has anyone made his own pad refills?

[FamilyBiker]

the moulds made by a mate of me.

once polyurethan´s polymerisation is done,you cant melt it again,you have to use 2-component-resin.

that thing is actually just bolted together,wich gives the shape of the pads.

i took my measurements from echo cnc pad refills and designed the cad to it.

afaik those are the ones which have the biggest recesses,so its basically aimed at having pads that can be cut to every other backing.

the mould is only to be pre-heated to 80° C,the curing time of the PU is around an hour,and steel would hold most of the temperature for long enough to get a homogene cured pad.

if not,i have an old microwave oven that i could use for post-curing.

you didnt really read the whole topic did you?

[tdubz]

I skimmed the topic but got distracted by the pictures

[FamilyBiker]

today i got something in the post,fitted a pad refill into it,fits perfectly,awesome!!!

[dave33]

That was fast. When is you resin going to arrive ?

[FamilyBiker]

i hope in the next days.

Edited September 11, 2013 by FamilyBiker

[FamilyBiker]

little update,stuff arrived.

weather seems to be shite tomorrow and i´m off work for the afternoon,so expect some chemistry to happen then

[FamilyBiker]

woohoo!

being the impatient guy i am,i had things going on in my kitchen lab 5 minutes ago!

cool things!

that means fresh pads will be finished this evening,how awesome is that?

Edited September 17, 2013 by FamilyBiker

[dave33]

Looking good. You just need to hire some cheap labour for mass production throught the night

[FamilyBiker]

haha, if this works i´ll need a mould with like A4 format for say 10 pairs or so.then i could make loads in no time.only downside so far is that it has to settle for a few days up to a week before it can be used as a brake pad...

2 days with 80°C,but i wont run my oven for that time lol

[BradJohnson]

fresh pads will be finished this evening,how awesome is that?

I'm actually excited for you

[dann2707]

Looks ace. But how will they Perform?

[FamilyBiker]

well,i dont know either,will have to try different mixtures,write them down and keep doing what works best.

first try was pretty freestyle,6ml of each resin component,a teaspoon of aluminium hydroxide and a drop of pigment fluid isnt really exact science haha

edited:6ml,not 60,that would be huge pads haha

Edited September 17, 2013 by FamilyBiker

[FamilyBiker]

okay,so its not THAT easy:

put them out of the mould a few mins ago,and over night they went shite(rhymes ahoy).

seems like the release agent i used evaporated some of its aerosol through the pads,so theyre pretty much foam now.

bubbles over bubbles.i´ll have to dry that stuff out better next time,seems like i was in a rush to try it out and didnt take everything into account.

next set is in the oven as we speak,now with bee wax as a release agent,no aerosols involved...

we´ll see

Edited September 18, 2013 by FamilyBiker

[hezzay]

What happens if you tap them out without using a release agent?

[FamilyBiker]

they break apart,because the bond between the metals rough surface is stronger than the internal structure of the polyurethan.

at least with the harder ones i made yesterday,too much filler and they get brittle.

atm i´m trying to get the right mix,have made too brittle ones with bubbles and too soft ones now,the answer lies in between that.

the other thing is how the curing affects the hardness in the long run,a soft pad today can be a hard pad in a week...

edit:second try finished,compared to the echo refill the mould was built after:perfect copy,except the surface.but that will be sanded though,so what?

i´m making the test ones with only 4-5mmof pad to save resin for the final ones

i cut the other one in 2 pieces to check if theres air trapped inside,the bubbly stuff is now only on the surface,so win!

Edited September 18, 2013 by FamilyBiker

[FamilyBiker]

next update,i have 3 test compounds ready to go on the bike,they just need tempering for 4 hours now,so i wont be testing anything today.

my kitchen lab:

my mixtures so far are compounds of:

-80a

-83a

-87a

thats calculated from the values on the data sheet the resin guys sent me with it,and after tempering.

tempering is 80°C,4 hours and gives + 2 in shore a hardness.

the weird shape of the proto pads doesnt matter,they have to hold up 1 ride in dry and wet weather each,so i´m just saving material now

little bit of input for those who fancy a try

if i ever will be giving away some pads theyll be a tenner or so,its much more work to make pads than i thought lol

except testing pads,some people will get free ones

edit:compared mine to the pads ive ridden so far (and liked em)in consistency,my tendencies to go for 87a are growing....

