Extra Tricks For Smoothing And Detailing

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Sigma LS

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There are a lot of tuts now on most of the major smoothing and basic detailing techniques for pepakura based models. This small specific detail instructional is mostly for those still using the fiberglass/aquaresin/hotglue route but you might find some useful tidbits for folks slushcasting and sanding the basic model. Example pics are from some of my old WIP’s.

Materials List:

Bondo Spot Putty
Elmer’s White All Purpose Glue
Dry Plaster Mix
Non-corrugated Cardboard
Sharpie Permanant Marker
½ inch metal file
Ice pick (the small kind with a screwdriver handle)
Xacto knife




1. You need a model that is fiberglassed or casted to begin to use these techniques. So you’ll start with something like this.

th_HPIM1339.jpg






Trick 1. Smoothing a large curve. (Only on low to moderate wear pieces: no handplates, boots, cod/butt)

Believe it or not, plaster is a very effective cheap compound for this. Since the final product is basically dry gypsum, it sands extremely easily especially while still slightly damp. This lets you get the shape you want with minimal effort. However, plaster is very brittle and will crack and detach from your armor without proper reinforcement. The dried and cured plaster (an hour to several depending on thickness) soaks up liquids like a sponge. What you want is for the gypsum to plastify. To do this, apply spot putty or white glue across its surface in a thin layer that the plaster will soak up. This material will solidify within the plaster matrix and strengthen it to something akin to bondo that will adhere better to the model’s surface. Giving it a layer or two of primer also will give it some additional protection from breaking.

Used here on the top and back of the helm.


HPIM1345-1.jpg









Trick 2. Squaring small platforms. (Cheeklights especially!)

A small, inflexible metal file is great for getting those sharp edges back on small platforms after sanding an area. Hold the file parallel to the platform and make 4-5 passes for each width of the file. This also works for getting rid of the occasional resin drop marring your perfect surface.

Used here on the cheeklights and lower visor platform.

HPIM0401-1.jpg









Trick 3. Recessed line details. (all pieces)

As I’ve seen on many HD builds, people will use various means to mark where they will cut detail lines and recessed details. The rule to remember is the old “measure twice, cut once”. Use a Sharpie (blue or black preferred) to mark where you think your lines should go. This serves a dual purpose, to give you an idea of the symmetry and accuracy of your lines and also a guide while you are cutting them. The marker tip will usually clog with dust or paint after awhile so be sure to have a spare or two. Cut the lines with a dremel cutting wheel (reinforced or EZ-LOCK) at approximately ¼ inch depth. At sharp corners, use some overlap to make sure you have all lines cut at a uniform depth. The bigger the wheel you use, the straighter your lines will be but the further your overlap at corners will be. Cover the overlapped lines with spot putty. Then use an ice pick to assure uniformity of dimension for your lines. Don’t be afraid to fill your lines with spot putty, smooth it out and do it again if it doesn’t look right to you. Use the same principle to cut the holes for recessed pieces when required. For most recessed details, you are better off using a small cardboard template that you can pour mud around in the regular smoothing process. Remove it later and clean the resulting recess with an Xacto knife.


Used here on the back of the helm.

HPIM1386-1.jpg









Trick 4. Adding small positive relief details. (All pieces)

4.1 Cardboard.

The best kind to use for this is the type that has printed ink on one side (most battery packages, cereal boxes, soda/beer case boxes, etc.). First cut a piece in the shape you want, ink printed side out. In the case that you have multiple or symmetrical pieces, use the first as a template to cut more pieces of the same size always with the printed side out. Use a small amount of Elmer’s glue on the non-printed side to wet the cardboard and make it flexible. It usually takes a good 30 seconds to rub it in to the point where the card is soaked. Now it will conform to any curve and stick permanently to your desired surface. Align it correctly and let it set and completely dry. The glue will make the card impermiable and after a coat of primer, it will be set to paint. It is critical that you keep all glue off the printed side. The surface you have when you primer it is the final one. Sanding will not help you.


Used here on the side vents of the helm.

IMG_0703-1.jpg





4.2 Odds ‘n Ends

Many times the best detail bits are already laying around your house in the form of small screws and bolts, old wires and phone chords, bits of pipe, caps of old bottles etc. Look around and find what works for you. One of my favorite little pieces is pink pearl erasers. You can cut them easily, sand them easily, and they take paint well.


Hope this helps a few folks.

