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Reading the Seams
Red4
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California, United States
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Posted: Monday, February 11, 2008 - 05:14 AM UTC
You are definitely on a roll here. Taking notes as we go "Q"
HawkeyeV
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Wisconsin, United States
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Posted: Monday, February 11, 2008 - 11:56 PM UTC
As I stated in the last segment, I found that there were a couple of spots on the right side that needed more stretched sprue to fill the gap,



I went ahead and filled them, then after curing applied some Mr Surfacers as I had done to the left side. Which after a little light sanding and polishing turned out rather good. A final touch will come a bit later when the rest of the seam issues have been corrected to this stage, then we'll finish them all at one time.



Cementing the wing center assembly to the fuselage also meant closing the seams on the engine fairings. Fortunately these will not require any fillers, but while I was filing them I made sure to use the edge of my file to reshape/scribe the details of the filler panels between the nacelle and the wing itself. In some cases the lines of the panels do not match between the upper and lower halves, but the file is the perfect tool to reshape these lines while filing the seam.




The next step I attached the lower outer wing section to the upper one. Another gap will need filling but this one is a little challenging because of the raise details associated along it. Again, the basic step is the same, stretched sprue to fill the gap and some careful skill with a file.



As I do this area I will endeavor to get some good photos to go along with my text to show how I do it.

I also dabbed a little Mr Surfacer on the card stock filler on the aft wing/fuselage seam.



This will remain this way until the final touches of all of the seams before painting because it too is like the left wing seam...just about perfect.

I may be spending more time on this project than originally planned. I've been pecking at this between calls and other daily tasks, but last night while shoveling snow I might have possibly torn my right rotator cuff. My arm today is all but useless so I am letting the swelling subside by pampering it. Heavy lifting is definitely out!

Until the next installment!
vanize
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Texas, United States
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Posted: Tuesday, February 12, 2008 - 12:55 AM UTC

Quoted Text


I may be spending more time on this project than originally planned. I've been pecking at this between calls and other daily tasks, but last night while shoveling snow I might have possibly torn my right rotator cuff. My arm today is all but useless so I am letting the swelling subside by pampering it. Heavy lifting is definitely out!

Until the next installment!



Ooo! I hate it when that happens! I am plagued by shoulder injuries of this type.

Get well soon - I look forward to your next installment.
HawkeyeV
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Wisconsin, United States
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Posted: Tuesday, February 12, 2008 - 02:05 AM UTC
Thanks Vance! I hope it is nothing serious.
HawkeyeV
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Wisconsin, United States
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Posted: Tuesday, February 12, 2008 - 02:21 AM UTC
The shaping of the engine fairings and cleaning up the seams can be tough. In this case the two halves don't exactly match.



Since I'm not a builder who is overly concerned about the shapes being 100% dead on...removing the lip might result in a imperfect shape, but once the cowling is in place it will be hardly noticeable.



So I simply file away the lip while at the same time making sure to keep the panel details of the area intact or restore them in the process.



Since this series is geared towards beginners, I won't tackle the steps to facilitate at getting an 100% accurate shape, that is for the more experienced builders, right now we want to get them building clean blemish free models...especially seam related issues.

As I mentioned before the under wing seams are somewhat more difficult because of the texture/panel lines adjacent to it. But with the right tool we can do this easily.




Again as we did on the engine fairings, use the edge of the file to keep the features intact or scribe them into being. Luckily for this seam the panels next to the wing joint fairing are flat, so it is easy to follow along the fairing to remove the stretched sprue in the gap, yet keep the panel undamaged. Once the filing is done, we can clean up the file marks with a sanding and polishing sticks.



HawkeyeV
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Posted: Tuesday, February 12, 2008 - 02:33 AM UTC
Now that the wing center assembly is firmly in place and the engine fairing have been addressed it it time to close up the gap at the forward section of the wing/fuselage joint. Again, use metal to replace metal...err...plastic to replace plastic. Using plastic stock and solvent creates a solid stronger bond that isn't susceptible to shrinkage, torsion, load issues.



I take a piece of sprue and insert it into the gap or hole to be filled. Once in place I simply lay it over until the gap is filled with the sprue and cement (solvent) it into place.



Once the sprue has had time to fully cure I will come back to file it into shape and dress it up for the final step before painting.

Again for quality assurance, every step of this project is being overseen by my supervisor...



Does anyone have any questions? Speak up! It's better for both of us if you do, that way I can cover what you need covered!
JMartine
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New Jersey, United States
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Posted: Tuesday, February 12, 2008 - 03:24 AM UTC
Excellent info, I keep re-reading and bookmarking the thread! Couple newbie questions...

I find that squadron white putty tends to "contract" (shrink) a bit after it dries (not a surprise really). I then brush in a tad tamiya white primer on top, easier to "feather".... does this make sense at all?

