Vacuum Pumps - School me please

[Shox Dr]

Im looking for a Vac pump to degas resin etc. Small bushes etc, though I might make some doors (600x1900x50) from carbon mat.
Have not a clue as to pros v cons regarding any type or make?

Suggestions and advise greatly received.

 

[Ross365]

Do you have a target for what kind of pressure you need to get down to? I guess it will not be be very low.
For a very long time the commonest vac pumps in the UK were the rotary backing pumps made by the Edwards company; they were the workhorse pump that would get you down to about around 1mm of mercury (see ebay or used scientific suppliers). I have one of them (there are numerous models) and use it generally including degassing.

Now there are cheap pumps from the far east, and if you want to get to lower pressures, turbo pumps are available.

 

[Kram]

I have a vevor one, it seems to work well, Ill find a link later.
Are you making, or buying a chamber?

 

[hotponyshoes]

For degassing resin the type that goes onto an airline will do the job.

For curing carbon and stuff you want something a bit better.

Either take your pick from one of the Chinese automotive Air con ones and hope it lasts or buy something old and quality like an Edwards but they do hold money.

If you want to diy it then an old fridge compressor will do the job.
It's a bit slow for laying stuff up but you can either use a hoover to get most of the air out of the bag then switch the pump on to finish/mantain the vacuum or add a tank with a valve as a vacuum store.

 

[Shox Dr]

For degassing resin the type that goes onto an airline will do the job.

For curing carbon and stuff you want something a bit better.

Either take your pick from one of the Chinese automotive Air con ones and hope it lasts or buy something old and quality like an Edwards but they do hold money.

If you want to diy it then an old fridge compressor will do the job.
It's a bit slow for laying stuff up but you can either use a hoover to get most of the air out of the bag then switch the pump on to finish/mantain the vacuum or add a tank with a valve as a vacuum store.

Deffinatley not going down the DIY route at least for the pump. it also needs to be 240v
As for the pot, a small one will do for the moment, though it would need to be big enough to just a mold in it so around 2-5ltrs?

 

[Ross365]

This is the sort of thing I have https://www.ebay.co.uk/itm/18563697...Hl7dG+Io49rPW7kdoxVb/hX0Y=|tkp:Bk9SR7rEyb6GYQ

 

[Shox Dr]

This is the sort of thing I have https://www.ebay.co.uk/itm/185636973881?hash=item2b38d36d39:g:TGIAAOSwWXNjXWth&amdata=enc:AQAHAAAAoE4mH1wgnLCS0qToFjL3xWi06OqqIrPjQHiF4RsmaW62gY8BYJZwoXFHtJvIb4LI8vUveOyVb21izlv/plzB2e/665+1x3G57tDcJrYq7NEBr8dgsPyZ/8xOnH+kAf3NNtWPZ5HJE7y3XmNDfacYAmgaE871Ibqe2cKrwIr+VrCRpjPvPnK1ufbhlIj27YHl7dG+Io49rPW7kdoxVb/hX0Y=|tkp:Bk9SR7rEyb6GYQ

I guess so. I know nothing about them. the price is right

 

[Shox Dr]

what is the benefit of a 2 stage pump?

 

[hotponyshoes]

I guess so. I know nothing about them. the price is right

That would be a decent choice for what you want.
Might be worth checking you can get spares for that particular model although I've never needed any for an eddy.
It will get you started with degassing. You will want to add a pressure switch for bagging

 

[hotponyshoes]

what is the benefit of a 2 stage pump?

Quicker.

 

[hotponyshoes]

Although if the budget was fixed I'd rather have an old cast iron single stage than a new Chinese aluminium 2 stage.

In terms of build/ proformance / price they are basically the same as air compressors

 

[hotponyshoes]

You can add a tank to a single stage pump and start running the pump while you mix the resin if you have a big pot and you are in a hurry

 

[carbon]

Robinair make vacuum pumps suited for this application, there are some on ebay at the moment but it depends on the voloume that you are looking for. Or if you are looking for new then Easy composites have a few options

 

[Shox Dr]

You can add a tank to a single stage pump and start running the pump while you mix the resin if you have a big pot and you are in a hurry

Im in no rush these days. whats the minimum cfm required

 

[cr500dom]

Depends on if you want to degas resin or use it to resin infuse and continue the pull a vacuum on a moulded part during cure ?

For years we used a 3hp compressor, modified to pull a vacuum on the tank rather than pressurise it (essentially connect compressor inlet to tank, output to atmosphere)
It was a piston compressor used for painting until it got silicon contamination, then it got repurposed.
It made a lot of Group C race car components and a run of F3 cars too

 

[Ross365]

This takes us back to what pressure you need to get down to. The Edwards are built more to get a low pressure than pump fast.

 

[hotponyshoes]

Im in no rush these days. whats the minimum cfm required

The size of the free space in the pot multiplied by the amount of time you can be bothered to wait

 

[daedalusminos]

You'd be surprised at how low a pressure you need to degas resins etc, speed will be relevant if the pot life is shortand the bigger the chamber the longer it will take although you can add 'fillers'

I have this pump...

BACOENG 4.2 CFM Double stage Vacuum Pump https://amzn.eu/d/ieY9XcO

And use it to gegas 4minute polyurethane in a 12l (I think) chamber

 

[MattF]

Im looking for a Vac pump to degas resin etc.

You sure that's all you want it for?

 

[Shox Dr]

@cr500dom good question. Ive a load of prepreg CF that's whey oot date. Hate to sling it so I thought of laminating it to make a some doors.