Acrylic or styrene sheet help for new guy?

[Mr. Race Bannon]

Hello, I'm new to the boards!

Would like some links for any process shots or tutorials on building model parts out of styrene or acrylic plastic, and what glues to use and so forth.

Did a search here and came up with nothing as of yet...

Thanks!

[Dufaeth]

http://www.starshipmodeler.com/basics/cj_pcg.htm

A basic primer to start with

[Woody]

This thread has some pictures of the secondary hull for my Baton Rouge class being scratchbuilt from 1/8 inch styrene sheet.

http://cs.finescale.com/forums/270069/ShowPost.aspx

[Lt. Z0mBe]

MEthyl ethyl ketone and methylene chloride can be had at hardware stores and will bond acrylic to styrene and styrene to styrene. The stuff is nasty, so don't go using it as aftershave.

I don't have much to add to the tutorials, but a nice tool I would recommend is the Olfa ratcheting compass cutter. I use it the standard (forward) way for scribing. Counterintuitively, it works best bacwards using the back of the blade for actually cutting the circle out. Erin (Dasphule) turned me on to this one.

Another one I bought and cannot get enough of is Northwest Short Line's Chopper II. The original Chopper is less expensive, but the base is made from pressboard and not as sturdy. There is a Chopper III, which is a large Chopper I. This thing basically allows you to miter chop styrene sheet of widths up to a razor blade's and thicknesses up to approximately .125-inch thick. The literature says you can go up to .25--inch, but the blade begins to flex and the cuts aren't as straight. Included are miter guides allowing various angle combinations. It works great for strips of balsa, basswood and sticks and will cut very thin brass and aluminum sheet.

The smartest thing I can recommend to you, if you are able, is to cover your bench with a cutting surface. Some guys use large cutting mats like those sold in hobby shops or craft stores. They work great, and are self healing. They will eventually need replacing, but the benefit is they have a grid on them, helping with alignment and measurements. Another option - the one I favor - is to cover your surface with a big thick piece of glass. I snagged one from a broken piece of furniture. It's tempered glass from the top of a desk, and short of dropping a hammer on it, holds up well to knives and paints. It will also allow you to make custom templates and tape them to it as you go when you are scratchbuilding. For example, on my current project, I marked the length of my fuselage on a long piece of wide masking tape, and marked all the locations, widths and thicknesses of bulkheads along the fuselage spine. I temporarily white glued the spine to the glass, let it dry and then added all the bulkheads. After everything was assembled and solid, I slid a knife blade under the two little spots of white glue and "popped" the entire thing clear. You get the idea.

A couple of other things to get if you're getting into scratchbuilding of any kind. First, get some diamond coated riffler files in fine grit, at least. They won't dull for a long, long time. If you have the cash, get some medium and coarse grit ones too. Secondly, get a steel square of some kind to keep things square in the vertical and horizontal. Pick up a mini carpenter's square if you can too. I cannot live without my steel rulers for scribing and measuring, particularly my machinists ruler. The first few centimeters are in .5 millimeter gradients. Speaking of measuring, your biggest obstacle once you have measured will be symmetry. You will need to be able to translate measurements from one area to another to do this. This is an easy one, fortunately. Get thee a digital caliper capable of metric and SAE measurements. You can go analog too, but digital will increase your accuracy. Make sure it is capable of measuring depth with the little probe on the opposite end and that it also has the "zero" button; this will enable you to measure "step" distances. Finally, an old pair of machinists dividers will allow you to translate measurements from or to just about any point on a model.

That's about all I have for now. I am heading back to building.

I hope this helps.

Kenny

[Mr. Race Bannon]

Thank you for the replies. I am trying to build onto existing plastic parts, or creating completely new ones. I have some acrylic sheet in clear that I bought at Lowe's, along with a "for sale" sign, which is a thinner gauge plastic, both of which I will try to use.

Will Superglue work for bonding? Or maybe crazy glue, which actually works for bonding ABS plastic. I am not familiar with the stuff that Lt. Zombie mentioned... Methyl Ethyl Ketone? What is that used for and where can I find it (at the hardware store). I have seen the Tenax stuff, and probably only at a model train/plastic kit store... Nobody mentioned that in this post, and I don't know what it's best for.

I might want to do some sanding/sculpting with styrene (or acrylic if I can). I recall seeing a thread here with someone showing laminated plasticard or styrene to get a block to work with, and then filing/sanding the corners to produce curved edges and so forth. I would love to produce completely curved parts (bi-directional) as opposed to just flexing the plastic, but that would probably require a sculpted block and a vacu-forming machine, which I do not have yet.

I'm just getting into this, as far as creating my own parts and add ons, so this should be a lot of fun!

