Great Internal Fillets
- Thread starter accooper
- Start date
Help Support The Rocketry Forum:
Charles_McG
Ciderwright
Your signature just inspired a new movement:
Prokaryotes Against Sexism!
Prokaryotes Against Sexism!
I use a large 50cc syringe, you could use much smaller, I cut a length of silicone tube (fish tank air tubing) based on the furthest distance and insert over the tip, then tape over it so it stays on, otherwise you will create a mess if the tube slips off...don't ask me how I know this. The end of the tube where the epoxy comes out of I cut on a 45 degree angle. I then tape the tube to a stick with the end of the tube just haning past the end of the stick then I use a different colour masking tape to mark where the fillets would be right on the tube and stick. Like putting a piece of tape on a drill bit to mark the depth, poor mans depth gauge. This way I only plunge when I don't see the tape. I just spent the better part of two weeks doing internal fillets on my 3" Darkstar too bad I could of taken some pics.
Very important when you feed the epoxy into the syringe I use a small Popsicle stick then insert the plunger to the point where it does not push anything down the tube, then I let it sit upside down for 15 min to drain back into the syringe, then I push forward. Otherwise you will be pushing a bunch of air through. I use Aeropoxy ES epoxy so my pot life is long enough to do this.
If you want I can mock up an example and post a pic?
Err meant 30cc syringe, which are pretty big, 50cc would be ginormous. Here are some pics to help visualize my explanation above. Of course this method only works if you left the bottom CR out, which I always install last along with the retainer.
View attachment 188625
I cut the tube so it has just enough length to get the entire fillet but minimize the excess which just makes it harder to push.
View attachment 188626
Sorry about the focus, but you ge tthe idea of cutting on a 45. I ensure the shorter part or inside part of the 45 is facing the fillet, this helps to keep the epoxy on the correct surface in tight places
View attachment 188627
Acquarium tubing fits perfect over this type of syringe end, plus I wrap in in tape once it is inserted
View attachment 188628
These are the syringes I use, I buy them by the box as they are very cheap from medical suppliers vs hobby suppliers.
View attachment 188625
I cut the tube so it has just enough length to get the entire fillet but minimize the excess which just makes it harder to push.
View attachment 188626
Sorry about the focus, but you ge tthe idea of cutting on a 45. I ensure the shorter part or inside part of the 45 is facing the fillet, this helps to keep the epoxy on the correct surface in tight places
View attachment 188627
Acquarium tubing fits perfect over this type of syringe end, plus I wrap in in tape once it is inserted
View attachment 188628
These are the syringes I use, I buy them by the box as they are very cheap from medical suppliers vs hobby suppliers.
- Joined
- Mar 27, 2013
- Messages
- 22,535
- Reaction score
- 14,942
I just use coffee stir sticks to drip the epoxy in, then allow gravity to pull it down the length of the joint. Once the epoxy has reached the CR, I place the rocket horizontally in a place where it can cure.
accooper
Well-Known Member
- Joined
- Oct 12, 2009
- Messages
- 920
- Reaction score
- 2
- Joined
- Dec 29, 2011
- Messages
- 2,980
- Reaction score
- 920
I do it an easy way... Do not attach the bottom bulkhead but only slip it on for centering purposes when gluing in the fin can assembly. Remove the bulkhead, and apply fillets from the rear. THEN glue in the bulkhead.
Gerald
Gerald
EXACTLY, the way I do it too. Can be difficult when space is limited but workable. I cut the tip of the tube at an angle, run it down the fin/motor tube interface and slowly pull it out while injecting. Of course this is before placing the last aft centering ring in place and one must keep the after portion from getting gobbed up with epoxy on the motor tube by wiping it clean. I cut off the Luer lock threads and use zip ties to hold the tubing on the syringe. I have the rocket tube lying horizontally on a table. Kurt
