CIDCrazyJay
Active Member
I recently stumbled upon the other part of their site. The side having useful tips and tricks, not their finished components for Cozy and EZ type aircraft.
It sounds promising, for a quick, cheap, DIY friendly way to improve the composite layup process, and finished quality.
In searching for info on this technique, I found a video explaining this "LoVac" technique in greater detail.
(Links in follow-up comment).
Upon determining the specific pump they show is rather difficult and expensive to obtain, taking their advice to find any ordinary cheap aquarium/hydroponic air pump. I picked up the cheapest one of these ubiquitous units, matching the general description, from everyone's favorite online jungle.
I was planning to modify the pump to pull a vacuum. But this was unnecessary, as it contains an O-ring in the suction-side filter chamber.
I confirmed with a clear PVC tube attached to said suction port, this little pump can readily pull a rather low, stable 1.57psi vacuum: "LoVac"! There are versions available which are over 10x as powerful, in wattage. Producing about double the output pressure as this one, (output is almost double its own suction pressure, I found in this case).
I opted for this pump due to price ($30) vs the larger $50-$80 units. Since for $80, you can get a cheap AC/resin degassing vacuum pump; I already know that will work! This is only a test, just an experiment, after all.
This little 15w pump, labeled as 0.02mPa (0.02 x 145.038) = 2.9psi output pressure. Was capable of pulling 1,1m, or 43.5"wc (water column) vertically up a clear PVC tube. At 5,000'MSL (0.83atm pressure). This corresponds to 8.34(43.5/231) = 1.57psi of vacuum. (226lb/ft^2, or 1,104kg/m^2). I'm not sure how lower elevation may affect it, but it would probably be toward improvement.
This pump can clearly provide an impressive, even clamping force. While also being gentile enough for the most delicate foam cores. Compared to a true vacuum (14.7psi/407"wc). Or even to a powerful shop-vac, (65" to 80"wc), this is not all that impressive: But considering these pumps are 1/2 the price of the cheapest vacuum pumps. Don't require any, nor spew oil while running. And run indefinitely, due to their large finned aluminum body and low wattage. Whereas only the higher-end vacuum pumps can run at 100% duty cycle for many hours on end. These little air pumps are also unable to crush or otherwise damage the lightest ~ 2lb/cuft foams often used in composite aircraft construction.
This setup cost ($39, with 10' clear PVC tubing) as compared to $800-$2,000 for a true composite, vacuum-bagging pump(only). It makes one believe this really is a viable stepping stone into vacuum-bagging for improved surface finish, and higher volume fractions, through reduced layup epoxy mass. With seemingly little to no down-side for trying.
Links to follow;
It sounds promising, for a quick, cheap, DIY friendly way to improve the composite layup process, and finished quality.
In searching for info on this technique, I found a video explaining this "LoVac" technique in greater detail.
(Links in follow-up comment).
Upon determining the specific pump they show is rather difficult and expensive to obtain, taking their advice to find any ordinary cheap aquarium/hydroponic air pump. I picked up the cheapest one of these ubiquitous units, matching the general description, from everyone's favorite online jungle.
I was planning to modify the pump to pull a vacuum. But this was unnecessary, as it contains an O-ring in the suction-side filter chamber.
I confirmed with a clear PVC tube attached to said suction port, this little pump can readily pull a rather low, stable 1.57psi vacuum: "LoVac"! There are versions available which are over 10x as powerful, in wattage. Producing about double the output pressure as this one, (output is almost double its own suction pressure, I found in this case).
I opted for this pump due to price ($30) vs the larger $50-$80 units. Since for $80, you can get a cheap AC/resin degassing vacuum pump; I already know that will work! This is only a test, just an experiment, after all.
This little 15w pump, labeled as 0.02mPa (0.02 x 145.038) = 2.9psi output pressure. Was capable of pulling 1,1m, or 43.5"wc (water column) vertically up a clear PVC tube. At 5,000'MSL (0.83atm pressure). This corresponds to 8.34(43.5/231) = 1.57psi of vacuum. (226lb/ft^2, or 1,104kg/m^2). I'm not sure how lower elevation may affect it, but it would probably be toward improvement.
This pump can clearly provide an impressive, even clamping force. While also being gentile enough for the most delicate foam cores. Compared to a true vacuum (14.7psi/407"wc). Or even to a powerful shop-vac, (65" to 80"wc), this is not all that impressive: But considering these pumps are 1/2 the price of the cheapest vacuum pumps. Don't require any, nor spew oil while running. And run indefinitely, due to their large finned aluminum body and low wattage. Whereas only the higher-end vacuum pumps can run at 100% duty cycle for many hours on end. These little air pumps are also unable to crush or otherwise damage the lightest ~ 2lb/cuft foams often used in composite aircraft construction.
This setup cost ($39, with 10' clear PVC tubing) as compared to $800-$2,000 for a true composite, vacuum-bagging pump(only). It makes one believe this really is a viable stepping stone into vacuum-bagging for improved surface finish, and higher volume fractions, through reduced layup epoxy mass. With seemingly little to no down-side for trying.
Links to follow;
