JB Weld Casting

If you need a small part and you have access to the original then use some JB weld to get 'er done.

JB weld did the trick on a missing piece for my airsoft gun.

UPDATE - Make sure you check out all the awesome comments about how to go even further and reinforce the epoxy.

Step 1 Playing with Playdough

Take some kind of casting medium, I stole some playdough from my son. I think this would work even better if you used modeling clay or something made specifically for such an application. Who knows.

Comments

[Capt. Kidd]

The only problem is, it makes a mirror copy of the original piece instead of an exact copy. I guess you could cast the copy to get the same thing as the original though. It just takes more JB Weld.

[chocables]

The playdough makes an inverted copy and the JB weld then inverts it again so it becomes the original.

[Capt. Kidd]

hmm... right. DERP

[jammin0]

umm, it doesn't create a mirrored copy. That doesn't make any sense.

[airsoftbeast40]

YOUR A GENIUS!!! i serioously wouldve never thought that would work with an mp5 selector switch, cuz theyre so intricate

[iloveairsoftstuff]

dude i believe i have that same airsoft gun. its firepower brand mp5 right?

[handyhippie65]

this stuff is the best! i just repaired the handle of a 150.00$ goat milker with it, it works great, and only cost $5.99. i've used it to fix auto interior plastic panels, even filling in pitting on aluminum intake manifolds. if you want more strength, embed finishing nails.

[meanbean]

Goat milker?

[handyhippie65]

a plastic, hand operated vacuum pump, with a milk container, and a teat coupler, to milk small numbers of goats. kind of like a one man brake bleeder pump. squeeze the handle to create a vacuum, which draws milk from the teat to the container, through a tube. the handle broke at the pivot . easy fix for an expensive piece of equipment.

[syco123]

I never go long distance hiking without JB weld. It's a lifesaver and worth it's weight, literally! I like this idea of casting with it. Hadn't thought of that.

[808create]

You could use JB in both steps, instead of PlayDoh, to get a better mold. Let it dry and spray with WD-40 to keep it from bonding.

[rhughes]

Quite a while back I read an Instructable (I think) on casting small parts from homemade ABS plastic resin. The resin was made by grating/grinding or otherwise pulverizing a section of ABS pipe and dissolving the result with acetone. The result (a custom part for a car interior) turned out pretty good!

[vernonstien]

I have used the same method (acetone and styrne plastic) to mold a small part for model car once, work all right. I work close to a plastic molding plant and once in a while I get raw pellets to use, PVC pipe cleaner (MEK) works good to melt styrne also. Would like to build a home made injection molder using chems instead of heat, any ideals on that?

[tornadoboy]

Check out lindsaybks.com, they've got a book on building your own plastic injection molder, and I'm will to bet it wouldn't take much to modify it to work with chems instead.

[vernonstien]

Just a thought, late but still a thought. the FDM or Direct Digital Modeling comes to mind it's the thing, molding with chems.....so I'm old and slow.....must be early stages of oldtimers.........still going to check out the site.....L8R

[vernonstien]

Went and checked out the site, the tube book caught my eye because I work on radio frequency welders, RF Welder, Dielectric welder , what ever you want to call it. It shows the schematics for a radio and it is very close to what I work with, kind of like a radio station, only instead of music, we bond plastics together....

[Alphonsus]

I'm Currently using this idea to fix some cosmetic problems on my motorcycle. there is a clip missing of one of the side panels so i used modeling clay to mold the other one.... waiting for it to dry now :D that has been bugging me for the last year!

[jjprice]

that is cool i never thought about that

[Marcos]

I'd like to see more instructions on technique, like how thick you rolled (cut?) the Play-Doh, did you level the surface of the mold, did you level the surface of the JB Weld or just let it stay above the surface of the mold and sand it off, etc.

Lots more info could be delivered here. So far you've shown what you did, but very little about how, which is often the critical part for those who want to repeat the process.

[Marcos]

Great idea. I saw a guy at the Maker Faire who does product development, and he advocates doing rapid prototyping with epoxy by modifying existing products ( he showed me some scissors and something else he'd done), and also making new, functioning parts from epoxy.

That year he gave people who stayed for his talks a tube of Oatey epoxy putty. It's good stuff. made in the U.S. , the label is also in French and Spanish, so it may be available in other countries too.

[Legend in your Mind]

Instead of steel wool have you tried cutting small bits of a scotch bright pad? They won't rust and hold pretty darned tough. I used them to sand pait down.. Lots of body shops do and the stuff will last forever.

[Legend in your Mind]

err paint..not pait ;)

[FeedTheGrid]

Nice instructable, Jammin!

For the mold, instead of playdough, I just used some of this stuff, recently; and it seemed to work really well.

http://www.youtube.com/watch?v=eDtCBEAWSvE

Let me know what you think.

