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Reading the Seams
HawkeyeV
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Wisconsin, United States
Joined: September 20, 2006
KitMaker: 319 posts
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Posted: Thursday, January 03, 2008 - 11:15 AM UTC
For many of you you're wanting to have a seamless build. Well, it took me many years to learn just how to accomplish that feat but I think I can help you along. On my website I published an article about Perfect Seams, I've been working on getting part two of that article ready so I decided to share some of its contents with you.

I use liquid solvents applied with a Touch n Flow. My two choices of solvents are Weld-On#3 and Tenax. The Tenax being the cooler of the two. One you have test fitted your parts to make sure they match up as best as you could ever hope for you simply hold the parts together and apply the solvent along the seam. This does take some practice. If you can apply it from the inside, say through the wing opening, cockpit or any other means that gives you access so the TnF can reach inside and deposit the solvent along the seam the better. Otherwise outside is okay too.

Once you get the solvent into the seam pitch the parts together and hold them until it begins to set up. You should have a line of bubbled plastic oozing slightly from the seam.


Once the seam has cured it is time to start to remove the weld bead from the seam. (Just like they do with steel.) Using a polishing stick, sanding stick or sand paper you want to take the bead down flush with the surrounding surface.



If you can see the seam while sanding like in the photo above, it tells you that the weld didn't penetrate evenly or completely. The line forms from the dust from the sanding. This needs to be filled. If the seam is deep...we'll talk about that later. But for seams as shown, one can use some Mr Surfacer or thinned putty.



When I apply the Mr Surfacer I use a brush. I blot it on, don't wipe it on like paint, you'll not fill the seams flaws and only make yourself more work sanding and polishing.



To really test your skills, build a model without using any fillers or paints. This will help you refine your skills as a builder. Ever notice those models the manufacturer display in plain plastic?



Would you like me to continue with this thread?
butchm
Joined: September 06, 2007
KitMaker: 7 posts
AeroScale: 6 posts
Posted: Thursday, January 03, 2008 - 02:17 PM UTC
Hi Gerald,

Awesome, lets have more!

PS, I don't think I'll ever get a job with manufacturer doing 'bare' plastic display kits. It must be a near impossible task if you have to do one with fit issues!

Cheers,
Butch
HawkeyeV
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Wisconsin, United States
Joined: September 20, 2006
KitMaker: 319 posts
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Posted: Thursday, January 03, 2008 - 02:23 PM UTC
The whole point is to develop your skills so your models are better.
Red4
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California, United States
Joined: April 01, 2002
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Posted: Thursday, January 03, 2008 - 02:56 PM UTC
Keep it going Gerry. There are a lot of folks who should be watching this. I've been building for over 30 years and still learn new stuff everyday. Keep the thread alive! "Q"
HawkeyeV
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Wisconsin, United States
Joined: September 20, 2006
KitMaker: 319 posts
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Posted: Thursday, January 03, 2008 - 05:08 PM UTC
Some seams are obvious that they need repair before proceeding on with the build.



Some seams will lurk wait to pop into sight after the paint goes on. Hence the title, reading the seams. Little clues can be spotted before the paint hits the plastic.





This little area of this seam shows the tattle tail sign of dust inside the flaw. Had I wiped down the model before inspecting this might have evaded me and not rear its evil head until paint was applied. Fortunately I learn how to read the seam!

HawkeyeV
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Wisconsin, United States
Joined: September 20, 2006
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Posted: Thursday, January 03, 2008 - 05:14 PM UTC
Filling with styrene whether it is stretch sprue of extruded stock is stronger and easier to work than CA.







