problem splicing two bodies together

[pantablo]

so I'm in the beginning stages of a new build, a quad cab jeep truck.




Tonight I tried to splice the bed to the cab using 2mm styrene splice plates that go from the front edge of the rear door to the rear wheel well. The body has a slight curve but the styrene doesnt.

First I tried Plastruct Bondene on the clamped in place splice plates. After I let them set for about 40 minutes I went to check on them and test fit the bed onto the plates but one fell off. So I checked them all and I could peel them off easily.
The Plastruct did turn pink so I think it was melting the plastic body. Actually, looking more closely at the body it looks to be factory painted.

I then tried putting 5-min epoxy on the plates leaving about 1/4" clean around the edges and clamped again. Then when that took, after about 15 minutes, I ran tenax 7r along the edges. its all clamped in place but I worry it wont hold, given this is probably the biggest stressed point of the body.

Why didnt the plastruct hold?
Am I still doing anything wrong?

currently looks like this, with the bed clamped onto the splice plates:


any advice or comments welcome.

[JBHardwear]

Woooh!, That is really scary......hmmmm I will see what I can find out and l let you know, not sure why the plastruct did not hold. That is what everyone told me to use

[2JSC]

Would it be because of the paint? Might want to either remove the paint or rough it up enough for it to grab better. Also why not try some other adhesive between the plates and the body to help fill in those curves that the plates do not have.

[Mnster]

I'd epoxy with some fiberglass. Get the standard plastic epoxy saturate some fiberglass with it and stick it to the inner body like tape.

[pantablo]

Originally Posted by 2JSC

Also why not try some other adhesive between the plates and the body to help fill in those curves that the plates do not have.

Thats exactly why I used the epoxy-its thick and I could use it to fill in the space. Then I used the tenax (or plastruct?) on the edges.

We'll see tomorrow how strong it is. I need it strong as I beat on my rigs pretty good...

[pantablo]

Originally Posted by Mnster

I'd epoxy with some fiberglass. Get the standard plastic epoxy saturate some fiberglass with it and stick it to the inner body like tape.

thats a good idea. I should coat the whole thing with fiberglass...thanks.

[BlueMonster]

If I am not mistaken, that is a solvent glue. It works by softening and chemically melting the two pieces together. If there is paint, that would be the problem. A clean surface should do you fine, but the epoxy should also work well.

[microgoat]

Paint won't interfere with a solvent joint, unless it's some kind of nuclear super paint. What usually happens is the paint just dissolves into the joint and makes the solvent easier to see.

My guess is that this isn't a styrene body; it's probably ABS or some other Chinese mystery plastic, ground from the bones of political dissidents or something. I've seen quite a few Chinese bodies that won't take solvent glues.

My solution is tack 'em in place with CA, and then reinforce with epoxy-soaked fiberglass cloth. Once the epoxy is dry, hit the edges with more CA to make sure they stick. Like Mnster said, roughing up the panels is a good idea.

[pantablo]

Originally Posted by microgoat

epoxy-soaked fiberglass cloth...

is that different than i fI got fiberglass repair kit?
this one by Bondo is readily available locally and what I used to repair my race bodywork on my motorcycle:



its a 2-part epoxy if I recall so it sounds like the right stuff.
I appreciate all the help.

[STANG KILLA SS]

as with plastic models, you must remove any paint or chrome plating off the parts before that style glue will work. ;)

[TeamDeweyRacing]

L0T's 0 SUPER GLUE that bondo brand fiberglass kit should do it ive used it before on these mystery plastic bodys it worked great for me

[microgoat]

Test it on a scrap piece. The solvents in some resins can dissolve some plastics (if it turns out to be styrene) into a puddle of goo.

[pantablo]

Originally Posted by microgoat

Test it on a scrap piece. The solvents in some resins can dissolve some plastics (if it turns out to be styrene) into a puddle of goo.

thanks for the heads up.

[tjb]

You got reply to PM

[sloppy]

heck to much of that red or green one part filler crap will warp the heck out of styrene.. stu has got a good point always test.

[T2NUT]

Had a thought on the gap problem. If it is styrene you are dealing with, I would use thinner styrene to bridge the two pieces being joined and make it conform to the inside of the body panels while using methylene chloride as a solvent glue applied before mating the surfaces. Once this has set up(give it a while, maybe even overnight) put another one or two pieces of styrene overtop the inside bridging piece to stiffen up the whole structure and do the same solvent glue procedure. Or alternatively, you could use a heat gun to form some bridging panels before gluing so that not as much pressure has to be used.

If you don't want to go thru all that trouble, then I would say epoxy with a bit of cabosil thickener in it would be a good choice(as others have suggested). Epoxy likes being thick to hold, but it can be brittle. Also the thicker the epoxy the more heat will be generated by the exothermic reaction of the two parts and could wreak havoc with the plastic.

Speaking of heat, how about hot melt glue? It seems to stick various dissimilar plastics together well, just don't get too much in a puddle or it will warp the plastic thru and thru. I have had some good luck with it. Again, testing with other pieces would be a good idea as was wisely suggested already.

[pantablo]

Tonight I undid the clamps. Then I took the ends of the body in my hands and twisted it up real good. back and forth, trying to emulate the force that the chassis might put on it. It twists up just fine without hint of weakness. Thinking of leaving it in place, but sanding around it (at the edges of the splice plates) and adding the orange label Testors Toxic glue to that area.
I'm more confident in it now than I was before.

I was expecting it to snap free as soon as I put twisting force on it.

[pantablo]

I noticed that one middle panel wasnt lined up right so I decided to take it apart and fix it, but it came apart a little too easy. So I took it ALL apart. Starting from step 1 again.

I took the dremel sanding wheel to the inside surface to remove the epoxy and discovered the red is actually the plastic color, not paint. The paint is silver overspray from the lights and such.

My next step is instead of using a 2mm splice I'll build up the splice using very thin peices, so that I can conform them to the body curve better. I'l also try that Testors Orange label glue.

[tjb]

Originally Posted by pantablo

orange label Testors Toxic glue

If it's toxic, causes nerve damage, cancer in California, birth defects or disolves skin, or causes frogs to have 12 eyed babies ect, ect.....It's normally the best place to start!



I would tack it with CA, hit it with plasti-weld, once that dries, rough the heck out of it with 40grit and hit it with the orange label glue and the thin styrene stips like I mentioned in the PM

[pantablo]

Originally Posted by tjb

I would tack it with CA, hit it with plasti-weld, once that dries, rough the heck out of it with 40grit and hit it with the orange label glue and the thin styrene stips like I mentioned in the PM

Will do. I was out getting more thin styrene and the orange label...being so toxic I'm actually surprised you can actually BUY it locally in CA, lol...

Thanks Jay (and everyone) for the help and advise.