Making colours

[Dorno]

I have just purchased some more mica to go with what I already have and I am still attempting to get the mixing colours thing sorted.
I would like to know that by using 2 colours both in mica do I have a better chance of both mixes going off at the same time thus making it a touch easier to mix the colours.
I am finding by mixing resin liquid pigments that one seems to go off before the other. so I hope this solves a few of my problems

Thanks Ian

[MBUMIK]

not sure mate, from what i have read colors do change gel time regardless of what is used

but i will stand corrected if someone tells us different

MIK

[Dorno]

I am just hoping somthing makes this Damm job easier. I dont mind having some stuff ups because I have a few mighty fine looking stuffups. But I am looking at trying to get this swirl bit down pat but would like to get some swirls not just a mix between 2 colours.

Ian

[Resination]

Different colors gel at different rates. The ingredients that make the color also affect it. Work with your colors and keep track of everything.

[dj_pnevans]

Ian the best bet is to write evey thing down as you do it.
David

[Dorno]

I am trying to keep track of what I do and will keep it all as a log. I am not happy with how brittle the blanks are comming out the are very very Brittle. I am using Barnes clear casting resin and as previously mentioned to me I am using 9 drops per 25 ml (22 drops per blank). Is there a way that I can make these blanks less brittle or am I better with a different product (open for suggestion) that I can use. I have blown out more blanks that I have label casted by chatter because of them being brittle than I have managed to finish.
As I have said in earlier threads I am using a resin pigments (as per surfboards) and mixed those with some micca.

Thanks Everyone
Ian

[dj_pnevans]

Ian are they chipping out or just blowing apart?
David

[Dorno]

Mainly Chipping and it doesnt seem what I do I cannot get what you call a ribbon comming off the the blank. the ends have blown out (cracked) on several occasions now and no matter what i do i have what can be described as pit type holes all over the blank and have to sand and sand and more bloody sanding before I can get them smooth and even then I fail to get all the marks out.

Cheers Ian

[dj_pnevans]

I had this happen to me some time ago all I did was use less then sharp tools, you may want to look at the ends of your tools to make sure that they are smooth.
David

[gawdelpus]

Try using a few drops less activater time is not of the essence in this exersize, {) try turning at a faster speed and use smaller tools to reduce the area in contact that can cause chatter such as a scraping tool . I have found the skew is the best for these blanks as long as you don,t try for too big a cut , another thing I do which helps a lot with the ends is to gently take the ends down to near the bushes at a fairly steep angle .about 60degrees .do this at both ends then finish your turning without having to worry about chunks flying off the ends . Cheers ~ John

[Resination]

I haven't used that brand of resin, but...
reduce your catalyst. 22 drops per blank is extreme. Those should be cured in no time, almost pour it right onto the spinning lathe.:p

[MBUMIK]

i just got some of the Barnes clear casting resin

my first and only batch so far i used 1% i.e. 250ml resin 2.5ml MEKP

i found these to be briittle, but they did turn fine with a skew chisel

my next batch (hopefully this weekend) i am planing to drop down to 0.75%, i think on the can they recomend 0.75-1.25% - don't quote me on this only working on memory

that last lot i did seemed to gel within 25 minutes, not sure if that is fast or not but it seemed fast to me

MIK

[MBUMIK]

Mainly Chipping and it doesnt seem what I do I cannot get what you call a ribbon comming off the the blank. the ends have blown out (cracked) on several occasions now and no matter what i do i have what can be described as pit type holes all over the blank and have to sand and sand and more bloody sanding before I can get them smooth and even then I fail to get all the marks out.

Cheers Ian

were you using a skew, i have found that scrapers and even the gouges will cause pitting/chipping

MIK

[Resination]

That resin sounds a lot like some resin I used to get call Castin' Craft. It didn't matter how it was mixed, it was always brittle to some degree. I was able to compensate with sharp tools and delicate operation of said tool.
I now use Silmar and can't get a brittle blank no matter what. Perhaps you have a similar brand available to you??
With the brittle blanks, spin the lathe at top speed, use sharp tools, and start with light shear cuts until you get the feel for them.

[dj_pnevans]

I used to do the measure how much I used but now that will do.
David

[Dorno]

Yes you were right I am not using a skew chisel I am using a small 8mm Gouge by memory so I will do what everyone has suggested in reducing the amount of hardener by heaps and also trying to use a skew chisel but being only relatively new at this I have found a skew hard to use. I will also slow down on how hard I attack the blank.

I Thank you all for your help

Many thanks Ian

[resin guru]

Hello resin casters!!!!

Firstly different resins have a shore hardness. Like a typical clear casting resin (polyester 60% styrene) will have a shore hardness of about 82D which is quiet hard and is very brittle like glass (due to its short polymer chain matrix). I have made an additive to use with this resin that is added to the pre catalysis resin. This makes the new cast stronger than before but much less brittle and much easier to machine down.

Reducing (mekp) catalyst from 2% to 1% (no less than 1% unless post curing is done) is ok, it will still fully crosslink but may take days or weeks to become 95% + set. Problems are that it will draw more moisture out of the air to give a tacky surface, but will be easier to machine after the tack is removed and the casting will shrink less due to a lower exothermic reaction. Casting a piece at 1% addition rate I recommend leaving the piece in the mould for a few days. (Most silicone molds can be preheated under light or in a oven before casting into to, this helps the initiators and catalyst kick off.

Your friend....

Resin guru.

[resin guru]

A less sharp machining tool was also good advice that was given earlier in the posts....

All my new drill bits are drilled into concrete for 10 seconds or so before I use them to drill holes in resin.

Luke.

[MBUMIK]

Casting a piece at 1% addition rate I recommend leaving the piece in the mould for a few days

1% and i knock it out of the mold in 4hrs and turn after 24hrs


A less sharp machining tool was also good advice that was given earlier in the posts..

tools should always be very sharp with resin, and light passes to try and get ribbons of resin coming off

try the skew laying on its side, i can't remember where i saw them but the guy from yoyospin has some movie clips on the web somewhere that shows how he turns resin pens and bottle stoppers.

as an archery coach i know that what works for one person won't work for the next person, so my further advice is listen to everyone, read as much as you can on the net, try as many ideas as you can until you find a system that works for you, continue to ask questions.

but the most important part of all - make sure you tell ME what you work out:U:U:U

MIK