Easiest epoxy syringe loading yet...

[snrkl]

I’ve been struggling with 15min epoxy to mix, load and dispense quickly enough using syringes. It’s also been very wasteful as you reach a point where you are getting more air than epoxy when trying to draw it up into a syringe.

Also, with my current project being the first time I’ve injected internal fillets from outside the airframe, my holes were a little smaller than I needed.

Two simple solutions I’ve found:
(Before anyone rants about epoxy and exothermic reactions in deep vessels, I did a test and the BSI epoxy I’m using never even got warm - I’m working quickly and the whole lot was mixed and injected in under 4mins)

1) heat shrink tube as a flexible syringe tip:


2) measuring and mixing the epoxy IN the syringe: (no pic, as it takes two hands and there’s no handy photographer around)

I have 6ml syringes, so I:
Fold over the heat shrink to seal the end
I fill to 3ml with epoxy,
start the stopwatch;
fill with hardener to 6ml.
I use a thin coffee stirrer to mix the epoxy up and down and round and around till the colour is uniform

Then, insert the plunger and inject away!

I’ve found sharpening the coffee stirrer with a pencil sharpener helps get the mix action down into the tip of the syringe.

 

[RocketFeller]

I mix the epoxy on a flat surface and then fill the syringe from the plunger end. If I do it right I have a full syringe with zero waste/mess. If I do it wrong I clean up the syringe with a paper towel after loading....

 

[jjwb22101]

As long as you get a consistent and thorough mix of the epoxy, this method should work great (and the fact that you have means it's something I'll probably try in the future at some point). One piece of advice to help with the draw-up issues is to use a thinner epoxy - I've never tried to inject something as thick as BSI - I usually stick to a thin laminating epoxy like West Systems or similar.

 

[Hobie1dog]

I'm still amazed that nobody in the rocketry world seems to know about epoxy guns and the commercial epoxies that are used in them. This eliminates mixing it up in a cup, trying to suck it up in a small syringe that doesn't hold much epoxy, and then running out on a long fillet. Commercial epoxies ensure perfect mixing, use only what you need, then throw away the used tip, put the cap back on the epoxy and you have zero waste. Guns are about $15.00 on EBay. Boxes of short or long tips are available for them.

3M, and Global Adhesives make quick or long setting formulations.

 

[H_Rocket]

I use these extensively.

• The DP105 is fantastic for internal fillets.
  
• The DP8005 is the second best thing in the world for adhering to Polypropylene nose cones. DP8010 is the absolute best.

Just beware, the epoxy is breathtakingly expensive.

I have not seen them in a while, however you can find empty cartridges that you can custom load. I was doing it with hobby epoxy with pretty good luck.

 

[Splinter]

I mix the epoxy on a flat surface and then fill the syringe from the plunger end. If I do it right I have a full syringe with zero waste/mess. If I do it wrong I clean up the syringe with a paper towel after loading....

Can the syringe be cleaned and used again and again or are they a throw-away?

 

[Steve Shannon]

View attachment 388471 I'm still amazed that nobody in the rocketry world seems to know about epoxy guns and the commercial epoxies that are used in them. This eliminates mixing it up in a cup, trying to suck it up in a small syringe that doesn't hold much epoxy, and then running out on a long fillet. Commercial epoxies ensure perfect mixing, use only what you need, then throw away the used tip, put the cap back on the epoxy and you have zero waste. Guns are about $15.00 on EBay. Boxes of short or long tips are available for them.

3M, and Global Adhesives make quick or long setting formulations.

Your premise that nobody in the rocketry world knows about them is incorrect.

 

[Hobie1dog]

Your premise that nobody in the rocketry world knows about them is incorrect.

Wouldn't be the first or last time I have been wrong, but in the 10 years I have been on here,I have never viewed a build thread on here or watched one on YouTube that has shown one in use. I'd love to see a picture of someone using one though.

 

[tfish]

There are a few of us that have/use the "professional Hysol" epoxies. I know of two of us that bought the guns and mixing tips..but don't use them. For me, the tips were a waste off money and epoxy. I like being able to mix it as long as I wanted to and dispensing right out of the tubes.

I really like the "professional epoxies" but they are very expensive. I got lucky awhile back and picked up 24 quarts of Loctite EA 9396 Aero. IIRC I paid about $8 a qt for it.

Tony

 

[H_Rocket]

Wouldn't be the first or last time I have been wrong, but in the 10 years I have been on here,I have never viewed a build thread on here or watched one on YouTube that has shown one in use. I'd love to see a picture of someone using one though.

I just don't do the whole build thread thingy. I would show how I prep a nosecone using DP8005/8010 except I doubt anyone besides me would use a structural acrylic adhesive that costs $45 for 1.7oz.