More later, I noticed my grammar errors in my picture captions...a long day at the office followed by too long at the bench, then at the computer.
Red4
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Posted: Thursday, January 03, 2008 - 06:41 PM UTC
I'll add my two cents worth here. A long time ago in a galaxy far, far away, I learned that if there is a signifcant gap, don't try to close it with pressure and a butt load of glue. It distorts things and you end up having a seam anyways. Instead, fill the gap with scrap plastic until it is closed, apply your glue, look for the plastic "ooze" spoke of in the first segment, and then drive on. So far the thread is great. Much appreciated Gerry. Keep it going. "Q"
gcn123
Joined: September 13, 2007
KitMaker: 69 posts
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Posted: Thursday, January 03, 2008 - 09:28 PM UTC
Definitely keep it going, very interesting and its an area I really struggle with
drabslab
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European Union
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Posted: Thursday, January 03, 2008 - 11:09 PM UTC
fantastic thread

keep it going
HawkeyeV
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Wisconsin, United States
Joined: September 20, 2006
KitMaker: 319 posts
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Posted: Friday, January 04, 2008 - 06:34 AM UTC
Lets first look at the wing root of the Ju52 previously shown with the card stock insert.
Its not perfect but can be cleaned up with a file and resprayed, which I'll be doing.



Another Ju52 in the works is this one. It has some serious fit issues which are compounded by the corrigated skin.









Now lets look at one of the true advantages of using liquid solvents. Here is a P-47 that has an not so perfect fitting between the wing and the wing root. The trailing edge of the wing was cemented first and allowed to cure. The next step is to get 'A' to line up for cementing. By leaving the leading edge of the wing untouched, we'll be able to lift the wing up a bit to close the gap and align the wing and wing root together with minimal issues. It is easier to add a filler to the leading edge of the wing 'B & C' and shape it, versus trying to fill a unruly gap at the wing fillet.



This tread is a bit hit and miss as far as order of the processes, but not having a project on the bench at the moment to use (other than the P-47) I've gone back through my old build files for these pictures. If you have any specific questions I'll try to answer them.

Watch one, Do one, Teach one.
HawkeyeV
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Wisconsin, United States
Joined: September 20, 2006
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Posted: Friday, January 04, 2008 - 06:36 AM UTC
I need to proof my grammar before I post the pictures! LOL
Murdo
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Scotland, United Kingdom
Joined: May 25, 2005
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Posted: Friday, January 04, 2008 - 01:17 PM UTC
Excellent stuff Gerald! Really helpful!

guitarlute101
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West Virginia, United States
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Posted: Friday, January 04, 2008 - 02:58 PM UTC
Gerald,

Great info. Many thanks for sharing. Keep it coming.

Mark
ejclide
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Ohio, United States
Joined: January 03, 2008
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Posted: Friday, January 04, 2008 - 03:07 PM UTC
awesome thread, very useful. I'll have you know that if I don't know how to fill a gap I'm coming to you!
HawkeyeV
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Wisconsin, United States
Joined: September 20, 2006
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Posted: Friday, January 04, 2008 - 04:25 PM UTC
Here are a few tools of trade that I use.

Fillers:


Application tools:


Sanders and polishers:


The tools, well you need to find what best works for you. I've collected these over the years, at some point they've all been used.

Fillers. the sprue should stand out as a no brainer, but many modelers never consider using it as a filler. Squadron Green and 3M Acryl-Blue are my two staples for fillers. CA is used only when no other recourse is possible. Many builders us it with great success. TIming with CA is crucial, it it sets too long it gets harder than the surrounding material. So, it is a necessity to work fast before it does, no interuptions! Mr Surfacer is something that I recently started using, I'm impressed! I'll cover the solvents later.

Sanding and polishing. Generally I rarely use sandpaper unless doing a major surface sanding project. Flex I File, sanding sticks and polishing sticks are the primary choice. The latter two are found at various sources, I tend to favor the drug stores or department stores...cheaper!

Once crucial thing to remember with fillers, work in small amounts and in small as an area as feasible. Troweling tons of putty over the gap or dimple will only create you more work in the end.

