Lancastrian pens
Apprentice Member
Pressure casting is not removing the air bubles just reducing the size.
-
Thanks for visiting The Penturners Forum today.
There are many features and resources that currently you are unable to see or access, either because you're not yet registered, or if you're already registered, because you're not logged in.
To gain full access to the forum, please log in or register now. Registration is completely free, it only takes a few seconds, and you can join our well established community of like-minded pen makers.
Pressure casting is not removing the air bubles just reducing the size.
Paul hd
Fellow
To the size the human eye can't see. Or at least my eye.
For resin casting the pressure tank is better than vacuum. It is not just about bubbles, it is also about getting the resin into every nook and cranny if you are casting with wood or other materials.
Pressure pot for casting
Vacuum for stabalising
You can use the vacuum for removing bubbles when you’ve mixed PR, but it can be pretty messy if you try it in the mod, trust me I know lol.
If you add pigments the vacuum process will just blend them together
Vacuum for stabalising
You can use the vacuum for removing bubbles when you’ve mixed PR, but it can be pretty messy if you try it in the mod, trust me I know lol.
If you add pigments the vacuum process will just blend them together
Bucks
Fellow
I’ve just read this thread & all the posts Alan, if you take everything brad has mentioned on board you shouldn’t go wrong.
I have vacuum chambers & pressure pots, but never use the vacuuum chambers for degassing resin (only silicone for my moulds) I use a pressure pot for all resins, but like Brad said you can manage perfectly fine using PR without a pressure pot.
Anyway it’s starting to look like your problem is more like chipping from the actual turning rather than air in the blanks, i turn my PR Blanks with the lathe pretty much on full speed, use very very sharp tools & take very light cuts.
I have vacuum chambers & pressure pots, but never use the vacuuum chambers for degassing resin (only silicone for my moulds) I use a pressure pot for all resins, but like Brad said you can manage perfectly fine using PR without a pressure pot.
Anyway it’s starting to look like your problem is more like chipping from the actual turning rather than air in the blanks, i turn my PR Blanks with the lathe pretty much on full speed, use very very sharp tools & take very light cuts.
Bucks
Fellow
What percentage of the catylist do you add to the resin Alan? Too much catylist certainly causes the blanks to be brittle & chippy, the instructions probably say use 1-2% but for pen turning I’ve got down to using 0.6%, I will even try less when I get time for more PR casting, the less MEKP catylist the less brittle/chippy the blanks, I guess it would probably set even with only 0.1% MEKP but just take longer to set.
What % MEKP do you use brad? or is that a trade secret? :wink:
What % MEKP do you use brad? or is that a trade secret? :wink:
Ha Ha Ha ..... I could quote someone " I've spent a lot of time and money learning this process and don't want to just give my secrets away"
I cut it right back, different % for different casts. Time is not an issue for me so I can wait for it to cure. Temperature control is important. But I can cast all year round no matter what the weather.
But I agree, the 100 - 1 ratio is too high. I once cocked up a loads of Watchparts, had a brain fart and mixed 100 - 10
. 1st blank effectively shattered. So rounded the corners and hit it with 60 grit, got there in the end. The glass shard pen I made was about 100 - .5, (5%) and PR, so the resin was easier to turn than the glass.
Bucks
Fellow
I fully understand & know where you’re coming from Brad, as I’m in the same boat. I’ve invested thousands of hours & thousands of pounds researching, learning, trial & error on all this pen turning, mould making & pen blank making malarkey, without hardly asking a single question on how do I do it, then you get some people on the likes of Facebook wanting to be spoon fed every single stage of the process without doing any research or trial & error themselves.
Bucks
Fellow
I also have a temperature & humidity controlled casting room (sounds a lot grander than it actually is lol) as at the moment because of ur day job as a gardeners & spending school holidays making sure the kids have a fun time, all our pen blank casting is carried out over the winter months, unfortunately it costs us quite a lot in gas & electric with not taking advantage of the warmer summer weather though. Happy to say we manage to keep on top of mould orders all year round though :-)
Ray7756
Full Member
Ok going to start my casting journey using polyester casting resin the slow setting type and see how i get on, looking through the posts on this subject, there is a lot of "disinformation" and some smoke and mirrors about the black art of casting, must admit I dont blame the people who have invested time and money getting things " just right" not wanting to give information away, but if you look carefully the information is there, but you still need to work out the exact process, but hey ho you need some effort, i did say to someone on here it was impossible to put genuine watch parts in a sierra blank, I now know its physically possible,,, but that doesnt mean I can do it',,,,,, forst time,,,, but I will figure it out
Cheers
Ray
Cheers
Ray
I did buy some blanks from the Internet and they turned perfect,well for me perfect,no chipping or sounding rough so I'm thinking it must be my mix,I'm going to try less hardener as advised,can't be any worse,thank you all for all the advice and lots of little tips,they all help people like me trying something new,thank you all