Author Topic: Easier way to sand these areas?  (Read 3136 times)

Runamuck

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Easier way to sand these areas?
« on: November 25, 2008, 10:07:22 PM »
I apologize for posting this here, since I don't wanna risk getting this post bumped (which still will, lol). Please move this thread if you must.

BTW, I might give someone in this forum a MG or something from Fulcy's store for Christmas or possibly a bit later on, (depending on my work schedule since I'm working a lot + extra shifts and overtime).

I'm working on a HGUC Zaku 1/144, and I'm having problems sanding areas shown in the pics provided. (I had to use pics from 1999.co.jp since my camera sucks).

Areas marked:
http://www.flickr.com/photos/19254782@N05/3059912825/
(Give me a break, I'm heading to work in a bit and this was as good as I could do it in such short notice).

Same pic just unmarked so you know what the areas that I'm having trouble with are:
http://www.flickr.com/photos/19254782@N05/3059914277/

It's not just these areas on this particular kit, but pretty much for all HG's in general. Fixing seams is not a problem for me and usually sanding isn't that hard. Around the areas that I marked on the pic, I sand to fix the errors with the molding. Problem is that it always comes out very... crappy. It's very misshaped, details are all crooked, and it's extremely hard for me to fix them afterwards. This has lead me to give up on a lot of kits that I still have.

Sandpaper is ok but it usually leads to having edges all round rather than to look sharp... or at least as nicely as they look when you're snaping the kit. Sanding sticks using popsicles and plastic sheet pieces, always leave detail all crooked around corners and such, making it very hard to fix. Flat surfaces... are ok, but again crooked.

This is what keeps me from finishing a kit. I don't have problems with priming or airbrushing since I paint on cars a lot.

So... any suggestions on making this easier?

Any help that can lead me to getting on the right track with sanding/fixing these parts, will give you bonus points for getting the MG or something from Fulcy's store.

Sorry for making you read so much, you can smack if ya want. You know you wanna :D.

Zircor

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Re: Easier way to sand these areas?
« Reply #1 on: November 26, 2008, 01:11:06 PM »
Subscribing to this thread, as I was having some of the same questions on my HGUC Zaku I.  The shield especially is ticking me off, but the forearms too have given me pause.

FichtenFoo

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Re: Easier way to sand these areas?
« Reply #2 on: November 26, 2008, 01:48:00 PM »
Sounds like you are sanding too hard and randomly. Use sticks to get those areas flat. Now one trick I use is to color that area with a sharpie (any color). That way you can see what's been sanded away easier and check to see if it's crooked or not. Also look for a small "bastard file" for metal, bt works great on plastic too, especially for large beveled areas. A 6-7" one is a great tool! With the sandstick, like the file, just sand that edge by pushing forward with long, but light strokes. Too hard and you risk sanding too much. Basically, take your time and use a sharpie as a guide.
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Runamuck

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Re: Easier way to sand these areas?
« Reply #3 on: November 28, 2008, 11:59:32 PM »
I have yet to try this out. Hopefully I'll get a chance tomorrow after work.

New questions:

Is Tamiya 400 grit sandpaper good to sand those areas, or should I use a different grit?

From your personal experience working on kits, would it be wise for me to sand these areas down smoother with 1000 and 2000 sandpaper?

I believe you use Mr. Surfacer (small bottle to mix with thinner) rather than Tamiya primer. If I sand the kit with 400 grit sandpaper only, is it better to use Mr. Surfacer 500 or 1000?

Is this the right kind of file you were talking about:

http://www.flickr.com/photos/19254782@N05/3067018831/

or this one:

http://www.flickr.com/photos/19254782@N05/3067018841/
(This one is 8" though)

FF, you have bought yourself some points for the MG or something from Fulcy's store. Thanks a bundle!
« Last Edit: November 29, 2008, 12:09:21 AM by Runamuck »

FichtenFoo

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Re: Easier way to sand these areas?
« Reply #4 on: November 29, 2008, 09:51:43 AM »
Heh... I have plenty of kits. Maybe you can donate it to the Model of the Year compy coming up.

The first file is the one I use.

I use spraycan Tamiya or Mr. S in the summer and jar'd Mr. S in the winter. The difference is spraying outdoors or in.

Depending on my finish with the 400 I occasionally go back with some 1000 grit to smooth it a bit. Or some "very fine" steel wool for rounded areas.
Rust is beautiful.

