I am looking at a bunch of vacuum pumps on Ebay and Craigslist. I have read through the forum here and found a lot of useful information, but I am still not sure which type to get. I want to build a simple setup for a home repair setup. Unlikely I will be building full boards, but maybe so would like the option of something that would suck down a whole bottom well. Probably just going to use a bleeder valve so continuous. I would also like it quiet as doing in the unfinished basement.
There seem to be a few types:
Those built for the AC industry, high vacuum, flows 3CFM-7CFM, oil in pump. Examples Robinair 15600.
Good prices, but have read that not designed to run continuously, eat up oil, smoke some if a leak (made to work near full vacuum), but there are many on craigslist cheap used
I was initially leaning toward one of these, but the smoking stories scared me(set off smoke detector etc).
Oiless, diaphragm based pumps, seem built for continuous use, high flow, but less than “high” vacuum, typically medical suction etc. GAST DOA-P704-AA Compressor/Vacuum Pump,1/8 HP,60 Hz,115V
These seem harder to find cheap and finding good examples of specific models to look for has been harder for me to sort out. Looking to keep under $150.
Electric Aquarium pumps (Tetra 150)
Looks like latest models don’t work as well, but older do pull 11-12 in HG, enough for what I am doing (glassing/sandwich over EPS).
Is there a way to identify the “good” ones"?
Do the AC type pumps (Number 1)work well, or the smoking issues if you have a small leak a problem (read that on Amazon review of someone using it for VB)? Would you just stick with a GAST type pump?
Read this. It tells you everything for a long lasting pump set-up. There are other ways of doing it cheaper, but cheaper might bite you when the pump breaks and you throw away your board because it didn’t pull enough vacuum. Or the pump overheats and catches fire.
if you already read the forum you probably already know this, but I found mine cheaply by searching for words other than vaccuum pump. I found an old medical ASPIRATOR on ebay for about 40 bucks.
Pulling water out of an EPS core for a repair takes some time. Couple that with continuous operation inside your home and you’re going to want a very quiet rig.
What are you going to be vaccuming? if its wood skins, I have and still use the Gast 704, it quiet and pulls 25 mmhg. it is a work hourse. If it’s good enough to save lifes in medical applications…It will run long enough for you to suck some wood down.
Those homemade Joe wood worker ones…you better wear some ear protection, and don’t expect to have a conversation around one. Maybe you can get a long hose and put it outside, or away from the building by 50 ft.
the Gast 704 on ebay is about $50, the hose from harbor freight is $10, the fittings etc another $15, get a roll of bagging material, another $20. This is my set up cost. it’s been amortized over 5-6 years now.
So thats about $1.25 per month to make boards with the set up.
This is how i pull water out of the eps boards. i use a mason jar to catch the water so it doesn’t suck into the motor…just like a medical set up…wierd.
We maintained dozens of Gast vaccum units back when chief engineer of a hospital, from small suction units on the patient floors to large beasts plumbed up to pull central vacuum for an entire hospital. Durable as hell, run forever, easily maintained.
A bleeder valve adjusts pressure, by allowing a slow leak. The pump will run continuously, getting hot, and shortening the pumps life. It works but a more complete system is better.
My gast diaphragm pump does not get hot when I run it continuously with a bleeder valve. The one I have I bought used on ebay 13 years ago. It draws down to around 25 in Hg which is generally way more than i need. I use it frequently at a hobbiest level and for a few years I used it at a semi-professional level.
The hoses i bought for it have all worn out and cracked. Nothing on the pump has ever required repair or maintenance.
resin head do you run yours non stop then without resivoior or vacuum switch for bagging? im asuming the nobs above the guages are what controls your presure? ive seen one advatised but the seller doesnt know a hole lot about it so trying to do some reasearch. The one i have seen looks to be almost identical to the one you posted except for the model nummber seams different but that may be becase it is 220v which we use here. In the past i have just used old fridge compressors and run them non stop but they run hot and not a great soulution and would love to be able to bin all the junk and replace it with one simple unit.
My Gast is still going strong. $40 dollars later from the used surplus store 5 years back. I have the full blown joe woodworker resiviors and pressure switch to control mine.
