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Gavino200's Layout phase II - Modeling


gavino200

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On 6/1/2018 at 8:31 PM, cteno4 said:

 

yeah like the flanges at the end of pipes. it could be a rectangle with the tunnel profile cut out so it slipped over the end of the tunnel and then just epoxy it in place to the tunnel. recess the tunnel a tiny bit in the flange (by cutting or sanding off extra) so that its only the flange plates touching each other. just make sure you glue the flange plates on the end of the tunnel with them all set up in the proper curve so the plates are flat against each other and in the proper orientation. put a piece of wax paper between the flange plates so no epoxy leaks in and glues the flange plates together (test your epoxy, but most dont stick to wax paper - an odd product that is harder to find these days!).

 

Yes, I think I'll do it this way. Though I'll probably use multiple layers of card, laminated together, rather than masonite, as I can't yet cut masonite. I think multiple readjustments would be necessary to continued trips to the cabinet makers would be annoying. First I'll make the basic card exoskeleton with the ends free. Then I'll add the flanges to it. 

 

 

 

On 6/1/2018 at 8:31 PM, cteno4 said:

then drill a few mating holes thru the mating flanges and little bolts and washers to hold them together. would let you pull it apart if ever needed or work on them separately to do the finish work and then just assemble at the end and do a skim coat of the seams to make them clean and just cut thru with the jewelers saw if you need to separate them later.

 

This too. I'll shop around for some suitable bolts today when I go to Home Depot.

 

On 6/1/2018 at 8:31 PM, cteno4 said:

 

I'll check this out, likely for future projects.

 

On 6/1/2018 at 8:31 PM, cteno4 said:

 

youre gunna hate me, heres another tool to look at. its a power saw but the most benign saw out there! its a power scroll saw. i started on one when i was about 4 years old and never cut myself on it. the worst you will get is a bit of a jagged cut if you were to jam your finger into it. not like a band saw that can zip a finger right off! these are very very handy to do all sorts of curved cuts like this and a handy saw to do modeling on without much danger at all. its sort of like a jig/saber saw on a bench. there are adapters for dremel tools to do this but they are puny and not well powered and about as expensive.

 

https://smile.amazon.com/WEN-3920-Two-Direction-Variable-Flexible/dp/B005UKGL58/ref=sr_1_3?s=power-hand-tools&ie=UTF8&qid=1527899009&sr=1-3&keywords=scroll+saw&dpID=41h8sBoRnDL&preST=_SX300_QL70_&dpSrc=srch

 

 

I'm giving this some serious consideration. But likely something I'll get right now. The airbrush is using up all my learn-space for now.

 

On 6/1/2018 at 8:31 PM, cteno4 said:

 

i would suggest just adding a like 2" strip of foam core (much lighter and easer to cut than the masonite) along the outside and inside bottom edges of each section, sort of a flange along the inside and outside base of the tunnel sections. just put the tunnel on a bit of foamcore and trace the tunnel bottom and then cut out a 2" arc bigger for inside and outside. then you can epoxy these onto the base of the tunnel and the flange ends (make your flanges like 2" wider than the tunnel on each side). again make sure to have wax paper under the glue joint so it does not get epoxied to the work bench! this should give you really good wrack support (ie twisting), light seal the bottom edge of the tunnel well, and give you something to attach any wiring to and such.

 

I'm going to use this basic side-flange idea. But likely I'll use some kind of card structure. I'm going to pick up some dowels also at HD.

 

On 6/1/2018 at 8:31 PM, cteno4 said:

 

 

if it still feels like it all twists too much when moving you could also add a few foam core braces like every 6" on the inside and outside of the tunnels. these could just be like pieces of foam core 1" wide and about 2/3rds the height of the tunnel. then cut out a little semicircle of the tunnel profile on one tall edge so it wraps around the tunnel some (doesnt have to go all the way down to the bottom/tunnel flange joint) and epoxy them in vertically. locking the tunnel side to the base flange in few pieces like this will really help. if still a little twisty then glue another curved piece of foamcore like 1" wide onto the tops of these side braces and also against the tunnel like 2/3rds the way up the side. 

