Best adhesive for fixing Powerbook 5300 cracks?

[FacnyFreddy]

The corner where the power connector on my 5300cs is now broken off (one piece, thank goodness) and can be easily re-attached.

But, what have folks been using to fix/re-attach case plastic?

 

[bibilit]

epoxy probably.

 

[FacnyFreddy]

I see this post for 2014 and I am wondering if it still holds true.

https://68kmla.org/forums/index.php?/topic/23017-what-glue-is-best-to-repair-powerbook-laptop-plastic-casing/

 

[Trash80toHP_Mini]

You can ignore the comments in that thread about modeling glue not working to chemically weld your ABS case. That formulation is specific to the styrene family plastics, don't even consider using it on ABS. Chemical welding with the proper formulation is the only way to go. JB Weld appears to be a more general purpose plastic welding/epoxy hybrid. But again, it's not specifically formulated for ABS applications.

For the epoxy/JB Weld approach, I'd do an ABS "cement" chemical weld of the crack after the sanding (40-80 grit AGGRESSIVE) roughing up and scoring processes for the inner surface. After the chemical weld of the surfaces of the crack is fully cured, epoxy or JB Weld (this formulation sounds almost ideal) in the reinforcement role would be an excellent approach. It should brace the welded case plastics against both shear and tension stresses.

edit: do the ABS solvent weld from the inside of the case to minimize chances of discoloring or changing the texture of the outer surface if you miss.

Haven't tried it, just thought of it. ABS cement from aHImprov plumbing dert. might work really well if you thin it with MEK. The standard formulation has a lot of ABS in the solution for void fulling purposes across large survaces. Thinning it to a consistency that will wick into a crack by capillary action could prove to be ideal. I'm thinking MacABS dissolved in MEK could prove to be the ideal approach. Check the MSDS for ABS cement online.

 

[Trash80toHP_Mini]

Looks like MSDS has been shortened to just SDS:

Oatey Medium Black ABS Cement has a very helpful SDS listing rough proportions of all three major ingredients:

Composition/information on ingredients

Methyl ethyl ketone______40-60%

ABS Resin_____________30-40%

Acetone_______________10-20%

Other components below reportable levels

WELD-ON looks like the ABS cement to use due to color availability, but its SDS only lists rough percentages of the MEK and Acetone components. The balance would be dissolved ABS like the Oatey product..

WELD-ON 771 ABS comes in "Milky" and Yellow

WELD-ON 773 ABS comes in Black

If someone knows the PMS numbers of the SpindlyPlast© color palette for desktops and PowerBooks offhand, we can get rough approximations of the color mix proportions. ISTR seeing a PVC to ABS cement available in green(?) and somethingorother in red, so trace amounts of colors outside the WELD-ON selection could be used to tweak final color matches.

The consistency of these pipe cements (ABS dissolved in welding solvent mixtures) is probably too thick for case plastics, you'd want to be able to use a "syringe needle" type bottle applicator or a brush to wick a thinned mixture into the cracks, so thinning will likely be necessary.

It's my understanding that the Acetone component is there to slow down the cure time of a pure MEK/ABS solution. Without it there wouldn't be enough open time (work window from application to curing past a workable state) to get a good weld between pipes and connectors. We don't need that much time in this application, so any thinning should probably be done with MEK, not Acetone.

I'll be doing a bit of experimentation before taking on a major case re-construction project in the near future. Maybe I'll copy these posts into a new topic in hacks and share those results.