The pump runs the whole time, no switches, just the 2 bleeder valves. The two thumb screws (bleeder valve) at the top regulate the amount of mmhg you pull, tight’n it down it sucks more, loosen it up it suck less… the gauges are to dial in the the exact mmhg. As you can see in the picture, the one is right side is working to suck, the other side blows.
I run it for the length of the cure, so it depends on the weather etc. But usually I’ll run the little guy for 6-24 hrs on a regular basis. It gets warm like any little electric motor would, but not dangerously warm or even hot etc. It really is a simple efficient set up.
The only draw back is that is doesn’t move a large volume of air at once, so bag suck down takes a few minutes. Or you can use a shop vac to get the bulk of the air out, then switch the little guy on.
Greg and the Cerritos guys were using bigger cfm pull pumps, but they were doing multiple bags at once. I just do one at a time…I’m not that busy.
My gast pump looks very similar to Resinheads except it does not have the built-in bleeder valves and gauges. I use a cheap automotive vacuum gauge and an aquarium valve for the bleeder.
When I used it to bag a standup paddle board I used a vacuum cleaner to empty most of the bag before closing it up and turning on the pump. I have even sucessfully experimented with vacuum infusing small parts, although a stronger vacuum probably would have worked better.
there are several on ebay from $50-$75 right now if you search for ‘medical vacuum pump’. they are not gast but same type…
i have a ‘medical specifics’ a hospital facilities friend gave to me - the hospital threw out a ton of them and he grabbed them before they went to the dump!
i dial it in and let it run. it will get hot when the ambient temp is up so i put a box fan next to it to keep it cool. it would be a fun project to outfit it with the resevoir/vacuum switch system but not necessary - i dont use it a lot. i was using an old fridge pump before that so it was a nice upgrade!
Thank you to all. I really appreciate it. I am fixing a large delamination on a Naish Bamboo SUP. I got the board for the price of blank so I was gonna use it almost as such to learn on. It is my first attempt at a major repair. I used pourable polyurethane 3lb foam to recreate the bottom(1/4-3/8" of foam came up with bubbled glass) and have sanded it down thin and fared it into the existing glass and was going to vacuum down glass, 1/8" divinycell(then sand), then more glass, (Board Lady style http://www.boardlady.com/bottombubble.htm) . Ideally I would do glass, wood verneer, glass to best appoximate what was there before, but had setttled on divinycell for ease of fairing at the expense of discontinuity. If folks have good ideas for getting cheap wood (I think this is bamboo) verneer (gonna paint over it, purely structural) I could do that too. It is 2/3 of the length of the board and almost to the undersid of both rails on a 9 ft board.
Based on the measurements on Joe Woodworker it sayes I am borderline to need 3 CFM for this “large” area (30 inch width, plus overal only rails x ~ 54 inches) which is why I was worried about the Gast 704 1.1 cfm pumps. The diaphragm pumps like the Gast seem ideal(quiet, no oil)l, but 704 is 1.1 cfm(Joe refers to the 704 as the 1.1 cfm). I was going to go with the Thomas (cheaper rebuilt than the Gast I have seen on ebay). New Gast 704 1.1 cfm $200, rebuilt Thomas 3 CFM $100. Noise is the big issue (45 db vs 74db).
I think most of the time I will be doing smaller repairs (just keeping the family fleet of kiteboards, SUPs, and Surftech longboards, in addition to some traditional construction EPS/epoxy shortboards in operating order). There are some really good ding guys around, but not real close, and only one of them vacuum bags to my knowledge. Hence the desire to do myself (and it is fun!). I know Joe wants 21 in Hg for his verneers but I think 10-12 in Hg is all I need for anything with a light EPS core (will implode), so maybe that allows you to get through with a smaller pump (although I would think that is more about cfm than vacuum level).
Remaining questions:
Have people done “big” area repairs with the Gast 704 1.1 cfm pump and been OK? My area is ~ 15 square feet, so I think the Gast would probably be OK (less than 4’ x 4’ in area Joe cites). If in the future I wanted to do whole boards maybe I get a bigger pump? Seems like others use a shop vac or vacuum cleaner to draw the bag down first then a smaller pump?
Anyone built the the Thomas pump version (3dfm) or use one (supposedly much louder, db scale is logarithmic).
Benefits of dropping $180 to build the whole Joe on/off system vs continuous run bleeder setup practically (probably depends on how loud your pump is!)
