I know it's a stupid question, but I just bought a plastic welder to fix a cracked fan shroud. But first I need to know what kind of plastic it's made of b/c the type of welding rod must match the type of plastic to be welded. I don't want to screw this up. I thought maybe ABS or PVC.........Anybody know for sure? o No:
Don't know for sure, but I'm pretty sure it's NOT ABS, as the fan shroud is more flexible and ABS is very solid
Now that you mention it, PVC is kinda solid too.........maybe I should just use epoxy and embed some fiberglass in it for strength.........I hear that "plastic welder" brand epoxy is pretty good because it melts into the plastic and forms a good bond. Besides, I was playing with this harbor fright plastic welder and it's really tough to use........it sprays plastic all over the place......I don't want to ruin this part. If I use the wrong filler rod it won't stick and I'll have melted this thing to all to heck. ou:
Hope this helps... Since you didn't seem to be making much headway, I called one of the "old timers" here at work (GM Truck): He said that today, and back in the mid seventies as well, most of the fan shrouds were made of polypropelene ("polypro"). If heat is a concern (like in a big block or diesel application) then fillers are added, usually in form of glass or mica. For structural applications, like an electric cooling fan module, nylon is usually used. Hope that helps... K
This is an extra shroud I have from a '66 Riv.......very hard to find part.......I'll bet polypropelene is the one. Thanks Keith! :bglasses:
If you have a piece of it you can cut off and put a lighter to it.....if it smokes when burning it's ABS, if no smoke then it's polyproylene or most likely so. One problem is any filler material in the fan shroud material in addition to the polypropylene may also create smoke. This is the test used for interior parts (ie dash bezel vs. bucket seat backs/bottoms or kick panels). The VersaChem two part plastic glue does not adhere well to fan shroud material--I have already tried it on a 70 spare shroud. It will fill a crack and stay in place but once you start tweaking the part or filing on the VersaChem to smooth it out you can see where it starts to lift off of the shroud material (it becomes apparent because the Versa Chem is kind of transparent when dried and as it lifts away from the dark fan shroud material the glue gets "lighter looking" again). JBWeld seemed to actually stay in place a little better but I didn't test it for tweak/twist resistance. The VersaChem does not melt into the fan shroud plastic like it does on ABS or PVC (grilles,dash bezels, etc). Of course JBWeld doesn't either. Any way you can "mask off" the areas of the fan shroud that you aren't gluing w/foil or something like that--thus limiting the filler rod that sticks to the repair area. I would try the polprpylene rod and report back w/results. Or.....you could try this new stuff I saw on TV called "CoolChem"---supposedly a new gluing technology advance beyond the "cycloanates"(or whatever that stuff that the "superglues" use/do). Application is a drop or less of 1st part spread over the contact surface, hold pieces together and spray with an activator....and supposedly INSTANT strong bond. Commercial showed a guy with a piece of rubber vacuum hose, the guy sliced it with a razor, applied Part 1, put the two pieces together and sprayed w/Activator, instantly handed it to a visitor to his booth and the guy pulled as hard as he could on it and it would not pull apart. Did same thing this time attaching end of rubber piece to an aluminum Coke can and started yanking on the hose---it tore the aluminum can around the hose and the hose stayed attached. They have a website CoolChem.com Have not tried it but it looks useful for some of our applications....who wants to be the guniea pig here???? o No: Patton
I think I'm gonna try it.......thanks Patton! Here's that link: http://coolchem.com/index.cfm?fuseaction=cyanopoxy&CFID=2295911&CFTOKEN=36577060
I repaired one three years ago by stop drilling the cracks. I then applied model glue to the cracked areas and let it set up for days. Then I scuffed the areas and applied JB weld. Sanded and finished with a plastic paint. It looked great and seemed very strong. I'm not sure what I would do if it was a large area. I'd probably find a donor shroud for the material and use the same process.
fan shroud That sucks about your fan shroud, I too had a problem with a fan shroud that I had bought from a guy in here, the right side top mount was broken off and I took it to a plastic shop hopping that they could tell me what kind of plastic it was and he did a lighter test on it in a out of a way place on the shroud and said that it wasn't ABS but he thought it was some kind of junk plastic that used to be used so you couldn't repair it, just buy new (thanks GM). So I got a pc of aluminum and machine the part to match and I bolted it to the shroud and repainted the shroud and the new mount, now you can't tell it was ever broke. I would like to know if you try that new glue let us know how good it works. Thanks, Chip