 

 

The entire tunnel will essentially have a complete exoskeleton that keeps it rigid. 

 

I just made my final track adjustments and glued it down. I also repainted the layout base where it will be visible. Tomorrow I hope to measure and mark all the tunnel segments.

 

The other thing I need to do is cut out a lot of identical "light guides". I also need to make some kind of painting jig. Basically I leave about 1mm unpainted and exposed to function as the "tunnel light". Beyond this he sides are painted. A sharp line is need for them to look good. So far I've used modeller's masking tape. But it's difficult to be precise with such a small margin. I'd like to make a block with an indentation for the end of the "light guide". As sort of painting mask. Then I could stick the guide into the mask and lightly paint or airbrush them. 

I'm not sure how I'll do this yet. 

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1 minute ago, gavino200 said:

I'm giving this some serious consideration. But likely something I'll get right now. The airbrush is using up all my learn-space for now.

 

 

The scroll saw you will be going on in 5 minutes! It’s the super easiest power tool to get using. It was my second power tool just after the electric drill when I was about 4! Then to get fancy it’s just practice. Airbrush is much more of an art in using it and a second learning curve on keeping all cleaned and adjusted well! Lots of practice too. I think in the time you take to cut out cardstock and try to laminate and harden you would have a little scroll saw assembled and all the pieces cut! Also will open you up to doing a lot of other stuff as well with it as it’s a tool you just go to and cut and done!

 

2 minutes ago, gavino200 said:

The other thing I need to do is cut out a lot of identical "light guides". I also need to make some kind of painting jig. Basically I leave about 1mm unpainted and exposed to function as the "tunnel light". Beyond this he sides are painted. A sharp line is need for them to look good. So far I've used modeller's masking tape. But it's difficult to be precise with such a small margin. I'd like to make a block with an indentation for the end of the "light guide". As sort of painting mask. Then I could stick the guide into the mask and lightly paint or airbrush them. 

I'm not sure how I'll do this yet. 

 

Mask templates like that work, just have to be very gentle with the airbrush not to not gob up paint on the template. Also need to let paint that may be on the edges of your template harden between pieces. The smaller the template open area the more prone it is to gumming up with the overspray on it. That’s a tough one.

 

Jeff

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22 minutes ago, cteno4 said:

. I think in the time you take to cut out cardstock and try to laminate and harden you would have a little scroll saw assembled and all the pieces cut! Also will open you up to doing a lot of other stuff as well with it as it’s a tool you just go to and cut and done!

 

I agree about the usefulness of the saw. But cutting thick card with a hobby knife is super easy. To "laminate" I just glue one layer to another with CA. It couldn't be easier and it's surprisingly rigid and strong. Three layers are easily as rigid and strong as masonite. You can even make the composite conform to an irregular surface. Kind of like 3D printing. 

 

Quote

 

Mask templates like that work, just have to be very gentle with the airbrush not to not gob up paint on the template. Also need to let paint that may be on the edges of your template harden between pieces. The smaller the template open area the more prone it is to gumming up with the overspray on it. That’s a tough one.

 

Jeff

 

Hmmm, I hadn't considered that at all. Perhaps the tape and patience method is best. I think I'll try it though. I could sand it lightly between uses. Maybe make a few troughs per block. Thanks.

Edited by gavino200
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On 6/1/2018 at 8:31 PM, cteno4 said:

youre gunna hate me, heres another tool to look at. its a power saw but the most benign saw out there! its a power scroll saw. i started on one when i was about 4 years old and never cut myself on it. the worst you will get is a bit of a jagged cut if you were to jam your finger into it. not like a band saw that can zip a finger right off! these are very very handy to do all sorts of curved cuts like this and a handy saw to do modeling on without much danger at all. its sort of like a jig/saber saw on a bench. there are adapters for dremel tools to do this but they are puny and not well powered and about as expensive.

 

https://smile.amazon.com/WEN-3920-Two-Direction-Variable-Flexible/dp/B005UKGL58/ref=sr_1_3?s=power-hand-tools&ie=UTF8&qid=1527899009&sr=1-3&keywords=scroll+saw&dpID=41h8sBoRnDL&preST=_SX300_QL70_&dpSrc=srch

 

 

 

After a lot of deliberation I decided to buy one. I agree that masonite plates between segments would be ideal. I'd like to also be able to make my own bits'n'bobs as time goes by.