More to follow...

gcn123
Joined: September 13, 2007
KitMaker: 69 posts
AeroScale: 60 posts
Posted: Tuesday, January 08, 2008 - 01:21 AM UTC
As I've said before this is a very useful thread. I'm particularly interested in this one

because thats exactly where I am at the moment in how to remove the steps where the wings meets the fuselage.
UNITEDSTATESNAVY
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Idaho, United States
Joined: July 07, 2007
KitMaker: 241 posts
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Posted: Tuesday, January 08, 2008 - 08:45 AM UTC
exceeeeeelent info! very helpful to me as I feel a little frustrated with my new hobby and have been taking long breaks
JViguers
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Newfoundland, Canada
Joined: May 22, 2007
KitMaker: 18 posts
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Posted: Wednesday, January 09, 2008 - 04:11 PM UTC
Thanks for the tips. I have a bottle of Tenax 7R and it works great! Bye bye seams.
CReading
#001
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California, United States
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Posted: Thursday, January 10, 2008 - 03:28 AM UTC
Excellent thread. Adding new tricks to the bag every time I read these. Keep em coming please.
Cheers,
Charles
HawkeyeV
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Wisconsin, United States
Joined: September 20, 2006
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Posted: Friday, January 18, 2008 - 10:05 AM UTC
If you have a few minutes take a little side junket over to my blog to check out how I do flush mounted nav lights. This too is a key to having a clean seamless finish.

http://hawkeyeshobbies.com/squawkbox/?p=77



Since it is a very cold and windy weekend, I may have time to add another chapter to 'Reading the Seams thread.
chris1
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Auckland, New Zealand
Joined: October 25, 2005
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Posted: Friday, January 25, 2008 - 03:45 PM UTC
Gerry
Thanks for the thread
As a figure modeller I generally go for less glue.
And have applied this method to aircraft so there was always a lot of filing etc...

your thread reminded me of the error of my ways

Thanks again

Chris


HawkeyeV
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Wisconsin, United States
Joined: September 20, 2006
KitMaker: 319 posts
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Posted: Sunday, February 10, 2008 - 03:24 AM UTC
Time for another installment!

Many of the older kits are notoriously known for their poor fitting of parts and assemblies. This 1:48 Monogram DC-3 is no exception. I've built a couple of these and they can empty a tube of putty in short course unless...you take your time and work slowly and use some planning and test fitting.

The fuselage seam fit was good but did require a lot of patience and working in small steps to get the seam to align properly. I used a lot of masking tape to hold the fuselage in position while I cemented the seam using Weld-On #3 (Tenax will work too).



Once cured I painted along the seam using a brush to apply some Mr Surfacer to see where any flaws or unclosed section of the seam occurred. Luckily I had a solid seam the whole length top and bottom of the fuselage. I used the file to knock off the 'ooze' and even out the seam. Then used a polishing stick to clean up the file marks. You might want to lay some masking tape parallel to the seam along both sides to protect the rest of the fuselage from errant filing.

Once I was satisfied with the fuselage it was time to install the center wing section. Here is where the real fit issues begin. I cement only the rear of the center wing assembly to the fuselage. Leaving the front free to facilitate the upper wing installation (to come). As you can see there is a very large gap to deal with.



Instead of using CA or filler putty I used a scrap piece of styrene card stock. The bigger piece makes it easier to insert it into the gap. Cement in place with solvent on both front and back of the card stock.



After the solvent has had a while to cure, you can trim it down to a more manageable size.



Here is a shot showing the forward side of the center wing section free...this makes it much easier to test fit the upper wing section to the fuselage and center wing assembly.



As I proceed on with the installation of the wings I include that in my next installment. Be sure to visit my website to view my blog (Hawkeye's Squawkbox) and sign up for my newsletter...I've been getting a lot of good feedback about both.

Until next time...
HawkeyeV
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Wisconsin, United States
Joined: September 20, 2006
KitMaker: 319 posts
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Posted: Sunday, February 10, 2008 - 09:58 AM UTC
Since it's so damn cold and windy here (-7F with windchill nearing -45F) today I managed to get some more work done on this DC-3 build I'm using for this section of the thread.

First off was to finish the aft gap where the wing meets the fuselage. I used a flat chisel type blade to remove the excess card stock so it was flush with the fuselage, then I filed it down and polished it out with a polishing stick for good measure. We'll leave the rest until we get the wings mated to the fuselage which is next.




