Finished (okay almost finished) my ladegaard today. But I have problems getting it floating.
I connected an aquarium pump to it, but apart from a quiet hiss, nothing. Not even the floater lifted (12cm of 20mm Al angle, 1mm thick).
So I dragged out the freezer compressor I have. This did the trick, but only if I closed down all bleeder valves. So now apart from the comprssor it hisses like a cornered cat.
Is this normal. I got the impression that a light aquarium pump should be enough. And I would prefer that as the freezer compressor makes a lot of noise, takes a lot of space and is to heavy to stow away after each use. And having 20m hose between the 2 is not my idea of fun.
Could it be that the openings are not large enough? Or should there be more of them? I drilled them 0.5mm, 20mm apart.
I connected an aquarium pump to it, but apart from a quiet hiss, nothing. Not even the floater lifted (12cm of 20mm Al angle, 1mm thick).
So I dragged out the freezer compressor I have. This did the trick, but only if I closed down all bleeder valves. So now apart from the comprssor it hisses like a cornered cat.
Is this normal. I got the impression that a light aquarium pump should be enough. And I would prefer that as the freezer compressor makes a lot of noise, takes a lot of space and is to heavy to stow away after each use. And having 20m hose between the 2 is not my idea of fun.
Could it be that the openings are not large enough? Or should there be more of them? I drilled them 0.5mm, 20mm apart.
Hi,
0.5 mm is too large: you got high flow and low pressure in such a way - the high the air flow is, the lower air cushion pressure drops, the louder a snake hiss, at the given compressor power. I pierced my holes with 0.3 syringe in the mylar tape glued under the anlge, with 1.5 mm holes drilled in aluminium above the tiny holes in mylar, exactly as it is recommended by Roscoe Primrose site authors. Works well even with one aquarium pump (350 l/h) with no audible hiss, but two pump connected in parallel, work better, though the hiss (rather quiet) is here.
Good luck,
Michael
0.5 mm is too large: you got high flow and low pressure in such a way - the high the air flow is, the lower air cushion pressure drops, the louder a snake hiss, at the given compressor power. I pierced my holes with 0.3 syringe in the mylar tape glued under the anlge, with 1.5 mm holes drilled in aluminium above the tiny holes in mylar, exactly as it is recommended by Roscoe Primrose site authors. Works well even with one aquarium pump (350 l/h) with no audible hiss, but two pump connected in parallel, work better, though the hiss (rather quiet) is here.
Good luck,
Michael
If you use 350l/h, then maybe the pump is a bit too small. It only gives 120l/h. I'll drill a second profile somewhere this week at 0.3. Might even try out a few more profiles.
Which has lead me to wonder; except for the difficulty in drilling through the aluminum, is there a reason to drill bigger holes and attach tape underneath? In other words, if it could be done, why not just drill .3mm holes in the first place? Just curious!
From my experience this is done for 2 reasons:
1: they need the small holes to build the cushion without needing too large a flow.
2: if you drill a small hole that is "long", the resistance in that "tube" is high and you will need a higher pressure.
So they drill large holes and cover those, then put small "short" holes into the covering. So they get both a low flow and can do that with a low pressure.
1: they need the small holes to build the cushion without needing too large a flow.
2: if you drill a small hole that is "long", the resistance in that "tube" is high and you will need a higher pressure.
So they drill large holes and cover those, then put small "short" holes into the covering. So they get both a low flow and can do that with a low pressure.
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