dbabicwa wrote:
I've just burned 2 3A fuses on 55-60C, luckily I've got them...
Mate 3amps is only good for about 700 watts at 240 volts.
What sort of watts are your mats good for? You might need bigger fuses.
Unless you built your mats for only lower temps. I'm going to keep mine to about 1400 watts each.
So it is about time for me to make my sidewalls. Before it happens I just want to run my plan out with you guys to see if I'm on the right page or not.
Going to be using Smooth on pmc 780.
Step one: Cores / core template
Step two: Attaching template to the cores with double sided tape/hot glue.
Step three: Using a router with a flush bit go around the template down to a depth around 13-16 mm.
Step four: This is where things might get a little crazy. The plan is to clear out the area for the tip and tail spacer with the router and using the urethane to create one solid wrap around the core. The length of the tip and tail spacers needed is 210 mm. Not to sure if that is asking to much from the urethane or not.
Step five: Pouring the urethane and using a heat gun or blow torch to help cure/release air bubbles.
Step six: Run the side that was routered through a jointer/planner to smooth it down.
Step seven: Flip the core and profile to correct taper for flex profile.
Dont do a tip spacer, run the same width sidewall all the way around!
And if you have not bought yet, get 790 , not 780. unless maybe your making park specific.
I plan on making very soft skis so 780 should be fine. That is why I was thinking about using it as the sidewall and the tip spacer to soften the tips up some more. But if it is a bad idea it is time to move on.
I just made a board with no top sheet, you can see the urethane all the way around the perimeter of the board. No need to rout out perfectly good core only to replace it with urethane.
If you have any means to degas the resins before pouring, do it. First degas part A and B separately and then degas again after mixing (mind your pot life though).
I use 305, 2 seasons and never had an issue.
I think the width of the sidewall is important, I make mine nice and wide which I feel adds to the overall strength of the sidewall.
thinking about pouring sidewalls quite a lot at the moment.
One basic thought I have:
As PU seems to be quite hard to handle, why not use epoxy?
Pure Epoxy will surely be too hard, but there are additives to make it more flexible (e.g. http://shop1.r-g.de/art/130140). Also some extras like cottom flocks or even short fibres could be added to make it more durable. Anyone tried this already?
I have what is known as a soft epoxy (65 shore) plus a bag of cotton flock and one of ground glass to try exactly what you are talking about. I'm traveling for work at the moment so won't have any results for two weeks.
This is the process guys over here use to make fins for their custom surfboards so the hardness, flex and durability is about right.
Last edited by gav wa on Fri Jun 20, 2014 5:53 am, edited 1 time in total.
gav wa wrote:I have what is known as a soft epoxy (65A shore) plus a bag of cotton flock and one of ground glass to try exactly what you are talking about. I'm traveling for work at the moment so won't have any results for two weeks.
This is the process guys over here use to make fins for their custom surfboards so the hardness, flex and durability is about right.
Cause really you basically want a 65 shore d and 500% elongation at break like uhmwpe. So is that what you are hoping to get from this? The uhmwpe is the best but bonding and prep and the machining is the time and tech issue.
MM - pretty much just hoping for something that is similar flex and hardness to most factory sidewalls, is easy to pour and bonds easily. Epoxy will obviously bond well with epoxy, and is cheaper than casting resin plus it means one less material to buy so bulk buying becomes more of an option too.
The resins can be tinted easily and the additives give it a more solid look so solid colors work well.
Go grab a surf board fin and flex it around a bit, they are quite durable pieces.
I know everyone here has ways they have spent a lot of time perfecting and I too have some smooth on 305. I'm not trying to reinvent the wheel or anything, but I already had the epoxy so thought it would be worth trying out.
