Pressure pot for resin casting pen blanks

**dai sensei** · 27th March 2015, 11:01 PM

The pressure relief valve is normally adjustable. Have you tried adjusting it?

Originally Posted by _fly_

I got given wax in styrene (small jar).
I use a few drops in the polyester resin and it takes the sticky away that you always get on the exposed surface.
The faces inside the mould don't seem to get sticky.

Another way to post cure is just put the heat gun on them for 20 seconds and then let cool. Cures all the sticky.

Interesting, what does the additive do to the cast overall? ie does it impact on how it sticks to items cast in the resin, make the cast resin harder/softer to turn, make it more/less brittle etc?

I post cure mine in an over whilst still in the mold, for 100C for 15mins, then leave to cool (silicon molds hold heat for quite a while). This unfortunately usually makes it a smidgen more brittle and increases hardness.

**Oldgreybeard** · 28th March 2015, 11:28 AM

Originally Posted by dai sensei

The pressure relief valve is normally adjustable. Have you tried adjusting it?

.

Took the pressure pot back to supercheap this morning and they took a relief valve out of another unit and gave me. I asked about adjusting the pressure setting and they didn't know and said "Keep the old one and see if you can adjust it"

Changed the valves over and the 'new' one was worse - blew at 32psi

So found an old large screwdriver and ground it to fit around the stem and was able to turn the 'retaining nut' (if that's the right term) in two complete turns. It now blows at 54psi

Thanks Neil for the hint - your blood's worh bottling!! And thank you to everyone else who contributed ideas. We now have an adjustment tool if anyone needs to borrow it and a spare relief valve

Bob

**Treecycle** · 28th March 2015, 09:18 PM

Looks like different brands must use different components even though they all look like the same unit. Mine is not Supercheap and it has a non adjustable relief valve.

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