Construct

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Re: Easier way to sand these areas?
« Reply #5 on: December 08, 2008, 09:47:57 PM »
Runamuck, for seams like those you may prefer scraping rather than sanding: Gently dragging a sharp new blade sideways along the seam will take feathery shavings and leave a perfectly smooth surface. You can also remove nubs this way if they are first cut all but flush with the surface (again, use a very sharp blade and very little pressure). It's cleaner than wet-sanding (especially when dealing with putty-filled seams) and easier to see what you're doing, though not as versatile.

FichtenFoo

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Re: Easier way to sand these areas?
« Reply #6 on: December 09, 2008, 06:27:30 AM »
Runamuck, for seams like those you may prefer scraping rather than sanding: Gently dragging a sharp new blade sideways along the seam will take feathery shavings and leave a perfectly smooth surface. You can also remove nubs this way if they are first cut all but flush with the surface (again, use a very sharp blade and very little pressure). It's cleaner than wet-sanding (especially when dealing with putty-filled seams) and easier to see what you're doing, though not as versatile.
I forgot about scraping. That works especially well on figures and on conduits where you don't want to sand it flat.
Rust is beautiful.

Runamuck

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Re: Easier way to sand these areas?
« Reply #7 on: December 16, 2008, 02:33:07 AM »
FINALY, I got some time to check my e-mail and stuff.

Anyway...

I would like to try scraping on the last spare part I have. I need to know:

Should I scrape during sanding, or after I prime?

Also, normally when I prime parts I leave them to dry and forget about them since I'm at work a lot. I've never really noticed how long Tamiya primer takes to dry. So I'd like to know:

How long is Tamiya primer drying time before it's ready to be sanded again to fix errors?

chaos_theory

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Re: Easier way to sand these areas?
« Reply #8 on: December 16, 2008, 05:26:01 AM »
Scrape before priming. As a rule of thumb... let tamiya primer cure for at least 8 hours, 24 hours is better. Light coats with about an hour in between will speed the curing process.
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igor57

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Re: Easier way to sand these areas?
« Reply #9 on: December 19, 2008, 02:41:41 AM »
Sanding!    Could write a book on It :D   In the course of my work I would go through maybe 400 sheets of the different grit sizes per year. 

Ok First tool to get:    One of these.  Have had one now for probably 10 years and they are wonderful for all sorts of applications.  Expensive but so worth it. 

http://www.progresstool.com/pd_jewelers_half-round_xtra_slim_hand_file_-_cut_6_long_2.cfm

Take the seams off with the file, then 240 grit, 320 and then 400.   Mostly on my builds I stop there but sometimes if the paint is going to be very thin and without primer I will go up to 800.

If you like sanding sticks, then it is very easy to make up your own.    Make up whatever profile of stick you fancy (I prefer ones about 25mm wide and made from firm tough wood, and then source some Disc Cement.  I use "Bear" also made by Holdfast over on this side of the World.  Smear in on thinly on the stick and onto the paper, give it a couple of minutes for the solvent to dry off slightly and then stick together.  The beauty of the Disc Cement is that you can peel off used paper and replace it on the same stick.   Also this method allows you to make shaped sticks for getting into specific areas. 

Another trick with sanding paper is to cut it into a strip, then fold it tightly onto itself as many times as you wish, starting at one end and working your way along until all the paper is folded onto itself.  The trick is tight folds.  A little "pad" of sandpaper is formed.   As one outer piece of paper is worn away, cut it off so exposing a fresh piece of paper, and so on. 

Another very interesting paper that is available is Trizac by 3M and Norax by Norton.   This product is termed as "structured abrasive".   Expensive and quite extraordinary.   I have used both types and they are good, really good.   Come in Micron sizes from 180 down to 6 micron.  On plastic the stuff just does not seem to wear out at all.

Scraping seams etc is really great, and I always file them first to ensure that when scraping there are no major bumps to start with.  I use glass.  Yes broken window glass.  3mm is best. Fantastic!   One pass and it's all done.   Very smooth.  Not for the faint hearted but excellent none the less.   I tape off the edges I will hold with masking tape and always wipe whatever I have been scraping, with a cloth, before touching it.  Sometimes you get tiny shards of glass left behind and the cloth sorts that problem out.   
In days long gone all furniture finishing was done with scrapers.   If you look for them you can still find the furniture makers scrapers, otherwise a firm bladed knife sharpened on one side only (to form a tiny hook on the cutting edge)  is perfect for scraping.   

Have fun, Cheers