where to get toy plastic?

[large_ghostman]

Let me explain first as I can not remember the name of the stuff I was using.

I have a vaccum pump and do a fair bit of RTV silicon moulds, when I fist started I watched videos on how best to make a mold to make a mold (if you see what I mean). The video showed a guy making a mould from Plasticine and then making a RTV mould from that, he then used a two part plastic and made toy soldiers.

The video had a link to the plastic, but now the video is gone and I cant find anything suitable. So does anyone know what the material is called that is mixed in 2 parts and hardens into a plastic thats not rock hard but more like that which toy soldiers are made of?

I want to get some as I want to cast a slightly larger set of blades for the copter I posted a long time go.

Its driving me nuts!!! I did get a tiny amount of something similar that was a little harder, I made a new set of the drive cogs for the copter with it. Now it look like the company is long gone and I cant remember what the stuff was called. I figured had to be at least one toy soldier maker on here

 

[Joe G]

have you looked at https://www.smooth-on.com/

 

[4pyros]

To bad you can't melt down some of your toy soldiers. LOL
Was it like a two part epoxy?

 

[alec_t]

Have you tried car body-filler? I think that's got a bit of 'give' to it.
Or maybe something from here would do?

 

[jpanhalt]

I do not think you will want to try vacuum forming per se for making the blades, but you may want to use a slight vacuum to facilitate getting a mold full and without bubbles.

There are many castable plastics. If you get into things like polyurethanes , the price will be quite high. Epoxy resins and polyester resins are frequently used for making "fiberglass" or more generally FRP (fiber reinforced plastic, also FRC) and are relatively cheap.

One use for polyester resins is in autobody work. The uncured resin has a very sweet odor and the second component is usually only a few drops per 30 mL or more of resin. Setting times for polyester resins are usually quite short. It can be difficult to work with because of its fast setting time. My preference would be a casting epoxy. West Systems is a common brand in the US. A good boat store will probably carry a similar epoxy in Scotland. With epoxies, you can pick a setting time from a few minutes to hours. I would not depend on either plastic for the full strength needed for helicopter blades.

One option is to make an FRP blade in a mold. Glass fiber will be the cheapest and heaviest. Kevlar will be the lightest, and carbon is quite strong and light. Carbon fiber FRP has a certain panache too. It is also quite expensive today.

Another option I would consider would be to fashion my blades from an easily carved wood. In the US, we use balsa, spruce (Stika preferred), or basswood. There is a wonderful wood available in UK that is light, straight, easily carved, and strong. If I could get it in the US, I would use that in preference to balsa, but I don't remember what it is called in the UK. Then, I would cover the blades with very light fiberglass, such a 0.5 oz/m^2 glass. It is almost like silk. If you can't get such light fiberglass, I would consider a synthetic fabric like Dacron. The advantage to using a wood blade it that you will not need a mold. Covering it with fabric will add to the strength and durability. If you need more strength, use more layers.

A mistake many people make when using fiberglass (FRP) is to have too much resin in the cloth. Shiny spots indicate too much resin and are bad. One way to avoid that is to blot excess resin from the glass with a roll of paper, then apply the impregnated fiber to your wood. Be sure to remove any air bubbles. Remember,most of the strength comes from the fiber material, not the epoxy binder.

You have not said how big the blades will be. If you get into big blades, say more than 66 cm diameter, I would be very cautious. I fellow hobbyist had a blade disintegrate on a larger helicopter at our flying site. The damage done to a parked car was impressive.

Good luck.

John

 

[large_ghostman]

Thanks guys, I have asked on a model site and apparently its a soft (ish) two part epoxy. Set very much like injection molded plastic. The vacuum is for getting the bubbles out before pouring. Stika is interesting as 4/5ths of our woodland is Stika pine. The blades are roughly 14" long and maybe 2.5-3" at the widest point, I cant find the pic but the helicopter was posted on here ages ago.

It flies ok but on landing last time I cracked a blade, you can buy them but they cost more than I think is worth paying lol, also I would like slightly longer and wider ones. I have seen some plans on a model site and the aim is to increase lifting capacity so i can use a small SLA battery. Its one of those projects I add bits to and tinker with off and on, the plastic would be handy for a number of things and as soon as I track it down I will post it. So many projects on the go at the moment so no rush.

I do have a large project I want to plan out, but will post this another time as I want to know if anyone else would be interested in doing it. Also with what I have in mind some suggestions for features would be great.

The carrot thing I will write up properly in a few weeks when I have investigated properly, I have a feeling its something you might be interested in John. Kind of biology and chemistry rolled together .

Been in town all day and totally shattered, the last few weeks studying until 4-5am in the morning has caught up with me. But one resit to do and just my project to hand in. Real exams oddly enough are in May!!! I was under the impression they were next year, but apparently I have been asked to sit them early with a higher year group.
This is going to massively shorten the dev time I had for the MK2 project of my project, which is what I am submitting for the real exam. Its not impossible to do the alterations in time but its really going to push my time to the limit, I hate working like that. Then again I guess in real life you have dead lines instead of the pick up and put down approach I normally have lol.

Guess my bedroom tidy is going to have to wait a bit longer

 

[cowboybob]

LG have you tried thermoplastics? I've used KYDEX and the stuff is easily softened with a heat gun (on LOW) and molds to any shape you wish. For a propeller it would probably require a two piece form (Top/Bottom). Pretty remarkable tensile strength. Easily cut to shape. Not sure how you'd deal with the hub.

And it's a memory plastic, so it can be reheated and easily returned to its original shape (flat). I've used it to make concealed carry holsters. It's used commercially for medical equipment covers, airplane seatbacks, overhead bin covers and the like.

 

[MaxHeadRoom78]

I have used molding plaster to make a female mold and FibreGlass resin for the pour.
Worked out pretty good.
Max.

 

[alec_t]

I don't remember what it is called in the UK

You may be thinking of lime (a.k.a linden). English lime (as distinct from European lime) has the more uniform grain. A favourite of wood-carvers.