Plasticine fillets and alternatives

[Dresca]

Hi all

We have some large steel moulds we are using in our applications. They are joined at one side and we use a fillet of plasticine to cover the sharp internal corner that is created here. This is fairly time consuming as the moulds are huge. But since the moulds are readily available through a family contact we want to continue using them. Rather than going over to Polyester moulds. The steel releases real easy, and is ruler straight etc..

I am aware of a wax fillet strip that can be bought. But the problem I think there would be making it stick to our shiny metal moulds. I have had all kinds of suggestions from non-GRP'ers on how to bridge this 90 degree angle.

I've tried silicon sealant. But it didn't make a large enough fillet - and looked poor, and didn't edge well onto the steel. Also tried tape, which looked shocking on the piece that I turned out.

We need a semi-permanent fillet as the side is bolted on and is removed to release the odd shaped object. So car body filler and the like are out.

Does anybody have a better suggestion. Would really help

Many thanks
Dresca

[Bergalia]

Dresca - not sure of what goes into your molds - plastic I assume. Hot plastic - if so I also assume that the heat reacts with the plasticine and causes some distortion in the fillet.
This is purely guessing at the problem - but why not try 'playdough' as an alternative. Don't buy the commercial stuff but make it yourself. Plain flour, a spoonful of olive oil and add cold water to mix to a putty-like constituency. It molds well and doesn't soften with heat - instead hardens and will retain its shape for re-use. Of course I may be on an entirely different track.:)

[Dresca]

Thanks Bergalia

Yes polyester resin goes into the moulds. The plasticine is from a GRP shop and doesn't react with the resin or the heat. But it does come to pieces when the piece is pulled from the mould, meaning that the entire fillet has to be re-made each time. The plasticine stays soft throughout the whole process.

I tried the homemade dough...but ended up with a stringy substance that I couldn't form. Any recipe with quantities for this dough?

Dresca

[joergen]

Cant you weld the inside of the moulds, they are from steel?

[Dresca]

Unfortunately the fillet needs to be a semi-permanent that will allow the plate which is bolted on this multi-piece mould behind the filleted part to be released and removed. So welding and body fillers are out.

Many thanks

Dresca

[tja]

The cultured marble industry use both modeling clay and also wax filets to creat radiuses. If you have two pieces that bolt together I don't see how you can avoid redoing it every time. You can buy the filet material in string form or 1x1x5 sticks that are put in a hand machine to exstrud different size string. I've always used either a pop cycle stick or tung depresser to form the final radius. Hope this helps. Tom.

[Dresca]

Yeh. I think the radius will need to be re-done each time.

Currently we use a chromed metal stick with a ball on one end..was just labelled a filleting tool at the GRP shop. We are getting pretty quick at running up these radii. So I guess we will continue until we work something else out. A ground out and tooled mould laser cut behind the radii seam would work. But our contact is in the welding and bending metal trade. Not the tooling trade. The latter I think would be big money.

Not sure what the tools you are describing are. But thanks for the reply :)