TheSamba.com :: View topic - Broken fan shroud

Thu Feb 23, 2017 7:11 am

The main damage to this fan shroud is the part which holds to fan itself is cracked in 3 places (completely broken off actually - I have it now stuck together with super glue).

Of course replacing would be the obvious thing, but since this is an EARLY ('81) shroud, finding one in good condition might be daunting... therefore I am considering repairing it.

Does anyone have any suggestions regarding how to repair this? Perhaps EPOXY glue would work (but would it stand up to the heat?)

I am also considering constructing an entirely new 'frame' for the fan to sit in... I could do this, but it would certainly take some time...

Just thought I would run this by you guys before investing a bunch of time into this... thanks!

The shroud is also damaged here... but this is less critical.

Thu Feb 23, 2017 7:14 am

Replace it! if the fan breaks free, it can damage the radiator.

If you do repair it, I would suggest that you use some sheet metal to mechanically reinforce the breaks in addition to epoxy, just in case.

Thu Feb 23, 2017 7:23 am

TDCTDI wrote: Replace it! if the fan breaks free, it can damage the radiator.

If you do repair it, I would suggest that you use some sheet metal to mechanically reinforce the breaks in addition to epoxy, just in case.

I wonder if normal epoxy would hold up to the heat in that area?

Thu Feb 23, 2017 7:54 am

I'd be more concerned about the vibration of the fan & vehicle causing adhesion failure.

Thu Feb 23, 2017 8:26 am

I think what I will do is make some small sheet metal pieces then epoxy them into place... then drill little holes and reinforce with tiny nuts and bolts... then put CA glue over everything.

I think fiber-glass is another option...

Thu Feb 23, 2017 8:30 am

epowell wrote: I think what I will do is make some small sheet metal pieces then epoxy them into place... then drill little holes and reinforce with tiny nuts and bolts...
That's a pretty good idea, I wish I thought of that.

Thu Feb 23, 2017 8:42 am

TDCTDI wrote: epowell wrote: I think what I will do is make some small sheet metal pieces then epoxy them into place... then drill little holes and reinforce with tiny nuts and bolts...
That's a pretty good idea, I wish I thought of that.

will be stronger than the original :) :)

Thu Feb 23, 2017 8:42 am

TDCTDI wrote: epowell wrote: I think what I will do is make some small sheet metal pieces then epoxy them into place... then drill little holes and reinforce with tiny nuts and bolts...
That's a pretty good idea, I wish I thought of that.

Yes but use substantial metal pieces. I'd look at 1/8" thick pieces of aluminum, no epoxy/glue will hold for very long in this situation. You need to create a reinforcement not dependent on adhesive. Adhesive can help that reinforcement but it should be OK without the adhesive.

Thu Feb 23, 2017 8:44 am

[quote="dobryan"] TDCTDI wrote: You need to create a reinforcement not dependent on adhesive. Adhesive can help that reinforcement but it should be OK without the adhesive.

exactly!

Thu Feb 23, 2017 9:10 am

CA is a terrible idea - its far too brittle. Of course, now you've contaminated the bond area with an inappropritae material...

Use GFlex epoxy for the basic repair - its great for plastics - and reinforce afterwards.

Thu Feb 23, 2017 10:12 am

make sure the repair is fool proof, if it lets go in use, the radiator could be ruined. Try to source a replacement. some plastics can be welded reinforcement should be considered if you repair. many palatic parts do have id as to what type of plastic it is, try to find a mark or code that tells what it is, naylon maybe? is it reinforced with fibers?

knowing the type of plastic can aid in glue or weld selection metal reinforcement is a good idea. remember plastic may crack around drilled holes anyplace ypu remove material for attachment, so choose wisely.

good luck

Thu Feb 23, 2017 10:29 am

epowell wrote: I think what I will do is make some small sheet metal pieces then epoxy them into place... then drill little holes and reinforce with tiny nuts and bolts... then put CA glue over everything.

I think fiber-glass is another option...

