DIY LEVER DRAG CF WASHER

[Robert Janssen]

Right then...

LTM, what are you going to bond? CF to the spool, or a free-floating donut washer 2 mm thick, or a 2 mm thick washer with tabs, or cf to disc? I'm sorry; i don't know what they look like exactly.

There are a lot of suitable substrates you can use depending on what you're after, but like alan said it would be wise to check and see if it really is neccessary. (0.6 mm might not be such a big deal. On the other hand maybe it is or you wouldn't ask)

High-temperature bonding is often difficult for the average fellow to achieve. It usually ends up on some industrial-application-only type thing (and there are fantastic products available for that) but luckily there is a terrific solution which was mentioned earlier: JB Weld, the high-temperature version. This is an easily available epoxy adhesive sold in small packages for a couple of bucks, that behaves like a regular epoxy but withstands temperatures well over 200 degrees Celsius.

I know it does, because i have used it for years for any number of applications to laminate friction materials and bonding drag washers, and tested them to extremes. Trust me; it is very good.

About substrates, it kind of depends on what you're making. Have a look at industrial gasket materials if you're just making a donut. Widely available in a range of thicknesses and temperature ranges, usually cheap and easy to cut. Not so good for tabbed washers though.

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[LTM]

Gentlemen thanx for responding, Alan and Robert as well

Robert I was just pondering this thickness challenge and I was wondering what your specific thoughts might be on the subject. Here's the situation. I have a 3" metal disc which a 2 mm thick cork-like drag material is adheared to. The challenge is that the thickest carbon fiber replacement drag material I can get is only 1.4 mm thick. So my options are glue two 1.0 mm drags together and glue that combination to the metal disc that I bolt to the reel. The unknown element here for me is can this be done effectively so that the heat and pressure from no more than 15# of drag destroy the bond.  The other option is to by some means find some sort of level substrate that I can fabricate (with normal power tools) that will be a flat surface that is 0.6mm to bond the 1.4 mm thick drag washer to. Thanx in advance and I will watch out closely for your responses,

Leo

PS  My middle name is "JB Weld" Im a big fan of the product, didnt think of using it as a bonding agent for this application. Always have some on hand. What do you think about me using the quick set version?

[Robert Janssen]

What do you think about me using the quick set version?

I don't. There are many types of JB Weld, sometimes sold with different badges. Stick to the original basic, two-part high-temp epoxy. Read the label carefully. Not these other kwik-set, putty, all in one yadayada versions; dunno know them.

As for the rest of it, use 1 mm hi-temp gasket sheet (ask at the hardware store. They might even have pre-cut 3" diameter) and 1 mm cf. Or 1.5 + 0.5 then if that feels better. Or almost anything you like.

Heres a tip though... Not so fast. Bond only one thing at a time. Washer today, disc tomorrow. Keeps things clean & under control.

Incidentally, what is keeping you from adding say 0.5 mm of cf to your existant drag washer?

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[LTM]

Robert,

Are you referring to the high temp gasket material that resembles cork?

Thanx Robert, will update this post when completed testing for this project.

[Tiddlerbasher]

Use JB Weld Original - >500F and almost 5x the bonding strength of the high temp putty they sell (the putty seems to be more of a quick set thick gasket/auto fix putty , check their own specs http://www.jbweld.com/products/surface-applications/automotive/). I have personally tested the Original epoxy to >250F,single plate 75mm diameter drag and large aluminium heatsink. If your drag is regularly going to exceed this you have other problems .

Also, the thickness of the final bond (from experience) is approx .5 to .7mm - Just take your piece of CF and twist and turn the thing to bed it into the epoxy (and/or clamp it - not too tightly!) - clean off excess with acetone - wait 24 hrs before trimming to size and testing!
The thickness should be close enough  .

[LTM]

Tiddlerbasher/TB,

This is just the info that I needed. With the thickness of the JB Weld of .5-.7 mm being just the amount of added material plus the 1.4mm disk I will achieve the desired drag height of 2.0mm that I need without adding a substrate to the equation. For my original premise didnt take into account the thickness of the bonding agent which would have made the height too much. There is trully nothing like experience and many councels.

Thanx guys, I have a solution now that I feel will totally work.

Leo

[Robert Janssen]

Robert,

Are you referring to the high temp gasket material that resembles cork?

No. I'm referring to flat, hard, stiff cardboard-like material, available in more types than can be explained. Google.

...With the thickness of the JB Weld of .5-.7 mm being just the amount of added material plus the 1.4mm disk I will achieve the desired drag height of 2.0mm that I need...

At risk of a misunderstanding haven arisen, i beg to differ. If you add .7 mm of total thickness, you are using way way way too much. The cf is not supposed to be floating on a bed of epoxy. Very little epoxy, and clamp between flat Surfaces. Total increase of thickness due to epoxy should be negligible.

I had a meeting about this and other things with the company that makes HT-100 a long while back.

i gotta go

[LTM]

Got it Robert, and thanx to all for your feedback.

Leo

[Bunnlevel Sharker]

What about a fiberglass core like the one in the ht-100s?

[bluefish69]

The rings in the picture look like plumbers composite gasket material. There are different thickness.

Mike

[locknut]

Sorry been away hunting for a week. It looks like you have got all the answers this place is the bomb. I used the JB Weld original good to 550 F 2 part epoxy it worked a treat.
Jeremy