Quick and simple rivets

[charliec]

I noted on another forum on building a Ju88 that the edges of some internal components were sealed with a PVA glue + acrylic paint mixture. This looked very effective and I thought the same idea could be applied to adding rivet details to models. Applied with a syringe so you can control the drop size this would be a lot simpler than various embossing techniques.

I've had a preliminary play with this and it looks promising.

I've got a couple of questions -

Have I reinvented the wheel (again)?
Is anyone interested in some images?

Regards,

Charlie

 

[jrts]

Hi Charlie

Yes please

Regards

Rob

 

[barry]

and me

barry

 

[Leif Oh]

Yes, definitely. As far as reinventing the wheel, I recognize the technique from larger scale aircraft modeling. I remember a very detailed plan of a 1/6 Curtiss Jenny, where it was suggested that you reproduce every bolt and rivet on the engine covering plates by small drops of two-component epoxy glue. I couldn't imagine mixing that amount of epoxy (just imagine how many times you would have to do it, considering how quick the glue would set).

What's particularly attractive to me is the promise of doing it in smaller scale, and with water soluble glues.

So I really look forward to your pictures and description of the technique!

Leif

 

[charliec]

After a bit more experimenting it seems as if this isn't going to work.

The problem is that with water based emulsions like PVA glues and acrylic paint that there is quite a bit of shrinkage as the emulsion dries. So if you start off with a hemisphere of wet glue/paint by the time it dries the initial hemisphere is reduced to a spot with much less relief. The gotcha is that if you then reduce the amount of water in the emulsion to reduce shrinkage the viscosity goes up to the point where it can't be applied with a syringe.

I can see now why ths idea works effectively as an edge sealer because although there is shrinkage on drying it will be uniform.

I'd guess that epoxy based glues/fillers don't have the same shrinkage characteristics so would be satisfactory (Leif's post).

I wonder if there is such a thing as a gel based PVA which won't shrink on drying?

Regards,

Charlie

 

[Gil]

Charlie,

Paper is easily embossed. It requires that you work on the inside so it must be done before the skin is assembled. It also requires that a template be made which is used as a guide for applying the detail. Waxing the template with bees wax makes the embossing work run smoothly. Hold it in place with Aleene's tack glue (it's like a postit adhesive and allows the template to be repositioned). Take a look at "pounce wheels". Once you've had a chance to experiment with these you'll only consider the syringe method as a last resort. Rib and longeron lines are easily applied with an embossing tool available at low cost from most craft stores. Get a set anyway as they're very handy tools for making fold lines for neat and tidy corners.

The amount of emboss is controlled by the pressure you apply with the embossing tool and the softness or rigidity of the underlying "anvil" surface. I commonly use magazines, cork pad, rubber gasket cloth and plate glass as the main anvil surfaces. Anvil surface selection will be dictated by the effect you desire.

A light box can be an invaluable aid in this process. The light box shines light through the surface work so you can follow the panel line detail (i.e. if the paper isn't too thick)..., a scrap piece of plexiglass with inscribed rivet lines and various panel lines serves as an anvil "emboss former" and greatly faciliatates the embossing process and makes it nearly fail safe (I said nearly....,).

Best regards, Gil

 

[jrts]

Gil

Sounds like your other half makes greeting cards. Mine does and I steal all the items you just listed off her and your right they work a treat :lol:

Regards

Rob

 

[charliec]

I know about embossing paper and have used it for a while. I was trying to explore another option beside embossing after seeing the PVA/acrylic used to good effect in an aircraft model.

One of the areas that paper models don't do well is capturing surface textures. In part this can be overcome by clever use of graphics but there are some models which don't seem to work particularly well in paper even though the model may be very precisely designed. This isn't of importance in aircraft but AFVs often have strongly textured surfaces. For example the castings used in WW2 Russian AFVs are often quite rough because the Russians didn't bother finishing the castings. I'd be interested in simple ideas to add texture to paper model surfaces.

