How to repair a hard case?

[theGringo]

The wife found a Contico two rifle hard case at the dump. There's a crack, about 3" long that runs from the lip of the case around to the underside, and which is open about an eighth of an inch.

Is there a simple way to make a durable repair to the crack? It's right along (actually inside) the lower part of the latch, which gets a lot of stress.

 

[Tater]

jb weld or apoxy made to bond with plastic

 

[rapture]

jb weld or apoxy made to bond with plastic

+1 Make sure to thoroughly sand the area first so the epoxy will have something to stick too, otherwise it'll keep falling off. Also, make sure to give it plenty of time to fully set before applying any stress to it. I usually give it at least 2 or 3 days, but I tend to be over cautious.

 

[MA_Shooter]

I haven't had much like trying to fix plastic with epoxies etc...so keep us posted as to how it all works out.

-MS

 

[theGringo]

I haven't had much like trying to fix plastic with epoxies etc...so keep us posted as to how it all works out.

-MS

Me neither. Never tried JB Weld. Maybe I'll try that. Where do you find it?

 

[rapture]

Working as a mechanic these days, we tend to work with epoxy a lot. Everything is plastic and whenever you try to fix something, you almost always end up breaking something else in the process. For example, if you're trying to replace a defective stereo, it's likely you'll break a retaining tab off the front dash bezel. It's become a fairly common occurrence.

Working with epoxy is fairly simple and straight forward. Just a few things to remember.

1: Prep the area ahead of time. Sand it down with some 220 grit paper, then use acetone to remove any oils or residues.
2. Mix the epoxy 50/50 with the hardener. Once mixed thoroughly, you only have a few minutes to work with it before it starts to set.
3. Once you have the area epoxied, leave it alone. Don't touch it, move it or play with it. Let it harden for at a minimum of 24 hrs.

Also, a little known fact with glues like epoxy and especially superglue, is that it's actually the moisture in the air that makes it harden. "The reaction is caused by the condensed water vapour on the surfaces (namely the hydroxyl ions in water). The water comes from the surrounding air." SOURCE. So contrary to popular belief, the less humid it is, the longer it will take to set.

 

[appraiser]

you near a auto parts store that does body supplies?

Get a bumper cover repair kit, pretty much an epoxy but easier to sand and do finish work on.

http://solutions.3m.com/wps/portal/...log/?nid=JSPNXHDFFBgsNGQGZXQ0C5glLXCCKC564Xbl

If you can bond something to the inside of the case to make it structurally rigid, then do the cosmetic repair it will be stronger than the rest of the case

 

[JonJ]

Epoxy the crack and rivet a gusset (?) made of sheet metal on the inside.

 

[RKG]

By itself, epoxy is unlikely to do the job, since what you're making is essentially a butt joint, and they will not take the bending moment that probably caused the crack in the first place.

What you want to do is get all of the foam out and then lay down one or two layers of fiberglass, filling in some of the resin into the crack from the front.

 

[dsm]

Also, a little known fact with glues like epoxy and especially superglue, is that it's actually the moisture in the air that makes it harden. "The reaction is caused by the condensed water vapour on the surfaces (namely the hydroxyl ions in water). The water comes from the surrounding air." SOURCE. So contrary to popular belief, the less humid it is, the longer it will take to set.

Superglue, yes. Epoxy, no.

Epoxy is self-catalyzing. Moisture won't make a difference one way or the other. Temperature does, though.

Urethane glues (like "Gorilla Glue"), though, are also catalyzed with moisture.

 

[vellnueve]

By itself, epoxy is unlikely to do the job, since what you're making is essentially a butt joint, and they will not take the bending moment that probably caused the crack in the first place.

What you want to do is get all of the foam out and then lay down one or two layers of fiberglass, filling in some of the resin into the crack from the front.

I agree, just epoxy by itself is not going to last. You need to reinforce it with some sort of rigid material.

 

[theGringo]

I should just take it back to the dump.