Unfortunately even after removing the locater pins and test fitting the upper wing assemblies several times I wasn't able to get the seam between the wing and the fuselage as tight as I would have liked without really screwing up the alignment of the engine fairings. So another rather large gap needs to be addressed.



Stretching some sprue from the kits parts sprue trees is needed to fill the majority of the gap. Here is a piece which I slowly stretched to get a sufficient diameter to fill the gap. The narrow end goes forward while the thicker end goes in the widest part of the gap. You may have to use more than one piece to fill the void. This one took two on each wing.

Now to do this without a second pair of hands, I tape one end of the stretched sprue under the wing.



Then I pull the other end over the top and hold tension on it until I can apply a couple of drops of solvent to hold it in place. I'm using Tenax by the way.



Once I have it snug and holding itself in place I trim the tails of each end removing the excess. I liberally apply (this takes practice to know how much will do the task without causing collateral damage to the surrounding area) solvent and press the sprue down into the seam with the tip of my hobby knife.



Don't worry if some areas stick up, we're going to take them down later in the build. Once you get both sides done, it is time to take a break and let the seam cure over night. We will start the next step of the process soon.

The wing to fuselage seams are a bugger to work without destroying surrounding detail. It is also one of the hardest seams to access easily especially in smaller scales. Having the right tool for the job makes it easier. Getting a sanding tool that has the same contour as the joint area is tough, but I found that using a round chainsaw sharpening files is fast and easy. Wood rasps are too course and machinist files have a taper to them! Chainsaw files are the same diameter their entire length. These are made by Husqvarna.



These files come in several different diameters to match the gauge of the chain they are applicable to. Their diameter allows you to work the seam and only the seam (I'll show you that trick soon) which makes short order of dressing the materials used to fill the gap cleanly and quickly.



Did I mention that this DC-3 will receive a highly polished NMF and sport markings made by Draw Decals? I'll be using my Talon Series acrylics for the NMF.

Well, thats it for now. Hopefully you guys are reading this thread...let me know so I know it is worth the time for me to continue with it.

Grifter
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North Carolina, United States
Joined: November 17, 2002
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Posted: Monday, February 11, 2008 - 01:40 AM UTC
I'm certainly reading, Hawkeye!

Wingroots are always a problem, Thanks for sharing!
HawkeyeV
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Wisconsin, United States
Joined: September 20, 2006
KitMaker: 319 posts
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Posted: Monday, February 11, 2008 - 03:19 AM UTC
Onward!
It only takes a little preparation and patience to work these pain in the butt seams. Some modelers go straight to CA or putty, others yet will use window glazing to fill this gap. Unfortunately they make more work in my opinion and do not create as strong of a 'weld' as using styrene does. Ever pick up a model by a wing tip and hear that tattle tale 'crack' noise from a seam letting loose?

First I rarely work without supervision by a supervisor who is keen on making sure the project is done purrrfectly.


I do know that sometimes the boss needs to leave me alone so I can get something done!

To protect from errant file scars, use some masking tape to protect the adjacent surfaces...also cover areas that might get bumped by the end of the file.



In some cases a single layer of tape will not offer enough protection...here I have three covering the vents that protrude out of the upper wing surface.



Then I file with the chainsaw file. You may find using a smaller rifler file useful to get into some areas. But the larger diameter allows for better control and less collateral damage. It's a technique I've learned after many failures and crappy wing joints. If the file is too narrow, you end up removing just as much filler as you put in leaving a trench or in the case of hardened CA, you remove surrounding softer material as opposed to the CA filler.



Once the initial filing has been completed, use some tactile senses to see if it is smooth. Your eyes will lie to you, run a fingernail over the seam. It doesn't have to be perfect at this point but close.



Now apply liberally some thinned putty or in this case I am using Mr Surfacer 1200. I dabble it in place with a brush.





We'll leave this to cure for a couple of hours. You can now move on to the other side...where I found that a section still needs more stretched sprue added to a section of the gap, which I will do and set the whole project aside to cure. Once it has had a chance to do that I will do to the right side as I did to the left, file and check the seam with my fingernail then apply some Mr. Surfacer.


See ya again shortly!