• Welcome to the new Flite Test Forum home! Please note that the migration is still undergoing and certain content, user privileges or features may be missing or limited until the transition is complete. Thank you!

Transferring plans to foam board

#1
When I do a scratch build FT plan, my chosen method is to lay the plan over the top of the foam board, and then go around the plan lines with a pin. I push the pin gently through the plan and into the board. Removing the plan then shows a foam board covered in tiny dots, and it's these I use to then draw the plans outline.

I'm just wondering what method some others might be using, and whether or not it might be better than mine.

Baz
 

nhk750

Aviation Enthusiast
#2
When I do a scratch build FT plan, my chosen method is to lay the plan over the top of the foam board, and then go around the plan lines with a pin. I push the pin gently through the plan and into the board. Removing the plan then shows a foam board covered in tiny dots, and it's these I use to then draw the plans outline.

I'm just wondering what method some others might be using, and whether or not it might be better than mine.

Baz
I like the pin poke method too. I have tried others and the pin method seems to be the most accurate and fastest one.
 
#3
I cut my plans out and trace the outline with a pen, just gotta cut to the inside of your pen line. I also don't have a working printer so I tape a piece of paper to my computer screen to trace the plans out!
 
#4
I print my plans at STAPLES in the "engineering print" size. Then I glue the plan to poster board with spray adhesive, and cut the pieces out to be traced to the foam board. Having the templates ready to go makes it quick to reproduce parts, or even whole planes. When we build the "Mini Sparrow" it takes under an hour from tracing to gluing.
 

Hai-Lee

Old and Bold RC PILOT
Mentor
#5
I also use the pin poke method but only poke a curved line to maintain the accuracy of the curve, for the remainder of the plan I only poke the line intersections and then play "Join the dots" with a 1 metre steel rule and a pencil.

Mind you I ensure that the plan doesn't move by clamping the plans to the FB first.

The only method which I find easier would be to buy the kit from the FT Store!
 

TEAJR66

Flite is good
Mentor
#6
I like the poke through method. I use a pencil to poke through so that the mark stands out against the foam board.

For the curved lines, I trace over the plan and this makes a very light mark in the board that I can follow over with my pencil.

When I am finished, the plans are still intact for use again. A cardboard mailing tube is a great way to store them.
 

JimCR120

Site Moderator
#7
I make paper templates that I trace around and then fold and store them in case I need to make a replacement part. Sometimes I also use the pin poke method and connect the lines dot-to-dot.
 

jhitesma

Posted a thousand or more times
Mentor
#8
I usually just use some low tack spray adhesive (the stuff sold for stencil painting to stick the stencils on things temporarily) and glue them right to the foam. Then when I'm done cutting the plans just peel right off. If I want to re-use a plan then I have some "waterproof posterboard" I picked up at walmart a few years back that's great for making re-usable templates. It's actually plastic and works great, I just trace around them with a pencil then cut on the inside of the pencil lines. Unfortunately I haven't seen it at the stores the past two years to get more :(

However I've recently upgraded to cutting my foam with a homemade CNC machine and a needle cutter. Which I learned about right here on the FT Forums: http://forum.flitetest.com/showthread.php?24251-Cutting-foam-sheets-with-a-needle!

I had more issues getting mine up and running than most of the others who've built them but am loving it now. Last night I cut a mini-corsair which I managed to squeeze into one sheet of foam:

20170205_182508.jpg

That took 40 minutes to cut, and I probably spent another 30-40 minutes preparing the files and generating the gcode. But I can now cut as many more as I want and it only takes the 40 minutes for the actual cutting.

Most of the things I've cut have gone considerably faster - this just has a lot of pieces on one sheet. Most full sheets are 15-30 minutes to cut depending on how many parts are on them. Preparing the files takes 10-20 minutes for most FT designs. The basic procedure is:

Open a new document in Inkscape and set it to 30" wide by 20" tall
Import the PDF - you have to do this one page at a time.
Ungroup the design (sometimes 2-3 times) to get the parts as separate paths.
Delete the text and logos and other stuff I don't need to cut.
Then I either just re-position the parts to fit nice on the 20x30 document - for some designs that's all it takes.
For others, I have to re-select and re-group the individual parts (many of the FT designs the outlines are multiple segments since they leave gaps for holding tabs when they laser cut them.) then move them around to fit them onto the 20x30 document.
On some designs I'll then import a second page of designs onto the same document if there are more parts and I have more room.
Finally I check for parts that need multiples cut and duplicate them.

I then save those as .SVG files for each sheet of foam I'll be cutting. I also put any posterboard parts into a separate SVG which I use to generate gcode for my 2.8w laser diode (another option on the machine) to cut. The laser diode can't cut DTFB, but will make nice clean cuts in posterboard at 300mm/min. I use an inkscape extension from jtech photonics to prepare the laser gcode.

For the foam, I open the .SVG files in estlcam and use that to generate the cutting paths. On some designs it's super quick and the automatic tools in estlcam do most of it for me. But on most of the FT designs those holding tabs mean I have to manually trace the paths - it still assists and auto connects the points so it's not like hand tracing...but is a bit more tedious. I also define my cuts at various depths - I've been using 6mm for full cuts, 2.5mm for score cuts, and 1mm for markings/optional cuts.