Sanding over seams... sorry to get very technical and quantify but... do you sand ACROSS or AGAINST the seam? seems (no pun intended!) that i sand enough to "feel" smooth, but I add primer and WHAM there it is! When you "sand down", you mean Med-Fine-VFine (Squadron sticks)?

Thanks again for posting this thread~!
HawkeyeV
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Wisconsin, United States
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Posted: Tuesday, February 12, 2008 - 04:43 AM UTC

Quoted Text

Excellent info, I keep re-reading and bookmarking the thread! Couple newbie questions...

I find that squadron white putty tends to "contract" (shrink) a bit after it dries (not a surprise really). I then brush in a tad tamiya white primer on top, easier to "feather".... does this make sense at all?

Sanding over seams... sorry to get very technical and quantify but... do you sand ACROSS or AGAINST the seam? seems (no pun intended!) that i sand enough to "feel" smooth, but I add primer and WHAM there it is! When you "sand down", you mean Med-Fine-VFine (Squadron sticks)?

Thanks again for posting this thread~!



Must putties do shrink, you might consider using 3M Acryl-Blue, I've switched over to it almost exclusively. A single tube will last you years. Its shrinkage factor is nearly nil and it feathers exceptionally well.



Filing and sanding a seam can be accomplished in several ways. Across, diagonally and with the seam. It may take a combination of all, but the key is to work the seam without remove material and details you want kept.

I use...I think I included this before...if not



Sanding and polishing sticks I use can be found in the fingernail care aisle at drug stores or department stores. Black is usually extra course/course and pink medium/fine. Polishing sticks have slightly different grits as well. Also look at beauty shop supply places, some don't require a retailers license to purchase supplies from, they sell to the general public...many cases they are a much cheaper source.

The whole idea is to get the seam as well aligned and closed during the cementing process as possible to eliminate the need for heavy removal of material or filling and sanding afterwards. In some circumstances it is nearly impossible. This DC-3 for the most part so far has been an easy build requiring minimal effort with the seams. I have built them before and they were not as easily done for two reasons. Some were subjected to heat thus causing warped parts, and the second is I've gotten better at this by learning techniques from others as well as repetition. 'Practice makes permanent'.

When removing excess material or reshaping it, you need to start with a medium/fine grit...jumping straight to course before finding out how hard the material is or isn't can and will make you more work. By starting the sanding process with a medium or fine grit you can see how the material responds to the process. If it is hard and taking too long, step up to a coarser tool. You find out it is very soft and you are gouging it, step to a finer one. The variable with all of these is the amount of pressure you apply. Let the tool do the work!..using the 'arm strong' technique will only make the process harder and a possible disaster.

The single most used item in my arsenal of tools are polishing sticks. I use them from the assembly process all the way through the painting and decaling process. Start to finish! I rarely use sand paper except for flat sanding mating surfaces or when a tool just doesn't accomplish the task at hand.



I hope this clears the soup for you...if not let me know.
HawkeyeV
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Wisconsin, United States
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Posted: Tuesday, February 12, 2008 - 07:56 PM UTC
After my last update I took a short break from the project to catch up on some other tasks around the shop. I did how ever test fit and mount the horizontal stabs as well as install the forward sections of the engine fairings. Again, these will be left to cure so the are good and secure, then we'll inspect (read) the seams for any fit issues. From first glance both areas will require a little work.





If you approach every build as it were to be build totally naked, that is to say no paints or putties/CA, your modeling skills will improve dramatically. Why, you'll concentrate on basic modeling techniques, and as we know it is all about the basics. Look at the progress thus far on this DC-3, doesn't it appear clean? Ready to display as is? Well close. ;-)

I built this P-47 with no fillers or CA, it is totally naked, a challenge to build but it will hold it's own against completely covered models, why? Basic modeling skills...you can't hide your mistakes!

I built this 737, figuring that using a few shortcuts would make the project go faster...nothing further from the truth, it actually took me longer because the process was more labor intensive.


In the next couple of installments, the DC-3 will be finished up and readied for paint. We're expecting a major winter storm to arrive tonight, so tomorrow I should be able to concentrate my efforts at completion of the assembly process and addressing the seams. Stay tuned!
JMartine
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New Jersey, United States
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Posted: Wednesday, February 13, 2008 - 07:23 AM UTC
Gerald/HawkeyeV - Thank you for your complete and thorough response. And good luck with the storm, I spend half the day "guarding" my basement against flooding, with a sumppump and a speed vac.
Again, t hanks for the thread and the information, will try many of your tips on my next build Cheers!
HawkeyeV
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Wisconsin, United States
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Posted: Wednesday, February 13, 2008 - 09:00 AM UTC
I think we're almost to the end of the DC-3 project, she's just about ready for paint. I only needed to fill the gaps on the horizontal stabs with a little Mr Surfacer, I got the tolerance a bit tighter than I thought so closing the gap was a cinch.



