JimJ
10-29-2009, 06:37 PM
We have a lot of inquiries about vacuum bagging.
Here is how I used the vacuum bagging to apply veneer to a transom.
The veneer, peel ply and wadding were cut slightly oversize. A few mm for the veneer and 20-30 mm for the peel ply and wadding. Then the transom and veneer were coated with slightly thickened epoxy. The veneer was held in place on the transom with staples. A layer of peel ply was placed over the veneer followed by a layer of wadding. These were held in place with tape. A precut piece of plastic was then place over the wadding and sealed all around with tape. I applied about 5-6 psi of vacuum and held it for 8 hours.
Photo of the process of veneering the transom of Sea Lark.
http://im1.shutterfly.com/media/47b9ce09b3127ccef82c0d7d4ad200000040O03McM3DlkD28-EA/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/
The fitting sticking out of he plastic is a plastic through-the-hull fitting tapped to take a brass 1/4" gas to plastic tube fitting. I tape the area of the plastic sheet where the hole is to be cut, cut a round hole and insert and tighten the fitting. After the plastic is in place, I can easily connect the vacuum tube.
The vacuum "machine" is made from two fridge compressors connect in parallel to three reservoir tanks made from one metre of pvc pipe that I cut into three and capped. The tanks are connected with 1/4 plastic tube again using brass 1/4" gas to plastic tube fittings taped into the end fittings of the tanks. One way valves from an aquarium shop allows either or both compressors to supply vacuum and to prevent the a reverse flow from the tanks to the compressors as they cycle.
I have pulled the tanks down to 28" as a test of integrity. I do not expect to pull this much while vacuum bagging. I have a cutoff switch set to turn off at 22" and on at 12." I wanted a switch that would cycle over a smaller range but could not find one within budget. The one I have was about $90.00 - the greatest cost. Other than the pipe and fittings, all the rest of the "machine" was reclaimed.
Here is the resultant transom
http://im1.shutterfly.com/media/47b8df31b3127ccec341f092899300000010O03McM3DlkD28-EA/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/
Here is how I used the vacuum bagging to apply veneer to a transom.
The veneer, peel ply and wadding were cut slightly oversize. A few mm for the veneer and 20-30 mm for the peel ply and wadding. Then the transom and veneer were coated with slightly thickened epoxy. The veneer was held in place on the transom with staples. A layer of peel ply was placed over the veneer followed by a layer of wadding. These were held in place with tape. A precut piece of plastic was then place over the wadding and sealed all around with tape. I applied about 5-6 psi of vacuum and held it for 8 hours.
Photo of the process of veneering the transom of Sea Lark.
http://im1.shutterfly.com/media/47b9ce09b3127ccef82c0d7d4ad200000040O03McM3DlkD28-EA/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/
The fitting sticking out of he plastic is a plastic through-the-hull fitting tapped to take a brass 1/4" gas to plastic tube fitting. I tape the area of the plastic sheet where the hole is to be cut, cut a round hole and insert and tighten the fitting. After the plastic is in place, I can easily connect the vacuum tube.
The vacuum "machine" is made from two fridge compressors connect in parallel to three reservoir tanks made from one metre of pvc pipe that I cut into three and capped. The tanks are connected with 1/4 plastic tube again using brass 1/4" gas to plastic tube fittings taped into the end fittings of the tanks. One way valves from an aquarium shop allows either or both compressors to supply vacuum and to prevent the a reverse flow from the tanks to the compressors as they cycle.
I have pulled the tanks down to 28" as a test of integrity. I do not expect to pull this much while vacuum bagging. I have a cutoff switch set to turn off at 22" and on at 12." I wanted a switch that would cycle over a smaller range but could not find one within budget. The one I have was about $90.00 - the greatest cost. Other than the pipe and fittings, all the rest of the "machine" was reclaimed.
Here is the resultant transom
http://im1.shutterfly.com/media/47b8df31b3127ccec341f092899300000010O03McM3DlkD28-EA/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/