Vacuum! That is the question!

[Tommi]

Dont know if theres problems with language and translation. But that seems rude towards, Steve?

Cheers
Janne Nilsson

Janne

Looks like a translation problem to me. Had the same issues when translating English to another launguage, it never quite reads the same.

Cheers
Tommi

 

[archimede]

Hi Tommi and thank you for the advice. Can you explain to me what you mean by a shallow tank?

 

[Tommi]

shallow pour reservoir​

Is the distance from the top of the mould hole to the bottom of the hole where the over fill resin sits for the bubbles to escape in to. Mine are fairly deep and I also use long feeder sprues to reach down to the model.

Tommi

 

[archimede]

This is the tank I use ... is it too small? They are 11cm in height and 20cm in diameter and the pump is just a pump to create the vacuum, very powerful. See the photo.

 

[archimede]

I begin to understand .... the holes are three? and how and what tool do you use to pour the resin into the mold?

 

[Tommi]

Where is the Vacuum gauge. You need to see and monitor the evacuation of air to make sure the process is working properly, not having one will not help solving any issues that you have as it could be an issue with the pump or an air leak during the procedure that is not pulling the correct amount of air. The Vac pump need to be adequate enough to pull 1 bar and and let the air back in before the on set of the maximum pot life of the resin.

The size of the tank should not effect the end result if the pump is matched to capacity of the tank.

My 50 Litre tank takes 35 second using a 20CFM pump
My 26 Litre Tank takes 25 seconds using a 12CFM pump
My 9 Litre takes about 20 seconds using a 10 CFM pump

Tommi

 

[Tommi]

I begin to understand .... the holes are three? and how and what tool do you use to pour the resin into the mold?

The resin is mixed in a plastic kitchen jug and mixes with a plastic kitchen spoon then just poured out of the jug into the mould like pouring water.

Tommi

 

[archimede]

The vacuum gauge is there .. please explain how you can pour the resin into the mold, maybe the problem is just the method of pouring the resin into the mold.

 

[Tommi]

It only shows three because of the design of the piece in the mould requires this may because of the shape and allowing the air to escape in the appropriate places. I can range from just 1 feeder to mat depending on the complexity of the part you are putting into the mould.

As Steve has stated you should only need 1 for a wheel.

Tommi

 

[Tommi]

The needle on the Vac gauge needs to be round to the 1bar position for about 30 seconds before letting the air back in.

The pouring of the resin is the easy part, weigh out the two parts in equal quantities, mix and pour from the jug like pouring water.

Tommi

 

[archimede]

I understand, but as you can see in the pictures of the wheel the part of the hub has a hole due to an air bubble. As Steve says then I should let the air out of that spot. Quite right?

 

[Tommi]

Also where is the rubber gasket seal on the top of the vac chamber or is it on the lid

Tommi

 

[archimede]

it's exactly what I do, but I do not have the result ... look at the pictures of the wheel ...

 

[archimede]

Also where is the rubber gasket seal on the top of the vac chamber or is it on the lid

Tommi

sorry but the translation does not make me understand ...

 

[Tommi]

The rubber seal between the tank and the lid. Is there one

 

[archimede]

The rubber seal between the tank and the lid. Is there one

yes the rubber seal is between the lid and the tank.

 

[Tommi]

Ok... Wrap parcel tape around the top of the mould, over fill it and vac it to 1 bar for about 30 seconds then let the air back in slowly before a second vac. Let it set properly before removing from the mould and see how you get on.

Tommi

 

[archimede]

I'll never make it ...

 

[archimede]

(then let the air back in slowly before a second vac) I do not understand this sentence...

 

[Tommi]

(then let the air back in slowly before a second vac) I do not understand this sentence...

When the Vacuum gauge resisters 1 bar let the resin bubble for about 30 seconds, turn off vacuum pump then let the air back into the pot very slowly so it does not pull any of the bubbles back into the mould and they stay in the over filled resin

Tommi