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Question about cutting parts from the plans

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Question about cutting parts from the plans

Old 12-29-2016, 02:54 PM
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Dave13579
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Default Question about cutting parts from the plans

After 40 years of kit building, I have finally taken the leap to doing a scratch build. I have a question regarding the cutting of parts from the plans...... I posted this photo to better explain. When cutting the part, do i take the line, the solid black line, with the saw blade, or will the part be the exact size of the drawing. I hope this question doesn't insult any ones intelligence, but don't know if the dark line is the boarder for the part, or the actual size of the part. Thank you for any help.....

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Old 12-29-2016, 03:04 PM
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ByLoudDesign
 
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Best way to check that yourself it measure the notches and see were the proper measurement is found. Most likely in the center of the line!
Old 12-29-2016, 04:01 PM
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that makes sense...... Thank you.
Old 12-29-2016, 04:03 PM
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All Day Dan
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Dave, you also have to take into account the width of the blade if you are using a scroll saw.. Cut a few pieces and see what you get. Also remember that some of the plans around from the "good old" days were hand drawn and not that accurate to begin with. Dan.
Old 12-29-2016, 05:31 PM
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Dave13579
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Do you guys always fiberglass your scratch builds, been reading a lot and fiber glassing has always come up. The plane I am building is completely covered with balsa sheeting. Wondering if fiber glassing is just a know, and the recommend eng size takes into account the added weight. Thanks for all the help, just got the plans today, and started to make a material sheet to start ordering it all. In other words getting ready to be in the dog house with the wife after buying everything.
Old 12-29-2016, 07:41 PM
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Dave, here's what I do for my gas powered models. Dan
With so many paints disappearing from the store shelves, it’s hard to find substitutes that will perform the same way. Use what you have available in your area and what you are familiar with. Here is how I finished the prototype. It is a finishing technique I have achieved good results with on other models. Brush on a full strength coat of Valspar Lacquer Sanding Sealer NAS1420. A well-stocked paint store that caters to the professionals will carry this. It is usually used for furniture finishing. One of those two-inch inexpensive disposable brushes is ideal for this application. Sand lightly with 220-grit sandpaper. Apply fiberglass cloth over the surfaces brushing through it with the sealer thinned 100% with lacquer thinner. Sand lightly with 220-grit sandpaper. Brush on another thinned coat of the sealer. Sand with 220-grit sandpaper being careful not to cut into the cloth. Brush on two more coats of the thinned sealer. Try to fill the weave of the cloth as much as possible. Sand with 150-grit sandpaper to keep the surface flat and smooth.

Spray on three coats of Pacific Coast Lacquer’s PCL 913 lacquer based primer thinned 125% with medium lacquer thinner. Sand the first coat with 100-grit sandpaper, the second coat with 150-grit sandpaper and the last coat with 320-grit sandpaper. You should now have a pretty good surface for your color coats.
Apply a coat of Kilz that is thinned to two parts Kilz to one part naphtha. This will improve the adhesion of the final color coats.
The prototype model was painted with Benjamin Moore’s oil based paints. It took two coats of paint, each thinned to a mixture of two parts paint and one part naphtha. The model was painted in a two color scheme, not necessarily representing any particular plane. All of the insignia and rudder stripes were painted with Rust-oleum. The letters on the wing were four inch vinyl letters available at a stationery store. The overall result was just what I was looking for.


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Old 12-30-2016, 04:16 AM
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Thanks for taking the time to give such a detailed answer..... Thats a hell of a job on that plane, very nice. Thanks again.

Last edited by Dave13579; 12-30-2016 at 05:53 PM.
Old 12-30-2016, 04:30 AM
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Glassing with lacquer like Dan describes has advantages that it dries very quickly and is easy to sand,,the down side is real Lacquer has a very strong smell that takes a couple days to go away,, so if you work in a well ventilated space like an open garage, that's great, but if you're working in the house or basement like I do, it's a no go.

Many guys use Minwax Polycrilic, a water based acrylic polyurethane,, that works much like the lacquer,, but dries somewhat slower and needs more time to full cure before painting,, Big bonus is virtually no smell

Personally I use West System epoxy for glassing,, it too is easy to work with, like many things, once you learn the process. It goes on much thicker so fewer coats are needed (2 typically) and is ready to sand and paint the next day

As far as paint goes,, I've switched to using Latex and then seal with Systems Three Top Coat,, these products are also both water based and have virtually no smell to deal with, and of coarse easy clean up, Plus the price is considerably cheaper than model or automotive lacquers or enamels. I buy the 4oz sample sizes from Home depot, those are around $4 a piece.

Good luck
Old 12-30-2016, 08:20 AM
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This may sound involved,but it is not.When you blow up the side view to the scale you want,measure with digital calipers,the part you want .Then,scale the image of the paper cutout sheet to suit the dimension you found on the side view,and print that 1:1 scale.You can pick what dimensional choice you have made on the side view...just be consistent,and follow it through on all your parts(ie,inside the line,middle of the line,outside the line).
Old 12-30-2016, 06:03 PM
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Thanks for all this info.... Building from plans, even kits now days, seems to be a dying art. I think we have about 70 or so members in my club, there are 5 of us who still build. ARF's have taken over the field, for that matter nitro or gas models are getting few and far between. Nice to have a site where people are willing to share their knowledge. Thanks again, I am sure I will have more questions...... Stay tuned.
Old 12-30-2016, 07:52 PM
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I've been using the bottles of acrylic paint from Hobby Lobby (the craft store). They are inexpensive, seem to cover well and are readily available. I clear with automotive urethane. So far no compatibility issues.

ken
Old 01-21-2017, 10:07 AM
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Originally Posted by Dave13579 View Post
After 40 years of kit building, I have finally taken the leap to doing a scratch build. I have a question regarding the cutting of parts from the plans...... I posted this photo to better explain. When cutting the part, do i take the line, the solid black line, with the saw blade, or will the part be the exact size of the drawing. I hope this question doesn't insult any ones intelligence, but don't know if the dark line is the boarder for the part, or the actual size of the part. Thank you for any help.....

Dave, I use to leave the black line on, cutting outside the line about 1/32" and sanding it back to the center of the line. If you use a template, consider the pen or pencil distance to the template, but always cut outside the line Alex
Old 01-21-2017, 09:55 PM
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Dave,the scratch build set.isn't lost.There is a group of builders,all with different techniques,that work.Glean what you can from that experience.
Old 01-22-2017, 06:31 AM
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Thanks everyone for all the help, I did exactly what you said to do Alex, then I will make all final adjustments to the parts when I do my mock up of the plane before gluing.

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