GeeBeer

Hi,

I never have attempted scratch building, because my building abilities have never gone to the part *before* the kit.

How do you cut all the pieces needed to complete your plans, or idea that you will be building?

I was guessing that for balsa, wing spars for example, the pattern would be trace onto the balsa sheet... then cut slightly bigger than the line... then sanded to final shape. Most likely not the easiest way... but probably would work for most balsa pieces. I haven't figured out anything for light ply

How do YOU do it?

Soar Head

My Feedback: (5)

One trick I have tried long ago was to print your patterns to a laser printer. (Check to see that the laser printer prints a true 1:1 scale). I have never tried this with an ink-jet printer.

Turn the paper over (ink side down) over the wood. Use your monokote iron and transfer some of the ink to the wood. I then use an x-acto to cut very close. A metal ruler guides all straight line cuts.

If you're concerned about left-vs-right, then use a CAD program that can mirror all your patterns before you print. The ironed on image will be a mirror image.

hope this helps.

mulligan

Print CAD images, cut out, outline on wood, use X-acto for balsa, scroll saw for heavier wood. Finish sand edges only (no shaping).

I never intentionally over-size my cuts; just take your time. Of course, since you're scratch building anyway, if you mess up, you simply get another piece of wood.

- George

omcusnr

Rich Uravitch has a very good booklet available from Model Airplane News that can get you started in the right direction with lots of tips & how tos to make your scratch building fun!!

http://www.rcstore.com/rs/general/li...t=10&catego=BO (scroll down)

I like to print a paper template, transfer it to a hardwood template, stack & pin together a slab of balsa sheets (how many depends on what you are using to cut with & trace the hardwood template to the stack. I NEVER cut to the part line. Overcut & sand to the part. (Ther will be less sanding later).

I really recommend that the following power tools are obtained for the most ease in "kitting" your parts:

variable speed scroll saw w/ 16" arm
belt-disc sander/grinder
drill press
& rotory tool (dremel) - grinder.

These will go a long way to reducing the frustration factor.

ProfLooney

when i used to like to cut my own kits before i went to laser cut short kits because i get a good deal here is what i did.

first i went to kinkos and had a copy of my plans made so i didnt dirty my originals.

next I cut out all the parts and using 3m77 spray glue or the equivelent glued the cutout paper parts on top of my wood. now heres the kicker. since you are cutting out 1 plane why not 3 or 4 in case you crash or you want to build one and sell it to fund retracts etc.

I next take the 3m77 glue and spray it on on surface of my wood and stack it together to get the number of parts i needed say 2 sheets of 3/32" balsa stacked to cut both winghalves at the same time or 6 of them to cut 3 wings at once. remember you may not build them at this time but who wants to recut a kit later when you can do it now and it takes the same amount of time to cut 1 or 10.

I then take my stack of wood to my scroll saw and sit there for a couple nights cutting all my parts out and labeling them. before i take them apart i first sand to final shape so all my parts are exactly the same.

Joe

PS in an earlier post i saw ironing on from paper. one method i have seen done but never done myself is that you can take zeroxed parts and put the ink side down on your balsa and use either alcahol or acetone on a rag and rub the back of the paper which will transfer the inked image but it is just as easy to glue the paper to the wood.

BMatthews

Lots of idea there for getting the outlines onto the wood already so here's a few for actually cutting the stuff.

Spars, leading and trailing edges and some other bits are often strips. I cut my own strips for everything under 1/4 inch thick using a good, wide straight edge and a fresh Xacto blade. If it's critical I step over to my full sized table saw ( I also do quite a bit of woodworking) but that's rare. For larger strips buy then precut but check for straightness.

For ribs I cut one out of hard balsa or 1/32 plywood as a template. Cut the rest, stack together, block sand to even out the differences and then cut the spar slots into the stack while it's still pinned or bolted together. Number the ribs as they come off the stack so any minor errors are spread out evenly over the whole wing.

For some parts I DO cut a little bigger but that's usually curved parts from thicker sheet. But if you use a scroll saw then you really don't need to do this. Also you'll find that as you get better the extra meat you leave on can be less and less until you're only cutting on the outside of the line thickness and then sanding that to shape.

And if you havn't figured it out already for the newcomer to scratch building it's best to start with good plans from magazines and the like as they go to great lengths to ensure all the parts are there and that they are drawn accuratley.

And last but not least. I never cut all the pieces out at once. I know some people can do that, and my hat's off to them for their patience, but cutting stuff out is boring so I like to cut the parts for one item like a wing and then build it so I can see something taking shape sooner. Also it really helps to prevent loosing pieces if you glue them all together right away.....

