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Rich (Staff)
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Hi Turk,
Yes, 5g equates to 2% of 250g. There is a degree of adjustability though, if you find it cures too quickly or you simply need more working time, you can lower the catalyst ratio slightly. 21'C is about the normal ambient condition quoted on most datasheets but its certainly warmer than over here in the UK at the moment - the warmer the temperature you work in, the faster the primer (or resin/gelcoat/etc.) will cure so with anything polyester (or vinylester) based gives you the added benefit of being able to adjust the catalyst amount to account for the temperature.
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Dravis
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I have a constant 21 - 22 degrees in my workshop -- I use 1,5% for both the EC Pattern coats --- otherwise I find that they "set" very abruptly.. I find that you need to develop a certain amount of skill to work with Polyesters or Vinylesters ... more so than Epoxy -- I also hate the smell of large amounts of Styrene .. 
"Sapere Aude"... Dare to KNOW! The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind... 103% of all people do not understand statistics... Do not adjust our mind, theres a fault in reality :-)
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TURK
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Many thanks guys, Glad I got a couple of things right 
Would you think that different materials would cause the pattern-coat to set at different levels, such as brushing it onto MDF as opposed to on Glassfibre ? Interesting to hear that you found it to set 'abruptly' Dravis. I may go down to 1.5% in that case.
What did you think I my unconventional way of working out the amount of resin required, such as .......
1Kg of 'Pattern-Coat Primer' per 1m² which is 10,000 cm²500g of resin - covers 5,000 cm² 250g of resin - covers 2,500 cm² 125g of resin - covers 1,250 cm²
Is that the normal way people work it out ?Or is there a particular formula ?
I am working with small quantities, after all, headlight assemblies are quite small compared to some of the things people are making on here, like car bonnets. The plugs that I'm making will be for vacuum forming, so hopefully they will be strong enough to vacuum form dozens of parts. I'm also working on the headlight covers, and will be making some out of carbon fibre, so plenty more questions will follow I'm afraid 
No doubt I will have to brush up on my math, as there seems to be a lot of converting to do.
Now that I know I need 2% catalyst for my mix, I'm stuck with something else. I've bought one of those MEKP Catalyst dispensers, but it's marked out in millilitres !
So as an example, 10ml is equal to what in weight ? ....... 10 grams ?
My entire project can be seen here > T4 Quad Headlight Project If you go straight to the last page you'll see the stage that I'm currently at.
Thank you all folks, I feel I'm now getting somewhere with your your help. |
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Rich (Staff)
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The density of MEKP is 1.0-1.15g/cm3 meaning that 1litre would weigh 1.0-1.15kg - as such, the volumes, especially in smaller quantities are so close to 1ml = 1g, that most people simply work on the basis of ml & g being equal.
In reality, working on this basis, you would be slightly under catalysing if the density is ever above 1.0. 5g at 1.15 for example is 4.34ml; but at least you would be under (slower) rather than over (faster).
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TURK
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Richie (25/09/2015)
The density of MEKP is 1.0-1.15g/cm3 meaning that 1litre would weigh 1.0-1.15kg - as such, the volumes, especially in smaller quantities are so close to 1ml = 1g, that most people simply work on the basis of ml & g being equal.
In reality, working on this basis, you would be slightly under catalysing if the density is ever above 1.0. 5g at 1.15 for example is 4.34ml; but at least you would be under (slower) rather than over (faster).That is excellent news Richie 
At least know I know how to use the measure on the catalyst dispenser ! Knowing that 1g = 1ml will surely make my equations much easier in the future.
I would much rather be slightly under the required amounts, as that will leave me a little more time on each piece. I don't mind waiting till the following day for things to dry thoroughly, as I'm never in a rush to get to the next stage. I like to take my time when I'm working, getting it right is far more important in my view.
My intentions are to build-up the Pattern-Coat Primer to create a very hard shell as it were, maybe up to 5mm in thickness eventually. Do you see any problems doing this ?
I will of course sand between the layers also, as it really needs to like a glass like finish in the end. |
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Dravis
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If you want a totally gloss surface, you will end up doing a lot of sanding down, and re-applying more layers of both the Pattern Coat Primer and the High Gloss Pattern coat. The really nice thing about getting a good layer of High Gloss Pattern coat on, is that it polishes up very nicely, and quite easily with both hand and machine polishing. Good Luck! Don forget to post pictures of your progress ..
"Sapere Aude"... Dare to KNOW! The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind... 103% of all people do not understand statistics... Do not adjust our mind, theres a fault in reality :-)
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TURK
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I'll be sure to post my progress Dravis ....... or you can just follow the entire |
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TURK
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Hi guys, Thought I would update my quad headlight project, and show how my moulds worked out. I'd also like to take the opportunity in thanking some of the guys on here and the guys at 'Easy Composites' for their help. I haven't quite got to the carbon fibre stuff that I'm going to make, like the headlight covers ........ still designing the headlight mounting brackets right now. And they'll be vacuum formed. But things are looking promising, hope you like. I'll begin by the vacuum formed headlight brackets. Moulds were constructed of 9mm MDF, covered with Pattern-Coat-Primer >>  Here's what the assembly looks like from the back >>  Then it's just a case of installing the headlight units. After much research I decided I would be using the Hella Modules, very very good quality and excellent performance and the correct pricing >>  A while back I had already made some basic headlight covers for testing purposes, using the original headlight glass as my moulds >>  Then it was a case of assembling everything >>  I then ran a few tests. I had to design an 'upgrade wiring loom', with the addition of diodes as I wanted the quad headlight setup to have all four headlight units on in high beam >>  The headlight switching test is a very basic test, just testing the potential of the wiring loom really, as bright as these look already I'm not getting the full potential of the Hella units right now, as they are powered via a computer power supply. So just under 12 volts at 16amps >>  Then I had to check the fitting to my van, yes ........ it's a VW T4 Transporter folks ! >>  All in all, I'm very happy with the outcome ......... still got a few things to work out yet, but things things are looking very promising  |
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TomDesign
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where you bought these lenses? any link or price
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TURK
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TomDesign (22/10/2016)
where you bought these lenses? any link or priceEer ........ they're not 'lenses' Tom ........... they're complete headlight units from Hella. They're the 90mm modular units. I bought a few sets directly through Hella UK just to get me started >> |
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