Comments and crits welcome. :D
 
thanks sigma, the ultimate smoothness is something I've always failed to do, and always admired on your work.. I need to try a few of these techniques out
 
Thanks guys. Let me know how this stuff works out for you too!

box o crayons- Yes, I did not use any mud/rondo on my Mk V helm at all. :)
 
Sigma-LS said:
Thanks guys. Let me know how this stuff works out for you too!

box o crayons- Yes, I did not use any mud/rondo on my Mk V helm at all. :)
oh ok i guess il be trying it out once i finish pepping my helm thanks
 
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Nice! I'll try it later today, is it possible to brush a layer of resin over it for extra strength? I like my helmets strong :p.
 
i have an idea for cooling the suit.. i know some of you have been talking about a cooling system. i have found that all so far needed some form of power to pump and circulate the coolant. my idea is to use the walking action of the warer to do the pumping if you use pre frozen ice packs or a intercooler you can use your walking action to pump the water. this is a pasive system and will last much longer than a powered system.

for those of you whom dont know who i am google me i think you will be surprised at my backround and enginering skills.

warren williams darpa

I am one of the top robotics experts in the country and i belive i can help you folks with some of the basic systems upgrades i.e. electroinics system integration etc. i just started last nite with my first pepakura component and i love it. cant wait for the glassing phase. <div align='left'></div> :not worthy:
 
<div class='quotetop'>QUOTE(sparten11 @ Oct 16 2008, 07:17 AM) <{POST_SNAPBACK}></div><div class='quotemain'>i have an idea for cooling the suit.. i know some of you have been talking about a cooling system. i have found that all so far needed some form of power to pump and circulate the coolant. my idea is to use the walking action of the warer to do the pumping if you use pre frozen ice packs or a intercooler you can use your walking action to pump the water. this is a pasive system and will last much longer than a powered system.

for those of you whom dont know who i am google me i think you will be surprised at my backround and enginering skills.

warren williams darpa

I am one of the top robotics experts in the country and i belive i can help you folks with some of the basic systems upgrades i.e. electroinics system integration etc. i just started last nite with my first pepakura component and i love it. cant wait for the glassing phase. <div align='left'></div> :not worthy:</div>

I am definitely hoping you are who you claim to be. Also, thanks for the tips Sigma. I'll definitely use the recessed line tip.
 
Can I get some more info on the plaster/glue technique? I don't quite understand what's being done, are you putting plaster POWDER over the glue or are you putting a liquid coat of plaster on it? OR is it putting a coat of plaster on it, letting it dry, and then putting the glue over that?
 
question that I couldn't find the answer to anywhere;
what happens if you start sanding and for some reason the card stock didnt fully soak up the resin?
its all fuzzy where I hit the paper and dont want to go any further x___x
should I just apply a layer of resin to the area? =\
 
sharkhead7854 said:
question that I couldn't find the answer to anywhere;
what happens if you start sanding and for some reason the card stock didnt fully soak up the resin?
its all fuzzy where I hit the paper and dont want to go any further x___x
should I just apply a layer of resin to the area? =\
this would have been a good question to go in the Question thread... but since i am here.

what i do when i sand down to the cardstock, i usually peal/cut as much of it away that is necessary. sometimes this will leave a crater if you didnt do a perfect job glassing the inside. then i will just pack in some bondo, and sand it... i wouldnt bother with adding more resin just to the small area when bondo will fix it.
 
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My two cents on the use of plaster: Infiltrate it with resin.

At my school we have a high definition ZCorp plaster printer for rapid prototyping. The gypsum parts that come out we either infiltrate with super thin cyanoacrylate (Krazy Glue) or 4 hour epoxy so that they keep their strength and don't break when you pick them up. The cyanoacrylate holds up a bit but becomes brittle on thin surfaces and doesn't penetrate as deep. The 4 hour epoxy that we use goes all the way through the part and creates a part that's very much stronger than a cyanoacrylate part. Polyester resin will work just as well for use with plaster, use a bit less hardener than you would normally use and brush it on liberally so that it soaks in fast. If it tries to stay tacky on you and won't cure after about 8 hours (or if you want to speed up the cure) pop it in the oven at about 120°F for about 5 minutes. Once the heat goes away it should be cured.

Another thing to use is a more specialized type of plaster such as pottery plaster but you will need to reinforce your part and work very quickly with this stuff. The cool thing is that it gets hot while it cures so you can infiltrate it with resin with a little bit of hardener in it once the watery film on the top goes away and the heat from the plaster should cure it all in one shot.
 
DreadMullet said:
this would have been a good question to go in the Question thread... but since i am here.

what i do when i sand down to the cardstock, i usually peal/cut as much of it away that is necessary. sometimes this will leave a crater if you didnt do a perfect job glassing the inside. then i will just pack in some bondo, and sand it... i wouldnt bother with adding more resin just to the small area when bondo will fix it.
aha! as reluctant as I was to do it I always try to take advice from peeps with experience.
Turns out that, like ya said, there were craters in the helmet XD
looks like there wasnt resin soaked through because the fiberglass didnt touch it. I did the "dip the glass in resin" method so there was no other coat on the inside.
good thing it was caught before I painted it with all those weak spots.
thanks for the reply!! ^___^
 
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