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914World.com _ 914World Garage _ Early rain trays
Posted by: Pat Garvey Jun 14 2007, 06:40 PM
I've been looking for a proper rain tray for my '72 for 3 years now. My original is cracked beyond repair (which I attempted with epoxy - lasted maybe 2 weeks).
I was told some time ago that they used some sort of specialized moulded plastic for these things, and that no glue, bondo, etc. would adhere (could be bogus, but don't know).
Has ANYONE had any success in rebonding small cracks (1/2-1") in these things?
Pat
Posted by: scotty b Jun 14 2007, 06:51 PM
I haven't actually tried it on a rain tray, and it's not gonna be cheap but Duramix makes a product to repair "plastic" bumpers that werks very well on them. It is a two part epoxy made to bond with the plastic and then can be sanded down. It requires a special application gun ( 60.00 ) plus the epoxy tube ( 25.00 )
Posted by: iamchappy Jun 14 2007, 06:57 PM
Why not just buy a nice used one.
Posted by: Eric_Shea Jun 14 2007, 06:59 PM
I would bet JB Weld would work wonders. It would need to be sanded and painted but... that stuff is rock solid.
Posted by: iamchappy Jun 14 2007, 07:03 PM
I'll check but I think I have one in good shape you can have it if you pay the shipping...
Posted by: Pat Garvey Jun 14 2007, 08:34 PM
Why not just buy a nice used one.
Maybe you didn't read my text, but that's what I've been trying to do for 3 years. If one is out there (uncracked), I haven't been able to find it!
Care to shoe me a "nice used one"?
Posted by: Pat Garvey Jun 14 2007, 08:37 PM
I'll check but I think I have one in good shape you can have it if you pay the shipping...
Chappy,
I'll give you my firstborn son or daughter for one that isn't cracked. Don't care about dirty. Bet you don't have one! Course, I don't have a firstborn son or daughter, but I'll make it worth your effort.
Pat
Posted by: Pat Garvey Jun 14 2007, 08:40 PM
I would bet JB Weld would work wonders. It would need to be sanded and painted but... that stuff is rock solid.
Eric,
Tell me about JB Weld (PM would probably be better, since we're beating this thing to death). I have one available with a small, tight 1/2 inch crack, and not in a stress area (wierd).
How does this stuff work?
Thanks, Pat
Posted by: iamchappy Jun 14 2007, 10:47 PM
Sorry Pat mine is cracked just like you said I may have another one up in the rafters, The tray is fine but the 2 mounting holes are gone....
JB it.
Posted by: Crazyhippy Jun 15 2007, 12:52 AM
I'll look @ mine, but i bet it's cracled too....
If not it's yours (and i dont want any damn kids, you can keep them)
BJH
Posted by: Eric_Shea Jun 15 2007, 07:49 AM
Naaaaaaaaa I think it's a good garage subject.
It would work something like what Scotty is recommending but you don't need all the fancy gear. Get a pack at Home Depot. These are all two part epoxy type resins. Here's what I would do:
1. Tape off the bottom and open side to basically form a cup out of the crack.
2. Mix the JB Weld together.
3. Using a toothpick I would carefully fill the cracked area with JB Weld.
If you do it carefully you may be able to get by with an enamel touchup pen. The JB Weld will be grey. That brings me to this:
I'd be willing to bet there's a black two-part epoxy style compound out there that one of our members knows about
Posted by: SGB Jun 15 2007, 10:49 AM
Is it unusual for the black RTV I used to fix mine to properly adhere? Mines been part glue for years, but it does not appear to leak...
Posted by: toomanyinkc Jun 15 2007, 06:24 PM
Where do they crack? I didn't see any cracks in mine.
Posted by: kwales Jun 15 2007, 07:46 PM
Ok guys...
Glue basics....
A glue joint is no better than the surface it adheres to..... If it is dirty or a fingertprint, your glue joint is sticking to that.
Raintrays are flexible, epoxies like JB weld set up hard........
Hard patch on a flexible material means breakage......
You want a flexible patch with a little give....
Try a urethane adhesive or mebbe the flexible silicone stuff for guing mirrors....
Some plastics like the polyethelenes are almost ungluable...... They sell some coatings that can enhance the surface to improve adhesion but they generally are worthless.....
Sheets or patches work well- crappy adhesion over a large area equals a working seal.
Ken
Posted by: Pat Garvey Jun 15 2007, 07:55 PM
The cracks are small, maybe 1/32" wide, but they are around the mounting holes. So, even if a patch of "something" works, what will keep it from re-splitting when the bolts are torqued down?
This drives my nuts!!!! I can't believe there isn't one of these out there in nice condition! Without it, it's going to really screw up my CW chances (yeah, that's right - I'm a CW!).
My later-style tray is perfect and, quite frankly, a much better engineered piece - but it doesn't belong on a '72. Will kill me at next year's Parade too!
Pat
Posted by: r_towle Jun 15 2007, 10:46 PM
My friend had a leak in his 928 gas tank.