Edited September 18, 2013 by FamilyBiker

[err]

they break apart,because the bond between the metals rough surface is stronger than the internal structure of the polyurethan.

have you considered polishing the internal faces of the mould with metal polish and a dremel?

i used to work with composites and the smoother the mould, the easier the release

[FamilyBiker]

have you considered polishing the internal faces of the mould with metal polish and a dremel?

i used to work with composites and the smoother the mould, the easier the release

thats a good tip,thanks.only thing is it´ll make the pads too wide by a few 1/100th mm.

have the next set in the oven right now,i´m unstoppable now!!!

edit:

baking the mould,baking the mould!!!!!

(imagine judas priests "braking the law" to it right now!)

and another edit:

couldnt stand it and made a full set,just to check the results in size etc

now if that doesnt look promising...

Edited September 18, 2013 by FamilyBiker

[dave33]

I was think that the height of the pad

Might affect performance? Think about cousts they are thicker and give a bit more compression.

I always feel my pads don't perform so well when they start to get close to the backing.

Don't forget to send me a pair

[FamilyBiker]

yours are the first ones that leave my kitchen after the protos i will glue into backings this weekend.

tempered 3 sets of pairs now,theyre completely finished,only testing,then rocknroll or back to the drawing board;)

you wouldnt believe how much harder they feel after tempering.

the shore values will be pretty interesting...

Edited September 18, 2013 by FamilyBiker

[*gentlydoesit]

Thread hopping firstly i have to confess i scrolled throught a lot so please forgive.

Did you put them on a vibrating table? Did the release agent work well? Ive seen moulds using vacuum and air pressure to release casts maybe you could dial somthing like that into your a4 sized cast.

[FamilyBiker]

fortunately that stuff doesnt seem to trap much air anyway,so i do it without vibrating.(ordered stuff with 45 min pot time intentionally to avoid this,its like sugar water with additive applied)

bee wax works a treat for releasing,i just put a little chunk in the mould and put it in the oven for preheating,then i mix the pu together,and right after i finished this the wax is molten.

pour excess wax out,fill pu in,baking time.all in all a pair of brake pad refills cost me around an hour of my time.

edit:hey,if a welder *cough cough* would make me a vacuum chamber,i´d be in to try it.but for now a vacuum system seems a bit much technical effort.

releasing isnt a problem,but under vacuum the pu gets alot more compact,because those microscopic bubbles dont appear.thats a thing even vibrating wouldnt help for...

I was think that the height of the pad
Might affect performance? Think about cousts they are thicker and give a bit more compression.
I always feel my pads don't perform so well when they start to get close to the backing.

thought the same and made the 3 sets i finished completely full size,theyre about 8-9mm when ground down faced

Edited September 19, 2013 by FamilyBiker

[FamilyBiker]

i´m baking,yes indeed....

6 sets now,i´ll stop moulding for testing now,once the pads are tempered dave and a few others will have to tell me their opinion.

i´m so f**king curious of what the shore tester dave has at work will tell,calculating the resulting shore hardness from component weights isnt exact really,so it could be a big surprise also.

they are harder than some 83a i have here for a sample,but less "springy",its hard to tell.

where are the guys that started making pads when this thread was in his baby shoes???

need more experiences from you about your own pads,how was the wear so far,did it tear,how was bite hold as the pads wore down etc?

pretty important to know.

Edited September 19, 2013 by FamilyBiker

[bing]

If I remember rightly from being with my old man in the print industry, a shore hardness tester is just a dial gauge with a needle that measures applied load. This gives you your rating. We used it to measure the hardness of rollers, and blankets which transfer the print from the printing plate to the paper. They are quite simple really

[dave33]

If I remember rightly from being with my old man in the print industry, a shore hardness tester is just a dial gauge with a needle that measures applied load. This gives you your rating. We used it to measure the hardness of rollers, and blankets which transfer the print from the printing plate to the paper. They are quite simple really

image.jpg

they just measure the deflection of the material for a know load and amount of linear travel. the one i used is just a digital version of that, simply calibrate it with the test pice which has a know value and away you go, but like any measuring equipment it no good unless you calibrate it.