[acesnanna]

This is an interesting premise....I'd never thought to use JB weld like this... It suggests all manner of possibilities...will it dry clear as well?....if not..what do you suggest that is economical.....but does dry clear.... Thanks for a great idea jumping off point...Instructables are so good for that...I see what you do....to find out what can be done..There is a GREAT group of people here too...The comments are GREAT...I enjoy reading them...Which can not be done in a lot of sites because of the filthy language.... Great work.....Wonderful people here... Laurel

[acesnanna]

Thank you so much for your reply....I'm a "piddler"....I see loads of things on here that are genuine inventions and probably could be patented...What a great group you really are to share your ideas, and inventions with all who want to look!!! Thanks again... Laurel

[jammin0]

Regular epoxies dry clear or clear/yellowish depending on the kind that you get. They usually have a really big selection at Home Depot and you can compare all the different types that there are to see what would work best. They also have some that come in a nifty little dual syringe package. I just remembered too that if you want to go the cheap route than the Dollar Store will sometimes have little tubes of clear epoxy.

[Pazzerz]

Check out Loctite's products. There are hundreds of different types of epoxies for different uses. Then go to McMaster or Grainger on the web and try them out. I would say you can't go wrong with purchasing a small tube to try out.

[curecreator]

I think that it is agreed J.B. WELD IS THE BEST STUFF THERE IS!!!!!

[ac-dc]

Well, not really. JBWeld has a tendency to fracture more than other epoxies do, it's smooth outer surface is hard but it's fairly granular inside. IOW, other epoxies would do better for high stress parts, though the slow-setting JBWeld is still stronger than the quick setting and reinforcing it with a filber fill or fiberglass cloth would help.

[curecreator]

Sorry if I offend your "feelings" but I still THINK that JB weld is the best ever. It can do most any fix-it job you want and it is cheaper than many other epoxys. Duct tape is good but "red-neck" if you ever show it off.

[ac-dc]

#1, factually speaking, the best epoxy for a job depends on the qualities the part needs, as different epoxies do deliberately have different properties. It is not any cheaper than many different epoxies, but if you really want that type of expoy you can pick up the same quantity in generic brands at dollar stores or Big Lots, one of the generic names is "American Steel Epoxy" or something similar to that. At the same time, IF you insist on JBWeld, AND you want it as strong as possible, you will get more JBWeld per $ if you bulk the larger bulk sized tubes, I think they are 4oz/4oz pair. Autozone is one place I recall seeing them, but of course online there are myriad choices for volume and type of epoxy. We could take the lazy way and just suggest one generic epoxy, like a generic roll of duct tape, but here as well as the rest of the internet allows us to trade information such as why other epoxies, firberglass, and alternate fabrication techniques exist depending on the need. If we were on Gilligan's Island and had only string, glue, paperclips and some JBWeld, in that case I would agree that the best resut would be saturating the string with JBWeld and using that forumulation, but fortunately we have more options.

[_soapy_]

What about duct tape? (I'm playing devil's advocate here, epoxy is far more useful.)

[rrowsome]

Personally, I prefer duct tape selector switches on my airsoft guns. But that's just me ;)

[curecreator]

Duct tape is all great and well but is not a permanent solution especially if you airsoft with guns that rank in your top 5 most valuable properties (as in they are really expensive) and plus all the people airsoft with would laugh at you - on a seperate note maybe I should reconsider if they are really friends???. JB weld is simply just a good thing to cast with. Plastic works OK but not the best and for many not readily available.

[Pazzerz]

Try adding some finely cut fibers (glass, plastic, steel wool) to it for some larger pieces. It helps to strengthen the finished piece.

[Calorie]

I don't think steel wool would be the best. It oxidizes fairly quickly (that's rust) and when steel/iron rust it expands. That'll weaken the cast part quickly. Even if the rust is contained at the surface there will be some damage at the first mm or so of the cast/wool mix and air.

[Pazzerz]

Most of the time in small parts it would be better to use glass or plastic shavings. The steel wool (cut into tiny little pieces) is better for larger things and it rarely rusts inside the epoxy. A better alternative is fine aluminum shavings. They tend to be curved and that acts like a hook to help keep the epoxy together. I have (for a couple of years now) steel wool in an outside steel shed in its original packaging, a plastic bag. The bag has been open all this time and there isn't any rust (???). Probably been coated with oil or something.

[dpocius]

Could be stainless steel wool. I've had some of that sitting around for 20 years or more and it doesn't rust.

[kill-a-watt]

(not exactly a reply to just kenbo0422, instead, think of me just piling on)

http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=1038

or google = ACRAGLAS Atomized OR bedding OR metal OR matrix OR powder

Riflemen and those who aspire to be riflemen have for years bedded their actions in their stocks with the aid of epoxy products. Anyone planning to make high strength items out of epoxy might want to stand on the shoulders of giants instead of reinventing the wheel themselves. There are plenty of tips out there if you only know what to search for.

For example, many people use paste wax as a release agent. Others use petroleum jelly.

[Vermin]

Good stuff! Thanks.