 

But I think I'll stick with card for the 'exoskeleton'. Below is a picture of the ugly side of the tunnel featuring the skeleton. You can see the trace of a few failed techniques in the photo, including the epoxy resin that I hoped would harden the tunnel but later stripped away. This exoskeleton is extremely ugly and crude. I really had no idea what I was doing when I made it. I just added strut after strut until the tunnel was rigid and stable. But it's surprisingly effective. I'm going to use the same basic idea  for the 'keeper' segments. The difference being that I'll use uniform pieces, and plan the structure in advance. I know it's stupid, and this stuff is not on display, but I really don't like how ugly it is. 

 

The other picture is of one of the new tunnel pieces, measured and marked. I'll build the exoskeleton around the important markers. I'll join the masonite plates to the ends, and then connect them to the exo for extra support. I think I'll make the flanges out of card. I picked up some 1/4 inch wooden dowels that come with a drill bit.

 

The measuring and marking was greatly facilitated by a bendy ruler that I picked up in the local art shop. I meant to include it in the picture. I was planning to keep chugging and mark the other four segments tonight, but it would be wiser to call it a day. I have a template and all the calculations have been made so it shouldn't take as long to mark the remaining segments. I moved the lights and cables down quite a bit lower on the tunnel walls, so it would be easier to see them without crouching. 

 

1d4AIiZ.jpg

 

 

 

 

LX0jQkX.jpg

 

 

Edited by gavino200
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Lol, I feel like a pusher! Get one you know you will like it! Really for the money it’s pretty useful for what you need to do and super nice to have it to zip thru stuff. You can get broader blades to do straighter cuts and round, scroll blades to spin cuts on a dime. I think your son might have good fun on it as there are loads of fun scroll saw woodworking projects. Lots of fun toys you can make as well. It’s a very handily power saw to have to do from tiny to big things. Nice thing is you would have to really work hard to really hurt yourself with it (know that’s a professional curse for you). 

 

Also with the kinds of projects you dream up like this it will be of good use for you I think. 

 

btw you might want to look into a little led light as the little work lights that power tools usually include are notoriously wimpy! More light is a real help and being able to position it just right really helps in cutting on the line! I have these on the drill press and band saws and the do a great job.

 

https://www.amazon.com/Multipurpose-Multifunctional-Magnetic-Daylight-Workbenches/dp/B01L64XZVY/ref=sr_1_9?ie=UTF8&qid=1528677597&sr=8-9&keywords=Led+magnet+light

 

also take the time to practice first as it’s like soldering, not hard, but takes practice to get the feel of it and get good! Also always practice with different blade and materials as you will find different permutations on how things cut and what works best. Also YouTube is your friend to learn!

 

yep that was what I was thinking for for a framework, just maybe a bit more uniform. Uniform is nice as you know where stuff is better if you do the foam coat. I assume the little light boxes will be removable to fiddle with lights if needed. With the scroll saw you can easily cut out foam core curved cross section pieces . The. once you have a curve set for the lateral pieces (use cardboard to get the right arc at each level to make a template) to go between the cross section arcs you can just clone those for each level.

 

Might think of foam core for the bracing as it’s less prone to humidity than cardboard. This is one place you don’t want a lot of expansion and contraction. Also nice flat 3/16” face to glue to the tunnel surface.

 

did you say the epoxy popped off the cast material? That’s odd, maybe wash the surface? Other option is gorilla glue, the polyurethane really should expand well into the rough surface of the cast gauze. Messy stuff, but it sticks well, especially to stuff epoxy sometimes does not as it expands into every available nook and cranny where as epoxy can just sort of glaze over the surface and not really get into the surface.

 

As always the project is really fun to watch come together, you’ve done excellent work on it and it’s very unique! Kudos to you!

