Xencast Flexible Polyurethane Rubber

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Xencast Flexible Polyurethane Rubber

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TURK	TURK posted 8 Years Ago HOT Topic Details
Group: Forum Members Posts: 101, Visits: 662	Hi all, I've got a few questions regarding the 'new' product 'XenCast Flexible Polyurethane Rubber' advertised on your website. Basically I'm making a couple of moulds with the intention of casting 'Vac-Cast Epoxy Resin' into them, what I need to end up with are two perfectly reproduced tooling plugs for vacuum forming my final parts into ABS plastic. The following image will hopefully explain in greater detail my procedure. I've recently used a product from 'Smooth-On' called 'OOMOO 30', but had a disastrous result. I must admit, as good as it seems to be I just hate working with it. Here's what my original mould box looks like with my plug secured in the base, I then poured the silicon rubber into the mould box ......... it was an awful lot of work, trying to mix what was a consistency of partly molten lava, and the impossibility of pouring made the job needlessly difficult, the result was a failed pour and a very badly formed mould ! >> Pouring the mix in a thin stream in a low corner was just impossible, I almost had to resort to 'trowelling' it in ! >> When I demoulded the following day, it wasn't too bad, but strictly speaking an appalling result. Not something I would want to cast resin into that's for sure ......... I put it down to a good learning experience >> Because the silicon rubber wasn't 'fluid' enough, full coverage of my plug wasn't achieved, leaving large voids and air pockets >> So basically, my question is, would that 'XenCast flexible Polyurethane rubber' be an alternative to OOMOO 30 ? I've been looking at the 'XenCast PX30', it seems to have the same characteristics as the OOMOO 30 ( both Shore A of 30 ), how will it react to Vac-Cast Epoxy Resin being poured into it ? To further explain my situation my entire procedure is here > Headlight mounting bracket moulds TURK Tags Condensation Cure CS25 RTV silicone rubber OOMOO 30 silicon rubber Xencast Flexible Polyurethane Rubber Edited 8 Years Ago by TURK
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Hanaldo	Hanaldo posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	Glad it helps mate! One of the things I quite like about the casting process is you can work out your material requirements quite accurately by filling the cavity with dry rice and then measuring the volume. Becomes somewhat trickier when you need to convert that volume to a weight for the sake of your ratios, but it is at least a starting point.
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TURK	TURK posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 101, Visits: 662	Yup, precisely Hanaldo ........ that's the method I've been using, easy when you're using a 1:1 ratio like OOMOO 30 though >> OK, here's some figures for you ......... as I got it wrong but can't find where I could of got it so wrong ! To help explain my situation better, here's a picture of the mould set up box and the plug positioned inside it. So that' the volume I'm trying to fill with silicone >> And here are the figures I used for working out the volume of the box, minus the volume of the plug in cubic centimetres ; 12cm X 32cm X 20cm = 7680 cm³ ( interior dimensions of mould box ) Then the dimensions of the model or Plug in this case 10cm X 29cm X 16cm = 4640 cm³ Deduct the size of the plug from the mould box : 7680 - 4640 = 3040 cm³ Multiply that number by the specific Gravity of the material you're using, in this case the density of the mixed CS25 silicon will be 1.14 ( g/cc ) = 3465.6 So that means I'll be needing 3465.6 grams of silicon in total. As a general rule of thumb I think it's a good idea to have a little extra left over ( the little bits of material left on the stirring sticks and in the bottom of the bucket ), so the addition of the catalyst to that figure will be the 'extra' amount of silicone just in case. So, 3465.6 grams of silicone would require 173.28 grams of catalyst as it's 5% Giving me a total of 3638.88 to fill that volume mentioned above ....... the thing is, as I was pouring the silicone, I knew I wasn't going to make it ! Luckily CS25 has a pot life of 60 minutes so I had ample time to weigh, mix and degas another 1000 grams of silicone plus another 50 grams of catalyst. Where did I go wrong ? it must be something to do with the way I worked out the volume, but I can't see it ! TURK Edited 8 Years Ago by TURK
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Xencast Flexible Polyurethane Rubber

TURK - 8 Years Ago

I'm sure the EC staff will be along soon to give you a better answer, but in the meantime my first...

Hanaldo - 8 Years Ago

Many thanks for your response Hanaldo, and your recommendations, all of which make good sense. I...

TURK - 8 Years Ago

Hi all, This is all getting very confusing now, to the point of being frustrating .............

TURK - 8 Years Ago

Tough one to answer really. It does sound like there's something up with the OOMOO 30 you have, but...

Hanaldo - 8 Years Ago

Thanks for your continued support Hanaldo, very much appreciated. I know this forum is oriented...

TURK - 8 Years Ago

Hi Turk, Must have missed this one. Although PX30 could be used in this way, as already pointed...

Warren (Staff) - 8 Years Ago

Hi Warren ....... No worries mate :) I think I've just sent you an email (...

TURK - 8 Years Ago

Hi Turk, If they replace it FOC then you might as well try it out. I'd push for a refund too for...

Warren (Staff) - 8 Years Ago

Hi Warren, I'm pretty sure that they'll say what I already suspect ......... I've had that...

TURK - 8 Years Ago

Unfortunately the road to knowledge in the composites and mold making world is paved with money!...

nc42 - 8 Years Ago

[quote][b]nc42 (12/01/2017)[/b][hr]Unfortunately the road to knowledge in the composites and mold...

