Plastic gas tank repair

cliffblue

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Hello, I have a large Trac Vac I rescued from the scrape yard that I repaired and have used 5-6 years. It has an 11HP B&S on it with the plastic gas tank. The horizontal seam at the middle has begun to leak. Checking availability of a replacement shows 1 available for $300, so I only fill it half way every time I dump it. Does anybody know of an epoxy of sealer that will stop this leak? I’ve inquired a couple of well known epoxy/adhesive manufacturers.I got a big nope both times. I went through this while repairing cracks in the body of a 79 6x6 Hustler I brought back. Any ideas?
 

StarTech

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Most plastic tanks are HDPE plastic which are highly chemical resistance. Most of these tank are sonic welded. Beyond plastic welding there is not much out there that will bond to them. Several years ago I did find a product that would but it was over $100 per once and not feasible to use on small engine tanks due to costs.

And definitely the JB Weld plastic weld epoxy will not work nor does the Permatex Plastic weld epoxy. Heck the JB Weld plastic weld will not even bond the ABS plastic it claims to bond. At least the Permatex version does.
 

bertsmobile1

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You can weld it back together with either one of the soldering iron attachments or a hot air gun
If CLEAN plastic is heated up to the glassy state it will weld together if two pieces are touched with light pressure
Note I said CLEAN
I have sucessfully welded dozens of tanks that are splitting at the seam
The cheap welding kits are about $ 60 ( AUS ) so that should be around $ 20 to $ 30 US .
The only catch is it must be the same type of plastic
Most chemical & oil drums are HDPE as is the frostly milk bottles ( clear ones are PET )
Ignore all the BS on face ache about using zip ties on everything or the same soldering iron tip you use for soldering, that will not work
HF should have some cheap Chinese kits and they will do what you want
Clean the surface using a STAINLESS STEEL ( and only stainless steel ) brush then clean with acetone .
V out the seam slightly.
If you have a heat gun, preheating till the region just starts to look glassy will make a better weld then apply the welding rods in the kit
Scrape the seam level & check it is sealed then I put a patch over the top using a lump of milk bottle .

Worthwhile to have a look for a discarded chemical drum and do a couple of trails first .
There is a very short temperature difference between glassy , slumps & melts and to be successful the latter two have to be avoided.
A clean & polished stainless steel ( not chromed steel ) putty knife or pallet knife is really good for smoothing out air bubbles .
Sounds difficult but it is very very easy to do once you get your eye in.

And as Star already mentioned, no goop in a tube will do the job regardless of what it says on the label .
Even worse, once you have polluted the surface with any goop in a tube, it can never be successfully welded .
 

cliffblue

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Thank you bertsmobile1 for a through and detailed description of your repair suggestions. I have blue chemical barrel pieces that should give me raw material to work with. I haven’t attempted plastic welding before, so I’m contemplating looking for someone local that does this. Hand tremors have made metal welding nearly impossible.
 

bertsmobile1

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Thank you bertsmobile1 for a through and detailed description of your repair suggestions. I have blue chemical barrel pieces that should give me raw material to work with. I haven’t attempted plastic welding before, so I’m contemplating looking for someone local that does this. Hand tremors have made metal welding nearly impossible.
Some body shops do plastic welding to repair plastic bumpers.
Note they are ABS usually and not HDPE but the techniques are the same
Some mower repair workshops ( they type that only sell parts & used mowers ) will also do it .
 
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