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Warren (Staff)
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Hi Turk,
You will find most battery scales will have an auto shut off to protect battery life. It is a bit frustrating if you need to leave the scales for a while mid measuring!
In terms of the silicone pulling from the wall of the box, I would not worry about it as in practice, the weight of the resin you pour into the mould will force it back against the box anyway so in practice there should be no problems.
I have a replacement vacuum gauge here which I will dispatch to you today so that should solve your problem. Only thing to note is be careful how deep you pierce the bung to equalise pressure. The max on the gauge is 4mm. Some people have gone a fair bit deeper then hit the mechanism so be careful how deep you go.
Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
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Rich (Staff)
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Just to add to Warren's last post - you could actually remove the bung from the gauge to pierce it before replacing it to make absolutely sure.
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Hanaldo
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Regarding the scales auto-off function, this is why I always take note of the weight of the container I am pouring the stuff into. Before you start, tare the scales and measure the container, write it down. Then zero the scales including the container and start pouring. If it flicks off on you while you are pouring, simply weigh what you have and subtract the weight of the container. As Warren said, most battery scales will have an auto-off function. I used to have one set that didn't have it, and trust me it is a LOT more frustrating having to replace batteries all the time because you were too focussed on the pot-life of what you were mixing and forgot to turn the scales off!
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TURK
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Thanks for the tips guys ........ I was totally aware of the maximum piercing of the bung as the warning is actually printed on the gauge itself. I used a map pin to pierce the bung that's only 5mm long and didn't go all the way. But that' a good tip Richie, removing the bung first and then piercing it. Many thanks Warren for the replacement Gauge. No doubt you've already found my details on my account for my address. Regarding the scales 'Auto Shut-Off' ...... It would be fine if the auto shut off wouldn't go OFF while in use ! to conserve battery life after the scales have been dormant for a few minutes would make a good sense, but not when you're halfway through weighing something ! 2 minutes while trying to pour silicone accurately is not long enough, the auto shut off should be longer. I did make a note of the bucket weight ( always do ), then' tarred' the scales so no issues there. The problem came up when I re-weighed .......... I got three different results ! TURK
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TURK
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Group: Forum Members
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Hi guys ....... ( and girls if there are any on this forum ) ! it seems to me that this is more of a male dominated world ......... so ladies, introduce yourselves ! 
This is going to be a lengthy post, because I'm simply going to cut n paste from my original forum group. So bare with me, my intention for doing so is to see if any of you clever guys can put me straight. Even though it worked, I got great results ......... but where can I make life easier for myself, and is it possible to get better results in a quicker time.
Anyway, onto my quad headlight project ........... In the last update I left you all with this. Two perfectly formed silicone moulds for casting aluminium resin tooling plugs for vacuum forming. The thing is, you couldn't simply poor ( cast ) resin in those as you would end up with a solid block of resin. Because of the intricate shape of the tooling plug itself, there must be vent holes coming from underneath the plug >>  There aren't too many ways of accomplishing this task, making a hollow tooling plug. One way the industry do it is to use sheets of a special hard wax, an A4 size sheet of wax cost £19 ! and the thickest they do is only 5mm. That's no way thick enough for the walls of a vacuum tooling plug, as mine have to be at the very least 20mm thick as they have to be able to withstand at least 20 pounds of pressure per square inch or the plugs would simply crack under pressure, so I would need dozens of sheets of wax. Making that particular method ridiculously over priced. Spending over £200 in wax on a mould that already costs in the region of £400 is not a cost effective method of producing hollow moulds. There is another method however, known as 'blocking-out'. Some people simply use blocks of wood ........ but I've had problems in the past using solid materials against one another in mould construction. Another method I believe would work would be the use of plasticine, but I haven't got enough of it in stock, so I came up with this .......... >>  I began by cutting out some templates indicating the area to be 'blocked-out', leaving me with about a 20mm gap as a side wall >>  I then transferred all those dimensions to a sheet of 5mm PVC foam, and cut them to shape >>  And then assembled the 'skeleton' with the aid of a glue gun ........ I now have my basic shape >>  You then have to block-out the gaps using a polyurethane foam, to create a solid structure >>  The reason why it's a good idea to use PVC foam for the ribs and PU foam for the blocks is, when you move onto the sanding stage, the sanding is so much easier as the PU foam is very soft and the PVC ribs are a little firmer, it's easy to see how far you have to sand ....... once you hit the 'green stuff', stop sanding ! >>  And you should end up with this ........ the inside of what will be your cast resin mould ....... minus 2cm all the way round >>  Then you apply a skim of body filler to harden the whole thing, and sand that down. but it doesn't end there ........ you now have your 'block-out' mould, but you have to be able to release it from your resin cast afterwards >>  I then turned my attention to working out how much resin I would need for casting. So I filled the silicone mould with dry rice to find out the volume >>  As it's so important to remove the 'block-out' mould from my resin cast afterwards, without damaging the resin tooling plug, I decided to use a flexible material as a 'glove' as sorts. People 'blocking-out' using wooden blocks in their resin casts, would have to chip out the wood with a chisel as resin sticks to wood like sh!t to a blanket, I chose a different method. I simply used the remainder of that OOMMOO 30 silicone rubber I had from the last fiasco, and just painted a few millimetres of it onto my foam plugs. I also found two tupperware containers about the same size as my 'block-out' mould and deducted them from my silicone mould volume >>  Now that I know the actual amount of resin I'll be needing to fill my mould, I still need to workout what that is as weight as the rice thing is it's volume ( the amount of space the resin will take up inside the mould ). You can't workout how much catalyst you need just by volume, you need it's weight. It so happens that the volume of the rice was equal to 2000ml on my measuring container. As I'll be doing the casting in two pours, I put an equal amount of dry rice ( 1000ml ) in each mixing container, then weighed that. So we get the weight of the rice which is 947 grams, but lets not forget the density of the resin ....... this particular resin because it has aluminium in it weighs almost twice as much as the rice ........ that is to say 1.80 grams per cubic centimetres 947 g X 1.80 ( g/cc ) = 1704.60 grams of resin And as the resin/catalyst mix is a 100:6 mix ratio ( for every 100 grams of resin you need 6 grams of catalyst )So the sum is 1704 x 0.06 -------- 102.24 grams of hardener required for mixture -------- Now it's just a case of prepping everything, you must give the resin a though mix before use, as the aluminium would of sunk to the bottom >>  As I'm doing this in two pours, I prepared both the resin and the catalyst, you don't want to be mucking about with weighing scales midway through casting resin >>  The two pour technique is to minimise on air entrapment, so I used Archimedes' principle on 'fluid Dynamics', where any object submerged in a body of water displaces it's own volume of said fluid. Same if you were to fill your bath tub up to an inch from the top, then stepped into your bath it would overflow. So I poured the first container into the silicone mould >>  I then positioned the 'block-out' mould very carefully into the resin being careful not to trap air underneath. An air pocket trapped under the mould would most certainly destroy my completed resin cast >>  I then poured the rest of the resin from the second container to fill the silicone mould, after securing the block-out mould in place. You'll also notice on this close-up that there's a millimetre gap between the silicone mould and the wooden side of the mould box ........ that's not good ! ........ that's due to shrinkage, most materials will shrink after they have had time to cure. The drawback with this is, the mould could end up a millimetre too small !  Now I just got to wait for it to cure .......... curing time is 12 hours >>  A couple of hours later I went back into the workshop to check on the progress, and saw this ! ........ that's not good As careful as I was, there had been an air pocket trapped under the block-out mould :eek: it caused the resin under the mould to escape thus causing this bubble burst ! ......... nothing I can do about it now, I just have to pray and hope ! The interesting thing is, notice the tape has come unstuck ....... that's down to the amount of heat that the curing process produces. The 'exothermic' reaction caused even the wood to heat up to a point where is was as hot as a cup of coffee, and even dried the adhesive on the tape ! >>  Moment of truth .......... I stayed up like a little kid at Christmas eagerly awaiting Father Christmas with my presents :confused: So at 4 AM it was time to demould, the foam block-out plugs ( or 'Bucks' Gaz ) are simply a temporary measure and will not be used agian, so I can simply break them apart. >>  Well, that worked out a treat ! after releasing the tension, the rest of the 'buck' just peeled away. The cavity isn't pretty to look at, but who cares ......... I've got a hollow mould. And it doesn't look like the air pocket did any damage to the inside of the resin cast. Actually, I think it was completely expelled, leaving that bump of cured resin on the sidewall >>  I struggled for almost 2 hours trying to demould this cast as the resin was stuck to the silicone mould ......... then I hit upon an idea, so I squirted some soapy water into the silicone mould. This is where I cut my fingers to shreds, trying to force my entire hand in between the cast and the silicone mould to break the 'seal', those edges are like razor blades ! It's amazing just how strong and flexible this RTV silicone is, it's tear strength is amazing. At one point I had both my hands up to my wrists inside that mould and it still didn't split ! And this is the result .......... an absolutely flawless resin cast ! T: >>  I am well happy with that not a single blemish on the resins surface, nice solid 20mm walls, should be strong enough to produce many vacuum formed parts. I've just got to tidy up the base a little, sand off that resin bump and smooth out the edges which are really like a knife edge >>  Was all this really worth the effort ? ........ you bet ya ! From a PU foam plug covered in Pattern-Coat resin to a silicone mould to a foam buck to a cast aluminium resin tooling plug ........ a lengthy process and an expensive one >>  I've learned a great deal from this entire process and had a lot of fun doing it, and now I'm pretty sure I can create just about any shape, that will lead to producing just about anything .......... I'll only be restricted by the size of my vacuum forming machine. Just look at the surface finish of that ........ flawless :db >>  And just one last shot of my first attempt at making a tooling plug. This thing is so heavy that it actually feels just like a solid block of aluminium >>  Next up will be to drill some vent holes in it, in order to allow the vacuum to form the shape required for the part. I'll have to work out where the holes will be positioned, as it's not just a case of drilling anywhere. And I also have to make another one ! Yes folks ....... the drawbacks of designing and fabricating headlights, every process is done in two's. I didn't have enough Vac-cast Epoxy resin left to start the other one, but it's already been ordered and it's already on it's way. I know that most if not all of you lot are well past this amateurish stage, but there's always a novice newbie out there ......... hopefully it will also help others out. Hope you enjoyed the update peeps ........ plenty more to come
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TURK
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Group: Forum Members
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Just received my order Warren
Ordered Wednesday the 8th ....... as I live in the boondocks in the middle of nowhere in central France, I think that's absolutely superb !
