Round Top skis 19/20

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Wheatlpa
Posts: 41
Joined: Fri Feb 12, 2016 11:14 am
Location: Sutton, QC

Re: Round Top skis 19/20

Post by Wheatlpa »

So, the skiing has been excellent and ski building has taken a break. It is going to pick up again soon as the SSR's, PIDs and thermocouple wire has arrived from Auber. Once i am back from my AIARE 1 course i will start the build for the two control boxes and then start testing out the heat blankets and figure out if the heat sensor on the blankets will work.

Ben_mtl has been a huge source of information and help on cutting templates on his CNC router. Of course I have discovered that simply designing a ski from scratch is not as easy as i thought it would be. I am using a free ware CAD application (nanoCAD) and i am trying to build a 180cm ski with dimensions 126/95/116 with rockered tip and tail. The first thing i did was measure in from the tip 22cm to where i wanted the widest part of the shovel. I then measured 15cm from the tail for the widest part of the tail. I then split the ski in half (cord center) where i wanted the narrowest part under foot. I drew an arc from tip to center to tail which will form the radius. I then drew more arcs at tip and tail to give the ski shape. I am not sure if this is how everybody does it but this seemed to be the logical way to approach it. Anyway, i am still doing some research on this and will trace some of the skis that i have here to see if this method actually works.

On a less frustrating note last weekend was great skiing, here is a picture of the skis i made last year at my friends place in Vermont. They ski really well and i just hope the first pair i make on my own turn out as well.
Image

Wheatlpa
Posts: 41
Joined: Fri Feb 12, 2016 11:14 am
Location: Sutton, QC

Re: Round Top skis 19/20

Post by Wheatlpa »

So it has been a while since i have made much progress but this weekend the temps were warm enough for me to spend some quality time in the unheated shop. Over the past month i have cut out the tip and tail parts to create the molds. I then got a used router table and figured out how to attach my old router to it to make the pattern routing easier and less dusty. Once they were all the same shape i was able to glue them up, scrape the squeeze out and sand them smoothish ready for use. I then decided to pressure test the vacuum table to see if it would hold a seal. which i am happy to say it did!
Before:
Image

After:
Image

The next step is sizing the middle part and routing the air channels which should not take long.

After that, i still have to figure out the best way to wire a heat blanket inside the vacuum. I suspect it will be two tight holes for the power and thermocouple wire and lots of silicone to seal any gaps. Then wire up the control box which is very straight forward. I should be making skis before spring is over...

Wheatlpa
Posts: 41
Joined: Fri Feb 12, 2016 11:14 am
Location: Sutton, QC

Re: Round Top skis 19/20

Post by Wheatlpa »

Well, it has been a while since I last posted. Summer has been busy with rediscovering mountain biking after 20 years and insulating my garage/workshop. I have finished a bunch of furniture projects and am now ready to start up ski building again. I have ordered enough material from Sandwich Tech to make 4 pair of skis, i have more than enough epoxy (thanks Ben for the group buy) and I just placed an order for breather and release fabric from a place in Montreal.

First up is the heat blanket control box, the thing is massive but for 30$ i was not going to turn it down. The christmas break will be busy, especially since we will be getting rain over the next couple of days.

Jonrezz
Posts: 35
Joined: Thu Feb 13, 2020 1:14 pm

Re: Round Top skis 19/20

Post by Jonrezz »

I'll be interested to see how you heat the bottom from the interior of your vacuum! Nice lookin setup you've got going on!

Wheatlpa
Posts: 41
Joined: Fri Feb 12, 2016 11:14 am
Location: Sutton, QC

Re: Round Top skis 19/20

Post by Wheatlpa »

Jonrezz wrote:
Wed Dec 23, 2020 4:37 pm
I'll be interested to see how you heat the bottom from the interior of your vacuum! Nice lookin setup you've got going on!
Funny you should ask, this is something that has caused me some sleepless early mornings. I have two heat blankets (top and bottom) but how do i wire the bottom one and maintain a vacuum seal...I think the stop gap (ie cheap and short term) solution is to drill an angled hole in the plate (so the vacuum does not kink the wire at 90 degrees), pass the wires through and then silicone the crap out of the hole/wire.