[Richard Baker]

Personally I hate the 'super-glues'. They stick tightly but have no tensile strength- some stress and the part is loose with just dust. I like to use styrene plastic since it is what I have used most of my life and I know how to push it. Acrylic is great for some uses but it is harder to work with IMO.
I owuld suggest before starting a big project with pices you care about try some simple builds just to get a feel for things.

.

[Lt. Z0mBe]

Thank you for the replies. I am trying to build onto existing plastic parts, or creating completely new ones. I have some acrylic sheet in clear that I bought at Lowe's, along with a "for sale" sign, which is a thinner gauge plastic, both of which I will try to use.

Will Superglue work for bonding? Or maybe crazy glue, which actually works for bonding ABS plastic. I am not familiar with the stuff that Lt. Zombie mentioned... Methyl Ethyl Ketone? What is that used for and where can I find it (at the hardware store). I have seen the Tenax stuff, and probably only at a model train/plastic kit store... Nobody mentioned that in this post, and I don't know what it's best for.

I might want to do some sanding/sculpting with styrene (or acrylic if I can). I recall seeing a thread here with someone showing laminated plasticard or styrene to get a block to work with, and then filing/sanding the corners to produce curved edges and so forth. I would love to produce completely curved parts (bi-directional) as opposed to just flexing the plastic, but that would probably require a sculpted block and a vacu-forming machine, which I do not have yet.

I'm just getting into this, as far as creating my own parts and add ons, so this should be a lot of fun!

Race,

Methyl ethyl ketone (MEK) and methylene chloride are solvents. They melt plastics like ABS and styrene. They are, in addition to xylene and toluene and other things what Tenax and Testor's liquid cement are made from. They work by melting the plastic together, and after evaporation, leaving the plastic as a solid piece, effectively welding them together. I get it from the hardware store and decant it 50/50 MEK to methylene chloride into a Testor's liquid cement bottle, as I cannot bring myself to pay $4 for a 1-ounce bottle, when I can get a quart of each constituent for $5 a piece. This is also a function of living 30 miles from a hobby shop. But, I digress. They can be had in the aisle with the lacquer thinner and other solvents. Again, the stuff is nasty, so don't inhale the stuff for kicks. Decant it into a bottle and go from there.

"Super" and "Crazy" glue, as well as their generics are all basically the same stuff, being 2-ethyl cyanoacylate. I'll disagree slightly with Richard on cyanoacrylate (CA or "super" glue) glue's tensile strength. It has excellent tensile strength, in excess of the substrate it bonds together. But, it has little-to-no shearing strength. But, as he said, the surfaces have to be clean and you must hold the surfaces together for a few seconds as the stuff begins to catalyze. It also takes time to get a feel for. The thing to remember, though, is CA glue is, truly glue, not cement - there's no welding going on. When dry, there will be something left behind. It will bond most things together and works great for attaching metal to styrene or some woods to styrene. It is not a cure-all, however, do to its shearing strength weakness. It will also not grab glossy surfaces well, meaning they will need roughing up and/or pinning.

As for working with for sale signs, that's what use the most often. If you're wanting to laminate and the like for sculpting, I might recommend foam to you. Specifically, You may try a scrap sheet of pink or blue styrofoam insulation or just pick up a sheet from the hardware store. Unless you have a hot foam knife, get the thinnest sheets you can (1/2" inch or thereabouts). They can then be clad in Aves Apoxie sculpt and sheet styrene when you have roughed out the shape. It's a lot faster and easier to control than blocks of styrene laminate.

I hope this helps.

Kenny

[Richard Baker]

I probably use 'tensile' strength incorrectly- what I was refereing to is what you called shear strength. I hate buildnig something and then having a part 'opo off when the model is stresses. I stick to epoxies (pun unintended) for resin kits and good old fashioned testors tub gell glue for styrene.
Istead of recyclin gfor sale signs check for phone book for sign shops or sign supply businesses. I work in a sign shop and we buy sheet styrene in 18"x24" stock and occasionally in 4'x8' sheets. Much cheaper to get it that way. There is a good change a sign company might actually give you the 'drop' from cut jobs as it is usually too weird a shape for use as another sign...

.

[Space Garbageman]

Styrene will bond to acrylic very well with Tenax or MEK.

[ajmadison]

This is really an advanced scratchbuilding topic, but I use superglue almost exclusively, precisely because it doesn't have good sheer strength, and because it takes several seconds to cure. Because alignment is usually so critical, especially with the much smaller scale of the projects I pursue, if the part isn't right, I just put the point of a no. 11 blade into the joint, and pop, off comes the part. When I am completely happy with the position and alignment of the part, I dab on some more ACC and hit it with accelerator. If there is an inside join, meaning these are interior parts, I'll even pour an ACC fillet and hit it with accelerator to lock the whole thing down.

