Glue for compass housing and dome

[Pythzepf]

Hi!

I'm restoring a set Plastimo Olympic 400 compasses. I'm finished with polishing the dome and want to re-seal the joint between the compass housing and the dome. During polishing I noticed that water pulled pretty deep into the joint (marked with a red circle on the attached image) by capillary forces and I suspect part of the leak has been through this joint.

I believe the body of the compass is basic ABS and the dome is acrylic. Before simply putting some superglue (a cyanoacrylate adhesive) there, I want to ask from here: is there some type of glue for ABS/acrylic that has good flow, is gap filling (I know these two do not really go hand-in-hand, however the gap is very small, 0.1 mm or less) and especially good for a marine environment considering constant exposure to seawater and fluctuations of heat? UV exposure is not an issue as the joint under question is covered by a protective nylon reinforced plastic ring.

Thanks!

[Nekton73]

https://www.eplastics.com/accessorie...s/acrylic-glue

[Pythzepf]

Thanks for the link. SciGrip has poor availability here in the EU (to private customers). After consulting with my local Loctite dealer, and ChatGPT by the way, I'm going with the Loctite 401. Product description here: https://www.henkel-adhesives.com/ee/...tite_4010.html

Key features: capillary action, small gap-filling property, good resistance to water and chemicals, plus it glues ABS and acrylic.

[Pythzepf]

And to finish this off: Loctite 401 worked wonderfully, it went right into the hairline gaps and filled them up.

[Pythzepf]

!NB! This is not the Plastimo Olympic 400 compass (which does not exist), but the Plastimo Olympic 100. The text on the compass is so worn that it looked like 400.

[thinwater]

Actually, the leak is almost certainly the rubber diaphragm inside the housing (compensates for expansion of the fluid). The diaphragm will be hard to find, expensive, tricky to fit, and most repairs fail. The joint you see just holds the dome to the bracket and is not the fluid seal. Go in through the back (screws).



Sorry for the news. You can either use it with low fluid, which is often fine, or get a new compass for $$$.

[Pythzepf]

The diaphragms seem fine (I've already taken the compass apart almost to the last screw). If a new leak springs, I'll know what the next culprit will be My first idea in replacing the diaphragms will be casting new ones from polyurethane. I can make silicone molds from the existing old diaphragms.

PS1 - the joint between the housing and the dome is a fluid seal too, technically speaking.

PS2 - I've already replaced the compass fluid and presently no leaks, however that'll need to be validated with a season of sailing.

[Lakesurfsailor]

Originally Posted by Pythzepf

The diaphragms seem fine (I've already taken the compass apart almost to the last screw). If a new leak springs, I'll know what the next culprit will be My first idea in replacing the diaphragms will be casting new ones from polyurethane. I can make silicone molds from the existing old diaphragms.

PS1 - the joint between the housing and the dome is a fluid seal too, technically speaking.

PS2 - I've already replaced the compass fluid and presently no leaks, however that'll need to be validated with a season of sailing.

Hey Pythzepf,

I am doing a similar repair to a plastimo contest 101. What did you use for fluid? has it held up?

I did a test with mineral oil and it made a whispy consistency with whatever was in there. It had no smell or taste so I don't think its any sort of solvent. I thought either silicone oil or maybe glycol... Appreciate any insight!

thanks