The next issue to face is the canopy and side windows. The canopy was very ill fitting and needed some serious sanding and I will end up doing some filling around it to close several nooks and crannies around it.



I am considering doing blackened windows much like the decals on 1:144 scale airliners, or I have the option of polishing them out and replacing the frames with foil. Or lastly a technique I'll leave for another time...but will show you if I use it.

Anyway she is really taking shape and I have to hold back the urge to start spraying paint on her until she is truly ready for it.



HawkeyeV
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Posted: Thursday, February 14, 2008 - 02:40 AM UTC
To finish reading the work you've done on the seams is to highlight them so the flaws if any, become glaring. My preferred method is to lightly mist a very translucent coat of a light colored flat paint, whether enamel or acrylic over all of the assembly seams, not just the filled ones!



Any glaring errors such as these spots (I purposely left to illustrate ) I forgot to sand really pop out at you with a little color contrast provided by the paint.



Along the belly seam I found a spot that appeared at first glance to require touch up but by using a closer peek with under my magnification lamp and a little tactile testing it really turned out to be fine.



So, what do you do if you do find a flaw, well simply lightly sand the area to remove the paint from the surface (hence the reason to only lightly mist a translucent amount), use the appropriate filler (if required) to accomplish the task (Mr Surfacer or ultra thinned putty) then sand and polish...repeat as necessary. Why remove the paint you ask? Because cement and fillers usually will not adhere to a painted surface.

As your skills improve, you will find that you'll nail it on the first attempt with just a few little spots that get missed. Learning how to 'Read the Seam' by noticing how the plastic oozes from the seam when it is cemented and pressure applied, how the dust from sanding forms a line along the minute gap along the seam and spotting flaws before you step forward to the painting process will really improve your models overall quality and appearance.

TIP: If you do end up using a fair amount of putty and it has even a slight contrast in color compared to the plastic you'll want to be sure to prime the thinner with a neutralizing color. A color that closely matches the plastic or if applying a light color such as white, yellow, light gray or pale blue you'll want to apply a primer to the surfaces that will be painted with those colors. This provides a solid base of color which prevents the contrast of the darker putty from bleeding through necessitating large (many coats) amounts of paint to get uniform color coverage.

Well guys & gals, I've reached the end of major assembly for the DC-3, she's headed into the paint booth to get an overall NMF. So, I need suggestions as to what you want demonstrated. It can be about seams and assembly issues or I'm open to suggestions for new threads.

Standing by!
gcn123
Joined: September 13, 2007
KitMaker: 69 posts
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Posted: Sunday, February 17, 2008 - 08:25 PM UTC
Hi Gerald

I think this is one of the most useful threads I have ever seen and I thank you for the considerable effort you have put into this.

Back on page 1 you showed this



This is an area where I have the most trouble with more often or not a large step that ends up ruining the underside of the model and no matter what I try I cannot get an acceptable result.

I currently have the problem on my Hasegawa Hurricane which has the added problem of a ribbed finish.

Any further tips on this would be welcome.

Regards
Gary
norherman
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Posted: Sunday, February 17, 2008 - 09:44 PM UTC
Excellent instruction, plus I like your subject the DC 3. I could build them for ever.
HawkeyeV
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Wisconsin, United States
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Posted: Monday, February 18, 2008 - 02:22 AM UTC

Quoted Text

Hi Gerald

I think this is one of the most useful threads I have ever seen and I thank you for the considerable effort you have put into this.

Back on page 1 you showed this



This is an area where I have the most trouble with more often or not a large step that ends up ruining the underside of the model and no matter what I try I cannot get an acceptable result.

I currently have the problem on my Hasegawa Hurricane which has the added problem of a ribbed finish.

Any further tips on this would be welcome.


Regards
Gary



Let me do some thinking on how to best present this as well as come up with some examples.

Some believe that whats under the model stays under the model...Never put a mirror under your butt if you don't want everyone to see it...same goes for a model.


Can you send me a picture or post one of what you are talking about...it will be of benefit to everyone.
gcn123
Joined: September 13, 2007
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Posted: Wednesday, February 20, 2008 - 09:10 PM UTC
yep will do hopefully tonight or maybe tomorrow
ejclide
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Ohio, United States
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Posted: Saturday, February 23, 2008 - 04:08 AM UTC
I hope I didn't miss something, but I have two questions. 1 is how you thin putty. I have yet to find a hobby shop with mr surfacer, or even a contest i've been to. I am just curious what you use to thin putty. #2, what do you do when you sand a seam on a plane with raised panel lines and you inadvertantly remove the raised panel lines? I try so hard to sand around them, but 90 percent of the time I sand off a little of the lines along the top or bottom of the fuselage, and then it's really obvious that it's not there.

