I think your control of pressure ramp is a good idea.
I usually try and pump things up a little then let it sit and squeeze before hitting full pressure.
I have a metal electrical enclosure mounted to the steel frame of my press. The enclosure has an earth pole that is wired back to earth on the electrical supply lead from the wall. The power point that I plug the blanket into on the enclosure also has its earth wired back to the common earth to the wall. I have run an earth wire from my Al cassette back through the powerpoint. I think this means everything is earther nack to the same point.
Grounding the press/cassettes
Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp
Looking forward to seeing how the pressure control works out. How are you going to check the quality of your results? I've noticed a 20 gram difference between commercial skis.
Wonder if anyone has access to a large range of commercial ski could weigh a few and let us know what the variation might be. Help with Q Assurance
Electronics included SSR for me, which deals with most of the power, hence the decision to isolated it from the press.
Wonder if anyone has access to a large range of commercial ski could weigh a few and let us know what the variation might be. Help with Q Assurance
Electronics included SSR for me, which deals with most of the power, hence the decision to isolated it from the press.
how will I know if the pressure control helps or not?
Good question fellas, I hope its just not an over complicated and expensive option thats for sure, its been fun building it at least! As suggested I will weigh them and I will be accurately measuring how much resin goes in also.
Obviously building snowboards I won't care as much but for ski's yes I'll be doing my best to keep them as similar as possible - hey lets see who can do the best/closest set eh? Bit of a competition , no cheating mind you they have to be finished before you weigh them!!!!
This idea popped up because I always had this feeling about slippage, the resin will provide a nice slippery lubrication and so I can see if there is any sideways thrust or forces left over from inserting the cassette then that won;t be too helpful, plus there is always the chance the core could just slide a whisker - I will be putting in some kind of registration pins or similar to keep the core from moving but still all up I think its gonna help anyway.
Pretty stoked it looks like I have 25 metres of 4001 1.4mm confirmed. I will have materials to build boards for this winter if I pull my finger out.
What edges are you guys using? There are so many CDW profiles and stampings.
I asked for this one? Looks pretty burly.
Ski 129
A 7.7
B 2.00
C 2.20
D 0.6
Thickness base 1.40
Stamping 5
G/m 52.33
m/kg 19.11
Also asked for similar in #1 stamping too.
Next job is to finish (start) the core profiler, I'm starting low tech but my "Generation 2 Profiler" will be a "hydraulic copier" which will have a x/y/z axis, the x and y being hand controlled for now and the z being hydraulic cam following a cnc-d template - poor mans CNC. I'm confident this will be super accurate!
Cheers
Rich
Obviously building snowboards I won't care as much but for ski's yes I'll be doing my best to keep them as similar as possible - hey lets see who can do the best/closest set eh? Bit of a competition , no cheating mind you they have to be finished before you weigh them!!!!
This idea popped up because I always had this feeling about slippage, the resin will provide a nice slippery lubrication and so I can see if there is any sideways thrust or forces left over from inserting the cassette then that won;t be too helpful, plus there is always the chance the core could just slide a whisker - I will be putting in some kind of registration pins or similar to keep the core from moving but still all up I think its gonna help anyway.
Pretty stoked it looks like I have 25 metres of 4001 1.4mm confirmed. I will have materials to build boards for this winter if I pull my finger out.
What edges are you guys using? There are so many CDW profiles and stampings.
I asked for this one? Looks pretty burly.
Ski 129
A 7.7
B 2.00
C 2.20
D 0.6
Thickness base 1.40
Stamping 5
G/m 52.33
m/kg 19.11
Also asked for similar in #1 stamping too.
Next job is to finish (start) the core profiler, I'm starting low tech but my "Generation 2 Profiler" will be a "hydraulic copier" which will have a x/y/z axis, the x and y being hand controlled for now and the z being hydraulic cam following a cnc-d template - poor mans CNC. I'm confident this will be super accurate!