He called his plastic engineer buddy who told him that it could be welded.
Apparently there are some new toys out there that someone needs to buy.
Its basically a torch, not sure of the gas, but I would be that propane would work, it does not need to be hot.
The filler needs to be of the same blend of plastic (why you need someone who can look at it and tell you what it is)
From there, the guy basically torch welded the leak, and you cant see it at all.
Same as steel.
Clean up the area, rough it up a bit with sand paper.
Clean up with alcohol to make sure its just plastic, nothing else.
Torch in one hand, rod in the other.
It took the same amount of time as it would to weld a steel item.
He told me that the rods are available at any local plastics supply house (like I know where that may be)
In any event, I guess its a pretty common way to fix plastic now adays.
Rich
Posted by: Johny Blackstain Jun 16 2007, 01:30 PM
Pat- found this on eBay:
http://cgi.ebay.com/ebaymotors/Porsche-914-Reconditioned-Rain-Tray_W0QQitemZ220121538296QQihZ012QQcategoryZ34204QQrdZ1QQcmdZViewItem
Posted by: RoninEclipse2G Jun 16 2007, 02:26 PM
My friend had a leak in his 928 gas tank.
He called his plastic engineer buddy who told him that it could be welded.
Apparently there are some new toys out there that someone needs to buy.
Its basically a torch, not sure of the gas, but I would be that propane would work, it does not need to be hot.
The filler needs to be of the same blend of plastic (why you need someone who can look at it and tell you what it is)
From there, the guy basically torch welded the leak, and you cant see it at all.
Same as steel.
Clean up the area, rough it up a bit with sand paper.
Clean up with alcohol to make sure its just plastic, nothing else.
Torch in one hand, rod in the other.
It took the same amount of time as it would to weld a steel item.
He told me that the rods are available at any local plastics supply house (like I know where that may be)
In any event, I guess its a pretty common way to fix plastic now adays.
Rich
I've been fixing plastic stuff like this for years. a butane pencil torch and zip-ties, kinda like braizing or soldering, helps if you have a putty knife or something to flatten/press it into place. come to think of it I bet this would work on the raintray for the creamsicle
Posted by: Pat Garvey Jun 18 2007, 09:40 PM
Pat- found this on eBay:
http://cgi.ebay.com/ebaymotors/Porsche-914-Reconditioned-Rain-Tray_W0QQitemZ220121538296QQihZ012QQcategoryZ34204QQrdZ1QQcmdZViewItem
JB,
Thanks, but that's lae later one - already have four of them!!!!!
I have bought from these guys before & thry're OK.
Pat
Posted by: 914nerd Jun 19 2007, 10:48 AM
A couple of things:
Fist off, if it melts, try repairing it that way, but it probably won't
More than likely it is a cross-linked polymer (plastic) that, once it links, has set irreversibly
I have a large and rather tragically damaged polyurethane part that is a cross-linked material and the real key to repairing it seems to be to use a material similar enough that it will flex the same amount (not more or less by much) and adhere moderately well
What I am trying for this is to use a polyurethane (cross-linking) bed-liner material which seems to have a comparable flexibility to the broken piece
I have a few rain trays lying around and can try repairing one of them this way if people are interested
Also, Pat, I believe I have an early one in very good shape (I think I say one hairline crack on an edge)
If you're interested, I can take another look at it and send you some pics (PM me your e-mail address)
Just another couple of thoughts
Charles
Posted by: davep Jun 19 2007, 11:05 AM
Many of the plastics shrink as they age, hence the cracks. Some of the softer plastics like PE and PP are very waxy and basically glue will not stick. It is almost better to get another bad one, or at least a section of it, to use as a donor for a fill material. Then it is a matter of 'welding' it in. Better to practice on the donor material first to develop the process. You may find a hot air gun better than a torch. You do not want to work directly with a flame on the plastic since this will cause a lot of degradation of the plastic, and thus more cracking shortly thereafter.
Posted by: 914nerd Jun 19 2007, 12:41 PM
davep,
I don't know what the material is on the rain trays, but melting might or might not work
A number of plastics set up such that they will not melt or dissolve
This irreversible change makes it difficult to try and "weld" the material in the manner you describe as it won't melt (it just burns or begins to decompose as a result of the temperature)
If this is the case, then you have to find something with similar properties, but that has not yet been set up and use it to patch the material
I am going to look into what the rain trays are actually made of (since I believe I have a cracked one somewhere to experiment on)
Posted by: davep Jun 19 2007, 03:57 PM
You are correct. However, in the absence of a definite identification of the material used I think trying to use the original material stands the best chance. Also note that I suggest a bit of practice on the donor material first. That way one can learn if it can work, and the techniques necessary to accomplish the repair.
I think for a lot of the plastic parts it would be very useful to learn the original materials. I have a 914/6 washer bottle that is crazed and in need of some repair. I believe it to be some form of nylon.
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