Bent Green Things 2014/15

[gav wa]

You will need a very solid hold down on whatever you cut if you use that spoil board surfacing cutter. Tools like that are usually really bad for chatter and pulling on the job. If you have a nice solid set up it might be pretty sweet, it depends on how you tool path it.

[rnordell]

I have the Amana spoil board cutter. Love it. Removes material quickly and leaves a fine finish. Indexable inserts are great for longevity, just rotate 90 deg after they start to dull to get a fresh cutting edge. Well worth the $180.

[amidnightproject]

1/2" carbide endmill is what I would use IMO. Those larger flute bits don't do as nice of a job. A roughing end mill is great for slamming through your roughing cut depending how your job is setup. It works well. But I usually just use a standard 2 flute for both jobs.

For the tips my guess is rabbet depth. Without knowing your setup I can only guess. It could also be your bladder not conforming to your mold properly and "pinching", causing to much pressure in a certain spot.

I wouldn't jump to actuators as that's over kill and not necessary. I would take the time to make sure your molds line up. I use to have the same problem. Spent a bunch of money on actuators only to figure out what the problem actually was while I was waiting for them to show up.

[falls]

Rather than get rolled for screen printing get some vinyl die cut stickers made. Stick them on as a template and paint yourself. After it's dry peel them off. Vinyl stickers are normal to the sign writer so hopefully will be cheaper.
Skis are looking great.

[skimann20]

Super good discussion all. thanks to all for the tips.

a few followups:
Rnordell: I think I'll pull the trigger on the amana spoil board cutter. what's another 180 ;-)

Richuk: can you elaborate more on: "you are fighting against the edge set .. leading to internal tensions raising the edge set." also the bottom of the ski heats uniformly the entire ramp (same with the top) takes me about 45min to get to final temp.

Amidnightproject: no pinching of bladder, it has a nice "pancake" look to in when its in the press. I was actually looking at actuators (they've been in my cart for a while) but like everything else, I have other things that are attacking my wallet... I'll take another look at how the profile of my molds line up with the lowers. to little of a rabbet cause this is your thought?

Falls: excellent idea. just get the negative use it as a template. cheers on that one. also thanks for the compliment.

[Richuk]

Try a set of racket straps in lieu of actuators. Add a couple of spacer between the top and bottom mold so that it isn't damaged during the trial. The thickness of the tipspacer. This is what co-surfer used for a while.

Edit:

Pinch points can be created during inflation of the bladder. Usually the body of the ski and the very tips of the ski are the primary contact points. As the bladder inflates, it fills in the remaining gap between the these two point and this can lead to low pressure points. The edge set becomes a bridge between these two points.

45min, is the time is takes to reach the prescribed cure temperature. What rate is prescribed by the manufacturer?

I'm assuming the layup symmetrical and this problem hasn't just appeared?

[gav wa]

One point I forgot to mention, that end mill ripper is a metal cutting tool. Anything with a sharp edge will cut wood, the serrated cutting edges are a waste on wood.
Solid carbide cutters are ground to a sharper edge than HSS as they have much higher hot hardness, hence why they might be using it. A 3 flute carbide slot drill would leave it for dead though, just got to be carefully on flute clearance.

[chrismp]

I guess jskis use it as their standard bit since they're also maching their own al-cassettes.

[skimann20]

Pinch points can be created during inflation of the bladder. Usually the body of the ski and the very tips of the ski are the primary contact points. As the bladder inflates, it fills in the remaining gap between the these two point and this can lead to low pressure points. The edge set becomes a bridge between these two points.

45min, is the time is takes to reach the prescribed cure temperature. What rate is prescribed by the manufacturer?

I'm assuming the layup symmetrical and this problem hasn't just appeared?

No pinch points that I can see at all. I'm making a pair tonight and I'll post a photo or two of the cassette in the press. I was trying to nail this before I put this pair in the press...

I'm starting to think that maybe the rabbet depth is to deep (can this be a thing?) and this allows the base to pull up in these section. I'm having a hard time wrapping my head around this one. I would think that the steel square tube going across the ski would not allow the base to pull up at all. only seems to be happening core start to about 10cm back.

MFG says work time is 45minutes and 18min at 180F.

layup is symmetrical and I've just "noticed" this. doesn't take much with the grinder but I would prefer to not grind this material away.

[Richuk]

What epoxy is that?

Can you detail your layup in more detail. Is the CF tape or fabric?

[gav wa]

I guess jskis use it as their standard bit since they're also maching their own al-cassettes.

Solid carbide tools rock in ally, the higher surface finish and lower coefficient of friction really helps with the stickyness of aluminium.
I was going to mention aluminium cutters. If you look at aluminum specific cutters you will see they have huge swarf cavities and big open flutes, probably really good in wood. Their approach and relief angles are bigger too as the tips don't get as hot as they do in hard metals.