Cheers
Rich
MonkeyCAM and SnoCAD - https://github.com/mikemag
Ski binding mounting https://github.com/splitn2/DrillSki
Richard Harcourt | www.splitn2.com | Christchurch New Zealand
rich@splitn2.com | www.facebook.com/splitn2
Ski binding mounting https://github.com/splitn2/DrillSki
Richard Harcourt | www.splitn2.com | Christchurch New Zealand
rich@splitn2.com | www.facebook.com/splitn2
router profiler
Hi, yep I'm using a variable speed 2000W router with a nice 40mm straight cut 2 flute 1/2" chuck, it cuts beautifully. The router will be on some linear bearings in the z axis and maybe on the shorter y axis too, the x axis will be 2 metre long angle iron with bearings and uhmwpe guides. Quite excited about this but it is Gen 2 ok, Gen 1 is more agricultural.....
cheers
Rich
cheers
Rich
MonkeyCAM and SnoCAD - https://github.com/mikemag
Ski binding mounting https://github.com/splitn2/DrillSki
Richard Harcourt | www.splitn2.com | Christchurch New Zealand
rich@splitn2.com | www.facebook.com/splitn2
Ski binding mounting https://github.com/splitn2/DrillSki
Richard Harcourt | www.splitn2.com | Christchurch New Zealand
rich@splitn2.com | www.facebook.com/splitn2
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doughboyshredder
- Posts: 1354
- Joined: Mon Sep 17, 2007 7:37 pm
IMO, there is absolutely no good reason to do that. In fact, it's a pretty bad idea, as far as I am concerned.falls wrote:I think your control of pressure ramp is a good idea.
I usually try and pump things up a little then let it sit and squeeze before hitting full pressure.
Especially, if you are using heat.
Unless, you're talking over the course of 10-30 seconds.
Why would you want your laminate to not be under full pressure as the epoxy starts to cure, and then crank it to full pressure after it's already starting to cure?
Get your pressure up as soon as possible. If your cassette / layup can't handle it, you're doing something else wrong.
good question!
Well the heat goes on last, so the pressure is ramped up over say 10 minutes in 10 psi increments, so the pressure still comes on before the resin has a chance to cure (unless its really hot day???) then the heat will go on once full pressure and squeeze out is achieved. Turn that around the other way, would you apply full pressure and heat at the same time and expect all the excess resin to squeeze out - sounds like the resin would start to cure earlier. Anyway thats my theory and I'm gonna run with it, I can't see how it will hurt to ramp up the pressure and let it squeeze out nice and consistantly. cheers
MonkeyCAM and SnoCAD - https://github.com/mikemag
Ski binding mounting https://github.com/splitn2/DrillSki
Richard Harcourt | www.splitn2.com | Christchurch New Zealand
rich@splitn2.com | www.facebook.com/splitn2
Ski binding mounting https://github.com/splitn2/DrillSki
Richard Harcourt | www.splitn2.com | Christchurch New Zealand
rich@splitn2.com | www.facebook.com/splitn2
I did the same tonight just not as long a period. Gradually increased pressure over 2-3 minutes. I figure a slower pressure increase allows what wants to be squeezed out to get squeezed out. Then hit max pressure and apply heat to cure the resin left in the sandwich.
I agree turning the heat on before the slow pressure ramp would cause resin to go very thin and then excess squeeze out. Not a good idea.
Also agree that hitting highest pressure quickly and turning heat on is ok.
The reason I add the pressure a bit more slowly is an idea that high pressure really fast could cause components in the layup to slide laterally on a thick ooze of resin. If you go slower the resin comes out slower and major slides are much less likely.
Having said that a proper core and base alignment method (which I think I have) probably means lateral slides are unlikely anyway.
I agree turning the heat on before the slow pressure ramp would cause resin to go very thin and then excess squeeze out. Not a good idea.
Also agree that hitting highest pressure quickly and turning heat on is ok.
The reason I add the pressure a bit more slowly is an idea that high pressure really fast could cause components in the layup to slide laterally on a thick ooze of resin. If you go slower the resin comes out slower and major slides are much less likely.
Having said that a proper core and base alignment method (which I think I have) probably means lateral slides are unlikely anyway.
Don't wait up, I'm off to kill Summer....
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doughboyshredder
- Posts: 1354
- Joined: Mon Sep 17, 2007 7:37 pm
Well, I can tell you guys that in production you put the laminate in, bring pressure up to full pressure and turn on the heat immediately.
ramping up the pressure, waiting to turn on the heat, etc.... is pointless. There is no benefit to it, other than what falls posted here:
The only purpose in ramping up heat is to equalize top and bottom heat, since typically the bottom will come up to temp faster than the top (due to cat track absorbing heat, unless very well insulated).
As far as squeeze out, if you are working your epoxy in to the glass properly, it's almost impossible to squeeze out too much epoxy, regardless of heat and pressure.
ramping up the pressure, waiting to turn on the heat, etc.... is pointless. There is no benefit to it, other than what falls posted here:
sliding = too much epoxy. I still have a problem with this one, occasionally, and as you said core and base alignment.The reason I add the pressure a bit more slowly is an idea that high pressure really fast could cause components in the layup to slide laterally on a thick ooze of resin. If you go slower the resin comes out slower and major slides are much less likely.