Excellent service mate 
Now I can make a start on the OffSide headlight tooling plug. |
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TURK
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Group: Forum Members
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Hi all, Quad headlight tooling plugs for vacuum forming now complete  just got to drill a few vent holes in them and then I can begin vacuum forming hundreds of parts !
I got to say, I am very impressed and very happy with the CS25 RTV silicone rubber, I did have de-moulding issues because it tends to 'grip' the resin but I think that's more down to the size and shape of my plug.But it's tear strength is absolutely amazing ....... you can tug, pull, spread and stretch it all you like and it will not break ! >>
 I would recommend spraying soapy water into your mould while trying to demould, makes life so much easier. Got another perfect resin tooling plug as well >>  Now I have two - NearSide and OffSide headlight tooling plugs for vacuum forming headlight parts >>  These tooling plugs will be subjected to a lot of heat for at least a couple of minutes ( about 120°C ), but with the Vac-Cast Epoxy casting Resin with it's aluminium content, that shouldn't be an issue. The plugs feel very solid, pretty much like a solid block of alloy, and very very smooth ........ I estimate I could feasibly make a couple hundred vacuum formed parts, before I need to make some more tooling plugs. TURK
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TURK
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Group: Forum Members
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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 able to vacuum form using these products are superb, better than I had hoped actually These are still prototypes, and as I'm planning on making three different versions of the quad headlights, I made a few spares >>  The parts look fine and I managed to get very good definition. 3mm thick ABS is surprisingly strong when vacuum formed >>  Then you have to trim and profile the parts, machining all those varying holes is the hardest bit! >>  But once the Hella headlight units are installed, it makes the entire project worth while >>  So now I'm having to make the actual headlight covers. Currently I just have my clear PETG prototype covers that I made last year >>  These are my new and improved headlight covers ( plugs ), for creating my moulds. A few coats of Pattern-Coat-Primer' and lots of sanding >>  While I'm working at that, I'm also thinking about the next stage. What process will I be using to create moulds from these plugs ? While checking out YouTube, and in particular 'Easy Composites' YouTube channel ( as I'm subscribed ), I came across this older video clip > So, it all boils down to this question ..................... Is that material ( paste ) he's using in the tutorial video, the same as the 'EMP60 Epoxy Moulding Paste' that can be found on your website? My plan is to make a 'negative' mould of this plug ( the plug in the images above ), to create a vacuum forming tooling plug ( positive ). So I would need the paste for the inside of the cover basically . TURK
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Hanaldo
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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 voids very very easily, which can then lead to blisters on the gelcoat. I would recommend watching EC's updated video on how to make a high temperature mould using tooling putty. This video demonstrates a different technique in applying the putty where you do little pieces at a time rather than the whole lot in one go, which is very important in reducing trapped voids.
Secondly, be wary of potentially thin sections going over any male radius. If you're less than 10mm thick, the stuff can be quite brittle and you may snap it when demoulding. Male radius tend to be the areas where you go thinner, so just watch that.
Glad to see any update, I did enjoy following this thread. Vacuum forming interests me alot, so I'll be following along again!
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TURK
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Group: Forum Members
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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 YouTube looks to be the best I can get my hands on right now > The putty does look like great fun to work with I take it it needs to be 'fibrous' like that, so it acts as a binding agent. My plan, as daft as it sounds, is to apply the gelcoat ( very thick ) into this PETG headlight cover, then add a centimetre or 2 ( preferably more ) of the putty. It's the only way I can think of for creating a positive mould of the headlights with the two headlight apertures. Once I have that I can continue onto the next stage, making a tooling plug for vacuum forming the headlight covers in 3mm ABS. Right now I'm just using two plastic containers to demonstrate where the headlight apertures will be >> A very crude mock-up of what I need to do, using two plastic containers where the headlight units will be positioned >>  My idea is to glue the cut down containers into the PETG plastic cover, and work from the inside, leaving me with a positive mould >>  I just need to familiarise myself with this moulding putty first, to see of this method will work. The only concern I have right now is, will the tooling gelcoat stick to the PETG plastic? I know this method will never give me a structure ( mould ) strong enough for vacuum forming, I'm only interested in the actual form right now. Once I have those I'm pretty sure I can make another mould to create some vacuum forming tooling plugs using Vac-Cast Epoxy Resin. Oh, almost forgot! .................. many thanks to Matthieu for the YouTube video TURK
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