Changing Camber

vinman · Post by **vinman** » Tue Jul 01, 2014 5:24 pm

My PID is spot on, no melting or deformation

MontuckyMadman · Post by **MontuckyMadman** » Tue Jul 01, 2014 5:34 pm

225f uhmwpe starts to go pretty soft. fyi.

vinman · Post by **vinman** » Tue Jul 01, 2014 6:47 pm

Maxed out well below that, good infoo know just in case.

MadRussian · Post by **MadRussian** » Wed Jul 02, 2014 12:26 pm

at 175° F on bottom controller edges in my press get overheated to the point where shoulders melded into p-tex from inside but not where ptex and edges connected. Bases ok overall. to present the problem I have to keep bottom blanket at 160

vinman · Post by **vinman** » Wed Jul 02, 2014 12:46 pm

Sounds more like edge press thru from lack of sidewall recess???

MadRussian · Post by **MadRussian** » Wed Jul 02, 2014 2:33 pm

vinman wrote:Sounds more like edge press thru from lack of sidewall recess???

I don't think it's possible to "press through" because ptex is high density product and IMHO press through only possible when plastic softened up under heat close to melting point.
In my case while it is true I don't do recess, appearance of clear sign of melted ptex cannot be contributed to sidewall recess.
It is what it is. Everyone approaches different and results are different

vinman · Post by **vinman** » Wed Jul 02, 2014 5:18 pm

I'm not criticizing you or your process only trying to add good info to the forum.

But press thru is definitely possible, What you are seeing is the outline/imprint of the edge teeth in the plastic correct? Don't you see the pattern in the fiberglass in your base or top sheet? I do, in every pair before they get ground. Look at the top sheet in commercial skis and you can see the faint appearance of the 45 deg. fibers in the triax imprinted.

A minor defect in your cassette or something like a piece of dirt or sawdust can leave an imprint when you put 20 tons of force on it, edge teeth are .6mm thick and can certainly leave an imprint.

A proper rabbet of .7 to .8mm minimizes or eliminates this in most cases.

But his thread is now getting off topic and I don't care to discuss this further. This will be my last reply here, good luck with your builds and your process.

chrismp · Post by **chrismp** » Wed Jul 02, 2014 11:02 pm

I've pressed a few boards at 266°F (130°C) without any problem. I did this because I had some trouble keeping the base flat after taking it out of the sublimation press. The elevated temperature in the press softened the base enough to get pressed flat again. No edge teeth showing through, so I guess it has someting to do with the lack of an edge recess for you MR.

MontuckyMadman · Post by **MontuckyMadman** » Thu Jul 03, 2014 8:30 am

Seeing edge teeth is from too small a rebate or non at all. Do a small test pieces, one with rebate at .8 and none at all. You will see.

Dr. Delam · Post by **Dr. Delam** » Thu Jul 03, 2014 11:17 pm

I concur. I don't rabbet my tip spacers and I get edge imprint on the base and usually some base concavity in the tip spacer area. I never came up with a good way to do it.

Does anybody rabbet their tip spacers?

MadRussian · Post by **MadRussian** » Fri Jul 04, 2014 1:57 am

Rabbet and wood sidewall didn't go together too well for me. This is a main reason not doing it. basically IPE splits in splinters or simply break of in last 3 to 6 inches of the core. Overall very happy with results without rabbit

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Changing Camber