Layup Table

Richuk · Post by **Richuk** » Mon Jan 20, 2014 11:55 am

I was wondering what peoples experience are? I've been thinking about the pro's and con's. One thought I have in mind, it creates the opportunity to cut the fibre to shape in advance of use, limiting/minimising the amount of flash. Silicone paper/baking paper (Twizz style) appears to be a good carrier, although my own tests included a sheet of veneer.

MontuckyMadman · Post by **MontuckyMadman** » Mon Jan 20, 2014 4:58 pm

you realize none of what you have written here makes any sense at all.
We have no reference to what part of the process you are talking about.
This sounds like Bot talk even though I'm pretty sure you are human but potentially not from this planet originally.

chrismp · Post by **chrismp** » Tue Jan 21, 2014 12:56 am

The top of our press is a large table top (250x110cm). We cover it with baking paper prior to layup. At the end of the table is a rack where we store rolls of fiberglass which are already cut to width (we get our glass in rolls with 127 cm width and cut them to 42 cm wide rolls with a bandsaw...a hacksaw works just as well). We just roll out the glass when needed in layup. Works like a charm.

falls · Post by **falls** » Tue Jan 21, 2014 1:45 am

If you are doing any kind of volume shaping ypur glass is going to cut down on resin use, maybe save a bit of money. Depends on how you shape the glass. I have thought about doing it, but reckon it will fray and get crazy. A big CNC drag knife deal like the guys at SCC skis use would be the ticket.

I use a layup table for wetting glass and then have the cassette on top of the press. Would be better if they were right next to each other but I don't really have the space.

I get the baking paper idea (I cover the table with painting plastic drop sheet), but am lost on how veneer comes into it.

Richuk · Post by **Richuk** » Tue Jan 21, 2014 4:50 am

You do save on epoxy. If you are using ambient cure epoxy, the opportunity to add a bit of heat under the table will aid impregnation and increase the quality of the laminate.

The same is true for heat cure ... but heating to 25oC does not change the viscosity of the resin that much. Anything above 25oC there are health concerns to consider because the resin is more volatile. Nevertheless the quality of the laminate is improved/insured.

The point I was considering falls is the step after the epoxy has been applied and is sitting on the table. If you take it away from the table, with the baking paper carrier, it cool quickly and viscosity increases once again. Well, my workshop is cold in the winter, so that's what happens. At this point the fibre can be cut using a rotary cutter and the fibre does not fray.

Assuming the veneer/topsheet you are using is cut to shape, then the it becomes the template for the rotary cutter.

Perhaps all this is academic if you are removing the flash with a bandsaw. If not, then you have potentially saved yourself a lot of time and additional materials, improving the quality of your build in the process. Clearly a problem may arise with this approach if your press suffers from a bit of core shift.

twizzstyle · Post by **twizzstyle** » Tue Jan 21, 2014 12:06 pm

Although I do use parchment paper, I do all of my layups in the mold. I think for one pair I did wet out each layer on a separate table and then moved it to the laminate in the mold, which i did like - but it was also a huge mess. For me, doing the layup directly in the mold is the easiest.

MadRussian · Post by **MadRussian** » Tue Jan 21, 2014 5:20 pm

I am using separate table for a layup. Tried only once to do cotton layer inside the cassette and don't like it. Almost every layup video I saw layup done inside the cassette… I don't like it so I'm doing separate table. Entire table covered with plastic. When epoxy applied each component it moved to table in front of the press with cassette on it. That's how I do it. Both tables are makeshift tables and put away when layup done. That's how I done in the past (before doing ski building).
My shop also unheated and only time I heat garage is when layup and doing work with the bases.
Next time I will definitely try heated layup table. Keeping table at 70° F shouldn't affect heat cure epoxy that much or that's what at entopy told me. Was the table I have low-power blankets (kind you can buy in a drugstore) was a huge loss into the table unlikely they can keep temperature much higher than 70° I'll test what temperature this table can produce in next couple days. Table will be: insulation, heat pad, metal tabletop, plastic. All this makeshift it take maybe five time minutes to set up and went down another 5 to 10 min. to take it apart and put table away
twizz what mess? I suppose it we do things differently layup was clean here... When done throw away plastic.

