exxos's Atari, Amiga & retro forum

OK, so I have had another go:


Should have the proportions of resin to hardener correct this time, so lets see what happens.

:crossed1:

HigashiJun wrote: 24 Jul 2024 11:28:crossed1:

Resin has already set further than the last time :)

rubber_jonnie wrote: 24 Jul 2024 13:07 Resin has already set further than the last time :)

Sounds good !

HigashiJun wrote: 24 Jul 2024 13:12

rubber_jonnie wrote: 24 Jul 2024 13:07 Resin has already set further than the last time :)

Sounds good !

Indeed it does.

Let's wait and see what the result will be.

Just hope you are close to the goal !

:D

:crossed1:

stephen_usher wrote: 24 Jul 2024 14:03 :crossed1:

Yes to that.

So, it's gone a bit better but still needs work. The mix was perfect, so that is something, fully set already this morning:


It isn't without issues though:


Unfortunately the blue cube mould got an air bubble in it at the fill hole, however the finish and weight of the cast ball was pretty good, and I can try again, but now just need to be sure I have a process to avoid air bubbles.

The spherical mould worked well from a size/weight perspective, however the alignment was poor leaving a lot of flashing on the edge:

For reference I weighed some of the mice ball replacements I have, plus actual balls, results below.

20mm steel ball:


20mm delrin ball:


22mm mouse ball


Hand rolled 'Milliput' (Epoxy filler):


20mm rubber ball:


20mm resin only ball:


20mm resin/iron powder composite ball from spherical mould:


20mm resin/iron powder composite ball from the blue cube mould made by me:


I think the other ball from the spherical mould is representative of the finished weight of the blue cube ball if it wasn't missing a piece given the air bubble it suffered.

Given the weight of the 22mm mouse ball, I think that 20mm composite ball is really quite close weight wise and far better then the other offerings, such as rubber or delrin, and the steel is rather too heavy.

I think I will give the blue cube another go, and I may also try making a new mould from the 20mm steel ball in which I can suspend a smaller steel ball and pour RTV silcone round it like a normal ball.

Is there any way that you can put the resin into a syringe and inject it from the base of the mould so that you don't risk getting the filler hole blocked by a bubble?