|
bunker?
May 30, 2009 21:31:44 GMT -5
Post by Heeriam on May 30, 2009 21:31:44 GMT -5
Hello!
I am taking on the endeavour of making a lightweight temporary pillbox. I wanted to make it from layers of piled on pink foam board. I was wondering is there a way to coat them with something to add a "shell" to it? Or does anyone have any other suggestions? I purposley want to use a foam of some sort as it is lightweight and easier to move around.
Thanks!
|
|
deacon
Private 1st Class
Posts: 748
|
bunker?
May 30, 2009 22:38:46 GMT -5
Post by deacon on May 30, 2009 22:38:46 GMT -5
Its called wood bud, and make it simple to dissamble.
|
|
|
bunker?
May 30, 2009 23:28:16 GMT -5
Post by lrich on May 30, 2009 23:28:16 GMT -5
I have found that epoxy makes a great shell over the insulating foam (and as a bonus, doesn't eat it) Generally, for what you are doing, i suggest getting some of the stuff that you mix your own, and doing just that. It is much more cost effective for a big job like that. I would probably use the biggest putty knife you have to spread it on there, and smooth it out. After it dries you can sand it, cut it, paint it etc.
While deacon does have a point that wood would probably be more durable, i can understand the reason you would want foam (put 3-4 layers together and it gives it a nice thickness like a bunker, and if you spread the epoxy, but don't sand it, it will give the outside a nice bumpy poured concrete shape)
|
|
|
bunker?
May 30, 2009 23:48:02 GMT -5
Post by Heeriam on May 30, 2009 23:48:02 GMT -5
Umm no Deacon wood is not what I am looking to use, If you read above once more, I clearly stated I would like to avoid anything but the foam. Thank you Irich for your suggestion I will research and look into that, would you reccomend a epoxy? I would have used google but I dont think "foam bunker" wouldnt bring promising results.
Thanks!
|
|
|
bunker?
May 31, 2009 0:22:14 GMT -5
Post by lrich on May 31, 2009 0:22:14 GMT -5
When you say recommend an epoxy, i assume you mean, a type/brand? As for that, i am a loyal west system user. It resists water, a little fire (that was an oops), drops, etc. Here is their website: www.westsystem.com/ss/ I personally have the set up with the mini pumps: www.westsystem.com/ss/pumps-and-metering-equipment as it makes it infinitely easier to pump when i don't want to do a massive batch. For your purpose you may not need them (as you will be mixing lots), but i would suggest getting them for when you want to mix small amounts and do touch ups, etc. Then i would use this chart to figure out your exact needs: www.westsystem.com/ss/product-selection-chart/ I use the 206 hardener, for a good compromise the time before it sets and not having to wait forever. You might want the extra slow (209) for you massive bunker coating batch, as it will give you more time to spread it before it becomes gummy. I also generally turn to microfibers for adhesive characteristics: www.westsystem.com/ss/403-microfibers/High density filler for strength www.westsystem.com/ss/404-high-density-filler/and low density filler for taking up space/thickening the mixture. You may also want to throw in a grey pigment (i have mixed in straight up paint before with the epoxy, and it works decently, using their pigments is better, but costs more) as you will get either a brownish or whitish coating (depending on what fillers you use) Finally, use this tool to find where to buy them: www.westsystem.com/ss/where-to-buy/Be warned, this is a bit expensive, especially the resins, however, the resin and hardener last forever, while you go through the fillers decently quick when using it to form a "skin" but thankfully, the fillers are a bit cheaper. As an idea, if you plan on sandwiching multiple pieces of foam together, here is personally what i would do: Mix up a batch of epoxy with the 209 (extra slow hardener) and mix it with microfibers for adhesion. Leave it a little runny (like runny ketchup) and spread a thinnish layer between each piece of foam you want to smack together. Then, slap them together, and use drive a few nails/pins through the pieces so that they wont slide around across each other. Also, play the various flat sheets you want together to get the desired length, and get some thin sheetmetal strips and epoxy them on the foam, spanning the two sandwiches (for strength) Once you have build up the required thickness and length, use the rest of the previous batch, and mix up lots of it (enough to cover the