Regards,

Charlie

 

[Gil]

Charlie,

Look into acrylic hard modeling paste. Golden and Liquitex are some of the more popular brands. These are sold with all kinds of additives to build texture. I have some that's got pumice in it and it makes and incredible ground for dioramas. Add plaster to it and it textures like stucco. Comb it with a fine tooth comb, paint it dark silver and it looks like a tin roof. You can have a ball just experimenting with the stuff. I also use acrylic gel medium varnish as a binder for raw paper fibers. Take a brown paper bag, put it through a shredder then put it in a blender with the acrylic gel medium. Balance pulp with acrylic till you have a workable pulp. This can be used to form all sorts of build-ups from trees, river rocks and stone walls to name a few. Need mortar for your brown stones? Just use newspaper instead and use it like mortar between your brown rocks. This stuff is fairly imagination intensive so be careful....,

Best regards, Gil

P.S. Zermit coats are a "piece of cake" with this stuff.

 

[Leif Oh]

Lightbox for embossing

Gil (and others) - for an example of a lightbox, see here and here. I built it for exactly this purpose (drawing rib lines on the back of the paper, etc.) The only drawback I've encountered is that if you use paper of some thickness, and dark colours to boot, you really don't see very much, in spite of the bright lights underneath. But for thinner (still thicker than ordinary copy proof) paper it's very good.

Charlie, my experience is the same as yours. Mixing white glue with paint is great (as I learned from Swinger's Ju 88 thread), but it does not make much of a rivet head. Next time I'm going to try a fast-drying variety of white glue, which seems to be thicker, and mix it with water colour. But, as you say, then it's more difficult to apply in really tiny droplets. Perhaps we'll have to learn (from Gil or somebody) what exactly to mix it with (preferably something easily available) in order to accomplish rivet heads.

But then again, perhaps embossing is the way to go. Pity I didn't think of that yesterday; I could have used it then. Now it's too late for that particular purpose, but there's always another day, and another model, right?

Leif

 

[Gil]

Charlie et al,

Sometimes reinventing something can be a good thing, especially if it goes awry and something profound comes out of it. Most times though it's just ignorance of the fact that it's already been done before. I seem to be an expert in the latter category...,

After a little thought I remembered something I posted a long time ago on this website several predecessor versions ago.

For a great texture paste try mixing Grahams Rock Hard Water Putty with white glue and a little water to thin it to the right consistency for your application. This can be anything from a clay like mud to a thin coating. Use a textured roller to get a stippled effect; a sponge for an uneven stippled effect. Adding graded sand can yield interesting textures especially after letting it setup a little and then washing the surface with a wet sponge. I've made some great looking columns for a model of the Temple at Karnak with this method. Didn't even have to wash with a base color as the water putty was perfect as is.

Anohter great combination is to use old water based house paint as a mastic base. Especially if it's white and it's partially dried up. That's the best as most people will want to throw it away. You can use water putty, plaster and other base thickeners to do the same as above. It makes a pretty good adhesive for paper mache and if it's the right color you won't have much finishing work when your done. Scorpio has already started down this path with his mixing acrylic paint with PVA glue.

In fact that's really what's involved here. Your looking for fairly low cost adhesives that are compatible with paper. Adding things like plaster and water putty adjust the viscosity and working qualities for the application at hand.

How to apply the paste as a rivet is now in the hands of Charlie who has gallantly been nominated and auto-inducted into that post. We'll all be expecting a full report on the progress you've been making within less than a week or so...., We're depending on you now...,

There...., that should be enough to keep you off the streets at night. Instead you'll be doing strange, unusual but constructive things late into the night....,

Remember to tell the unbelieving, "Did I tell you that's it made from paper?"....,

Best regards to all, Gil

P.S. Nice light box Leif. Think I'll make another one along those lines...,

 

[Leif Oh]

You sure are burning the midnight oil, aren't you Gil (considering the difference in time zones)? - Leif

 

[Gil]

Leif,

I'm just finishing up now. I have to be quiet and pretend to sleep now for several hours or they'll all get suspicious again and that will lead to accusations and then I'll have to disappear again and ....,

Best regards, Gil

 

[charliec]

Thanks for the ideas on textures.

I think I'm being "volunteered" again - strange that this is happening in my
hobby as well as work. "She who must be obeyed" - my boss - is a notorious,
serial volunteerer.