It's not really as much work as it sounds like...and gets quicker once you get a bit of practice at it. First time it took me an hour or two to convert a simple plan. The corsair was one of the more complex ones I did and it was only about 40 minutes to prep.

The big expense is building a large CNC...the MPCNC design I used makes that very affordable. 2 rolls of filament for my 3D printer and I spent almost every evening for a month or two printing the parts a couple a day. The hardware for it is very affordable, the rails are just 3/4" EMT conduit from the hardware store which is usually about $1-$2 for 10 feet, to cut foamboard you'll need about a 3'x4' machine so 4 sticks of conduit is still <$10. The designer of the MPCNC sells a parts bundle with all the electronics, motors, bearings and nuts/screws/washers you need for $245. But I bought my parts here and there as I went to spread out the cost. I may have saved $10-$20 over the bundle price but it was a lot more work...the bundle really is a great deal. (He also sells the printed parts for $190 if you don't have a 3D printer.)

Of course you don't have to use the MPCNC. If you look at the thread I linked you'll see a few people using other CNC machines they've built or bought with the needle cutter. The MPCNC just happens to be a very cost effective way to build a suitable machine.

JasonEricAnderson was working on a low cost CNC design here in our forums as well: http://forum.flitetest.com/showthread.php?6971-Idea-The-Flyplotter&highlight=flyplotter but he hasn't updated since August so I'm not sure how that's going :(


So...short answer - low tack spray glue :D Long answer - CNC rocks!
 

ofiesens2

Professional noob
#9
I use the pin-poke method and it seems to work fairly well.... my only issue is that sometimes I go into the foam at a not-vertical angle, so the hole on the other side of the foam is misaligned from the one on the top. No big deal though.

Just out of curiosity, how long does it take you all to cut out a piece of foam out of the plans? I built a Simple Soarer over the winter break and it would take me a solid 45 minutes to cut out one half of the wing, and the fuselage was at least an hour and a bit. Granted I do consider myself a perfectionist so I take my time, but even then I still feel like I might be the slowest scratch builder in the world.
 
#10
I use pin-poke as well. When marking a slot I will push all of the way through the foam so that the pin makes a mark on the bottom paper as well. Then, when cutting the slot, I will only cut one side of the paper, then flip it over and cut the other side (paper only). This gives a slot that is not skewed.

For a Spitfire or something that takes 3 sheets, I will:
Night 1_Pin-poke and then draw it with pencil
Night 2_Cut all of the parts out
Night 3_Decorate with colored packing tape
Night 4_Glue together
Night 5_Add electronics

I only get about 2 hours at night to "practice my craft". 10 hours total?
 
#11
I use the template method. It's a drag cutting everything out twice but the ease of making spare parts more than makes up for it.
 

FoamyDM

Building Fool-Flying Noob
#12
Spurring the Conversation on

Has anyone tried using the pumpkin pattern tracing wheel? Based on doing this on a pumpkin, foam board should be a cinch.
NPT10-3.jpg
 
#13
I use the template method. It's a drag cutting everything out twice but the ease of making spare parts more than makes up for it.
I thought sure I was going to get to use a template after bashing the end of a Bloody Baron wing. But, there were enough bits left to design a piece to graft on after making a clean cut of the damaged area.

Anyhow, I like the template method.

Mike
 
#15
Damn some of you guys seem to go through so much work. I am old school. I printer the out tiles. Cut them and tape them together. Glue them to the board with an roll on stick glue. Cut them out with a razor blade and then assemble. The plans are only used once. Then I have to print more. Speed build kit are so much easier but at a cost of course. I've got stacks of printed plans I'll probably never build. My favorite FT models are the Tiny Trainer, FT Flyer, and Storch. I've scratch built the hell out of these 3 planes.
 
#16
Damn some of you guys seem to go through so much work. I am old school. I printer the out tiles. Cut them and tape them together. Glue them to the board with an roll on stick glue. Cut them out with a razor blade and then assemble. The plans are only used once. Then I have to print more. Speed build kit are so much easier but at a cost of course. I've got stacks of printed plans I'll probably never build. My favorite FT models are the Tiny Trainer, FT Flyer, and Storch. I've scratch built the hell out of these 3 planes.
I used to do that. I got tired of taping them together. And anything I learned during the build got lost. Now I just
write on the template.

Mike
 

FoamyDM

Building Fool-Flying Noob
#19
No erasing mistakes :)
un-eraseable marks can be scary:eek:

Your mistakes are on the inside of the plane. To me there would be no more or less than an with an exacto as I'd use a straight edge . The spur/pattern tracer was an idea that sewers use. I thought I would offer a suggestion used by pattern makers of another ilk for the poor souls trying to mark out patterns with a pin.

I am personally spoiled, and print the plans full sized. I cut and loop tape them to the DTFB. Then use the #11 bladed exacto. I just print more if I need another plane. I image the taping of say, the sea duck, printed 8 1/2"x11" would get old.