Ski Builders Forum

So the discharge hose says psi ratings are for use at 70*. I've brought it as high as 200* at 70 psi. Wondering if anyone uses higher temps? and what pressure?

Hotter isn't better - depends on the epoxy you're using, but generally too hot will give you a brittle cure.

180 deg F seems to be a common temp for the epoxies folks use for skis/boards. I've never gone hotter than that. I actually go a little bit cooler now (150) just so that I get less camber change after the cure, just takes a bit longer to cure.

QCM cures at 160f entropy cures at 180f. No reason to go hotter then what is on the mfr. tech sheet.

If you are nervous about overheating the bladder you can always insulate it. A wooden cat track doesn't really conduct much heat. Aluminum of the other hand would.

i was going to thermomold the topsheet onto my skis! no i was just wondering about other resins that have higher cure temp schedules. twizz are you curing entropy at 150? thanks!

summitskier wrote:i was going to thermomold the topsheet onto my skis! no i was just wondering about other resins that have higher cure temp schedules. twizz are you curing entropy at 150? thanks!

I've done it on a number of my test skis (and skiied them many days after) successfully.

As twizz said they just need a little bit longer to cure

Yes I use entropy CPM at 150 degF. I leave it in the press at least an hour at that temp, sometimes longer.

It's kinda unclear what your question aims at.

If you want to know how much heat your hoses can take -> look at the datasheet or ask the supplier. Most PU hoses are rated up to 160F. If you're concerned about overheating your hose, you might want to consider a wooden cattrack or a silicone mat between your hose and cattrack.

If you want to know how to properly cure your epoxy -> refer to the datasheet of your epoxy. Each epoxy has different cure cycles and there's no right answer for all epoxies. I'm using Sicomin and Entropy ski specific epoxies and they both need to be cured at around 180F, but for different periods of time.

Chrismp,
What Sicomin are you using? I have been experimenting with SR 8500 / SZ 8525, pressing for around an hour heating up to 100oC. But seems to be a bit brittle and not a great bond to UHMW-PE even with flame treating.

Suggested curing time at 100C for the sicoimn 8500/8525 combination is only 10 minutes.
1 hour at 80C.
My cycle for this combnation is increase from ambient temp to 80C over 30 minutes then 1hr 15min at 80C, then cool down.
Adhesion with all components has so far been very good.
Perhaps 1 hour at 100C is too long?

Here is the datasheet if you don't have one.
http://www.matrix-composites.co.uk/prod ... 25-ski.pdf

I'm using the same stuff. I cure it by ramping up the temp to 90°C (takes about 15 min) and keeping it there for another 15 min. Then I let it cool to about 70°C and pull the board out of the press while it's still hot.

No problems so far. Maybe you're cure cycle is too long.

Sounds like I need to get my PID up and working as have been running of a variable resistor calibrated using a infrared thermometer. But generally tried to ramp up to around 100 on the heat mat, which is about 90 on the ski, and hold that for 45 mins. Funnily enough I know the guys at Matrix because thats where I have got most of my supplies from.