 

cheers

 

jeff

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7 minutes ago, cteno4 said:

Lol, I feel like a pusher! Get one you know you will like it! Really for the money it’s pretty useful for what you need to do and super nice to have it to zip thru stuff. You can get broader blades to do straighter cuts and round, scroll blades to spin cuts on a dime. I think your son might have good fun on it as there are loads of fun scroll saw woodworking projects. Lots of fun toys you can make as well. It’s a very handily power saw to have to do from tiny to big things. Nice thing is you would have to really work hard to really hurt yourself with it (know that’s a professional curse for you). 

 

Also with the kinds of projects you dream up like this it will be of good use for you I think. 

 

btw you might want to look into a little led light as the little work lights that power tools usually include are notoriously wimpy! More light is a real help and being able to position it just right really helps in cutting on the line! I have these on the drill press and band saws and the do a great job.

 

https://www.amazon.com/Multipurpose-Multifunctional-Magnetic-Daylight-Workbenches/dp/B01L64XZVY/ref=sr_1_9?ie=UTF8&qid=1528677597&sr=8-9&keywords=Led+magnet+light

 

also take the time to practice first as it’s like soldering, not hard, but takes practice to get the feel of it and get good! Also always practice with different blade and materials as you will find different permutations on how things cut and what works best. Also YouTube is your friend to learn!

 

yep that was what I was thinking for for a framework, just maybe a bit more uniform. Uniform is nice as you know where stuff is better if you do the foam coat. I assume the little light boxes will be removable to fiddle with lights if needed. With the scroll saw you can easily cut out foam core curved cross section pieces . The. once you have a curve set for the lateral pieces (use cardboard to get the right arc at each level to make a template) to go between the cross section arcs you can just clone those for each level.

 

Yes, I'm looking forward to experimenting with it. I think it'll be extremely useful

 

7 minutes ago, cteno4 said:

 

Might think of foam core for the bracing as it’s less prone to humidity than cardboard. This is one place you don’t want a lot of expansion and contraction. Also nice flat 3/16” face to glue to the tunnel surface.

 

I have a bunch of foamboard that i'm planning to use for the city. But I've never used it. I have zero experience with it. I mainly bought it so I could sink building bases into it an bring everything to it's correct level. I'll take a look at it. An alternative would be to sort of "paint" the card with thin CA before putting it in place, to make it essentially moisture proof. 

 

7 minutes ago, cteno4 said:

 

did you say the epoxy popped off the cast material? That’s odd, maybe wash the surface? Other option is gorilla glue, the polyurethane really should expand well into the rough surface of the cast gauze. Messy stuff, but it sticks well, especially to stuff epoxy sometimes does not as it expands into every available nook and cranny where as epoxy can just sort of glaze over the surface and not really get into the surface.

 

No it didn't come off by itself. The first material that I used was completely the wrong stuff. It was rubbery stuff used for making casts. I peeled that off myself but couldn't get it all off. The epoxy stuck fine, but was useless for the intended purpose - making the structure rigid. I think you suggested the frame many pages back. Alas, I was too foolish to listen. 🙂

 

7 minutes ago, cteno4 said:

 

As always the project is really fun to watch come together, you’ve done excellent work on it and it’s very unique! Kudos to you!

 

 

Thanks. 

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Thinking through things while marking up the tunnel segments, I came across a problem. On the practice tunnel segment, I used 'Great Stuff" expanding foam to make the connecting piece between the fascia and the open tunnel. I'm fairly happy with the result, but it may be a problem If I want the tunnel segments to be "lift-out" in case I need to do track work. The "Great Stuff" is sticky and sort of bonds to structures.

 

Possible fixes:

1. Put some barrier (wax paper) over the fascia and the layout base, before applying the foam. That way the foam would only bond to the tunnel and could lift out with it.

 

2. Another alternative would be to find some less sticky and noxious expanding foam than "Great Stuff". I'll start searching for some. I remember seeing a type of expanding foam on TV,  maybe about twenty years ago, that might be suitable. It was a science show about the evolution of early hominids. Anyway, the scientist reconstructed the brains of hominids and primates by spraying foam into skulls (through the big hole where the spinal column exits), He waited about five seconds and then pulled out a perfect foam cast of the brain case, while it was still soft. I remember he said, you had to remove it before it got harder, or it wouldn't come out. It seemed like it (whatever it was) would be perfect for model railroading. Great detail, easy to handle and non-sticky.