 

[clerk.mvgc]

Different plastics require different repair materials. The best repair in this instance may be to have it plastic welded. Many bodysops have plastic welders, they are relatively inexpensive kits that use a hot air gun and compressed air. A piece of compatible "welding rod" can usually be cut from some inconspicous place inside the case. Obviously if you have to pay for the repair it may become cost prohibitive but maybe someone that is a bodyman owes you a favor ;>)

 

[tung tide]

I agree, just epoxy by itself is not going to last. You need to reinforce it with some sort of rigid material.

Duct tape and popsickle sticks........

 

[tung tide]

I should just take it back to the dump.

There is no fun in that, Mister. Just think how much you stand to learn.

I learn from stuff my wife brings home all the time

 

[Madmarek]

I have used Acetone on some plastics. Some nail polish removers have it.
Acetone softens some plastics so I put a little on the crack then keep brushing it on till the whole area is soft and it sort of melts together. Has to be the right combination of chemical though.

Also used epoxy and drilled little holes either side of the crack. Used a little dental floss to shoelace the whole thing together and then filled the holes and all with epoxy. Doesn't look great but holds up good.

Not a professional at this just a home hack.

 

[theGringo]

Duct tape and popsickle sticks........

That I have on hand.

 

[bambame2]

Epoxy the crack and rivet a gusset (?) made of sheet metal on the inside.

What he said.

 

[oneswithfunes]

Why not just weld it? Use a soldering iron or heat gun. I fix my kayak that way all the time. Is it cross linked?

 

[theGringo]

Why not just weld it? Use a soldering iron or heat gun. I fix my kayak that way all the time. Is it cross linked?

What am I, a chemical frigging engineer?

Back to the dump.

 

[tung tide]

You could Karma the bad boy.

 

[Maj. Boom Boom]

why not use it in a karma with a link to this thread? someone might want to tackle the job.

edit: beat out by 1 min. great minds and all that.

 

[theGringo]

Here in Otis, we have "dump karma". Saves on shipping. We got a nice lamp last week. Pressure cooker a couple of weeks before that.

Anyway, I'll take a stab at repair. Just not sure how, yet.

 

[tung tide]

Here in Otis, we have "dump karma". Saves on shipping. We got a nice lamp last week. Pressure cooker a couple of weeks before that.

Anyway, I'll take a stab at repair. Just not sure how, yet.

Ahhhh, Dump Karma

Land of the free, home of the brave.......

I think they do that in Duxbury, but it's pretty limited to self-help books.

Good luck on the fix, and we want pics

 

[TomH]

Another vote for epoxy!

 

[oneswithfunes]

Its a pretty easy fix if the case is a quality one. Otherwise karma it.

 

[Cabinetman]

I agree with Jon J and the others that recommend some type of reinforcing material. Adhesives, alone, will be worthless.

What I'd do is simple. I'd use some thin tin, cut a strip that is about 2" wide and 6" long. Strattle the break on the inside of the case with the tin and, using a pop-rivet tool, drill and pop-rivet some steel or aluminum rivets, a few on each side. You can, if you want, use the proper adhesive between the metal and the case but you'll have a hard time finding anything that sticks to that polyproplyene. Most adhesives will simply pop right off. Riveting that damage, however, will make it a functional case once again.

Rome

 

[Atlas]

Why not just weld it? Use a soldering iron or heat gun. I fix my kayak that way all the time. Is it cross linked?

+1 I've had great success with repairing white water kayaks that get abused as well as other broken plastic stuff that get's hard use. Using similar plastic is key, it's not hard to get a strong permanant repair.

 

[FiremanBob]

Make him enlist in the Army.

Oh, that kind of hard case...never mind...

 

[Timberwolf]

As stated, rough up the area each side if the crack plus top and bottom. Smear JB Weld over the crack and roughened area, then add a preformed strip of aluminium (about 1/2" wide and about 3 1/2" long) along the length of the crack over lapping the ends, recover with JB Weld. Let dry.