 

[Ez2cDave]

I would show how I prep a nosecone using DP8005/8010 except I doubt anyone besides me would use a structural acrylic adhesive that costs $45 for 1.7oz.

Got that right . . . It ain't happening !

Dave F.

 

[Hobie1dog]

I guess I'll have to disclose that I get my epoxy for free.

 

[David Schwantz]

View attachment 388471 I'm still amazed that nobody in the rocketry world seems to know about epoxy guns and the commercial epoxies that are used in them. This eliminates mixing it up in a cup, trying to suck it up in a small syringe that doesn't hold much epoxy, and then running out on a long fillet. Commercial epoxies ensure perfect mixing, use only what you need, then throw away the used tip, put the cap back on the epoxy and you have zero waste. Guns are about $15.00 on EBay. Boxes of short or long tips are available for them.

3M, and Global Adhesives make quick or long setting formulations.

Actually there are many post about this. I for 1 use Hysol 9462 A LOT. It comes in a tube as you have pictured and uses the gun. But you should not use the short tubes as they do not provide enough length to mix the epoxy properly. I have had glue that did not harden due to this. Also the longer tubes, there is a lot of waste left over in them, but, if you put them in the fridge you can use the epoxy again after it warms up, therefore, no waste.

 

[David Schwantz]

Can the syringe be cleaned and used again and again or are they a throw-away?

I also use a syringe for many things. If you let the epoxy harden in the syringe, then squeeze it with a pair of pliers, that will crack the epoxy loose from the inside of the syringe, and don't forget about the tip, then you can pull out the plunger and hard epoxy all in one.

 

[Hobie1dog]

Actually there are many post about this. I for 1 use Hysol 9462 A LOT. It comes in a tube as you have pictured and uses the gun. But you should not use the short tubes as they do not provide enough length to mix the epoxy properly. I have had glue that did not harden due to this. Also the longer tubes, there is a lot of waste left over in them, but, if you put them in the fridge you can use the epoxy again after it warms up, therefore, no waste.

I used these everyday at my last job but never knew that you could put the tubes in the fridge and re-use them. I thought once the two chemicals were mixed, there was no turning back.

My apologies to the OP for hijacking his syringe thread.

 

[prfesser]

I use large (60 mL) syringes to dispense epoxy and curative (I don't mix the epoxy in the syringe). You can dispense as little as 1-2 mL accurately. Rather than drawing liquid into the syringe to fill it---which takes a long time---I remove the plunger, and with the orange plug snapped onto the end, simply pour epoxy into the syringe. Hold the plug in place, insert the plunger just a little, invert syringe, then remove the plug and push the plunger farther in.

Instead of a solid rubber piston, these syringes use an o-ring. Much less swelling of the rubber with extended contact with the liquid. I've left epoxy in the syringe for over a year with no ill effects.

I have some extras for sale, if you're interested contact me privately.

 

[H_Rocket]

Actually there are many post about this. I for 1 use Hysol 9462 A LOT. It comes in a tube as you have pictured and uses the gun. But you should not use the short tubes as they do not provide enough length to mix the epoxy properly. I have had glue that did not harden due to this. Also the longer tubes, there is a lot of waste left over in them, but, if you put them in the fridge you can use the epoxy again after it warms up, therefore, no waste.

I can't find it right now for a picture, however I took the end of a spent cartridge, cut the place where the mixing tube attached and built an adapter to an air hose. Once I am done I connect the air hose and force the last of the epoxy out. I use about 10PSI to do so. I did try cleaning the mixing tubes for re-use, but that was more effort than the $1.50 they cost.

 

[David Schwantz]

The tube may only cost 1.50 but there is 10 bucks worth of epoxy left in the tube !

 

[H_Rocket]

The tube may only cost 1.50 but there is 10 bucks worth of epoxy left in the tube !

No, I was trying to clean out the tube for re-use after I blew the epoxy out. That was more trouble than it was worth.

 

[H_Rocket]

Ok, here is my "build thread" using gun style adhesives. This is how I build out a basic HPR nosecone

First, the adhesive. This stuff is 3M Scotch-Weld DP8010 Structural Acrylic. It is designed for assemblies using low energy plastics. Slippery things like polyolefin and polypropylene without any specific surface prep. It is also impact resistant. Don side is that it's $45 for 1.5Oz


Cut the end off the nosecone


Build the bulkhead to your spec.


lay a bead of adhesive on the step at the base of the visible part of the NC.

Slip the bulkhead in sideways and turn to sit on the lip. Apply another bead of adhesive and smear around with your fingertip/

Hang to cure (~24 hours)