foam boards) and make it thick (like soft serve ice cream) using particularly lots of the low density filler (it will be a lot easier to shape, and a decent bit lighter, as well as barely less durable, as in, still able to take some bbs, than if you use the high density stuff). Then using your big putty knife, spread it all over the wall. You will only be able to do the top and sides, so what i suggest is letting the top/sides of A dry, and then mixing a new batch of epoxy for the next side, and finishing A's back while you do B's front, then let B dry, then C's front B's back, you get the idea, until you are finished with all of them (depending on how many you have to do, it might make more sense to do half, let them dry, flip them over and do their other side while you do the first side of the other half). Finally, some things on epoxy: don't let it dry on anything you don't want it to be on forever, as it is a bastard to clean off. (Possible, but a ton of trouble when it is dry) It has a potlife, which means that if you leave it for too long, it will harden, and be unusable. That is why you figure out which hardener, based on how long you want it workable. When mixing big batches it takes longer to harden, but it still will. Any excess you mix and leave out will harden in the same amount of time as the stuff you used, therefore, tailor the amount you make to how much you use, and obviously, use it while you can. Unmixed it has an indefinite shelf life. Big thing:Epoxy, especially large quantities can create lots of heat, therefore, don't put it near anything flammable. While i have never actually had epoxy light anything on fire, my dad did manage do return to a project and have char marks on some paper that he had laid his project on. If he had had just a little more epoxy, he could have lit it on fire, potentially causing some problems. In that sense, i usually leave my projects to dry in the middle of my concrete floor in my garage, to prevent anything bad from ever happening (i figure, if i don't do it, that will be the one time something bad happens)
|
|
|
bunker?
May 31, 2009 9:22:41 GMT -5
Post by shadycadence on May 31, 2009 9:22:41 GMT -5
Have you considered good old paper mache? Far less expensive, no need to worry about lighting stuff on fire, and you won't pass out from the fumes. You could apply entire sheets of newspaper for faster coverage, and paint it a nice concrete gray when you're done.
|
|
|
bunker?
May 31, 2009 12:29:13 GMT -5
Post by Heeriam on May 31, 2009 12:29:13 GMT -5
Hmm, I never thought of that! Paper mache is another great option!
Thanks!
|
|
|
bunker?
May 31, 2009 13:15:38 GMT -5
Post by lrich on May 31, 2009 13:15:38 GMT -5
paper mache might actually be easier, the only problem is, depending on how you are using it, you may have to figure out a way to waterproof it, as all the paper mache stuff i have made has ended up melting when it got wet, usually by my brother being a dick (which means either i did it wrong or you would need some serious clear coating to keep it from melting)
|
|
|
bunker?
May 31, 2009 13:26:33 GMT -5
Post by volkssturm on May 31, 2009 13:26:33 GMT -5
If you're working with large amounts of epoxy you should seriously think about getting a respirator approved for volatile chemicals. Epoxy puts off a lot of fumes when you start coating large areas and they are hazardous. A materials safety person once told me that if you can smell it, it's doing damage. Also, good impermeable gloves that come up your fore arms and long sleeves to keep it of your skin. Excessive exposure to epoxy can cause sensitivy to it, like an allergy. Work clean and have really good ventilation. [/end of safety police rant]
BTW, a cheap filler I've used is wheat flour. If you just need a thickener it works fine, and if it's outdated or being thrown out because maggots got into it the price can't be beat. Filter out the maggots, though. Fine sawdust works also.
|
|
|
Post by Heeriam on Jun 1, 2009 0:14:27 GMT -5
After considering all of these I have chosen a different option/method of choice. A bit unorthodox but I will post pics of the finished product. Thank you for all help!!
|
|
deacon
Private 1st Class
Posts: 748
|
Post by deacon on Jun 1, 2009 1:55:58 GMT -5
I know you stated you only wanted foam, but a bb will punch right through paper mache. and especially foam. Like I said, you can always make the bunker disassemble very easily, and still use wood with the light-weight factor.
|
|
|
bunker?
