Castin Craft vs. Silmar 41 Casting

Signed-In Members Don't See This Ad
S

soligen

Member
Joined
May 11, 2010
Messages
1,090
Location
Sterling Heights, Michigan
I am posting this for the benefit of anyone thinking of giving PR resin casting a try. Hopefully it will get search hits down the road as new people consider this question and provide them with value.

The bottom line - Skip the Castin Craft and get the Silmar 41. Read on for details.

My Background: I'm a beginner caster and a fairly new pen turner. Before casting I had never turned any sort of plastic, and to date have only turned my own castings.

I bought the Castin Craft from a local retailer using a coupon. I thought what the heck - lets give this a try, and although everone here mentioned the Silmar 41, I didnt want to pay the shipping for a small order - buying local seemed to make sense, and I firured there couldn't be too much difference (I was wrong)

To date, I only have 2 pens made, and one blank left from the whole can of castin craft. I have had many failures. Some failures are just normal learning curve failures that you would expect. However, many of the failures is due to the Castin Craft being very difficult for me to turn (Using a Woodchuck Pen Pro). It was so bad that I was on the verge of giving up on the home casting.

Well, I ran out of resin after a casting blunder and need more, so I bought the Silmar 41 in hopes it was better. OMG SOOOOO much better. By comparison it turns like a dream. The casting craft is just too brittle and chips out very easily.

Take my advice, skip straight to the Silmar 41 - get a gallon to make the shipping more tolerable. If you decide not to use it all, there is probably a local member who would take it off your hands. Only get the Castin craft if you want a bad expierence that turns you off from casting.

I know I'm not being too kind to castin craft. I dont mean anything bad about the company, it just that the product is obviously intended for a different use and isnt very good for pen turning. I'm sure it is just fine for the purposes for which it was designed.
 
Signed-In Members Don't See This Ad
First of all I'm not a fan of the Castincraft resin but that's mainly due to price . It is a different formula of resin compared to Silmar 41 . The main difference is in the amount of catalyst recommended . If you use the amount they say , you will get a very brittle blank . Also if you use any heat (even sunshine heat) to post cure your blanks you will make it even more brittle . That said , it is no worse then the Acrylester blanks and some Tru-stone blanks that you can buy from many vendors .
These type of blanks require a different technique to drill and turn them . Very sharp tools are only part of the things needed to turn any brittle resin blank , technique is the most important thing . You cannot attack these blanks like other resin or acrylic blanks . Their brittleness requires that you use a shearing cut with your tool to get a clean cut and if you are starting with a square blank it's even more important .
Chipout is the main problem when turning Acrylester , Castincraft and Tru-stone , if you cause the resin to chipout you create fractures in the resin that can go all the way through to the tube . Once these fractures are formed there is no real way to save the blank , it will shatter at the first chance it gets . To avoid this the general wisdom is to knock off the edges with a band saw or belt sander to to create a more rounded blank which is generally a good idea since most of the worst fractures are caused in the first few cuts . You can also successfully turn these kinds of blanks round with a Skew using a shearing cut . You do this by holding the skew at a 45 degree angle to the blank and ride the bevel tipping the cutting edge into the blank so you are shearing the material off the blank . Ed Brown (ed4copies) has made several excellent videos of this process . Using this process and a little practice you will be able to take the most brittlest blanks to round without any chipout and fracturing .
Drilling these blanks are different as well . You must take very light cuts clean out the hole very often . If you take to heavy of a cut you will cause the resin to fracture from the inside out and again you will have a failure at some point due to the fractures .
There is no need to avoid these brittle types of blanks , in fact they can be some of the most beautiful blanks you will ever turn . These types of blanks will out shine (a glass like finish with proper polishing) almost any other blank on the market , but they do require allot of care when turning .
 
Hmmm - I let mine post cure. I eased up on the hardener and they seemed to stay soft, so I post cured them. That could be why they were so brittle. I've heard of brittle blanks before that are really amazing. and worth it. I'm just point out that it is not a good place to start.

Drilling didn't seem to pose me any problems. It was the turning. Even a very minute error casued chip out of varying degrees. Blanmks were already round as I cast them in PVC. I have one brittle blank left. I guess I'll save it and try it again after I get more practice - maybt to practice up right before I try Trustone :)
 
Last edited:
Some of the Tru-stone turns very easy some , like the dark lapis , are very brittle and will shatter if your too aggressive . It's all a matter of technique , a light touch and a shearing cut and once you get a rhythm going they turn down fast . Watch Ed's video , it's on youtube and I think he has a link on exotics . His video is one of the best on turning plastics that I've seen . Look closely at the way he is holding the skew and the way he presents it to the blank . That is a shearing cut and is the best way to turn ANY plastic .
The carbide cutting tools are great but can be too aggressive on certain types of plastics , especially if you are not using a shearing cut , can fracture the blanks very badly . As sharp as they are they are usually used in a scraping position and brittle plastics don't like that .
I will try to find the link to Ed's video a little later .

