Acrylic blanks

[Dutchy]

I made some of my own blanks the other day for the first time and when I turn them they seem to be very brittle and don't turn like the ones I have bought.Am I possibly using the wrong resin or maybe too much catalyst. Any thoughts would be greatly appreciated

 

[jttheclockman]

I made some of my own blanks the other day for the first time and when I turn them they seem to be very brittle and don't turn like the ones I have bought.Am I possibly using the wrong resin or maybe too much catalyst. Any thoughts would be greatly appreciated

Don't know. Why don't you tell us what you are using??? It will help.

By the way welcome to the site.

 

[Dutchy]

Sorry that might have helped. Im using casting resin and catalyst from my local hardware.I followed the mixing ratio and it just seems to be chipping off and not coming off like the bought blanks

 

[jttheclockman]

Sorry that might have helped. Im using casting resin and catalyst from my local hardware.I followed the mixing ratio and it just seems to be chipping off and not coming off like the bought blanks

I am sorry but maybe this is some off brand or something but it is going to be hard to tell you anything. Give us a name of it or a photo and maybe we can do a search.

We have no idea how much catalyst they tell you to use or what kind of resin it is. There are many types and not all are made for casting into pen blanks. Some are surface resins that are made to be used in thin layers.

Is the catalyst added in drop form or poured in weight form??? You will have to supply us with more info. As I said a photo of the stuff and maybe a description of how you go about mixing and or measuring. Other than that it will be just guess work and people can tell you what they do and all but if you are talking different things it won't matter what anyone says. Sorry.

 

[MrBassMan]

Sorry to hear about your experience, but it's all trial & error FWIW.

I cast all of my own resin blanks and what I found are 3 things...

1. Ambient tempretrue when casting (72+ degrees, minimal humidity seems to work for me)

2. The amount of catalyst used.

3. The type of mold (I use 3/4" PVC, 6" long)

Too much catalyst will definitely yield brittle blanks. However, sharp tools make a huge difference too (I prefer a skew chisel for acrylic because I get a much smoother cut as opposed to a gouge).

As for catalyst, for me, for every 2oz of resin I use 11-13drops of catalyst

 

[jsolie]

I made some of my own blanks the other day for the first time and when I turn them they seem to be very brittle and don't turn like the ones I have bought.Am I possibly using the wrong resin or maybe too much catalyst. Any thoughts would be greatly appreciated

If it's the type where you put in a few drops of activator (MEKP or Methyl Ethel Keytone Peroxide) you might have put in a couple drops too many. Polyester resin can get pretty brittle, especially if you use too much MEKP. A few of my early blank are pretty brittle, so I just go slow when drilling and turning them.

 

[Dutchy]

Thanks for your replies. I have a product called diggers casting and embedding resin which to me sounds more like a product for fishing lures and jewellery etc.Mr Basman you say you use 11-13 drops per 2 oz which according to me my product tell me to use between 1.5 and 2 ml per 100 ml of resin. Since 100 ml is 3.38 oz and 1 ml of catalyst they say is 45 drops then that doesn't add up to me. I will try to lower the amount of catalyst used as the resin I cant use for anything else so Ill have a bash and see how it goes

 

[jttheclockman]

http://www.recochem.com.au/files/downloads/Cons_Casting__Embedding_Resin_PDS_Apr11.pdf

Oh this is going to require a lot of math. I am going to bed.:doctor:

 

[79spitfire]

Home cast Polyester Resins can be chippy. I have also found (just to add to the confusion) that different vendors resins seem to have different properties as well. The 4 I have used are Simlar 41 from US composites, it seems to be the least chippy, Tap plastics Polyester Casting Resin, and Castin' Craft's products are very similar, and Bondo's Fiberglass resin (without the fiberglass) all are somewhat chippy, but that can be dealt with by using scary sharp tools and fast speeds on the lathe.

And if your curious, the Bondo did cast just fine, but it has a funny amber color. I used it with strong opaque pigments in dark colors, it causes color shift in light colors. Why use it? It was cheap at Lowes one night I felt like experimenting.