Having said that a proper core and base alignment method (which I think I have) probably means lateral slides are unlikely anyway.
The only purpose in ramping up heat is to equalize top and bottom heat, since typically the bottom will come up to temp faster than the top (due to cat track absorbing heat, unless very well insulated).
As far as squeeze out, if you are working your epoxy in to the glass properly, it's almost impossible to squeeze out too much epoxy, regardless of heat and pressure.
I think it is reasonable to apply below final pressure/heat and allow epoxy to flow/gas. Movement of laminates within the press is a process issue, we all get it and resolve in our own way. I would suggest that it is different to resolving void growth, which is a quality issue and so what a commercial company is doing may not give us the whole story.
I posted a few links on void growth and it appears that minimising void growth tends to be done a temp below the gel temp. Once this is done, I ramp the heat and pressure - to final pressure. At this stage you need to keep an eye on pressure. As the heat comes up, your pressure may rise depending on how your cat track deals with the heat. I noticed a rise of 4 psi above 50psi, so when I hit 50 psi, I give the relief valve a tap. It is set at 50 psi, so it continues to vent silently during the rest of the cure and hold at 50 psi.
Too much epoxy is something I have tried to do some work on, I don't have full results, but the process I am using appears to ensure the fibre is wetted out fully and quickly using a minimum amount of epoxy. It also appears to reduce the amount of waste. The result appears to be skis with minimum weight difference - early days on these results though. Just started to look at this issue in more detail.
The question in my mind is 'is this a point of difference', I think cosurfer is right when he talks about how people get a kick from locally built equipment, but you need to be able to back it up with build quality?
If anyone would like to participate in setting quality control targets, I'd like to discuss this. Not a league table or anything like that, just expressed in terms of percentages?
I posted a few links on void growth and it appears that minimising void growth tends to be done a temp below the gel temp. Once this is done, I ramp the heat and pressure - to final pressure. At this stage you need to keep an eye on pressure. As the heat comes up, your pressure may rise depending on how your cat track deals with the heat. I noticed a rise of 4 psi above 50psi, so when I hit 50 psi, I give the relief valve a tap. It is set at 50 psi, so it continues to vent silently during the rest of the cure and hold at 50 psi.
Too much epoxy is something I have tried to do some work on, I don't have full results, but the process I am using appears to ensure the fibre is wetted out fully and quickly using a minimum amount of epoxy. It also appears to reduce the amount of waste. The result appears to be skis with minimum weight difference - early days on these results though. Just started to look at this issue in more detail.
The question in my mind is 'is this a point of difference', I think cosurfer is right when he talks about how people get a kick from locally built equipment, but you need to be able to back it up with build quality?
If anyone would like to participate in setting quality control targets, I'd like to discuss this. Not a league table or anything like that, just expressed in terms of percentages?
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doughboyshredder
- Posts: 1354
- Joined: Mon Sep 17, 2007 7:37 pm
we actually agree I think
Hi, yep sliding is exactly the reason I want to gently squeeze out first, I'm talking 10 minutes, possibly shorter. I don't see it as a biggie, regardless of whether its 5 or 10 however long it takes to get any excess resin moving to avoid any sliding - I did say I am using some registration pegs etc to position the core etc too. All good I reacon. cheers
MonkeyCAM and SnoCAD - https://github.com/mikemag
Ski binding mounting https://github.com/splitn2/DrillSki
Richard Harcourt | www.splitn2.com | Christchurch New Zealand
rich@splitn2.com | www.facebook.com/splitn2
Ski binding mounting https://github.com/splitn2/DrillSki
Richard Harcourt | www.splitn2.com | Christchurch New Zealand
rich@splitn2.com | www.facebook.com/splitn2
bubbles and other empty spaces
http://books.google.co.uk/books?id=ke7T ... le&f=false
Richie, if you are using pegs, then I'm thinking you've got some cable ties handy too. I had a look at movement of materials. Ended up letting wet materials sit on the dry core - it doesn't interrupt the lay up. They amalgamate and stay put: viewtopic.php?t=2405&postdays=0&postorder=asc&start=75.
http://books.google.co.uk/books?id=ke7T ... le&f=false
Richie, if you are using pegs, then I'm thinking you've got some cable ties handy too. I had a look at movement of materials. Ended up letting wet materials sit on the dry core - it doesn't interrupt the lay up. They amalgamate and stay put: viewtopic.php?t=2405&postdays=0&postorder=asc&start=75.