CNC Build: The Bed and Breakfast at 4 years and 40,000 miles

[KCStudly]

Kerosene makes an excellent cutting lube for aluminum.

Maybe radius the corners at the bottom of the buck slightly. Also, if the piece begins to work harden and shows signs of cracking, you can anneal it again by heating gently with a torch. It's best to use oxy/acetylene so that you can apply a coating of soot as a guide coat, then cook it off. Another option is to use a temperature indicating heat crayon, but off the top of my head I forget what temperature is needed. Also, if you leave a little tab on one edge of the corner, you could fold this around the corner in a second operation and make it easier to rivet and seal the corner up (or just scab a bent 'L' on after the fact, riveting thru both verticals).

Another option (though not something that I am very familiar with) would be a heat formed plastic slumped over your mold. This would actually be a great way to make all of your troughs, and depending on the plastic, could be glued or heat sealed together. Quick search found this instructable.

[pchast]

I've been wondering about using epoxy and glass on a form.
Would it adhere well enough in the molding to the Aluminum
gutters?

[KCStudly]

That's another good option, and you could make a plug for the top gutter, and a symmetrical one for both sides, then bond the three pieces together. Skip the aluminum altogether.

Or just make it all out of wood and coat the ba-jesus out of it.

[RandyG]

I'll throw an option in there, but with typing it something will be lost in translation so I'll make a model and send a few pics later tonight.

[capnTelescope]

Wow! This thread went to a new page, and I didn't even notice. OTOH, Y'all did really good while unsupervised. These are all good ideas. I'm having an embarrassment of riches. Let me take some of these points one at a time.

Kerosene makes an excellent cutting lube for aluminum.

That jogs my memory. I have heard that before and forgot. This saves me going down a whole new R&D path. Thanks, KC.

Maybe radius the corners at the bottom of the buck slightly.

Did that before I even picked up the hammer. Check. I think a major reason for the split is that a poor job of snipping the radius left a stress riser.

... Quick search found this instructable.

This takes me back to college days. We Industrial Engineering students made a field trip to the Igloo plant outside Houston, where they vacuformed many of their big cooler parts. Big sheets of plastic on a merry-go-round over gas burners, then to the vacuum station. They were turning out shells and liners several times a minute. Way cool. I could use my buck for a pattern. This is doable.

I've been wondering about using epoxy and glass on a form.

Me too.

Would it adhere well enough in the molding to the Aluminum gutters?

I ass-ume so. Anyone know the answer to this?

That's another good option, and you could make a plug for the top gutter, and a symmetrical one for both sides, then bond the three pieces together.

I'm not sure I get it. Could you draw me a picture? Pretty please?

Or just make it all out of wood and coat the ba-jesus out of it.

I'm shying away from wood due to my experience with the crappy 1/4 ply I cut out for the inner gutter walls. Both pieces have broken. One as I picked it up off the router table(void), the other where I drove a screw through it. This is why I'm so enamored of Al. The weatherstrip needs/wants a dependable, consistent thickness edge to clip onto. 1/4 Marine ply is $50 a sheet. A new length of weather strip for 1/16 edge is $20 cheaper.

I'll make a model and send a few pics later tonight.

I can't wait to see what you have up your sleeve!

Thanks to all for the great ideas. Standing O.
Let's keep going.

[KCStudly]

Shown with the side gutters separated a bit for perspective. Could also be molded as one big piece. Note the squared outer corners, and the tapering from the middle getting wider toward the outsides across the top.

[capnTelescope]

Thanks, KC. Got it. I think it looks pretty spiffy.

[GuyllFyre]

The corners you're trying to make remind me a lot of wiremold aka wire raceway corners.

http://www.homedepot.com/p/Legrand-Wire ... 5yc1vZbmc0

[capnTelescope]

The corners you're trying to make remind me a lot of wiremold aka wire raceway corners.

I wonder if they have it in my size?