richuk I'm not fully understand what you're trying to describe in the last paragraph. For what it's worth I cut flush with bandsaw and my sidewall is IPE.

richuk
Layup and starts at 1:50

Hope somebody can contribute on subject of heated table

MadRussian · Post by **MadRussian** » Wed Jan 22, 2014 10:16 am

I did test today.
Outside temperature is 10°f. In unheated shop I could maintain table surface temperature of 54°f

Richuk · Post by **Richuk** » Wed Jan 22, 2014 12:03 pm

Ok, so you could probably reach 25oC when the shop temp is around 0oC. Have you tried the same approach using your silicone blanket?

MadRussian · Post by **MadRussian** » Wed Jan 22, 2014 12:42 pm

Richuk wrote:Ok, so you could probably reach 25oC when the shop temp is around 0oC. Have you tried the same approach using your silicone blanket?

No. My silicone blankets way to big and I don't want take it out of the press.If this heating pads end-up not powerful enough for the table I would have to build silicone blankets specifically for the table but I will not take blankets out of the press
Probably when temperature between 25 to 40° f shouldn't be any problem keep table at 70° F even 60° F would suffice.

This is my thought about pressure/temperature ramp-up in cold shop:
assuming heated table work and epoxy stay relatively warm on the table but when components moved to cassette epoxy will cool off and viscosity increase. I think would be good idea to set the temperature on the blankets for 70° F with low-pressure maybe 5 to 10 psi to rewarm epoxy. Because, as I understand, at high viscosity and high-pressure more forces will be to make core/ base shift. After that normal temperature/pressure ramp-up

Richuk · Post by **Richuk** » Wed Jan 22, 2014 2:23 pm

I would speak to your epoxy supplier about these issues - especially cure cycle. If you have measured out your epoxy correctly, allowing for waste on the layup table and a little flow, then you should be good to apply full pressure. The figure I have quote allows for a bit waste etc, but you will come to your own conclusions once you have done this once or twice.

I think the viscosity of the epoxy is designed to support the pressure. Assuming you have a reliable method for holding the core in place, then all's good (DBS et al), as your parts aren't floating around in epoxy i.e. add full pressure and begin to ramp. You may interrupt the ramp with dwell ... or perhaps not depending on the ramp rate. Heat generates flow. A little bit of flow is good. You want a bit of flow to avoid trapping air/aiding penetration of the epoxy into the core. You don't need to see epoxy dripping from the press. This is something you will need to judge for yourself and adjust accordingly. I suspect this issue will vary from press to press. The less accurate the press/parts, the more epoxy will be required as a filler.

A mix of low pressure and heat within the press will not lead to a good result.

falls · Post by **falls** » Wed Jan 22, 2014 3:25 pm

Rich, wouldn't the biggest savings come if you shaped your glass before you applied the epoxy.
If you do it after you are still using the same amount of epoxy just leaving the waste on the table not in the finished flashing.
?

Richuk · Post by **Richuk** » Thu Jan 23, 2014 2:34 am

Sure, that would save the most epoxy, but when I cut dry fabric slightly off axis it starts to fray. I think this is a common experience with skis, maybe not so much snowboards though.

What I'm experimenting with at the moment is about reducing the amount of material within the press, getting a sense of what pre-preg has to offer and saving time once the ski has been pressed.

This approach maybe useful to others, particularly in given what chrismp is saying and provided they have found a way to stop the core shifting. The absence of fibre within the flash ensures a quicker and safer removal of excess sidewall material - less dust, fewer dulled blades and no damage to the fibre. I think???

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