SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Oct 30, 2012, 02:42 AM
PB of 733kph
ALEX HEWSON's Avatar
Christchurch, New Zealand
Joined Jul 2005
5,659 Posts
Well starting the long process of repetitive waxing for a new mold.

Wing mold needs re-doing. Should have Durateched and then sanded the wing plug beforehand as mold has a really bad cloth imprint in it. May be able to use it as a test/experimental mold.

Hopefully will pull a fuse out sometime this week, most likely next week. Will start it this week
ALEX HEWSON is offline Find More Posts by ALEX HEWSON
RCG Plus Member
Reply With Quote
Sign up now
to remove ads between posts
Old Oct 30, 2012, 03:00 AM
Registered User
New Zealand, Auckland
Joined Apr 2012
37 Posts
Fuse mold looks great, bet it will be great to take the first fuse out.
ReaperRob is offline Find More Posts by ReaperRob
Reply With Quote
Old Oct 30, 2012, 04:58 AM
PB of 733kph
ALEX HEWSON's Avatar
Christchurch, New Zealand
Joined Jul 2005
5,659 Posts
I'm getting super excited! Really looking forward to popping out the first one!

What are people using to inflate a bladder inside fuse? How do you regulate to around 10psi? Do I need to buy some nice pump to regulate it at that? Can I use something I already have?
ALEX HEWSON is offline Find More Posts by ALEX HEWSON
RCG Plus Member
Reply With Quote
Old Oct 30, 2012, 06:00 PM
Registered User
New Zealand, Auckland
Joined Apr 2012
37 Posts
I haven't done it but I would have thought if you fitted the valve off a bike inner tube and used a car tire/bike pump with a dial you would be good enough.
ReaperRob is offline Find More Posts by ReaperRob
Reply With Quote
Old Oct 30, 2012, 06:01 PM
Registered User
New Zealand, Auckland
Joined Apr 2012
37 Posts
Double post
ReaperRob is offline Find More Posts by ReaperRob
Last edited by ReaperRob; Oct 30, 2012 at 06:02 PM. Reason: Double post
Reply With Quote
Old Oct 30, 2012, 10:33 PM
R.I.P
josh18's Avatar
Australia, QLD, Toowoomba
Joined Jan 2010
3,510 Posts
Looking great Alex, bad luck on the wing mould- Will the print polish out?
I use my compressor with the regulator set to zero, connect everything up and then slowly turn it up to ten psi. If you can support your bladder all round you can go heaps higher. Anyway I reckon one of those cheap comressors would do the job- better than a pump because the bladders always seem to leak down a bit and a regulator will keep up the pressure, even if the bladder pops you can keep ten psi, it just cycles pretty often.
Cant wait to see the first one!
josh18 is online now Find More Posts by josh18
Reply With Quote
Old Oct 30, 2012, 11:53 PM
PB of 733kph
ALEX HEWSON's Avatar
Christchurch, New Zealand
Joined Jul 2005
5,659 Posts
I need a regulator. My compressor doesn't regulate, just has a relief valve
ALEX HEWSON is offline Find More Posts by ALEX HEWSON
RCG Plus Member
Reply With Quote
Old Oct 30, 2012, 11:54 PM
PB of 733kph
ALEX HEWSON's Avatar
Christchurch, New Zealand
Joined Jul 2005
5,659 Posts
Put the 8th wax on this morning and then painted it up. Need to sort the bladder before laying it up. Will hunt around work for an old regulator
ALEX HEWSON is offline Find More Posts by ALEX HEWSON
RCG Plus Member
Reply With Quote
Old Oct 31, 2012, 04:14 PM
R.I.P
josh18's Avatar
Australia, QLD, Toowoomba
Joined Jan 2010
3,510 Posts
Nice one, reg will be well worth it.
josh18 is online now Find More Posts by josh18
Reply With Quote
Old Nov 01, 2012, 04:10 AM
Where is the inspiration
wdeighton's Avatar
Moira
Joined Feb 2006
825 Posts
I have a accumulator (Old Fire extinguisher) and a pressure switch on mine.
I like the way it works.
Vacuum regs are too expensive