This whole table is a trial attempt so even though I have spent way too much time worrying about it i will just go ahead and give it a try. I mean i see guys pressing with woodworking clamps so a little air leakage for the hour it will take to press and heat the epoxy can't be any worse.

As you can see I tend to over think things :D

Wheatlpa
Posts: 41
Joined: Fri Feb 12, 2016 11:14 am
Location: Sutton, QC

Re: Round Top skis 19/20

Post by Wheatlpa »

Between glue ups for a shelving project I finally got to the control box. I cut all of the holes for the PIDs, heat sinks and power switches. I just need to cut the holes for the temperature sensors and wire it up. https://photos.app.goo.gl/9Mrm22dz3W8h2Nb56

Pheeps
Posts: 14
Joined: Wed Dec 11, 2019 5:17 am

Re: Round Top skis 19/20

Post by Pheeps »

Nice.

What power input are you using? I haven't found the time to start putting the pieces together, but have assembled the components to have two controllers up to 30 amps (240 volt) each. I was thinking of having just one 30 amp input to the box, then splitting off to each SSR/PID from there.
Pheeps
Western Washington

Wheatlpa
Posts: 41
Joined: Fri Feb 12, 2016 11:14 am
Location: Sutton, QC

Re: Round Top skis 19/20

Post by Wheatlpa »

I am going very simple for this controller. I am planning on using two extension cords to power each blanket. I spec’d the blankets to run on 15 amps so I can plug them into the wall sockets. This is in contrast to the controller for my brewing set up which has a 30amp power cord and then complicated internal wiring to run two kettles and a pump.

Once I get the wiring set up and tested I will post some photos of the internal wiring.

Wheatlpa
Posts: 41
Joined: Fri Feb 12, 2016 11:14 am
Location: Sutton, QC

Re: Round Top skis 19/20

Post by Wheatlpa »

I have finally finished the basic wiring of the control panel. The photo shows just one of the PIDs wired but they are both wired the same way with a separate extension cord. Next up is the dry run with the PID to make sure they are set correctly and that the TC and the heat pad works as hoped. Then again, it is snowing this week so skiing might push this work to the weekend when they are forecasting rain.

Image

Wheatlpa
Posts: 41
Joined: Fri Feb 12, 2016 11:14 am
Location: Sutton, QC

Re: Round Top skis 19/20

Post by Wheatlpa »

Last night I was able to add the plug and receptor to the TC wires on one of my heat blankets to test out the controller. First attempt the temp on the PID started dropping...wired the TC incorrectly but that was quickly fixed. Second attempt and the heat blanket rapidly warmed up although the light in the shop dimmed...might have to get 15amp breakers instead of the 10 that are installed now. A little worried about what will happen when I plug both blankets in and turn on the vacuum pump.

Lets see if this image will work Image

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chrismp
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Joined: Fri Feb 13, 2009 9:00 am
Location: Vienna, Austria

Re: Round Top skis 19/20

Post by chrismp »

Is the tip of the thermocouple right where the wires go into the blanket or does it extend further into the blanket? You might want your sensor to be in an area where the skis/boards you are pressing are located to get an accurate reading.

When I press boards the thermocouples located over and under the board are at up to 90°C while the parts of the heat blanket that extend the mold area can still be touched by hand as they cool of quickly when in contact with air.

Wheatlpa
Posts: 41
Joined: Fri Feb 12, 2016 11:14 am
Location: Sutton, QC

Re: Round Top skis 19/20

Post by Wheatlpa »

Honestly, I don't know. I guess I would assume that it extends into the mat but since this is an Alibaba purchase it might be just at the edge. I will be working on the mold for the press this weekend and then take the leap and install the heat blanket that will be inside the vacuum. Once I have all of that set up I will be running a test run on the whole system, before I mix up any epoxy, to see if it all works together. At that time I will be able to see what the temps are mid blanket in the press.

Thanks for the heads up though, it could very well be an issue, but I am not sure how I would fix that. Not comfortable ripping the TC wires out of the blanket and I assume the TC wires used are special and not really available at my local big box hardware store.

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