Abrupt Rush

Hi everyone,
All the supplies from Giant Leap, including the kevlar sock, arrived last week and my modified kit from PML, a Sudden Rush, arrived yesterday. Between last night and so far this afternoon, I have assembled the extended QS2000 motor mounts adapters and the mother tube. I also have laminated (1 layer of 5 oz. 'glass on each side), trimmed, and sanded all the CR's. My next step is heading out to the garage...brrr...its 16 degrees outside...to sand the tubes before I apply the sock to them. I have reread John Coker's site on the material but I am still nervous about using this stuff. If anyone has any suggestions, please chime in.

I'll let you all know how it turns out ASAP.

David

PS- So far the project is ahead of schedule...hmmm...that's odd...something has got to go wrong...things are too good...

Well, something did go kinda wrong...

I had not anticipated just how much epoxy I was going to need for the kevlar. After doing one tube, I had gone through half of my suplly of finishing resin

I didn't realize just how much I was going to need and ended up mixing about 5-6 batches until I got the tube fully soaked. In fact, the epoxy started curing on me as I was doing my final squeeging.

Luckily, I managed to finish just as it was curing and it turned out alright. After a trip to the hobby store to pick up plenty more epoxy, I laminated the following two tubes. Overall, on three tubes, I used 16 oz. of epoxy.

The tubes are completely dry this morning and are rock hard, also rock heavy in my opinion (compared to glass). There don't appear to be any wrinkles or spots that didn't turn out. One downside though. I forgot to check on the tubes often enough while they were curing and so I ended up trimming the ends off when they were dry. A little tougher but it all turned out okay.

I guess I should sand the ends a little to remove the burrs and then give the tubes a quick sanding with some 100 just to take off the rough little fuzzies, correct? Then apply the 'glass?

David

Okay, the ends have finally been sanded straight. I might add that the fin slots have been re-cut. Kevlar really is some tough stuff!

A grinding bit I was using on the dremel exploded just as I started using it. I ended up using a general purpose cutting drill bit. It worked quite well but there was a lot of dust that was so fine it was more like smoke. The shrill sound of the dremel was also close to deafening...worse than the table saw. Next time wear ear plugs.

Anyway, I am not sure how much to sand the kevlar before I apply the 'glass. Should I sand it relatively smooth or just take off the burrs or somewhere in between? Help me!

Thanks all.

David

I'd just sand it to take off the burrs, Kevlar can get quite nasty when you try and sand it. It gets really fuzzy and you can't work with it at all. If possible, I wouldn't sand anything-- just put a layer of glass over it, and follow with copious amounts of UV Smooth Prime (I LOVE that stuff) and SuperFil, and sanding then.

HTH.

Okay, the glass is on. I have sanded it a little with some 150 just to take out the buldge a bit and find my low/high spots. Now, I would like to prime it. However, I don't want to spend $40 on primer (smooth prime). I also want to do this today or this week. So, what could I get from homedepot or a hardware store or such? The only KILZ I saw there was acrylic and I shouldn't use acrylic if I will be using spray paint over it, right? or not?

Would a couple coats of spray primer do the job or would I need like 4-5 coats?

Ahhhh, who would have thought my biggest problem during glassing would be choosing my primer??????

David

Hmmm... well, I highly recommend Smooth Prime, that's about all I can say. 1 qt @ $40 will last you many years... I bought mine back in 2000 and it's still got 1/2 left, and I've built 1x 6" model, 4x 4" models, 1x 3" model, 1x 54mm model, and 2x 38mm models. You only need one or two coats to get a glass smooth finish, so it goes rather slowly.

I would recommend against using spray primers just because they have very little solids to fill in the weave, and they are extremely difficult to sand.

I've never had any experience with Kilz... try asking Jerry O'Sullivan. He used it on his N3 project. https://www.vahpr.com.

A last option would be to use SuperFil and heat it with a hairdryer, then squeegee it on like Bondo. Then you can prime as you would any other rocket.

HTH.

Hi All,
Well, project abrupt rush is finished...now titled Delaminate THIS. It has flown on an I284 and next up is a J275 with smoke canister for tracking. I know how everyone loves pictures so here is two, including a close up of my sponsor: EV HILL. They are providing the smoke canisters at a discounted price. The finished weight of this rocket is 7.5 lbs. It should hit 9k on a K550...hopefully in September of this year.

David