My new plastic fuel cell sags badly so i drilled a hole through each mounting strap and i'm trying to get something to bond a couple bolts to the plastic so i can draw it up to the straps but nothing sticks to the plastic, i've roughed the surface and cleaned with alcohol but no good. So far i've tried 2 part epoxy, super glue, loctite stick n seal and of course construction adhesive. Any ideas? Thanks.

Are fuel cells made from polypropylene? Check this site for a possible solution:

http://www.urethanesupply.com/identify.html

I can tell you PlastiFix is a killer product but it won't work on Poly and related.

My father in law said to try fiberglass resin I'm just gettin tired of re-prepping when nothing sticks but somethings gotta adhere to this stuff

Ahh the website says it's made of polyethylene


Oh great this explains it......

Polyethylene is used in some underhood areas such as windshield washer bottles and radiator overflow tanks. In non-automotive applications, it is used on ATV fenders, dirt bike fenders and gas tanks, motor home water tanks, and agricultural water/fertilizer tanks. Because Polyethylene is very stable (meaning few things will react with it), it is almost impossible to get quality repairs using adhesives, and also why it is used to contain chemicals (gasoline, pesticides, etc.) that would react with other plastics. Welding is the best repair method for polyethylene. This package contains 30 ft. (9.1 m) of low density polyethylene plastic welding rod. Each rod is 12 inches (30 cm) long and 1/8th inch in diameter.

use NORON auto body adhesive. make sure you use the ADHEASION PROMOER. apply the adhesion promoter and let that dry for 15 min. then glue in your bolts. then wait till the glue is fully cured. the 5 min glue cures in 45 min.
i use the norton adheasive all of the time reparing polypropeline bumpers without any problems. i have even repared atv fenders with the stuff so it should work on your fuel cell.
i am sure there are other manufactures. 3M fusor duramix and others, who make similier stuff that works great. remember with poly based plastics you must use adheasion promoter or nothing will stick to it.

I had the same problem with my cell.

Totally different plan - what if you put two vertical supports (like dowels) inside the cell from the bottom up to where the straps are on either side of the opening? They could push the top back up to where it should be. Have to be made out of a gas-resistant material though.

Quote:

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Polyethylene is used in some underhood areas such as windshield washer bottles and radiator overflow tanks. In non-automotive applications, it is used on ATV fenders, dirt bike fenders and gas tanks, motor home water tanks, and agricultural water/fertilizer tanks. Because Polyethylene is very stable (meaning few things will react with it), it is almost impossible to get quality repairs using adhesives, and also why it is used to contain chemicals (gasoline, pesticides, etc.) that would react with other plastics. Welding is the best repair method for polyethylene. This package contains 30 ft. (9.1 m) of low density polyethylene plastic welding rod. Each rod is 12 inches (30 cm) long and 1/8th inch in diameter.

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This is absalutely the only repair I'd reccomend on a fuel sell, it works very well, adhesives are a failure waiting to happen on PP. The one thing that you have to be careful of is UV degredation, if the plastic has had prolonged exposure to sunlight (or heat) it will degrade and get brittle (often turning yellow) this is what happens to washer bottles that yellow and crack. Once this has happed you are all done, time for a new fuel cell. Repairs will only lead to other cracks when you least expect them.

I'll check on some Norton adhesive and see if it's safe to use for this application, Thanks.


I thought about propping it up from the inside but didn't want to distub the foam in the bottom of the cell and was concerned it might wear on the plastic from vibrations. Good suggestion though Thanks.


Scott the heat tool kits are $249 and i just can't justify buying all that stuff, i might see if a body shop localy has the tools and see what they would charge me to do it. Had i know it was going to sag this bad i would have bought an aluminum cell, mines sagging 2" or so when it's hot out and basicly looks like crap and i lose alot of volume on a 15 gallon cell and at 10mpg it don't get ya far LOL. Thanks.

The typical temperature envirnoment in a car tends to be on the warm side (even in a shaded place like the trunk) sun/heat builds in confined spaces and temps can often exceed 160F during the summer heat. HDPE and LDPE, (High density Polypropylene and Low Densisity Polypropylene) have some of the lowest melt temperatures of any plastic, and to further that, it becomes unstable and starts to warp/sag at even lower temps. It's also one of the most dimensionally unstable plastics out there having little "backbone" or rigidity meaning that large flat unsupported areas of a molded part are likely to sag or warp with very little weight applied to them or when subjected to only moderate heat.

Bottom line? If you want a dimensionally stable long term fuel cell, get an aluminum one (I'd get with a good liner to prevent any future).

Yeah i'm seeing the Plastic isn't very good for this application, i was originaly going to drill through the cell and use plastic bolts to draw it up but that got shot down for safety reasons. I guess it's just going to sag, just sucks cause it's only a little over a year old and wasn't fun to install. Thanks for the help

Heres a Loctite product that looks like it will work? What do you think?

http://thegluedepot.com/index.asp?PageAction=VIEWPROD&ProdID=145

I think the same as I did before

Ok , point taken.

I'd suggest urethane windshield adhesive.
I'd also say your best bet is to ask somebody who should really know ... look through your yellowpages under plastics and find a place that sells plexiglass, lexan, etc.. These places usually carry a vast array of plastics, usually in sheet form, for various uses. They should be able to tell you what, if anything, will work. Don't be surprised if the answer you get is "nothing works on that stuff".