Beginners' Advice Needed!

[Davec_24]

Hi all,

I'm looking to get a set up for casting the odd bit that I can't be bothered to scratch build lots of (helicopter blades or bits for models I intend to do several of, etc.). I was having a look around online and there seem to be several types of resins and moulding compunds. If I'm honest, I haven't got a clue what's suitable for the sort of thing I want so was wondering if anyone had any particular reccomendations?

I did see this one that looks a reasonable price to just see how I get along with it before buying huge vats of resin, etc. - is this the sort of thing that I'd need for casting bits, mainly for model aircraft?

Thanks in advance!

[Davec_24]

I've not looked there, thanks for that rich! Am I talking about the right sort of stuff with this G26? Also, what about the mould rubber - is that about the right sort of thing? Are there any on Tiranti's site that you'd reccomend?

The resin appears to be Biresin G26. 2Kg of that is £26 from Tiranti. Have you looked at the Tiranti site?

rich

[Mike]

Dave - I do a bit of my own casting, and have been using the Biresin G26 for a while now. The only downside of it is that it "feels" a bit greasy,and is quite susceptible to heat deformation. When mine runs out I was going to try the polyester resin that Tiranti have started stocking, as it sounds more like the stuff the pros use. Shame is, it's more expensive.

When I get back to the workshop, I'll let you know the type of RTV I use, again from Tiranti

[Davec_24]

Cheers Mike, that'd be good. Did you mean this type of polyester resin?

That seems slightly cheaper if anything, but then that's by weight so I don't know - I'm a rookie at this resin thing!

[Davec_24]

Shrinkage could be an issue - I guess you're always bound to get some, but 8% seems a bit OTT so maybe best to try polyurethane first. Is there any sort of resin you'd recommend, Rich?

Dave.

Polyester is generally a VERY high shrinkage system, in fact up to 8% with some versions. The only systems that don't have this are heavily filled, and generally the viscosity will suffer. I'll have a look at this, but I'd be surprised if the data sheet will give me the info I need.

Polyurethane's are pretty good for shrinkage, generally in the same order as epoxies <1%. I would also be very careful as to which RTV you use, some can be susceptible to the Styrene content in Polyesters.

Cleaning the greasy residue off of PU resins is not difficult, and Polyesters can suffer with a surface that may not cure properly when in contact with some moulding materials.

This whole area can be a mine field. The one advantage to a kit is it's all compatible.

I have to be honest. I've used Biresin infusion and hand lamination Epoxies and won't be rushing back to use the stuff again.

rich

[Edited due to attrocious spelling ]

Edited March 12, 2010 by Davec_24

[Simon Cornes]

Hi all,

I'm looking to get a set up for casting the odd bit that I can't be bothered to scratch build lots of (helicopter blades or bits for models I intend to do several of, etc.). I was having a look around online and there seem to be several types of resins and moulding compunds. If I'm honest, I haven't got a clue what's suitable for the sort of thing I want so was wondering if anyone had any particular reccomendations?

I did see this one that looks a reasonable price to just see how I get along with it before buying huge vats of resin, etc. - is this the sort of thing that I'd need for casting bits, mainly for model aircraft?

Thanks in advance!

Dave

I expect you're sorted out by now but my two pennerth may be worth it! Firstly, I used Tiranti casting resin and their RTV rubber about 10 years ago. Loved the stuff but the shipping cost was exhorbitant!! Last year, at SMW, I bought the equivalent kit from Sylmasta and have just used it. Perfectly okay material and compares well with Titanti. I may well try to buy RTV rubber locally as some people in the yellow pages do sell it for various purposes so may be worth considering. In my earlier moulding phase I was using mainly one piece mould with just 1 two piece affair and the ghole to pour the resin in was quite large. I am now moulding much 'thinner' things like bombs where the hole is 2-3mm. I was a bit worried about how to get the resin in and ended up injecting it in with a 5 cc syringe. It works beautifully and you can use the syringe again, I was certainly glad about that!

Cheers

Simon