I'm about half way through a set of KV-2 tracks i.e. don't expect quick results.

Regards,

Charlie

 

[Texman]

I believe the word your looking for is

"voluntold"

Ray

 

[Gil]

Charlie,

One good thing about treads, you either get very good at making them or your desire to build armor suddenly changes.....,

Best, Gil

P.S. I did mix up some white glue and plaster of paris for something else last night and took a little of it in a syringe and did some "cake decorating" on a scrap piece of cardboard. Worked great but just the same use plaster or water putty to give yourself a longer pot life.

 

[charliec]

I sit at the feet of the master on building tracks - Jim Nunn. His technique
of cut down chisel blades works really well but it's still very tedious even for simple track models. Someday I'll tackle the Halinski Panther with 7 (from memory) parts per track link. You don't see too many finished Halinski Panthers around - wonder why.....

I must try the Plaster of Paris in PVA idea - might be the answer I'm looking for. Calcium Sulphate (Plaster) expands slightly when it hardens which might be useful property for this application.

There is a view about armour models that they should be built from roughly scale card to represent the armour to allow accurate modelling of the interior. For a model Panther this represents about 3mm of card on the glacis which pretty much rules out embossing. I know you could emboss a thin sheet then laminate but the embossing would have to withstand the lamination process - from experience this can be a bit fraught. The idea of adding surface detail directly onto the card has a fair appeal with this construction technique.

Regards,

Charlie

 

[Gil]

Charlie,

Jim Nunn is the Master of Tread. That's why some time ago I experimented with making steel rule dies so that the treads could be punched out one hammer slap at a time. Didn't get around to doing a tutorial on it as there wasn't enough interest in the technique at the time. Grinding chisel blades down is a great idea and is useful beyond just whacking out tank treads. I keep a set ipermanently in handles because they're very useful for modeling in general.

One method of achieving the plate thickness that you might want to try using 100# card stock. Cut out two layers and emboss one. You could coat both with acrylic matte sealer to help prevent the "sags" but it's not really mandatory. Laminate together by spreading a layer of acrylic hard modeling paste over the surface of the embossed part and also a layer on the backing card. Gently work the two together and let set to dry. You might want to experiment a little before commiting to a model but I think you'll be suprised at how rigid the composite is. It's pretty tough and can withstand a lot of abuse. The underlying paste supports the suface emboss which is now "cast" in place. I also use this method for curved pieces where I want to set the curve in with a monokote iron by tacking it in several places to hold the curve while the piece dries. Makes planking a ship a piece of cake.

Best regards, Gil

Note: A hard acrylic paste can be made from house paint and whiting (Powdered Calcium Carbonate). Mix in the whiting till you have the desired consistency. Patching plaster will also work.

 

[charliec]

I remember the "steel rule dies" thread. I think the problem was that people didn't really understand the concept or technology - I know I certainly didn't.
Searching the Web didn't help much - seemed to turn up high tech machining
products which are obviously beyond most people.

Steel rule dies sounds as if they would be beyond most modellers. If this is not the case how about a primer for the ignorant - maybe the technique is within the capabilities of many modellers and would be a great addition to the techniques toolbox.

Regards,

Charlie

 

[Jim Nunn]

You guys are making my head swell, on to rivets. This is something I have been thinking about since I purchased GPM’s R17, lots of rivets on the R17. One thought I had was to add talcum power to glue to give it some body and use watercolor paint to give the glue color. The Idea of using plaster is one I’ll have to try.

Well this thread got me off my can and I gave it a try. You can see the results, not great and not to bad either I think with practice I could make consistent sized rivets. The large rivets are about 1 mm wide (1 inch in 1/25 scale) and about the same height. The small rivet is a little under .5 mm. I doubt if I could make them smaller then .5 mm.

The recipe. Start with talcum power add watercolor paint to make a crumbly dry mixture. Now add glue until you have the consistency of thin toothpaste. I used a Cryo glue syringe with a small tip to make the drops. The rivets did not shrink when they dried and the talcum power gave the rivets a “flat†finish.