Jun 1, 2009 23:16:17 GMT -5
Post by Heeriam on Jun 1, 2009 23:16:17 GMT -5
Mmm, not at all, with a foam or mache design you can keep it under 200lbs, with Wood...yea not so much. Wood is too heavy and will not retain the look of a convincing pillbox. With foam it is coated in a epoxy, which will be give it a hard shell. Foam is much easier to mold than wood.
|
|
oberst42
Private
"Oh du Deutschland, ich muss marschieren!"
Posts: 387
|
bunker?
Jun 1, 2009 23:18:40 GMT -5
Post by oberst42 on Jun 1, 2009 23:18:40 GMT -5
and then some texture paint to make it look like concrete, good idea!
|
|
gryphon
Master sergeant
shchi e kasha, pisha nasha.
Posts: 250
|
bunker?
Jun 2, 2009 11:24:05 GMT -5
Post by gryphon on Jun 2, 2009 11:24:05 GMT -5
There is now a polyester resin on the market that will not dissolve styrofoam - I just used it to make a full-sized foam-fiberglass composite King Kong hand for a waterpark. Laminate your foam with 3M foamboard spray adhesive, fill any gaps with Great Stuff, and carve your foam to shape (cheese-grater Surform rasps and drywall cut-out saws are great for this.) Make sure to radius all inside and outside corners, then totally cover the foam piece inside and out with a layer of 1-1/2 oz fiberglass matte wetted out with styrofoam-safe polyester resin catalysed with MEK. Lay up a section at a time, positioning the piece so that the section you are doing is flat - always choose to do horizontal layup instead of vertical or overhead layup whenever possible. Replace the styro with plywood squares hot-melt glued in place at all stress points or bolt-through areas before you lay 'glass. Use fumed silica (Cabosil) and chopped strand (kitty hair) mixed into catalysed resin to make a reinforced filler paste (catalyse filler resin lightly, those thick areas heat up FAST with a exothermic cure cycle!) Pin the sheets of 'glass in place with clothspins or small nails pushed halfway into the foam.
Work in a place where a serious chemical stench and extremely sticky toxic puddles on the floor will not be an issue. Wear a respirator, rubber gloves and barrier cream on your thighs and arms up past the elbow and expect to totally trash your clothes and shoes. Clean up with acetone and LOTS of paper towels - I keep a lidded 5-gallon bucket 1/3 full of the stuff and just toss my tools and brushes into it after wiping them down. Keep all-metal putty knives, a sharp metal-handled paring knife and a sharp pair of all-metal scissors in your bucket of acetone for emergency wet fiberglass trimming and fitting to corners. Sand any nasty sharp bits off after the resin has completely cured, prime with sprayed automotive primer or brushed-on Hirschfield STIX and finish as desired.
I've used this exact method for years to make lightweight yet rugged theme all-weather pieces of up to 25 feet tall for playgrounds, parks, museums, arcades ,and zoos. The very first paintball armored vehicle I ever built had a foam/fiberglass composite turret and its armor shell is still in use as a bunker element on a nearby paintball field to this day.
|
|
deacon
Private 1st Class
Posts: 748
|
Post by deacon on Jun 3, 2009 0:30:50 GMT -5
Be careful with Acetone, that applesauce goes straight to the liver, when in contact with the skin.
|
|
gryphon
Master sergeant
shchi e kasha, pisha nasha.