Very helpful thread though, thanks!
HawkeyeV
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Wisconsin, United States
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Posted: Saturday, February 23, 2008 - 04:55 AM UTC

Quoted Text

I hope I didn't miss something, but I have two questions. 1 is how you thin putty. I have yet to find a hobby shop with mr surfacer, or even a contest i've been to. I am just curious what you use to thin putty. #2, what do you do when you sand a seam on a plane with raised panel lines and you inadvertantly remove the raised panel lines? I try so hard to sand around them, but 90 percent of the time I sand off a little of the lines along the top or bottom of the fuselage, and then it's really obvious that it's not there.

Very helpful thread though, thanks!



Mr Surfacer is going to get harder to find. It doesn't meet the US labeling requirements so it's importation has been halted. You'd have to order from an overseas retailer.

You can thin putty usually with either alcohol or lacquer thinner.

Raised panel lines are and have always been an issue when it comes to sanding. There is a method of replacing them, but it is tedious and difficult. I will post up a how to on that shortly to give the readers some idea how it works.

What I do is to protect as much of the surrounding raised details as possible. Cover them with masking tape as I did above on the DC-3. If you have to sand a...lets say a top seam, try to sand within a band of lines running parallel to the seam. The cross over or intersecting raised detail will be lost, but I found as long as it is consistent the whole length of the seam it didn't draw much attention. It will appear that it was meant to be that way.

The other option is to remove all of the raise details and either rescribe or use painting techniques to replace them. Sometimes you just have to use a combination of both or leave them off all together. I've done many of those 50's vintage kits with raise details including markings by removing all of the details completely...they look great!

Let me get back at the bench to demo and photograph how to replace raised details. See ya shortly.
HawkeyeV
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Posted: Saturday, February 23, 2008 - 02:20 PM UTC
So you want to restore those raised panel lines you sanded off while filling a seam. It is always easier to remove than fill back in, but your in luck this process is fairly simple.

First you'll need to determine which material you want to use. I prefer stretched sprue, but you can use precut styrene. One thing you all should be aware of...if you find a specific model which has sprue that stretches easily and uniformly without breaking KEEP ALL OF THE SPRUE TREES. Not all sprue is created equal.

I start by stretching several pieces of sprue. Remember the faster you pull the heat softened plastic the thinner the diameter...slow=thicker. Light a candle and practice...you'll have resources for many different applications...antennas, actuators, spars and longerons etc.



Place some reference marks on the model where you want the sprue to be placed. Then you can either use the CA method or the solvent method to apply it onto the models surface.

I like the CA method because it is faster. Take a piece of masking tape and stick it to the edge of your workbench (see picture below) place a puddle of thin CA onto the tape. Stretch the sprue taunt and draw it through the CA, then immediately press it down over the area between the reference marks. Hold the sprue down firmly until the CA sets. Again refer to the picture.



The solvent method: Use a 'cool' slow acting solvent because too hot of a solvent will only cause the stretched sprue to melt and disfigure before it can be properly placed.

Start by painting a line of solvent along the line between the reference marks to soften the surface where it is going to be applied.



Again lay the stretch sprue into position then sparingly apply a little solvent to bind the sprue to the surface.



Once the sprue has had a chance to cure, you can trim it to fit then polish off the rough spots with a polishing stick. If it doesn't work, simply sand and repeat. Since the popularity of recessed panel details have become the mainstay, this technique hasn't been discussed much...but now ya know!
ejclide
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Ohio, United States
Joined: January 03, 2008
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Posted: Sunday, February 24, 2008 - 01:20 PM UTC
alright, I've got one more question for you, kinda off topic. Where do you get your touch n flo's? I can't seem to find them anywhere, even online.
HawkeyeV
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Wisconsin, United States
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Posted: Monday, February 25, 2008 - 01:07 AM UTC
Try http://www.spruebrothers.com/.
HawkeyeV
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Wisconsin, United States
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Posted: Tuesday, February 26, 2008 - 09:20 AM UTC
Just for those who have shown interest in my DC-3 build, here is an update.

She's sporting a Talon Series Acrylic NMF! I've installed the deicer boots and will be moving on to installing the engines, landing gear and decals.







More to come!
ejclide
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Ohio, United States
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Posted: Wednesday, February 27, 2008 - 04:00 AM UTC
did you preshade under the NMF? It looks amazing!
HawkeyeV
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Wisconsin, United States
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Posted: Wednesday, February 27, 2008 - 07:30 AM UTC

Quoted Text

did you preshade under the NMF? It looks amazing!



No preshading it was all a result of the polishing process.
Moeggo
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Wellington, New Zealand
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Posted: Sunday, March 16, 2008 - 08:30 PM UTC
is there a difference between the 3M Blue and Green putty? I only can find the Green stuff localy..