Welcome to the next step towards real modeling. We'll have you designing your own models in no time.....

bullseye000

I have used tried all of the above. Some more successfull than others. I usually make copies, spray glue, then cut and sand. The only area that continues to give me fits is cutting accurate slots for spars in ribs or longerons in formers. Anyone have any tips other than sandpaper cover sticks for getting nice accurate cut outs in these?

bill white

My Feedback: (13)

So far I have built, or am in the process of building, three scratch builts, (I am in the process ob building a Ziroli Stuka), The first two planes I cut all the parts using a scroll saw, a band saw, and a belt/disc sander. I copied the parts onto tracing paper, and then onto the wood using carbon paper. It worked OK. But on the last project I used a kit-cutter. Be very careful in obtaining a high quality balsa for sheeting, and stringers. Some of the balsa supply outlets, such as Lone Star, will hand select the wood for a modest sur-charge. The finished product makes the additional effort worth it. I woul also suggest that you be VERY careful on plan selection. As there are some plans on the market that are not easy to build from, (no instructions, no parts list, and worst of all the parts do not fit after cutting, I.E formers do not fit over crutch, and are uneven). I highly recommenr Ziroli, but there are many other high quality plans.

Hope this helps, Bill

ProfLooney

Yea bullseye there is 2 methods i use usually in combination to each other. buy you abt half a dozen to a dozen hack saw blades. break them in half (they too hard to cut in half) then use small bolt cant remember think it is a 10-32 that fits nice and snug in the blade mounting holes. you then stack blades next to each other and if i remember correctly 2 blades = 1/16th of an inch. when you get the width you want say 1/8th of an inch take some duct tape and tape the other side together. you can tape a stick to the back for a handle. now when i cut a notch say 1/8 x 1/8 notch i make my blade 1/8" wide then i measure up the blade and run a piece of tape down the blade 1/8th of an inch. now when i use the saw i made to cut I know when the tape hits the balsa it is exactly (or as close as my tape is) 1/8th in deep.

Next part is i take a piece of spruce the size of the notch i need and glue a piece of sandpaper onto one side of it. i then use it to sand down the notch taking a scrap piece of balsa and double checking the fit as i sand to fit.

thats all there is to it. you get a nice tight fit.
Sorry it all sounds rough but i have a cold and brain not working fully right now.

Joe

boxbeam

My Feedback: (188)

I have just joined this site today, and am glad I stumbled across it. Was out looking for a "hobby saw" last night, and saw a 16" scroll saw, and a larger band saw. The price on the scroll saw is very much in line with Santa's budget, and is more compact to fit in his sleigh.
I am building a Ikon N'wst T craft and would like to make some spare parts for a sister ship.(actually in truth a replacement if needed) but am getting ready to take on after this one a tri pacer. The plans are from Capitol RC and the right tools to build this one will downgrade the project to just an "intense" one.
I have never done a kit this advanced, but have built some telemasters, one from scratch before and need to know what will aid me in getting the fastest and cleanest cuts on ply, spruce and other hard woods with critical notches and curves in them.
From what I have read in the past 15 minutes, I will have any answers to my questions from all of you fellow modelers who have already walked the path I again will walk.
Is the scroll saw recomended over a small band saw? What about maintenance of the both of them? (blades?) Thanks for your help.

Ron

ProfLooney

Hi Ron and welcome.

the difference over the band saw and scroll saw is 2 fold 1st it is personal preference 2nd you can cut more plane parts with less hassle with the scroll saw over the band saw.

I prefer the scroll saw because you can turn tighter radiuses with it than you can with the band saw. the reason is the narrower blades. I have a ryobi scroll saw and like it. another reason is we work with some really small parts and the scroll saw is a little safer to put your fingers real close to the blade with. my ryobi has a gurad setup on it that makes it almost impossible to get my fingers into the blade (when i use it shhhhhhhhh). a scroll saw cuts with an up and down sawing motion which i feel eliminates wood splintering a little better than a band saw which the blade goes in only 1 direction.

Like I said it is personal preference but basically you can turn tighter radiuses, the blades are cheaper, you can cut up to 2" thick wood (dont laugh when stacking balsa to cut multiple kits at once it adds up fast) also can cut 2x4's for stuff around the house hehehe so it will do most everything a band saw can but is more in tune for rc planes.

Joe

boxbeam

My Feedback: (188)

Thanks Prof.!!!

Santa's on his way! To Home Depot no less! He saw a saw I'd like to see on my work bench. HO HO HO, its a 16" scroll saw and I bet I get a stocking full of CA and spare blades too! This dilema is solved, and thanks again.