Edited by gavino200
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Yes wax paper is your friend! Practically nothing sticks to it! Ironically it’s harder to find in stores these days. I keep little 4”x4” around for sticky stuff.

 

most polyurethane foams are pretty sticky, the expanding part tend to get a shell of more cured on the leading edges and not so sticky but what you pour it on it usually sticks very well to. We use to use it a lot to fill air pockets in small sailboats to keep from sinking a lot. But once in it was a devil to get out. When you mix it it’s like epoxy a base and then small bit of catalyst. Not run into something that wouldn’t stick.

 

the stuff that you reference sounds like a foam rubber that would be flexible. The polyurethane is pretty hard stuff pretty fast.

 

jef 

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The sections are all marked, except for the cutout windows. I'll mark those tomorrow after getting some opinions (wife and boy) on window positions. 

 

Next task is to cut out apporximately 30 light guides. I'm not sure I'll have enough plastic. I may have to scrounge for Kato decoder boxes. I'm hoping to start on the exoskeleton/scaffold next weekend. I looked at the foamcore today. It does look like it would be rigid enough. I've been sort of curious about it for a while now, and would mind messing with it a bit. It'll be practice for when I start making my "city". 

 

AZpBVhf.jpg

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Once youuse the foam core as a bracing it becomes pretty rigid and very light weight. Experiment a bit with some. You can make some amazingly strong frameworks with it once glued together well. 

 

jeff

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1 minute ago, cteno4 said:

Once youuse the foam core as a bracing it becomes pretty rigid and very light weight. Experiment a bit with some. You can make some amazingly strong frameworks with it once glued together well. 

 

jeff

 

What glue do you recommend? I was planning on using CA and accelerator.

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1 hour ago, cteno4 said:

 

 

the stuff that you reference sounds like a foam rubber that would be flexible. The polyurethane is pretty hard stuff pretty fast.

 

jef 

 

This is the technique. It's called "endocasting". I'm calling it a night. I'll pick up the trail again tomorrow.

 

http://humanorigins.si.edu/human-characteristics/brains

Edited by gavino200
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44 minutes ago, gavino200 said:

 

What glue do you recommend? I was planning on using CA and accelerator.

Hi Gavin,

foamcore board is ideal for making structures especially with cross pieces in to add strength.It s a principal they use in the aircraft industries to manufacture aircraft and wings and it’s called a monocoque structure. So long as the framework is nt going to be seen I always use a hot glue gun as it dries really quickly but pva is just as strong but takes longer to dry.

just my 2 cents worth buddy.

Another good investment are the woodland scenics foam nails,they re ideal for holding stuff in place while you glue it or it dries.

http://www.osbornsmodels.com/woodland-scenics-156-c.asp.

Edited by Pauljag900
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Looks like cranial endocasng is usually done with liquid latex, swirl it around inside the skull then pull the inside skin out the foramen magnum. Then they fill the latex ballon with foam, plaster or clay to fill it back out.

 

pva is a good solid glue for forms core as it can get into the foam well. Epoxy as well. Hot glue works pretty well and is fast but is not quite as solid of a joint as pva or epoxy.

 

ca glue does not work well as even with thick pva there is a lot of gap that has to be made and the paper can soak in the pva well (white foamcore paper is less permeable that the Black foamcore) and the foam takes a lot to get in there.

 

one trick I have use when building stuff out of corrugated cardboard and foam core is to glue with pva and tack in place with little point fillets of hot glue in the corners at joints. Hot holds things in place while the pva glue sets.

 

cheers

 

jeff

 

 

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First experience with foamboard. I like it. It's not as rigid as card but it's much easier to cut. I haven't added cross beams yet. I used hot glue as it's very 'space filling'. That's an advantage as the tunnel surface isn't completely regular and gaps tend to be present. It also dries very quickly.

 

WqInTHh.jpg

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Nice!  Foam core is nice to work with. It also sands pretty well. Once glued it’s a pretty good stiffener. 