Or are you talking compressed pressure
wdeighton is offline Find More Posts by wdeighton
Reply With Quote
Old Nov 01, 2012, 04:47 AM
R.I.P
josh18's Avatar
Australia, QLD, Toowoomba
Joined Jan 2010
3,510 Posts
Compressor, for the bladder
josh18 is online now Find More Posts by josh18
Reply With Quote
Old Nov 01, 2012, 05:12 AM
PB of 733kph
ALEX HEWSON's Avatar
Christchurch, New Zealand
Joined Jul 2005
5,659 Posts
I have a regulator now. No problems. Will set it up next week when have time
ALEX HEWSON is offline Find More Posts by ALEX HEWSON
RCG Plus Member
Reply With Quote
Old Nov 01, 2012, 05:19 AM
Dave Pope Manawatu NZ
pope's Avatar
Palmerston North NZ
Joined Dec 2006
1,260 Posts
Have not tried the bladder method yet, it will be good to see it comes out out.
pope is offline Find More Posts by pope
Reply With Quote
Old Nov 01, 2012, 05:36 PM
R.I.P
josh18's Avatar
Australia, QLD, Toowoomba
Joined Jan 2010
3,510 Posts
Alex, make sure you pump up your bladder with the mould flanges ever so slightly apart, then clamp them up tight after 20 minutes or so. I skipped this step last time and got voids in the seam. I can only think trapped air could have caused this. Next time Ill run a bead of splooge right round the seam before closing too.
Good luck mate
josh18 is online now Find More Posts by josh18
Reply With Quote
Old Nov 06, 2012, 08:06 PM
AvB
Wind, hill, ... I'm keen ...
AvB's Avatar
Australia, QLD, Woody Point
Joined Nov 2006
4,642 Posts
I've done a lot of bladder infusions. If your mould is an absolutely perfect flush closure then you can get trapped air pockets. There are some good pics of this in a Zone V2 DLG thread - fuse mould got air pockets. But you really have to have an absolutely schmicko gloss perfect clean mould flange for that to happen. Mine are not that good. Any paint overspray, a few carbon fibres or crap on the flange will allow a minute gap which is all you need to get the air out. So unless your moulds are "Wyowindworks" quality, don't worry. If they are, you can slip a few small strips of very thin plastic, or thread in between and inflate at say 5psi for about 10 mins then remove the threads and pump up higher.

More frequent problem with basic moulds like mine is the bag popping out at the mould join. You absolutely must make sure that you have cloth overlapping at the joins or the bag can have an aneurysm and blow/pop into the gap. Even one layer of fine cloth is enough to prevent it. I don't think splooge prevents it. Common place to pop is the nose tip because it's hard to get the overlap right there. So a good tip is: cut a circle of floppy cloth (eg satin) and wrap it over the tip of the bladder, like a small parachute, so that as you inflate it, it pushes the cloth into the nose tip and seals off any gaps.

It's definitely a bit of an art, but once you work out the basics it's easy and you don't any fancy stuff. I made an open nose cone mould recently, and the first one I made was too tight on the fuz ... I'd designed it all originally from a cone made by inflation, and when I made it using the open mould and rolled seam it was thicker and rougher compared to the cones made with a nice flat tight seam from my old inflation mould. So I just worked out a way to screw a flat plate onto the end of the new open mould and converted it into an inflation mould! Lay it up and close the mould open-ended fashion, and then put the bladder in and screw the plate on the open end (bladder stylet pokes thru hole drilled in the ply plate). I used a piece of that soft closed-cell foam (like roll camping mattresses are made of) as a squishy seal between the mould and the plate, and I pumped it to 25psi and it's the best nose cone I've made yet!

Another big tip is make sure your bladder is slightly oversize. I tended to whittle my template down and it took me a few blown bladders to realize I'd started making them too small.

You can make lighter thinner layups with the bladder, and you can use the pressure to push the cloth into sharp corners with very little use of splooge ... particularly if the cloth sections overlap just either side of the corner and can slide over each other as they press tightly into the corner. Don't lay a big section of cloth over a corner because the pressure won't be enough to press it right in there. You need to either splooge the corner or cut the cloths either side of the corner to let them press in.

Oh, and another thing ... I've had a few where I've got a leak and let it keep going. As Josh said, for most leaks, usually the compressor can keep running enough to keep enough pressure in there. But the results aren't good. Each of those has had areas of really porous cloth and it seems that the air tracks around the place, taking resin with it. If it's an important one, and it leaks early, it may be best to dismantle the whole thing and put another bladder in (very messy). I like to heat the thing up fast once the bladder is in so that it gels sooner and I can stop worrying about leaks!
AvB is offline Find More Posts by AvB
Last edited by AvB; Nov 06, 2012 at 08:30 PM.
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion 10 in1 servo tester (professional servo tester) flydreamrc Radios 21 Jul 17, 2012 02:50 AM
Alert RT Models Beaver Pre-release build St. Martin Scale Kit/Scratch Built 86 Jun 29, 2008 05:01 PM
Build Log kin'Brilliant Build Pics (PU-RT) wdeighton Slope 30 Mar 18, 2008 03:38 AM
Discussion RT Models MIG-15 Build AeroDude Electric Ducted Fan Jet Talk 34 Mar 02, 2008 05:49 PM
Discussion RT Mig 15 Build nut Electric Ducted Fan Jet Talk 8 Jul 30, 2007 01:17 PM