Ron

ProfLooney

hahaha hohoho hope you appreciate santas gift and dont let it just set around gathering dust. :0) well sitting around gathering dust in this situation could be good hehehehe

Joe

rtideas

After being frustrated at finding a small tooth coping blade, I broke down and picked up a nice Ryobi 18" scroll saw on sale at Home Depot for $129 (down from $159). It has a bright LED lamp at the end fo the blower tube. The cheaper one seemed too cheap. The demo had a kink in it's blower tube had had cuts in the base plate.

I need to cut 3/32" ply. What's the best blades to use to cut it?

Also, am I correct in saying, pinned blades are easier to change? The unpinned blades seem harder to get proper tension.

There is spiral blades for cutting in any direction. Other than blade thickness, what are the disadvantages?

It certainly is a dang fun tool.

ProfLooney

Rt Ideas thats the problem I found with the Ryobi in that it only really likes pinned blades could never get the circular cut non-pinned blades to work. What i do is get the standard blade as they are all abt the same toothed. now the width of the blade is what I look at. now I like the ones abt 1/4" wide for thick stacks and ply and the narrower ones abt 1/8" wide for cutting tight radiuses and balsa. Usually I just get a package of each. it is more personal preference than practical but the narrower ones like to turn better in the balsa without the back of the blade cutting into the balsa as you make your sharp turn.

Joe

pjwright

One more tip for our friend 'snaught' -- never, never sand without a sanding block or bar. Seems like a no-brainer...but the temptation to grab a sheet of 150 grit and knock off the rough spots (especially on a curved surface) is almost overpowering.
I also use the print paper and 3-M spray cement method for making templates. Remember that your cheap-o flatbed scanner turns your printer into a photo-copier...(just check for scale creep).
;-)

rtideas

Joe,

Thanks for the info.

Here are some spiral blades i found that have flat ends. Also, he suggests hammering the round reverse blades to get flat ends.

http://www.mikesworkshop.com/blades.htm

Looks like great pricing, too.

The neat thing about my new saw and a good selling point was a 30-day satisfaction guarantee from Ryobi. If i don't love it, I can return it.

The regular blades it came with leaves a rough bottom edge on the right side of a cut. The narrower and reverse bladed I bought extra cut much slower but leave a polished edge.

I really like the light on the end of the blower. It's a bright white led.

Also, the zero angle stop can be flipped out for 12 degree tilt to the left as well.

This is a neat saw for the money.

ProfLooney

thanks youi are right great prices also I like the double cut blades hard to find decent blades at wallyworld, meynards, or lowes they only have 1 blade basically

Joe

rtideas

i have some thin blades. Can I cut inside 90 degree corners without pre-drilling a hole?

This is my first scroll saw. I had a jeweler's/coping saw, years ago, in high school and it seems very similar in techniques, but only powered. I've done some searching (hence the blades above) but have yet to find a good primer on basic scroll saw work.

Joe,

Email the guy and he'll send two sample blades. He also has a large sample pack with a dozen each of 5 kinds of blades for $12.95 shipped.

It's interesting that Flying Dutchman blades are made in Germany. Shouldn't it be Flying Deutschman? <grin>

rt

ProfLooney

hehe thats funny or flying doucheman hehehe. no you only need to drill a hole if you cutting out something inside a part and dont want to cut through ie a lightneing hole in a wing rib

Joe

AV8TOR

My Feedback: (2)

Probably not what you want to hear but I built a vacuum box to hold down the sheets and I CNC machine out all my projects. (I have been blessed with fun toys at work)

rtideas

My new 18" Ryobi scroll saw has 4 holes in the Teflon deck. Can or does anyone use a fence on a scroll saw for straight cuts?

rt

ProfLooney

I have once or twice when splitting some wood but for the most part I found that on a scroll saw they dont help very much as the blade is so thin and can flex fairly easy

Joe

rtideas

Thanks Joe. There's got a be a use for the holes.

I ordered a small assortment of blades, including some reverse spiral, from Mike's Workshop. I''l tell you how it goes. He's seems like a good egg--like you.

er

a088008

If you are a sucker for punishment, like me, then... (I do not have the space or neighbours (in apartments) that will tolerate power saws at 2am in the morning.)

I hope to make my own QUITE CNC machine someday ... sniff, sniff.

I usually build one-off original designs. I take a CAD printout from my inkjet printer and then tape it to some poster cardboard. I then cut out the shape, with a x-acto knife, to make a card template. I then hold this over a sheet of balsa and lightly cut an outline with a x-acto knife. I then trace the outline 3 or 4 times to make a complete cut (works well on 1/8" sheet) all the way through. I cut exacly on the line and if I make a mistake I cut another piece. This teaches you accuracy in a hurry.

There is minimal sanding afterwards and any errors are hardly noticable, but it takes practice - like most things do.

P.S. I agree with BMatthews in that this is the beginning of REAL modelling for you. Welcome to the upper crust, friend.

-Q.