Posts: 250
|
Post by gryphon on Jun 3, 2009 9:01:37 GMT -5
Absolutely right - hence the respirator and the solvent-resistant barrier cream. Warning signs of toxic loading: watch out for a dull, constant lower back pain (kidneys,) nausea, headaches, disorientation/dizziness, discolored urine, fruity-smelling breath, bouts of either insomnia or borderline narcolepsy, and contact rashes (usually on the forearms or around the waistline first.) Personally, I am utterly convinced after watching a number of shop assistants' reactions that people taking prescription anti-depressants should not work with polyester resin. Epoxy doesn't seem to phase them in the same way; I, however, am rapidly sensitizing to epoxy and figure I probably only have about 80 to 100 working hours left with epoxy layup in my lifetime before my reaction becomes too severe to manage. Oh, for the joys of bioaccumulation!
|
|
|
bunker?
Jun 8, 2009 12:23:01 GMT -5
Post by gunfighters on Jun 8, 2009 12:23:01 GMT -5
I know @ least a few places use spray on truck bed liner over foam I know you want foam, but after you coat it you relay won't save much in weight compared to 1/8" ply and theater style construction you might also look in to (taking a page from the PUGs) corplast www.corplast.com/products.html#poly
|
|
TommyGunner
Staff Sgt.
Hackjob Mauro
1st Marine Division, 1942
Posts: 2,265
|
bunker?
Jun 8, 2009 12:43:35 GMT -5
Post by TommyGunner on Jun 8, 2009 12:43:35 GMT -5
Well at this past Illinois event we had this guy at our event and he brought his bunker with and I gotta say this thign is perfect for airsoft. To guys could carry it into the field and it was set up in about 5 min with minial effort. Plus when we wanted to move it the several times we did it was very easy to do.
TommyGunner
|
|
|
bunker?
Jun 18, 2009 16:40:20 GMT -5
Post by savage94 on Jun 18, 2009 16:40:20 GMT -5
What about foam insulation boards thats what ill be using
|
|
2nd Bat
Master sergeant
Posts: 11,813
|
bunker?
Jun 20, 2009 12:03:34 GMT -5
Post by 2nd Bat on Jun 20, 2009 12:03:34 GMT -5
The Army actually employed a system for creating fake bunkers with a foam applicator. They built simple frames with 1 x 1 wood slats and simple triangle cuts at the corners for strength. The attached chicken wire with a staple to the frame and them spray applied foam onto the chicken wire. The foam was grey in color and the end result were very convincing fake bunkers that as noted could be easily moved around. In our case they would effectively impede BBs. Over time you would have to spray boack over the areas that got shot up but I have always thought that would be a cool way to go.
It's also concievable you could pre-shape sand bag emplacements out of foam and epoxy on burlap for a great visual effect. A concern I heard expressed was where do you store them? If you did them in a graduated slope inward toward the top you could stack several on top of each other requiring less room and being foam they could frankly be stored in the elements. The effects of weathering having a positive visual impact.
I used bed liner spray to coat a plywood framed half scale tank my son and I created and it did a decent job of protecting it while eliminating the plywood appearance.
|
|
|
bunker?
Jun 21, 2009 13:10:19 GMT -5
Post by blackhawk11 on Jun 21, 2009 13:10:19 GMT -5
This would make for a realistic bunker as well. Cover disintegrates under heavy fire in real life. The trouble is, what is considered a realistic amount of fire in Airsoft?
|
|
|
bunker?
Jun 21, 2009 13:44:12 GMT -5
Post by lrich on Jun 21, 2009 13:44:12 GMT -5
This would make for a realistic bunker as well. Cover disintegrates under heavy fire in real life. The trouble is, what is considered a realistic amount of fire in Airsoft? Well for a bunker, that should be concrete, a realistic amount of fire would probably be at least 200 rounds in the approximate same spot (considering bunkers were many inches of concrete, and could take a ton of fire) it would be interesting to make "cover" out of foam, so like have foam fences and walls that simulate drywall and wood where only 4-5 rounds could rip it apart, while other foam was thicker and more protected to make it nearly impossible to shoot through (bunker) That would be sweet for a big game.
|
|