TURK - 8 Years Ago

Hey Pascal, you do have the latest generation of Condensation Cure Silicone 'CS25' - we just haven't...

Rich (Staff) - 8 Years Ago

Thanks for explaining that Richie ;) I kind of suspected that, as the 'LOT' or batch number does...

TURK - 8 Years Ago

You require 5g of Catalyst for every 100g of silicone, therefore you have 20 x 100g (2,000g) of...

Rich (Staff) - 8 Years Ago

:w00t: Crickey, I got it right ! :laugh: I did go about it in a different way than you, but...

TURK - 8 Years Ago

there are lots of ways of working out so long as you arrive at the correct amount, that's al lthat...

Rich (Staff) - 8 Years Ago

Hi all, Just in case somebody is interested, with reference the EC Vacuum degassing system...

TURK - 8 Years Ago

Why have my pictures been reduced to the size of a postage stamp !? They were 900 x 600 when I...

TURK - 8 Years Ago

Just on the topic of calculating catalyst ratios, thought I would add my formula to the mix in case...

Hanaldo - 8 Years Ago

As I'm at the beginning stage, learning the ropes as it were, I think that 'exact' measurements is...

TURK - 8 Years Ago

Glad it helps mate! One of the things I quite like about the casting process is you can work out...

Hanaldo - 8 Years Ago

Yup, precisely Hanaldo ........ that's the method I've been using, easy when you're using a 1:1...

TURK - 8 Years Ago

Turk, if its only 5mm, I would shave down the chipboard ends of the box or use something thinner. It...

Warren (Staff) - 8 Years Ago

That's OK Warren, at least now I'll know for next time ........ as I constructed my mould set up...

TURK - 8 Years Ago

What is it with this site, that you can't use a quote from a member and that it adds your response...

TURK - 8 Years Ago

Anyway guys ......... as it turns out, my silicone moulds made of CS25 came out absolutely superb !...

TURK - 8 Years Ago

Looking good mate! Is there any real reason to be concerned about the hardness of the silicone?...

Hanaldo - 8 Years Ago

Hi Turk, Glad the moulds came out ok. With densities and volume, you will find in most cases, the...

Warren (Staff) - 8 Years Ago

Hi guys, Thanks for those kind words guys ........ yeah, really happy with the way it turned...

TURK - 8 Years Ago

Hi Turk, You will find most battery scales will have an auto shut off to protect battery life. It...

Warren (Staff) - 8 Years Ago

Just to add to Warren's last post - you could actually remove the bung from the gauge to pierce it...

Rich (Staff) - 8 Years Ago

Regarding the scales auto-off function, this is why I always take note of the weight of the...

Hanaldo - 8 Years Ago

Thanks for the tips guys ........ I was totally aware of the maximum piercing of the bung as the...

TURK - 8 Years Ago

Hi guys ....... ( and girls if there are any on this forum ) ! it seems to me that this is more of...

TURK - 8 Years Ago

Just received my order Warren :D Ordered Wednesday the 8th ....... as I live in the boondocks...

TURK - 8 Years Ago

Hi all, Quad headlight tooling plugs for vacuum forming now complete :) just got to drill a...

TURK - 8 Years Ago

Hi guys, I realise it's been a while since my last update, but I feel some members may wonder how things are coming along. And how I'm getting on with EC products and materials. The ABS parts I'm.....

TURK - 7 Years Ago

I'm sure the paste will work in exactly the same way if it isn't still the same product. I love tooling putty, it makes a lot of jobs so much simpler. A couple of things to watch out for - it traps.....

Hanaldo - 7 Years Ago

Hi Hanaldo, Many thanks for your input, very much appreciated mate ;) EC have an update version of that video? ............. looked everywhere, can't find it :( Matthieu Libeert' video on...

TURK - 7 Years Ago

Ah I forgot EC are uploading their latest videos to Vimeo. This is the updated one here: http://easycomposites.co.uk/#!/composites-tutorials/High-Temp-Tooling-Gelcoat-Putty-Mould Realistically.....

Hanaldo - 7 Years Ago

Thanks Hanaldo, I was going to use Easylease anyway as I keep in stock, and maybe apply a few coats of release wax first. I don't know if it's the recommended thing or even if others do that on a...

TURK - 7 Years Ago

Oh, never apply a solvent based release agent over a wax release agent! You can apply wax over the Easylease, but not the other way around. The solvents actually dissolve the wax, and the wax...

Hanaldo - 7 Years Ago

You know, now you mention that ................. I kind of thought at the time that the Easylease rubbed the wax off anyway! As you say, I got lucky! The other valid point you make is, even though I....

TURK - 7 Years Ago

Easylease should be applied in layers, typically a minimum of 6 layers for a pattern or new mould. Check the TDS for details, but it will be something like 15 minutes between coats.

Hanaldo - 7 Years Ago

Ah, yes, I'd forgotten about that ................. been a while since I used it. Thanks Hanaldo ;) I'm going to order from EC today. EG60 Epoxy Tooling Gelcoat EMP Epoxy Moulding Putty I think...

TURK - 7 Years Ago

I'd be hesitant to do 40mm in one hit, I think much over 25mm in one go may provoke a pretty high exotherm. You could do it in 2 layers, you would just want a 'coupling coat' of the gelcoat in betwee...

Hanaldo - 7 Years Ago

Yeah, I was going to apply the layers gradually, a cm or two just like the video shows, wait for it to cure then apply another cm or two. I don't know what a coupling coat is Hanaldo, I'll ask the...

TURK - 7 Years Ago

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