And because my construction is interlocking, there is usually a profile-cross section that I start with, with orthogonal formers attached to that, then either there is either more cross bracing as the beginning of externally visible details or the application of an exterior skin. Basically my models have monocoque bodies, meaning stressed skin exteriors. This method is extremely adaptable, even to some of these wildly composed CGI ships, albeit, I use hints from the original mesh to figure out how the whole thing is put together.

[AbsoluteSciFi]

This is really an advanced scratch building topic, but I use superglue almost exclusively, precisely because it doesn't have good sheer strength, and because it takes several seconds to cure. Because alignment is usually so critical, especially with the much smaller scale of the projects I pursue, if the part isn't right, I just put the point of a no. 11 blade into the joint, and pop, off comes the part...

I use superglue to no end on my models, and while you might claim it does not have good strength, I beg to differ. Superglue will hold, if applied to a properly prepared surface, beyond the strength of the sheet styrene- no exceptions. There are a lot of tips on the many different applications of superglue here @ starshipmodeler.com, and superglue can be used to do a lot more than just tack weld a piece in place for spec.

When super-gluing styrene, first sand the pieces with 150, and then 300 grit sandpaper. Do not go any further than 300, you want to create a micro-scratchy surface that will lend itself to the glue on both sides. Then clean off the excess dust, then place a bead of glue along the seam to be joined, last, accurately place the two together- no second chances, otherwise, re-sand and start over. The glue bonds nearly instantly, and if you "break" the initial bond, then the superglue "re-glues" over itself and thus breaks atop of the weak joint now in place. What you are left with is two pieces with superglue on top of them, and the only way to get it off is to grind, sand or otherwise forcibly remove it. The "illusion" of a weak seam is what most people conclude, over their poor craftsmanship of the use of superglue.

Another way to apply the superglue, and solve the problem of placing two pieces together perfectly, is to put them together first, (tape helps) then use the "capillary" action to allow the bead of glue to run the distance of the seam, and thus you never have to move the pieces. The sanded surface facilitates the capillary action, but it will only go so far before you have to apply more superglue at a later point. Wipe any excess away and allow the seam to cure. In about five minutes the seam will be very permanent.
Post#16

[kerick]

If you need a strong joint and can place the glue on the backside so it won't be seen try CA and baking soda. Place the CA and then sprinkle a little baking soda over it. Shake off excess and repeat if needed. This gets very hard almost instantly and will get hot if you try a large amount at a time. DO NOT have your fingers near this !! I've used this to repair the feet on kitchen counter appliences and it lasted a long time. And sticks to darn near anything.
By the way, some have mentioned traveling with model building supplies. Keep the baking soda in the original container, something about white powder in a plastic bag in an airport security check....

[ajmadison]

If you need a strong joint and can place the glue on the backside so it won't be seen try CA and baking soda. Place the CA and then sprinkle a little baking soda over it. Shake off excess and repeat if needed. This gets very hard almost instantly and will get hot if you try a large amount at a time.

Eek. Not Baking Soda. This was an idea that was started some 20 years ago and has been deprecated by many a modeler. Baking Soda, even encased in superglue will absorb water from the air. Eventually, the baking soda will dissolve into a liquid solution and leak out of the glue joints. One A/C modeler described his fighter plane model as "foaming at the wing joints."

There are alternatives, albeit one I know for sure, micro-balloons, provides strength & bulk but do not have cure-accelerant properties. I have heard of experiments with off the shelf fine ground minerals (e.g. Talc) having dual bulk & accelerant properties, but do not know about their long term stability.

[Kolschey]

Eek. Not Baking Soda. This was an idea that was started some 20 years ago and has been deprecated by many a modeler. Baking Soda, even encased in superglue will absorb water from the air. Eventually, the baking soda will dissolve into a liquid solution and leak out of the glue joints. One A/C modeler described his fighter plane model as "foaming at the wing joints."

I'll second that strongly. Over at Finescale Modeler, there are several horror stories from folks who used Baking soda as part of a diorama. It's NOT a stable long term material. Now talc seems to be more inert, so I've used it without mishap as a mold release for resin casting, among other applications.

[Mr.Sci-Fi]

Plastruct also make a welding agent to bond various plastics.

[ajmadison]

Plastruct also make a welding agent to bond various plastics.

IIRC, Plastruct's welding agent was Chloroform with some additives. There was another solvent I used way back, which is a close cousin to CHCL3, Carbon TetraChloride, CCL4. But you needed something very strong to dissolve the PVC used in some (all?) of Plastruct's plastic products.

I do have Tenax in my scratch building supplies, and it does have its uses. If I hollow a tiny piece of scrap out with a no. 11 blade (because its not a round hole), and want to smooth the cavity, a drop of Tenax will clean it up like I had used a .5mm sander.

I prefer CA, and maybe a bit too dogmatically, but the solvent glues have their uses as well.