Here's a link to one of the videos and theres another if I can find it
http://www.exoticblanks.com/index.p...e&id=59:article-1&catid=37:articles&Itemid=66
 
Last edited:
I hear what you're saying. I also started out with castin craft...I think it's just a natural progression to ease into casting. Just like most turners stick with slims/sierras/cigars at first and then branch out into the more expensive kits and materials. I actually pulled one a pen made with one of my first castings (castin craft) and turned it down a bit bc it was seriously too pregnant. I was a bit nervous at first bc I remember how brittle it was but I'm using a carbide tool now and I had absolutely no problem with it. Like Butch said....sanded properly you just can't beat the shine you get. Since I started turning I've refined my finishes and man let me tell you the one I redid today, by far the highest gloss of all the pens I've got in my collection right now. It does take a careful touch but sometimes it's worth the headache. That doesn't mean I'm chucking my Silmar 41 out the door anytime soon though!:tongue:
 
Thank you Dawn , yes either of the first two show Ed using the Skew . These two videos are perfect examples of how to turn resin , especially brittle ones , without blowing them up . The third shows that even a roughing gouge can be used on plastics if you have the proper technique .
 
soligen said:
I am posting this for the benefit of anyone thinking of giving PR resin casting a try. Hopefully it will get search hits down the road as new people consider this question and provide them with value.

The bottom line - Skip the Castin Craft and get the Silmar 41. Read on for details.

My Background: I'm a beginner caster and a fairly new pen turner. Before casting I had never turned any sort of plastic, and to date have only turned my own castings.

I bought the Castin Craft from a local retailer using a coupon. I thought what the heck - lets give this a try, and although everone here mentioned the Silmar 41, I didnt want to pay the shipping for a small order - buying local seemed to make sense, and I firured there couldn't be too much difference (I was wrong)
Click to expand...


Reguardless of what others may say, (I've been involved in the fiberglass boat business for over 30 years), ALL FIBERGLASS/PR RESIN HAS AN EXPIRATION POINT. It is somewhere around six months to one year. Until such point that the manufacturers stamp a "born date" and an expiration date, it is better to buy directly from a manufacturer (reseller) than from a retail store.

Even if the the "Castin Craft" resin and Silmar S41 were exactly the same formula ( THEY ARE NOT- inert ingredients can and do make a difference)) , the odds of getting a fresher product are in your favor if you buy directly from U.S. Composites ( huge reseller, not the manufacturer).

In fact, my last S41 order (4 containers) three containers had the old "white" label on a silver can and one was in a totally "white" can. I called U.S.C. to make sure it was the same product. They told me it was the same product, but the white can indicated a small change in the formula.

At Hobby Lobby,et. al, pallets of resin may sit on a pallet in a warehouse that has minimal temp control for up to a year (depending on the volume an individual store sells and where the "break point: was on the purchase agreement with the corporate office).

Have I bought and used "castin craft" and did it work? YES. My point is that you can expect more "predictable" results time after time with Silmar 41. If you don't believe this, try pouring a mold with half clear CC and half S41. iIf you look very closely (with a loupe), n the finished blank you can actually see a "line" where one resin stops and the other begins.
 
try pouring a mold with half clear CC and half S41. iIf you look very closely (with a loupe), n the finished blank you can actually see a "line" where one resin stops and the other begins.
Click to expand...

I'm not quite sure what this is supposed to prove???
 
It proves that the resins are a different product. With S41, you can pour half of a clear blank today, then pour on top of it tomorrow... Or next week. The new pour bonds seamlessly with the older pour.
 
With S41, you can pour half of a clear blank today, then pour on top of it tomorrow... Or next week. The new pour bonds seamlessly with the older pour.
Click to expand...

Have you tried this with Castin' Clear? Not that it matters. Just curiuos.
 
Question on pouring over top of things. I poured the leftovers of the S41 into a PVC pipe mold - not enough to do anything with, but I'm wondering if I can just keep pouring leftovers with potentially a few weeks between pours and have a usable (if somewhat odd) blank after several casting sessions. I started doing this to give it a try. Just wondering if anyone knows if it is going to work. I put a piece of tape over the end of the mold just to keep any foreign material out.
 
soligen said:
The bottom line - Skip the Castin Craft and get the Silmar 41
Click to expand...


and isnt very good for pen turning.
Click to expand...

I don't really agree with either of those. I've poured a lot of the CC resin and have made some great pens from it. While there may be better products out there, I wouldn't think twice about suggesting someone using it while they're learning to cast. Just my personal experience.
 
soligen said:
Question on pouring over top of things. I poured the leftovers of the S41 into a PVC pipe mold - not enough to do anything with, but I'm wondering if I can just keep pouring leftovers with potentially a few weeks between pours and have a usable (if somewhat odd) blank after several casting sessions. I started doing this to give it a try. Just wondering if anyone knows if it is going to work. I put a piece of tape over the end of the mold just to keep any foreign material out.
Click to expand...

You absolutely can do this with the S41 because it stays tacky on top. I pour my leftovers into a pendant mold that I have. Makes interesting pendants after several different pours.
 
Skye;1075840I don't really agree with either of those. I've poured a lot of the CC resin and have made some great pens from it. While there may be better products out there said:
I glad someone has had good expierience with it. Care to elaborate on your expienece? Then new people deciding can get both viewpoints. You may be doing things differently than I have, which improved things for you. BTW the pens I succeded with are great pens too. I just didnt like the failure rate as a relative newbie.
Click to expand...
 
Well, it's been a while since I've poured anything but I didnt do anything special. I believe I used 7 drops of catalyst per ounce of resin. I was casting clear when making snake skin blanks and then stamp powder to make colored blanks. Unfortunately I have no real secrets to reveal, it just seemed to work lol
 
I just finished my first pen from the Silmar 41. I held it up to teh pen made from Castin Craft. Ok, I see it. The Castin Craft does have a better gloss. So, I guess a more brittle blanks are harder and gloss better.
 
I have used Castin Craft Polyester Resin for all by bubble free castings and after trial and error I have had no problems with being brittle.

I have found that if the PR is too warm, if you add too much catalyst and post cure at too high a temperature that you will end up with brittle castings.

Les
 
You must log in or register to reply here.
Back
Top Bottom