Anyone in the plastics bus that can identify the type of plastic used on the early (pre-73) rain tray? Have a couple of hairline cracks at the screw mounts that I need to "weld". Tried epoxy - no luck. Held until it got brittle & made matters worse.

Any new glue compounds out there for this wierd plastc?
Pat

try www.waysideadhesives.com I think they have a glue made for plastics.

I always thought they were polyethylene or a PE derivative Pat. Not sure there is an adhesive that will work. Maybe wetsuit glue?

Pat,

Buy a used one from a different car that is all messed up for cheap.
Cut welding rod from the broken one.
Weld up the crack.

Rich

Pat,

If it's polyethelene, then it's a lot like teflon- nothing sticks to it.

There are some tapes that can stick , but I haven't found much else.

Rough rule of thumb, if it looks and feels like it ought to be used for a kid's toy, it can't be glued.

These flexible plastics are composed from long chain molecules. When they break, the long chain molecules are severed and you are trying to glue the broken end to broken end. When you weld with a piece of an old tray, it might work but it won't be as strong because the long chains are broken. The welding will sorta melt a short piece of a broken long chain between the crack. A lot of the time, you will find the patch is brittle adn can break.

Hope that helps.

Ken

yes that is what the guy said polyethylene. For heat and around the engine applications. Does not glue well. Our molder doing the abs panels was looking at the two types to mold them for us along with the two types of relay boards

Pat,

I have been in plastics for 35 years. You need to have someone plastic weld that part. Glue will never work. My water tanks in my yacht are made of the same material and when I had to put in thrusters I had to downsize one and I had to have it plastic welded.
It worked great. No leaks in 5 years.

Now the cost? Look it up on the web and see what a guy may charge you for minimum work.

Bob

swartz

I was thinking it was polypropylene

Here ya go, old school engineer tricks...

Take a small sliver or shaving of the material to be welded and light it with a match,

observe the flame and smell the smoke.

On PVC blackish smoke and acrid smell
On Polyethylene no smoke, the material drips like a candle and also smells of wax
On Polypropylene no smoke, the material drips like a candle and smells of burnt oil
On Polyamide no smoke, pulls to form thread, smells of burn horn
On Polycarbonate yellowish sooty smoke. Sweetish smell
On ABS blackish smoke, soot flakes, sweetish smell

New engineers can't identify plastics unless there is a triange and a number inside it.....