So, I have been wanting to dry my board out a wee bit faster using vacuum and I have got hold of this cheap single-stage vacuum pump, which so far I have been reluctant to use as I am a bit nervous about collapsing or delaminating the board (despite having drilled an extra 6mm hole in the bottom from where I am using an aquarium vacuum pump to suck out of; air flows in to the board via the vent hole).
The pump specs say 2Pa (15micron) Partial Pressure and 150micron Total Pressure, which is about 20Pa, the latter which is (apparently) a paltry 0.00019736atm (approx. 1/5000) or 0.003psi (WTF?), but I can feel this much more acutely on my tongue than my aquarium pump. It's not been quite warm enough here yet to really heat up the board consistently over a clear stretch (I am expecting 2 to 4 weeks), which is what I really need, hence the foray into the vacuum (unless that's considered not that useful, or even that "very bad things" could happen 
).
Pics of my fish-aquarium vacuum pump are here www.seabreeze.com.au/forums/Windsurfing/General/Sanding-back-extra-coat-of-paint-to-reduce-weight--while-I-wait-for-sun-to-dry-it-out-?page=1, but TBH I am less than impressed by the suction generated, it is pretty minimal, even when I stick it on my tongue. I mean it is working, just with a very, very low suction.
I have read a number of threads on seabreeze about suction pressures including this one, www.seabreeze.com.au/forums/Windsurfing/General/sailing-with-the-plug-out?page=1 (which seemed to end up being a bit of a pissing contest between barn and DrJ) but I remain unclear on what sort of pressures I should limit it to. One other thread says stay above 0.3atm. www.seabreeze.com.au/forums/Windsurfing/General/Getting-water-out-of-board?page=1, this one says 0.5atm. www.seabreeze.com.au/forums/Windsurfing/General/Forgot-to-tighten-the-vent-screw?page=1. Some others have mentioned a duty cycle of 3 to 4 secs on, then 3 mins off. The pump itself says don't run it for too long.
I am about to go buy a vacuum gauge and rig up a bleeder valve to control the suction (if needed), but before I do any of that, I thought I would come see what the collective wisdom on seabreeze about pressures. Thoughts, recommendations?
k.
Those little Chinese copies don't move much air but they will draw down to almost full vac - as they're designed for evacuation of fridge systems - so can definitely implode a board
limit to about 8psi and you should be fine.
With the other hole you might not even be able to achieve that anyway = safe
Select to expand quoteMark _australia said..
Those little Chinese copies don't move much air but they will draw down to almost full vac - as they're designed for evacuation of fridge systems - so can definitely implode a board
limit to about 8psi and you should be fine.
With the other hole you might not even be able to achieve that anyway = safe
Cheers thanks Mark, just what I needed to know 
.
I have a big pump, as long as I have 2 holes, I just let it rip, pressure doesn't drop much until you seal the 2nd hole. but don't do that.
It's good to have a water-trap inline before the pump intake. most pumps don't like water in them
Select to expand quotedecrepit said..
I have a big pump, as long as I have 2 holes, I just let it rip, pressure doesn't drop much until you seal the 2nd hole. but don't do that.
It's good to have a water-trap inline before the pump intake. most pumps don't like water in them
Cheers and will do on the trap, totally intend to do that.
Thinking a bit of end-capped PVC with in-out hoses and a wee tap at the bottom to check my winnings.
Select to expand quotejksmurf said..decrepit said..
I have a big pump, as long as I have 2 holes, I just let it rip, pressure doesn't drop much until you seal the 2nd hole. but don't do that.
It's good to have a water-trap inline before the pump intake. most pumps don't like water in them
Cheers and will do on the trap, totally intend to do that.
Thinking a bit of end-capped PVC with in-out hoses and a wee tap at the bottom to check my winnings.
So I've got my first draft of the pump system working OK, need to get a few more bits of pipe work and elbows to make the gauge vertical and easier to adjust, plus make some sort of an oil mist collector (messy little beast that it is) around the oil cap. Will mount the trap a bit better too, plus put a baffle between the two vacuum pipes.
For keeping the vacuum at the recommended 8psi (about 55kPa) I found a little blue manifold at a marine shop and the white knobs have decent fine threads so I could adjust one of the ones that is not connected (I.e. I essentially have 3 bleeder valves if I want) and it stays around the target vacuum.
Water trap is as shown, I tapped a couple of holes into a thick PVC pipe with end caps and a plug. Pretty happy with the result. Let's see if it draws water out a wee bit quicker.
k.
Forgot to warn u most of the oil trap exhausts are crap
vent it to outside, just put the pipe where it doesn't matter
Select to expand quoteMark _australia said..
Forgot to warn u most of the oil trap exhausts are crap
vent it to outside, just put the pipe where it doesn't matter
Yeah I've been looking at making my own one from some PVC tubing and steel wool from pot scourers, bit of a mission though. The stock ones are incredibly expensive. Hard to find 24mm threaded pipe too.
i wanted my wife to try the board tomorrow, will some silicone in the drilled drain holes fore and aft plus some duct tape hold up do you think? I need to put it back on the pump afterwards, hasn't lost any weight at all yet, must be sneaking cookies at nighttime.
