Roman

Fibreglass, Carbon Fibre, Paper Mache - The composites chat thread

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I've got a little old wheezy air compressor, about 1/4 hp. If I put an 8 mm hose onto the inlet side it acts as a pretty effective vacuum pump. Used it to suck oil out of my mower and whatnot before.

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18 hours ago, Roman said:

I've heard sandbagging works well but havent tried it. 

Re: Vac pump I just recently bought this and this:

https://www.aliexpress.com/item/32596684494.html?spm=a2g0s.9042311.0.0.27424c4dxRsPKo

https://www.aliexpress.com/item/32580819002.html?spm=a2g0s.9042311.0.0.27424c4dxRsPKo

So far so good, pulls vacuum right down to zero on the gauge when you've got a good bag seal. If I leave the pot shut off it'll hold a vacuum overnight at same place on the gauge.

I bought the pot as well, because I use it as a catch can for any epoxy that might zing up the pipe to stop it from stuffing the pump.
Just have a second pipe on it instead of that filter.
But also good for degassing epoxy or rubber or whatever else for other projects. And having the large volume means if you've got a tiny leak you dont lose overall pressure as quickly.

The only catch was that it doesnt come with vacuum pump oil, and you need special oil that doesnt evaporate when the pressure gets really low.
I think it's flammable or something like that so they cant ship it internationally.
Can get it from Repco though so no dramas.

I've still got a love/hate with vac bagging though. Can be very fiddly.

If my glass blowing is successful would you be able to de-gas some tubes for me?

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5 hours ago, Ghostchips said:

If my glass blowing is successful would you be able to de-gas some tubes for me?

Possibly, what does that involve? Just putting them in vacuum pot for a while then back into atmo?

I live in Morrinsville now but if you post them down or drop them to my Dads place in Glendene I can give it a go.

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17 hours ago, kicker said:

Have seen a few cheapo setups using compressors from dehumidifiers and fridges.

I guess it also involves punching captain planet in the dick when you release the refrigerant

I do genuinely wonder how bad it is compared with how much fuel people waste. I mean carbon monoxide is pretty bad too but it's suddenly ok because everyone is doing it.

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49 minutes ago, Roman said:

Possibly, what does that involve? Just putting them in vacuum pot for a while then back into atmo?

I live in Morrinsville now but if you post them down or drop them to my Dads place in Glendene I can give it a go.

If i put in a one way valve that might work for a while.

I was thinking of making a glass tube with metal contacts in it.  A long tube to suck out the air, and when it's done you heat & pinch off the tube.  Much how nixie tubes are made.

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30 minutes ago, SiRge said:

I do genuinely wonder how bad it is compared with how much fuel people waste. I mean carbon monoxide is pretty bad too but it's suddenly ok because everyone is doing it.

It's not as bad as cfc's, one gram of r134 is equivalent to 1410 grams of CO2 as far as warming is concerned, cfc's were equal to 8500 grams of CO2! :)

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3 hours ago, Ghostchips said:

If i put in a one way valve that might work for a while.

I was thinking of making a glass tube with metal contacts in it.  A long tube to suck out the air, and when it's done you heat & pinch off the tube.  Much how nixie tubes are made.

Would you be better off purging the tube with an inert gas before pinching off?

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1 hour ago, flyingbrick said:

Would you be better off purging the tube with an inert gas before pinching off?

I was thinking flush with argon at atmo' pressure, then vacuum out what i can.   And i have 2 special 'getter' materials that's needed for this application.

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17 hours ago, kicker said:

It's not as bad as cfc's, one gram of r134 is equivalent to 1410 grams of CO2 as far as warming is concerned, cfc's were equal to 8500 grams of CO2! :)

Interesting, however internet tells me it's still not as bad as we think. "Every gallon of gasoline burned creates about 8,887 grams of CO2" So that means a full tank of gas (Say 10 gallons or ~38 litres) produces around 89k grams of C02. More internetting says car aircon units use about 350+ grams of r134.

So i mean it's not ultra bad for the environment, worth a few tanks. Then again Diesel is even worse. And how much heavy ship fuel does a cargo ship use, or a coal power plant...

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On 11/07/2019 at 07:52, SiRge said:

Interesting, however internet tells me it's still not as bad as we think. "Every gallon of gasoline burned creates about 8,887 grams of CO2" So that means a full tank of gas (Say 10 gallons or ~38 litres) produces around 89k grams of C02. More internetting says car aircon units use about 350+ grams of r134.

So i mean it's not ultra bad for the environment, worth a few tanks. Then again Diesel is even worse. And how much heavy ship fuel does a cargo ship use, or a coal power plant...

Wtf.. isnt 8,887 grams 8.7 kg? That doesnt seem right? Lol

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Fuel is 87% carbon atoms

Gallon of fuel weighs 6.3 pounds

 

Weight of carbon in a  gallon of gas 5.5 pounds

 

Then most of the weight comes from oxygen added from burning it which comes out to 20 pounds

 

 

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11 hours ago, flyingbrick said:

Wtf.. isnt 8,887 grams 8.7 kg? That doesnt seem right? Lol

As above

image.png.66fb0f0ff5a169cb692080b7a0bab4d0.png

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5 hours ago, Roman said:

You guys are polluting this threads atmosphere with emissions chat 

Sorry, yes sidetracked.

Found link for someone posting aliexpress carbon https://www.aliexpress.com/item/32785723466.html?shortkey=ymqQvqei&addresstype=600 

Anyone else got links for the other products you need? I'd buy locally, however I just want to have a bit of a play at some point with minor investment

Need wax, pvc mould release, resin and cloth like in above link. Have found some examples below locally and aliexpress, any advice?

Roller kit (Locally seems to be quite expensive) - https://www.aliexpress.com/item/33030075213.html?spm=a2g0o.productlist.0.0.2e667dfet84S09&algo_pvid=a1a6fc64-1021-466b-ab21-bd5a817d7f84&algo_expid=a1a6fc64-1021-466b-ab21-bd5a817d7f84-0&btsid=9ba89dce-fc3a-4287-a2d3-3f842992ca12&ws_ab_test=searchweb0_0%2Csearchweb201602_8%2Csearchweb201603_53 

Resin - https://www.trademe.co.nz/motors/boats-marine/parts-accessories/paints-glues-resins/listing-2234612263.htm?rsqid=4c6e53a236e548c0b5a47f89a666875b-001 

Mould release wax - https://www.trademe.co.nz/motors/car-parts-accessories/paint/listing-2236031923.htm

PVA release - https://www.trademe.co.nz/motors/boats-marine/parts-accessories/paints-glues-resins/listing-2236138894.htm?rsqid=0c17b6ce555b4b90b126bbd4163d8f4a-001 

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I reckon the roller kits are bit of a waste of time. 50c brushes from bunnings are the go, plus cheap mixing cups. 

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+1 to that, but just make sure not the kind that ends up leaving bristles in your resin. :unsure:

Whatever kind that is.

Also in my experience PVA release is just yuck to deal with / wax instead.

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1 hour ago, mjrstar said:

I reckon the roller kits are bit of a waste of time. 50c brushes from bunnings are the go, plus cheap mixing cups. 

Agree. So good. 

Iv used some foam rollers that break down in resin and fail during use. That sucks.

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