where there's no cloth) and will reach the vacuum side before the entire seat has been wetted out. This speed bump keeps the resin from getting sucked out of the bag too soon.
20161117_009 by Alan, on Flickr
Now the final bag goes over the top to seal up the whole works. Make a slit for the fittings to poke through:
20161117_010 by Alan, on Flickr
More tacky tape to seal:
20161117_011 by Alan, on Flickr
All sealed up and ready to suck down:
20161117_012 by Alan, on Flickr
The vacuum line goes to a resin trap before attaching to the vacuum pump. This keeps any resin that gets sucked out of the bag from ruining the pump. Resin traps are expensive to buy. I used 3" pvc pipe with both ends capped off. In the top I drilled two holes and epoxied (thickened) a pair of vacuum fittings in place.
20161117_013 by Alan, on Flickr
Vacuum gauge, shut off valve, and vacuum pump:
20161117_014 by Alan, on Flickr
The resin inlet line is blocked off and vacuum has been applied. Check for leaks and make sure everything is staying in place. There's always leaks to track down and seal.
20161117_015 by Alan, on Flickr
Oh boy, here we go:
After the video stops the resin continued to slowly creep across the seat. At about 90% saturated I started to worry the resin would start to gel before it fully wetted out the seat, if it ever did, so I mixed up another ounce and sucked it in. This is generally a no-no because you don't want to introduce air, which happens because the inlet tube is empty. But it didn't seem to do any harm and the seat fully wetted out. You can see the sharpie outlines where I was tracing the resin front and marking the time to check its progress. At that point it was taking two minutes between lines. Then I added the extra ounce and it took no time at all.
20161117_017 by Alan, on Flickr
Pulled the seat out when I got home from work tonight. Just need to trim off the extra and sand the edges:
20161118_001 by Alan, on Flickr
Alan
Infusing is similar to vacuum bagging except that the bag is sealed up and the vacuum pulled with everything dry. Once you've got the bag sealed up and have achieved good vacuum you then suck the resin into the bag. I think it's a way better deal since not only do you not have to worry about the epoxy setting up while you're struggling to seal a bag but you're also not dealing with resin getting smeared all over everything in the process. You do need a very thin resin though so I've been using vinylester instead of epoxy. Another benefit to infusion is the lack of stink from the vinylester since it's sucked into a sealed bag with no open layup.
First put a ring of tacky tape around the edge of the mold flange and coat it with PVA. This hopefully keeps the part from sticking to the mold. The tacky tape needs to go down first or else it will just peel the PVA off:
20161117_001 by Alan, on FlickrLay out the cloth. Two layers of 20oz. carbon seems to be about right.
20161117_002 by Alan, on FlickrThen peel ply. This keeps the seat from sticking to the layers yet to come:
20161117_003 by Alan, on FlickrAs you can imagine it's hard for a liquid to flow through a plastic bag that's smushed flat by a vacuum pump. So on top of the peel ply you put the flow media. This is a semi-thin piece of "woven" plastic that lets the resin flow through the sandwich:
20161117_004 by Alan, on Flickr20161117_005 by Alan, on FlickrNow spiral tubing with a vacuum tee. One side connects to the vacuum pump and the other to the resin cup:
20161117_006 by Alan, on Flickr20161117_007 by Alan, on FlickrIf I can remember I put tacky tape around the fitting before the final bag goes over the top:
20161117_008 by Alan, on FlickrI stop the flow media short of the vacuum side and put a piece of peel ply down to bridge the gap. This still lets the resin flow but slows it down considerably once it leaves the flow media and hits the peel ply. Some of the resin will short circuit around the edges of the seat (where there's no cloth) and will reach the vacuum side before the entire seat has been wetted out. This speed bump keeps the resin from getting sucked out of the bag too soon.
20161117_009 by Alan, on FlickrNow the final bag goes over the top to seal up the whole works. Make a slit for the fittings to poke through:
20161117_010 by Alan, on FlickrMore tacky tape to seal:
20161117_011 by Alan, on FlickrAll sealed up and ready to suck down:
20161117_012 by Alan, on FlickrThe vacuum line goes to a resin trap before attaching to the vacuum pump. This keeps any resin that gets sucked out of the bag from ruining the pump. Resin traps are expensive to buy. I used 3" pvc pipe with both ends capped off. In the top I drilled two holes and epoxied (thickened) a pair of vacuum fittings in place.
20161117_013 by Alan, on FlickrVacuum gauge, shut off valve, and vacuum pump:
20161117_014 by Alan, on FlickrThe resin inlet line is blocked off and vacuum has been applied. Check for leaks and make sure everything is staying in place. There's always leaks to track down and seal.
20161117_015 by Alan, on FlickrOh boy, here we go:
After the video stops the resin continued to slowly creep across the seat. At about 90% saturated I started to worry the resin would start to gel before it fully wetted out the seat, if it ever did, so I mixed up another ounce and sucked it in. This is generally a no-no because you don't want to introduce air, which happens because the inlet tube is empty. But it didn't seem to do any harm and the seat fully wetted out. You can see the sharpie outlines where I was tracing the resin front and marking the time to check its progress. At that point it was taking two minutes between lines. Then I added the extra ounce and it took no time at all.
20161117_017 by Alan, on FlickrPulled the seat out when I got home from work tonight. Just need to trim off the extra and sand the edges:
20161118_001 by Alan, on FlickrAlan
?