Agreed superglue is WRONG for this (CA =CyanoAcrylate = superglue). Use a reinforced epoxy. Fiberglas could work too.

Epoxy with small embedded sheetmetal reinforcements can be much stronger than the material it's attached to. JB-Weld is a good example of epoxy suited for repairs like this.

Gluing plastics is dicey. Sometimes I can tell by looking at an item, or scratching it, if it's glue-able, other times I have to test it. If you want to be certain just test-glue a little piece of sheetmetal to some un-important area and let it cure, and see if its adhesion satisfies you. Often you can't get the adhesion you want to plastics, but if you encapsulate a mechanical sheetmetal reinforcement with thick epoxy, the combination with rivets or small screws results in a strong repair. Sounds like you are familiar with this method.

That thing looks pretty spindly to begin with. That tells me the forces on it are not much, and it's pretty likely you can achieve proper strength in a repair.

You could just glue it up keeping aesthetics in mind, then add 3 simple metal supports from those bolt holes outward to the rim. Then there's 6 supports to hold it from here on out. Which could look better than large epoxy goobers.

You asked about temperature. JBWeld is suitable for sustained 500F. Your cooling system runs up to 200F and will explode before 250F. Not sure you have JBWeld where you are but there are many similar products available, just look at their temperature ratings. JBWeld reports cured epoxy strength to be 3960psi, thats pretty good. There's a wide range for plastic strength, of course but 3960 is in the midrange of 1000-7500psi for plastics.

Thu Feb 23, 2017 10:52 am

I have repaired many plastic fan shrouds when restoring 60's cars using fiber patch and Fusor plastic bumper repair epoxy. It sands well and bonds very well, is paintable and has lasted many years.

Google plastic bumper repair techniques.

Thu Feb 23, 2017 2:01 pm

Thanks guys...

I went out and bought some absurdly expensive epoxy (the only thing available in our village in the north-eastern corner of Czech)... came home and realized pretty quickly that I could make the repair with sheet metal and bolts (no epoxy at all!). Originally I was thinking about 0.6mm aluminum, but went with 1.0mm stainless steel. The bolts are very small so to guard against them vibrating loose, I will mar the threads then douse with CA.

The fan is all in there now and feels PLENTY solid!

Thu Feb 23, 2017 2:03 pm

If you fill the gaps under that steel with epoxy it will be really strong.

Thu Feb 23, 2017 2:06 pm

Sodo wrote: If you fill the gaps under that steel with epoxy it will be really strong.

Yeah, there are a bunch of gaps > so why not fill 'em up :)

Thu Feb 23, 2017 2:09 pm

epowell wrote: Sodo wrote: If you fill the gaps under that steel with epoxy it will be really strong.

Yeah, there are a bunch of gaps > so why not fill 'em up :)

The epoxy may have some adhesion (with luck LOTS of adhesion).

If the adhesion doesn't work out a huge benefit is the filler will reduce stressing on the (many) bolt-holes.

Thu Feb 23, 2017 2:16 pm

Sodo wrote: epowell wrote: Sodo wrote: If you fill the gaps under that steel with epoxy it will be really strong.

Yeah, there are a bunch of gaps > so why not fill 'em up :)

The epoxy may have some adhesion (with luck LOTS of adhesion).

If the adhesion doesn't work out a huge benefit is the filler will reduce stressing on the (many) bolt-holes.

I theoretically could disassemble it all, then reassemble with all epoxied > but this epoxy dries in 4 min(!!!!!!) so this procedure might be impossible. [or maybe disassemble one joint at a time, and reassemble with all the whole joint epoxied and sheet metal epoxied to it. Then move to the next joint. (?)]

But as is it is plenty strong > I even feel to do something to reinforce the other existing joints because it is all really wimpy.

Thu Feb 23, 2017 2:20 pm

I'd replace it.
I know talk is cheap, but we've already spent a few $.02

Thu Feb 23, 2017 2:58 pm

Consider proactivly reinforcing the other two spokes on the outer side just as you have done the one that broke. same forces that broke one may break one of the other two.

good luck