 

Make sure you have a nice and hot hot glue gun, as cheap ones sometimes are lower temp and the glue does not get very liquid and does not stick well. Also you can’t use it to glue long sections well as glue will start to harden before you get the part in place. What it works great for is doing the space filling fillets like you have done. Go slow on the fillets and the glue will be nice and hot and get into all the cracks well. I use to build quarter and  half scale and even some full scale exhibit models with corrugated cardboard and hot glue! For big chunks I would just put a fast dab every 6” onnthe edg and quickly put in place to tack the part down (no way you can lay down a full 3’ stream of glue as it will be hardening at the far end by the time you get done). The I would come back and lay in the fillets one one or both sides and they would hold very solidly. Someone actually sat on one of the counter constructions thinking it was build from wood. It held up with only a few crushes if the corrugated cardboard on the top flat!

 

jeff

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That’s exactly what I do jeff,tack it in place then go back and do the bead and filling in.

I bought a dual voltage for doing the foamcard and polystyrene,if it’s too hot it melts the polystyrene boards.Low for polystyrene and high for everything else.

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3 hours ago, cteno4 said:

Nice!  Foam core is nice to work with. It also sands pretty well. Once glued it’s a pretty good stiffener. 

 

Interesting. I could probably get is just right by oversizing it and sanding it down. Not really necessary in this case as the hot glue fills in nicely. But it could be useful on another project. Especially for visible joints.

 

Quote

 

Make sure you have a nice and hot hot glue gun, as cheap ones sometimes are lower temp and the glue does not get very liquid and does not stick well. Also you can’t use it to glue long sections well as glue will start to harden before you get the part in place. What it works great for is doing the space filling fillets like you have done. Go slow on the fillets and the glue will be nice and hot and get into all the cracks well. I use to build quarter and  half scale and even some full scale exhibit models with corrugated cardboard and hot glue! For big chunks I would just put a fast dab every 6” onnthe edg and quickly put in place to tack the part down (no way you can lay down a full 3’ stream of glue as it will be hardening at the far end by the time you get done). The I would come back and lay in the fillets one one or both sides and they would hold very solidly. Someone actually sat on one of the counter constructions thinking it was build from wood. It held up with only a few crushes if the corrugated cardboard on the top flat!

 

jeff

 

That's pretty much what I've been doing. My gun is plenty hot, I think. It's hot enough for the glue to burn you. I don't think I'd want it hotter.

 

Incidentally, I picked up an interesting product at the local art shop. I went looking for hot glue sticks. What I found instead (as well) was a long role of glue stick. Like a long string of the stuff, so you don't have to keep replacing the sticks so often. Looking forward to trying it. 

Edited by gavino200
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I d be intrested to see that buddy,I ve never seen that before,is nt it funny how the glue stick runs out just as you ve got your hands full holding things in place? I ve sorted that now and always keep a spare stick In my mouth ready😂😂👍

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Good news/bad news. The bad is that the foamboard is useless at resisting lateral or tortional stress. So it can't be used to make cross struts.

 

The good is that this forced me to christen the new saw. I LOVE it. With masonite  struts this thing is really quite rigid. It wasn't hard to do at all. I'll probably just make the whole scaffold out of masonite or  wood for the remaining tunnel sections.

 

uvzmcl5.jpg

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Did you try the lengthwise struts going vertical  out of the tunnel? But you are right it can twist some. Masonite is a much beefier (but heavier) material. Also may look at 5mm luan ply from the big box stores. It’s ver stiff and easy to work with and even more sturdier than Masonite (but a tad thicker). It’s also very impervious to moisture (used a lot as underlaminent in bathrooms because of this).

 

glad to hear you like the saw, I thought you would and I can hear the gears in your head whirring from here with new things to do with that saw there! Nice when you can quickly whack up ideas in it. Ou can cut styrene and foam core on it as well.

 

cheers

 

jeff

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I'm calling it a day for now. I was going to make the scaffold and then add the endplates. But now with the saw..... I think I'll do both at the same time so that access to the bolts can be optimized. I'm going to lay out a replica of the track so I can get the geometry right before going further. I'll probably do a bit more during the week. The saw is a bit addictive. I already want to get back to it.

 

I made thirty or so, identical light guides yesterday. Very tedious, and took forever, but I'm glad it's done. 

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