I love the green, lee. That wing looks sweet.

Sam, I appreciate the offer. I may take you up on it, but I do want to try a couple hollow wings still.

Brandon,

If the wing design is something familiar, then it isn't too bad. But I am slow at cutting cores. Really slow, just don't get the shop time I used to. Definitely try a couple hollow wings, just know that doing so without Rohacell isn't really worth your time, and you need to go through Clarisonic in Thailand to get the 1mm IGF31. Evonik will only do HF in 1mm sheets stateside, and I believe their minimum order is $2500 without incurring fees. CST which is pretty close to you do stock IGF51 in 1mm sheets for OK prices (it's like a 50% markup, but they have it), however you are looking at a 5-10g weight penalty just in the foam.

Sam, this is an all new design with unpublished airfoils. You would have to do all the too loathing and make all new vacuum hold downs. It's truthfully probably not worth the effor for 5-10 wings.

Originally Posted by bwill6

Sam, this is an all new design with unpublished airfoils. You would have to do all the too loathing and make all new vacuum hold downs. It's truthfully probably not worth the effor for 5-10 wings.

I'm not so sure about that. If you drew up the vacuum hold down tooling and all I had to do was toolpathing, it isn't bad at all. A few hours of work at most. Drawing up the hold down tooling in CAD is the time consuming thing. To me it is entirely worth it, since you may build more wings than that, and you can use easily sourced and inexpensive materials to build test wings. Just my 2 cents having been there done that.

I do understand that you may not have female molds drawn up, in which case it is a fair amount of work.

Having one person draw things up for another to machine adds an exponential level of complexity... especially when dealing with vacuum hold downs etc. It can be done but it takes a lot of coordination. Before I had a CNC machine I was working with a CNC service and it was frustrating.

Originally Posted by bwill6

too loathing

Nice one, autocorrect.

Glad you guys were able to figure out what I meant.

Originally Posted by tom43004

Having one person draw things up for another to machine adds an exponential level of complexity... especially when dealing with vacuum hold downs etc. It can be done but it takes a lot of coordination. Before I had a CNC machine I was working with a CNC service and it was frustrating.

There is a huge difference between working with someone that knows exactly what the end goal is and has the capability to do it themselves and someone that has the machine and a vague idea of the end product. It's why I offered, plus I'm far far cheaper than a real shop with high overhead.

Most CNC shops I am familiar with (and that list is pretty long) don't do vacuum hold down setups nor do they generally do custom jigs to machine parts. When they are forced to due to the geometry, you tend to pay out the wazoo for it, or more than likely they will no-quote you and you are left searching for a more capable shop, which may not exist, at which point you redesign the part...

That's why being able to cast your own mold and skip a lot of machining can be so great to begin with!

I pulled the first fuze from the DIY mold yesterday -- it worked GREAT!

The model's a Shrike, not too big -- 30" tip to tail, including the CF boom -- so it made a nice first try. After wax and PVA, I used some 1.4 oz veil, then two layers of 3.25 oz FG, and some carbon fiber cloth around the canopy. The boom is 10" of 8 mm. roll-wrapped CF tube...super stiff and strong.

I tinted the epoxy yellow, it's not painted in the mold.

Weight of the fuze is 3.03 oz, and feels plenty strong.

This has got the finest seamline of the three mold projects I've made. The squeezed-out splooge was like tissue.

The screwdriver slots worked great for cracking the mold open -- none of the issues of having to find a small gap to open the mold, work wedges in, etc, etc.

A couple issues of some chipping along the seam edge of the mold -- there must have been some small gaps between the gel-coat and the poured corian. I'll have to get in and touch it up with a small brush and splooge.

Lesson learned -- you can get away with the plug not being exactly halfway in the parting board, EXCEPT for a small round surface like a boom. I had a hell of a time getting the boom released from the "deep end" of the mold. I touched the mold up with some 600 grit sandpaper, so next time it shouldn't be as much of an issue.

-= Dave

Looks great.
Nice idea with the handles. Is that to move them around with?

Originally Posted by TLHover

Nice idea with the handles. Is that to move them around with?

Exactly -- and it works like a charm.

-= Dave

Nice work Dave .

It has probably already been asked before but can people share their sources of the ATH material needed for this process? Particularly in Europe / the UK as that is where I am.

I assume Resin wise, I can use most any ultra slow curing Epoxy resin?

Another idea I had, once you reach the highest level of the plug, there is no real reason why you could not introduce Poraver into the mix. This would significantly reduce the weight of the mould. May have to let the pure ATH layer go of slightly but I don't think this is needed as the lighter Poraver glass balls will tend to rise to the surface anyway.

Originally Posted by jjmouris

It has probably already been asked before but can people share their sources of the ATH material needed for this process? Particularly in Europe / the UK as that is where I am.

I assume Resin wise, I can use most any ultra slow curing Epoxy resin?

Another idea I had, once you reach the highest level of the plug, there is no real reason why you could not introduce Poraver into the mix. This would significantly reduce the weight of the mould. May have to let the pure ATH layer go of slightly but I don't think this is needed as the lighter Poraver glass balls will tend to rise to the surface anyway.

In the UK there are a few

Alchemie
Polyfibre
easy-composites


Rick

A word to the wise: After pulling your mold off the plug, the first thing you should do is grind the sharp edges off. Those edges that form against the dam all around the circumference of the mold are like razors. Ask me how I know...

From page 17 of the thread, December:

Originally Posted by Zenmaniac

Looks good, Lee -- a bit of a molded Weasel, eh? I LIKE it! I made the fuse for my Orca plug out of MDF, carved, sanded, saturated with epoxy and sanded again, and it worked well. Keep posting your progress.

Yep, wax and PVA. Nice and reliable.

A cautionary note: When curing, it appears that the material shrinks a very small bit. When you open the frame, you'll find that there's a VERY sharp edge where the corian was up on the frame. My hands look like I've been juggling 5 lb razor blades -- so hit the edge with some sandpaper before you handle it much.

-= Dave

Originally Posted by bwill6

A word to the wise: After pulling your mold off the plug, the first thing you should do is grind the sharp edges off. Those edges that form against the dam all around the circumference of the mold are like razors. Ask me how I know...

The warning is a waste of time, bwill -- it's obvious no one pays attention to these cautions.

-= Dave