Resin Casting - UK Suppliers for Mould making materials

[Guest]

I'm working on some scratch built vehicles and am looking for a good UK Supplier for Casting Resin and RTV Silicon for mould making.

The parts I need to cast are small Tank wheels approx 12mm diameter and track links - I plan to either mill or turn the wheels to make a set and then cast in resin to batch produce the parts.

I've used RTV for white metal casting and it always seems to cost a bomb and there's never enough hardner in the pack to mix the whole pot. It's also struck me as being prohibitively expensive - around £25 per 500ml tub.

I'd be interested if anyone has working experience of resin casting and could point me in the direction of a good UK supplier - mail order or online suppliers and can recommend any brand names which they know work well.

I prefer a supplier rather than buying tiny cans of the stuff in model shops / art shops and paying "craft shop" type prices.

[wonwinglo]

Alex Tiranti is a well established UK dealer,check out our 'Modelers Resource Directory' for full details,plus some other suppliers that New To Trains uses for his own casting work.

[Guest]

If You Still Need Details I Have Also Found Another Supplier Who Has An Ebay Shop And Rapid Mail Order Business, - Plus Service Is Faster Than Tiranti And Its A Tiny Bit Cheaper, Pm Me For Details If You Still Need 'em

[Guest]

I finally got around to using the RTV Silicone and Fast Cast Polyurethane Resin.

I purchased the items from TOMPS Mould Making Supplies, the service and support has been really helpfull and they cater for the hobby user as much as the professional. Products are also available in small size containers and they sell all the accessories too, reuseable mixing cups, catalyst dispensers etc for measuring quantaties.

The products I used where:

Condensation Cure RTV Silicone with Slow Catalyst (Blue colour with 40min potlife)

Polyurethane Fast Cast Resin [PU Fast Cast] (30 minute cure 4-6 minute potlife)

I'd recommend either of these products, I've had problems with RTV's in the past taking days to cure but this stuff could be demoulded in 4 hrs and mould is good and rubbery - easy to demould and has lots of nice detail too!

:dancing1:

[Guest]

Glad To Hear Tomps Did The Business For You !

[Guest]

My first attempt at casting in the polyurethane was quite successful although the mould still had a little bit of water in some of the low parts as I'd previously water filled the rubber to give me some indication of it's volume. Some of the bolt heads where missed on the resulting casting.

One thing I was considering was adding a filler powder to the resin, to bulk it up and make for cheaper castings, as the filler powder has a lot of air in it I was a little concerned that by adding the powder I'd suffer with a lot of air bubbles and lose a fair amount of detail. The fast cast resin by nature is very thin, probably like a double cream consistency and even without a pressure pot I was quite pleased with the quality. I'm sure adding a filler would make the polyurethane a lot thicker and would be harder to get into the intricate corners. Also I'd assume I'd need a resin with a longer pot life than the fast cast stuff.

Does anyone have experience using fillers to reduce the amount of resin required?

[Guest]

Some of the fillers are very very fine, - not sure how small the details are, but its got to be worth a trial surely... fillers are not that expensive....

[Guest]

Hi Allan,

have you ever tried dentist's quality plaster as a mould medium and linotype metal for copies? It has an excellent copying quality and you can make a lot of copies before the mould shows signs of ageing.

George

[wonwinglo]

Just a thought,could you use Micro Balloons to add to the casting material ? would they bulk out without adding too many air bubbles,you can buy bags of micro balloons in model shops for experimentation.

[Guest]

Hi Allan,have you ever tried dentist's quality plaster as a mould medium and linotype metal for copies? It has an excellent copying quality and you can make a lot of copies before the mould shows signs of ageing.

George

George,

I'm not familiar with linotype - is it just a form of lead or white metal casting?

Alan

[Guest]

Hi Allan,

well, my English being what they are, result in possible misunderstandings. The best metal to my satisfaction comes from molten typeletters if such a word exists in your language and I mean the type of metal letters that were used until a few decades ago to print on paper.

The copies are very good indeed with minimal finishing and the end result is from metal with all the pros and cons of it. Nothing really difficult, but suggest extreme care with molten metal, particularly with kids, wife or other animal around (no pun, but if you step on your cat's tail....).

Hope I made myself more clear,

George

[Guest]

Alan

Try here - http://www.glasplies.co.uk/glas/gpshop.htm for your resins.

They do a water fillable polyester resin. As it is mixed you spin in water with a stirrer, you can almost double the volume, and it pours and fills really nice. Very good for bulky items, but does shrink slightly (makes coming out of mould easier). Not quite as lightweight as the specialist resins but does mean you can make twice as much for your money.

If you can call into here they are the most helpful of people and I used to come away with a useable sample to try before buying the full 5 litres of resin.

When I used to do casting using the very expensive lightweight resin, if it was a large item I would make a cradle using plasticard around the mould so that I could clamp a sealing plate on the top. This sealing plate had a hole in it with a plug. The two seperate resins were injected into the mould seperately, then the plug stuck in, and the mould was given a good shake to mix the resins, then for about two or three minutes the mould was just rolled about thru all axis in the hands to spread it about inside the mould until it had set up then just put it on one side to fully cure. You end up with very light and hollow cast item, usually with no air inclusions, and picking up all the fine detail, using only about a fifth of the resin for solid casts. There was one problem, the sealing plate had to be on a side that is not seen, say on the bottom or back of a locker or under the base of a gun mounting. For a large piece that built up using smaller parts, the sides with the plate could be used on the joint faces. I suppose you could make the sealing plate with detail on it, and just fill the injection hole afterwards, you just need to get the register correct.

John