exxos's Atari, Amiga & retro forum

I always find that epoxy fails quite quickly. Superglue has been the only type which has been strong enough to hold the Apricot case together. The epoxy joints just peeled away with any flexing. Cyanoacrylate bonds (if the surfaces are very clean and close fitting) are stronger than the material, being hydrogen bonds between one molecule thick layers.

stephen_usher wrote: 04 Aug 2021 18:36 I always find that epoxy fails quite quickly. Superglue has been the only type which has been strong enough to hold the Apricot case together. The epoxy joints just peeled away with any flexing. Cyanoacrylate bonds (if the surfaces are very clean and close fitting) are stronger than the material, being hydrogen bonds between one molecule thick layers.

Unfortunately superglue, even gel, doesn't seem to be working very well, it's quite gappy. As long as the joining faces are rough enough, which they are, the epoxy should hold once the whole thing is screwed back together and shouldn't flex very much. I've never had much luck with superglue and Atari plastic. I guess the Apricot has a different formulation that doesn't play well with epoxy.

You can also buy a crystal clear version of araldite, it's good stuff. By the way - depending on how good your cherry switches feel (mine were worn and scratchy) you can de-solder them and replace with brand new cherry switches. I replaced mine with cherry mx brown and they're lovely.

Steve wrote: 04 Aug 2021 20:49 You can also buy a crystal clear version of araldite, it's good stuff. By the way - depending on how good your cherry switches feel (mine were worn and scratchy) you can de-solder them and replace with brand new cherry switches. I replaced mine with cherry mx brown and they're lovely.

I haven't seen that clear version TBH, though the damage is so bad it'll be getting painted anyways. I will have a look for some though for future projects.

Ok, so I have now received some small fibreglass patches which I will add to the casework to help reinforce the damaged areas. I'll try to keep it to the inside only, but will see if it is required in external areas. The glue so far has taken well, but I want to improve the overall strength.

They're the kind used for false nails so small and light, but very tough when impregnated with glue/resin.

I'll start by keying the plastic with a stiff wire brush so that the glue/resin has something to grip to, and hopefully get some pictures of the process along the way.

If I can dig out one of my Megas, I can test the mechanics at least, but getting stuff out is being slightly delayed whilst waiting on some more furniture for a) The spare room so we can empty a load of clothes boxes allowing me to get to the workshop boxes behind them b) more desks for the retro area.

Should be here on Monday though, so that will get things moving again.

Acetone mixed with plastic and you get a slurry that bonds very well. However acetone slowly melts the plastic so it's tricky to use. Small amount to get the end 'sticky' and then mush it together. The acetone evaporates after a while and the plastic that got hit with acetone will be stiff again.

I wouldn't use it the first time trying it out getting a precious Atari case together though.

DoG wrote: 10 Aug 2021 15:27 Aceton mixed with plastic and you get a slurry that bonds very well. However Aceton slowly melts the plastic so it's tricky to use. Small amount to get the end 'sticky' and then mush it together. The aceton evaporates after a while and the plastic that got hit with aceton will be stiff again.

I wouldn't use it the first time trying it out getting a precious Atari case together though.

I don't have any acetone to hand, I have heard it is good, which is why I am going with epoxy + fibreglass. It is a precious case and at least I know the epoxy won't melt it.

I have previously glued plastic with acetone and iut can be tricky as you've suggested.

Note to self for later, paint code of RAL7030 stone gray looks very good!

Don't forget the sealant spray on top. :-)

rubber_jonnie wrote: 19 Aug 2021 13:47 Note to self for later, paint code of RAL7030 stone gray looks very good!

I'll be interested to see how close a match that is.