开云体育

Note to group, my 2465B scope had cracked rear tan plastic cover. JB Weld "Plastic Bonder" tan color is a 2 part polyurethane adhesive with a great color match and adhesion. Should work other models I would think.

I uploaded photo to Photos folder.

/g/TekScopes/album?id=300551

I suppose it is good in the region that you glued. The most common cracks in the rear cover are at the four corner screws.
I have not had good luck gluing the corners using this plastic epoxy repair. The epoxy is so brittle, it immediately cracks again with even the slightest tightening of the corner screws.

Hi,

I had very good results using glass fiber reinforcement with epoxy. Usually
I only need a few strands of glass or an appropriately sized patch. One has
to figure out how the stress forces will go and place the fiber
accordingly. When wetted with the resin, it is practically invisible.
I used laminating epoxy used in marine construction, because that is what I
have, the only drawback in this case is that it cures fairly slowly, but
otherwise it is very strong once cured.

Szabolcs

victor.silva via groups.io <daejon1@...> ezt írta (id?pont:
2025. febr. 7., P, 2:18):

Yes, little stress where I used it and it seems strong enough that I could have used 75% less in hindsight. We will see if this was a good choice for my first experience with the product, if any issues I will follow up here.

It stayed in place very well even on the vent grill posts that were vertical, and was easy to use.

J&B others offer a plastic adhesive epoxy AND polyurethane and manufacturers state different applications, one being polyurethane has more flex than the epoxy. I have not used the epoxy products on plastic so I can't speak to that. I think it is important to note two part formulation is not exclusive to epoxy. I did not know this before I did my research, nor did about 50% of the internet experts so best one goes to the source.

I had related experience adhesives and coatings when I laminated a new transom for my ocean boat. This was 25 years ago and that work is still like new, well tested by chasing Pacific coast tuna far offshore. I bought a book on boat building and followed every product datasheet step to the letter. I used (expensive) epoxy resin instead of polyester and proper fiber additives, and finished with (very expensive) two part polyurethane coating applied by brush. It leveled out to a perfect gel coat like finish with no brush marks or runs, even on the vertical surfaces. It is beautiful.

Same boat, got tired of ugly cheap covers. Bought a book on canvas work, purchased high quality (again, expensive) acrylic fabric and made a cover. 25 years in the sun, still in great shape.

With quality (yes, usually expensive) products for the application and humble respect of reputable manufacturer instructions a hell of a lot can be accomplish. I hope everyone continues to take on these repairs and keep improving our collective knowledge.

It's not about me, I am not gifted. I just follow gifted people. That is why I am in this group.

On Fri, Feb 7, 2025 at 02:17 AM, Szabolcs Szigeti wrote:

Szabolcs

Szabolcs, agree 100% with merit of fiber - good point. I always keep it on hand. There are also many epoxy fillers in addition to fabric for different applications. Marine supply is where I find these.

On Thu, Feb 6, 2025 at 03:36 PM, Don N3DEB wrote:

rear tan plastic cover.

Does anyone know what kind of plastic that is?
For a start, is it a thermoplastic, or a thermosetting plastic?


--
Roy Thistle

Chuck Harris said he uses Acrylic solvent with the needle applicator if that helps. I would not have thought to try that because I would guess it is for sure not acrylic, and have never used that solvent for any other types.

Yes, it would be nice to know the plastic types on Tek equipment or how to identify them as that is the best approach. You could shave a sliver with a razor blade and do a flame test and compare to online photos for plastic ID.

I don't know if this is applicable or not in this case.

I recently found out about a primer that can be used with super glue so that it can be used with materials that it normally will not bond with - even teflon.

It is available on eBay for a fraction of the price of local suppliers - Just look at Super Glue Primer or CA Glue Primer.

Regards,
Brian.

Araldite is better stuff that jb weld.