Shown with the side gutters separated a bit for perspective. Could also be molded as one big piece. Note the squared outer corners, and the tapering from the middle getting wider toward the outsides across the top.

So if I were to attempt this, and made a male plug of the trough like so:

where the red "X" shape hatched represents something I have to make...

Would I stuff it full of chopped glass and make a casting like the top right, or would I lay up epoxy & glass cloth like bottom right, or something entirely different that you can point me to? No aluminum?

Anyone that knows about glass-epoxy is welcome to opine.

I'm drinking wine tonight.

[KCStudly]

Wine? What does it say on the label?

That might work with thickened epoxy, but I would be concerned about air bubbles and voids down in the tips of the walls.

I think it depends on if you want one good side or both. I'm no expert, but I don't think you would get a very good result stuffing chop glass (or more likely thickened epoxy) down into little crevices like that. Putting weave over the outside of a male form would probably be easiest, and would give a nice inside surface. IMO, the next difficult would be, laying weave or tape down inside of a female mold; probably a little more tricky getting it to pop out, even with some lead and mold release.

A two piece mold is the most complex, but will make both sides smooth. I'm assuming that the way to do it would be to lay the glass and resin into the female mold of the back side, then press the male plug down into the side where the water will go, allowing excess resin to squeeze out at the tips of the channel (to be sanded flush later). Of course the molds would have to be very accurate, and they would need to have alignment tabs or flanges on them so that they can be fastened or clamped together accurately. I bet it is also critical to match the layup schedule (number of plys and amount of resin) to the space in the mold (not too much and not to little) with a very even application. My buddy Karl has experience with this; I will ask him Monday when I see him next.

Here's a trick. If you make your mold out of foam with a mold release on it, you can use gasoline to melt the foam out if need be, so long as the epoxy resin is good and cured.

Another big picture way of looking at this is, regardless of what you make the gutter out of, you will still need to install it into your wooden structure in such a way that the wood is sealed and protected. So why not lay the glass and epoxy up right in position in the gutter made from wood. That way it is done and glued in already. The more you mess with materials making a mold, the less expensive that extra piece of plywood starts to look.

Not being a nay sayer, just spewing thoughts for your consideration. Too many options, it seems. Have another glass.

[capnTelescope]

The bottle sez "Apothic (HIC) Dark.

[Heifer Boy]

Check out Jeff's molds for his Trail Top design http://www.expeditionportal.com/forum/t ... ost1502388

It would be easy to make up your gutters using his methods. There are more details of his work and how he does his fibreglassing in his other threads too but the Trail Top design seems to be the closest to your needs. You could get the nice shape and gutter transitions you are after using his methods

[capnTelescope]

Thanks, HeiferBoy. You da man. I'm on my way to check it out now.

[RandyG]

My idea isn't going to work for ya, after I tried it, I realized you want to have the radias on the inside lip of the gutter. My idea put the curve on the outside.

[capnTelescope]

My idea isn't going to work for ya, after I tried it, I realized you want to have the radias on the inside lip of the gutter. My idea put the curve on the outside.

I was so looking forward to it, too. It's almost like Christmas was cancelled.

Field Trip to Expedition Portal

Check out Jeff's molds for his Trail Top design http://www.expeditionportal.com/forum/t ... ost1502388

So I did, and Jeff is impressive. He's a self-taught hobbyist designer and fiberglass mold-maker who has a deep interest in off-road TnTTT designs. He has some excellent concept ideas, and you will want some of his stuff. Hope some company picks up his product ideas, because he doesn't want to start his own company and sell himself into slavery. I can identify with that.

After seeing what Jeff is doing, my conclusion is that I want to save this for the "Next Build." I will probably learn to make the molded gutter first, then start the "Next build." Plus, molded fiberglass has many applications in the hatch area, including the hatch itself.

In the highly unlikely (IMHO) event that Hatch 3.x is unworkable, I want to get in there and find out sooner rather than later after learning a whole new skill.

Thanks for the tip, Heifer Boy.