Low viscosity epoxy

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OK, OP here. There have been some good thoughts on my efforts to get some epoxy through an 8 gauge needle. It seems like the options are...
1) find some lower viscosity structural epoxy.
2) use laminating epoxy.
3) use laminating epoxy with additives (but wouldnt this thicken it?)
4) heat the epoxy carefully.
5) add denatured alcohol to. the epoxy (but this weakens it)
6) ditch the needle and use a
dowel to apply the epoxy.
(I'm not always happy with
this method, I find this to be messy and I dont always get the internal
fillets as even as I
would like.


Which one is strongest do you think?

And thank you to all who posted.

I wouldn’t be concerned with the aesthetics of internal fillets. It’s very difficult to make them look neat. I simply go for strength and don’t really care what they look like. No one’s gonna see him after the rear center ring goes on anyway
 
Just as an aside - if someone needs a very low viscosity epoxy, one of the more readily available ones is Sikadur High Modulus - LV "low viscosity". This is a industrial structural repair epoxy intended for crack injection. Just slightly thicker than water, and will gravity wick into a 1/32 inch crack. Available in cans, but also in 6 ounce cartridges with the mixing nozzle at some home stores.

Not for general purpose. Will find any crack or pinhole and leak out on you...

https://retail.usa.sika.com/en/products/concretestucco-repair/spallcrack-repair/sikadurr-crack-fix
 
Thank you to all who replied. As always I value all your opinions and have learned a great deal.

Charlie
 
I know you have used Aeropoxy and John Coker recommended it above. Let me add a little experience about the Aeropoxy PH3363 super low viscosity hardener added to PR2032 resin. This hardener was specifically developed to be low viscosity. The hardener seems runnier than water when it comes out of the can. The instruction sheet claims it is suitable for structural applications.

I have successfully put the mixed epoxy through needles down to #22.
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With small needles don't expect to suck up the epoxy into the syringe. Pull out the plunger, fill syringe, insert plunger while plugging tip, turn over, wait for bubble to rise up, push out extra air. I see there is one 'typo' on the drill size for the smallest needle sizes. Probably should say #60.

I read a post the other day about mixing epoxy in a syringe with a cable tie in a drill. I haven't tried it, but it looks intriguing.

Overall, I don't find this epoxy as easy to work with as West 105/206, but it isn't designed for boats. My first experience was that it seemed to clog up brushes. It felt like it was hardening early. I then realized that it likes to be warmed a bit to flow well. I think viscosity is highly dependent on temperature. I am working in a cool basement. In the 70 to 90 degree F range it is runny and you get plenty of working time. Pot life is stated as 90 minutes at 77 F.

I have the more standard PR3660 hardener on the shelf, but I haven't gotten into it yet so I cannot offer a comparison.
 
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Just as an aside - if someone needs a very low viscosity epoxy, one of the more readily available ones is Sikadur High Modulus - LV "low viscosity". This is a industrial structural repair epoxy intended for crack injection. Just slightly thicker than water, and will gravity wick into a 1/32 inch crack.

Thanks for the tip, have you tried it? Sounds useful for airframe edges and odd jobs.
 
Thanks for the tip, have you tried it? Sounds useful for airframe edges and odd jobs.

I have used the Sikadur for crack repair in concrete. There are tricks and techniques but relatively easy to use for horizontal cracks. For vertical cracks on masonry or walls, you have to cap the cracks with a gel epoxy or mortar first, otherwise the Sikadur will run right out. One nifty trick for really thin cracks in slabs or walls -- you can cover the crack with duct tape, then stick your shop vac on one end of the crack and draw a slight vacuum through the crack. Then you slowly apply the epoxy to the crack at the other end, and it will get sucked right it, without air pockets. You pull the tape off as you go, working towards the vacuum.

I haven't had need to use this Sikadur for a bonding application, and you would have to thicken it. As others have noted, any of the laminating epoxies will flow through a syringe just fine. You have to load the syringe the way kbRocket explains.

Another application for super thin epoxy - I like to soak the ends of cardboard tubes in epoxy to strengthen and water proof them. Helps keep nosecones and ebays form getting stuck as the humidity in the air changes from summer to winter. Low viscosity epoxy soaks in best.
 
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