Nup too hard I vented into a bucket of coarse sand and u still get oil vapour wafting out. Not worth it as it will screw up every other job in lamination or painting.
A clear pvc tube is a good fit, run that outside and stick the end in the garden
neighbours garden, even.
I would not use that pump...
Get an aquarium electric pump, they are real cheap,quiet and made to run 24/7.
Put an entry and exit hole in the board ,plug the pump in and place the board in the warmest room you have.I use the boiler room.
Leave it for days and weigh it to see how it evaporates and pushes the vapor out.
Select to expand quotemcrt said..
I would not use that pump...
Get an aquarium electric pump, they are real cheap,quiet and made to run 24/7.
Put an entry and exit hole in the board ,plug the pump in and place the board in the warmest room you have.I use the boiler room.
Leave it for days and weigh it to see how it evaporates and pushes the vapor out.
Lol You mean like this one ?
www.seabreeze.com.au/forums/Windsurfing/General/Sanding-back-extra-coat-of-paint-to-reduce-weight--while-I-wait-for-sun-to-dry-it-out-?page=1#7
Tried that one for two weeks but I think the board has been water logged for a very long time and I don't think I have enough warmth from the sun atm.
is there a specific reason you think it's not as good or detrimental?
Select to expand quotemcrt said..
I would not use that pump...
Get an aquarium electric pump, they are real cheap,quiet and made to run 24/7.
Put an entry and exit hole in the board ,plug the pump in and place the board in the warmest room you have.I use the boiler room.
Leave it for days and weigh it to see how it evaporates and pushes the vapor out.
Why not? You can build boards with it.
they're designed for continuous use in hvac. fair enough the 5cfm and larger are far more useful but this being only 1.8cfm perhaps lends some aspect of safety to his endeavour
I don't think I've heard of anyone actually drying a board with a tiny pump.
Select to expand quoteMark _australia said..mcrt said..
I would not use that pump...
Get an aquarium electric pump, they are real cheap,quiet and made to run 24/7.
Put an entry and exit hole in the board ,plug the pump in and place the board in the warmest room you have.I use the boiler room.
Leave it for days and weigh it to see how it evaporates and pushes the vapor out.
Why not? You can build boards with it.
they're designed for continuous use in hvac. fair enough the 5cfm and larger are far more useful but this being only 1.8cfm perhaps lends some aspect of safety to his endeavour
I don't think I've heard of anyone actually drying a board with a tiny pump.
Because they are very noisy, dirty and designed to pull a strong vac which you do not need.
You just need 2 holes, heat + airflow
If the board is very waterlogged gravity will do the heavy lifting.
When it stops coming out plug the pump in to get air circulation going.
My point is that "vacuuming" the board dry will not take out much more water than gravity if any.
Afterwards you can only facilitate the transfer of liquid water between the EPS beads to water vapour and then push that moist air out replaced by warm dry air...again and again.
The more heat (within EPS limits) and airflow the better.But you need both.
If you want to run that pump for days go for it, i just think it is unnecessary wear on the pump plus noise torture.
You could try spinning the board, I recall doing it 20+ years ago, drilled a hole at the tail and nose of the board used an old office chair base and run a belt and pulley(similar setup to spit ) and used motor off my spit, strapped the board on it upside down and let it spin for few hours.
I'll get probably massively burned for saying this, but I just leave my watery cracked boards in a warm car on a sunny day* in the car park at work, with the windows open a 10cm crack, and check on the board every 30 mins or so. The water bubbles out - in quite a satisfying way - once it stops bubbling I leave it for a few hours more and reckon it's probably fairly bone dry by that point. Job done.
None of my boards have exploded so far, and as far as I know, I haven't died.
*Yes, I know you really aren't 'supposed' to do this and it is a really, really bad thing and baby robins will die.
Select to expand quotesaid..
I'll get probably massively burned for saying this, but I just leave my watery cracked boards in a warm car on a sunny day* in the car park at work, with the windows open a 10cm crack, and check on the board every 30 mins or so. The water bubbles out - in quite a satisfying way - once it stops bubbling I leave it for a few hours more and reckon it's probably fairly bone dry by that point. Job done.
None of my boards have exploded so far, and as far as I know, I haven't died.
*Yes, I know you really aren't 'supposed' to do this and it is a really, really bad thing and baby robins will die.
Apart from the dead robins, I don't see an issue with this, assuming you take out the vent plug. yes they will vent through the cracks but I'm not sure I'd rely on those alone. The way I understand it you want the heat to cause the water to vaporize, the added airflow I'm trying to pass through the board is just to help that along. I don't think using heat and plug in to pressurize the board (if that's what happening) is too good for the board.
The little aquarium pump I linked above didn't seem to do much by way if any suction, hence the big dog (hvac) machine limited to the query I posed in the original post.
I'm not able to put it on a spinner unfortunately, but I like the swivel chair idea ! I can see it being difficult to get it balanced though, wonder what the local tyre balance guy would say if I brought it down and asked "can you balance this?" ;-)
Tidied up the setup so the gauge is vertical and added a SS bracket for the trap. It's good, light, portable, not too noisy but the exhaust is a WIP and I agree it's dirty. Wouldn't run it 24/7. Seems to throw a lot of oil out that exhaust too.
Yeah you don't need that much vac but I can use it for other repairs and I have the (blue) bleed manifold to limit the vac. As per this and my other thread, I think it's water well saturated into the EPS foam, I.e. it's well past the initial water gushing out, or even moistening the wick, hence supplementing with the vac. I've got a hole drilled fore and aft, which I've tried one at a time (and both).
Select to expand quotemcrt said..Mark _australia said..mcrt said..
I would not use that pump...
Get an aquarium electric pump, they are real cheap,quiet and made to run 24/7.
Put an entry and exit hole in the board ,plug the pump in and place the board in the warmest room you have.I use the boiler room.
Leave it for days and weigh it to see how it evaporates and pushes the vapor out.
Why not? You can build boards with it.
they're designed for continuous use in hvac. fair enough the 5cfm and larger are far more useful but this being only 1.8cfm perhaps lends some aspect of safety to his endeavour
I don't think I've heard of anyone actually drying a board with a tiny pump.
Because they are very noisy, dirty and designed to pull a strong vac which you do not need.
You just need 2 holes, heat + airflow
If the board is very waterlogged gravity will do the heavy lifting.
When it stops coming out plug the pump in to get air circulation going.
My point is that "vacuuming" the board dry will not take out much more water than gravity if any.
Afterwards you can only facilitate the transfer of liquid water between the EPS beads to water vapour and then push that moist air out replaced by warm dry air...again and again.
The more heat (within EPS limits) and airflow the better.But you need both.
If you want to run that pump for days go for it, i just think it is unnecessary wear on the pump plus noise torture.
He is doing exactly what you do it's just a bigger pump.
it seems most people here give up on aquarium pumps as the move bugger all air. I never had any method work at all, except for a big hole at damage site and time.
when it's had a number of points of ingress and it's spread evenly through the board, nothing works to get the last say 500ml out
With lot of care you can put some pressure in board from one point with a hand pump. You MUST go very low and keep a very light pressure, i use a pump for bicycle wheel with a mano. After some up an down you will see water go out from cracks. Effective but dangerous for blank integrity MUST keep a very light pressure.
Select to expand quoteMark _australia said..mcrt said..Mark _australia said..mcrt said..
I would not use that pump...
Get an aquarium electric pump, they are real cheap,quiet and made to run 24/7.
Put an entry and exit hole in the board ,plug the pump in and place the board in the warmest room you have.I use the boiler room.
Leave it for days and weigh it to see how it evaporates and pushes the vapor out.
Why not? You can build boards with it.
they're designed for continuous use in hvac. fair enough the 5cfm and larger are far more useful but this being only 1.8cfm perhaps lends some aspect of safety to his endeavour
I don't think I've heard of anyone actually drying a board with a tiny pump.
Because they are very noisy, dirty and designed to pull a strong vac which you do not need.
You just need 2 holes, heat + airflow
If the board is very waterlogged gravity will do the heavy lifting.
When it stops coming out plug the pump in to get air circulation going.
My point is that "vacuuming" the board dry will not take out much more water than gravity if any.
Afterwards you can only facilitate the transfer of liquid water between the EPS beads to water vapour and then push that moist air out replaced by warm dry air...again and again.
The more heat (within EPS limits) and airflow the better.But you need both.
If you want to run that pump for days go for it, i just think it is unnecessary wear on the pump plus noise torture.
He is doing exactly what you do it's just a bigger pump.
it seems most people here give up on aquarium pumps as the move bugger all air. I never had any method work at all, except for a big hole at damage site and time.
when it's had a number of points of ingress and it's spread evenly through the board, nothing works to get the last say 500ml out
I wear a carbon kneebrace so i ding my boards often, sometimes the dings are tiny, plus the usual plastic insert/carbon joint suckers.
I have dried my boards to the last gram (after 1kg/1 liter ingress once) a few times with a tiny palm sized aquarium pump, a boiler room (around 30? C ) and two 5mm entry and exit holes.One at the tip,one at the tail.And patience, might take a week.
-Drain by gravity
-When little comes out plug the aquarium pump in at high hole.This way condensed water may drip out by gravity too.
-Leave for days.Weigh.
-Patch holes.
People normally do not understand that heat alone will only vaporize the water at the hottest points inside the board but it will not come out by magic unless you force a constant airflow (dry air in,moist air out).
Without airflow the moist air will just condense on a colder area inside the board.
Think of a wet sponge inside an open bottle placed in the sun, it will take ages for it to dry fully.Force (dry) air circulation and things get moving.
Bigger pump will work quicker,sure, but runing an oil lubed vac pump for a couple days would get me evicted from my own home :(
