I thought I'd document a method I've used several times to repair leaking barrels. This explains how to repair plastic beer barrels (King keg and such like) that have developed leaks due to holes or cracks. They must be made of polythene (aka polyethylene or HDPE) for this to work. I doubt you can fix major defects this way but you can repair âpin holesâ or small cracks.
You will need:
A heat source to melt the plastic. This shouldnât be too powerful or it will melt too much plastic, too fast. You need to be able to control whatâs happening and do the job gradually. I used a little hand-held gas soldering iron, with a hot air attachment. Iâll refer to this as the heat gun. Also, donât use a naked flame, like a blowtorch, or youâll set the plastic afire and wreck it.
Some âdonorâ plastic. This must be a similar plastic to the barrel, as dissimilar plastics wonât mix together. It needs to have the approximately same melting point as well or itâs never going to weld together. Fortunately HDPE is used for a lot of containers. The best stuff Iâve found is washing liquid bottles (EG Surf, Persil) but make sure there's no trace of detergent left on it.
A small knife. A craft knife type thing, with a small blade.
Gloves. Iâd recommend gloves, as the molten plastic burns like **** if you get it on your fingers.
Wash the barrel and rinse to make sure any soap is gone. Leave the tap open or the top off.
Clean out the hole or crack with the knife to get any debris out (EG beer residue). Itâs good to cut away some surrounding plastic to get a bevel or cone effect so your repair will start on the far surface (the inside) of the barrel. Just like preparing metal for welding.
Clean the area with some ethyl alcohol (or maybe cheap nail varnish remover at a push â good stuff has additives to make it âskin friendlyâ!). This will get any grease or other muck out of the area.
Cut a small piece of donor plastic that approximately covers the area to be repaired. It will shrink a bit when it gets hot.
Use the heat gun on the area to be repaired to start melting the plastic in and around the hole. BE CAREFUL â donât heat it too fast or heat too much in one go. As the plastic gets to its malleable state, it will change from white to almost transparent â once it is transparent be careful not to heat it much further or will become a liquid and the hole will become a whole lot bigger! When the original plastic is softened, put on the hole your piece of donor plastic and apply heat to that as well as the surrounding area to get the whole area and the donor plastic just molten.
Now the tricky bit: you have to get the damaged area just molten enough to weld it all together, without melting a hole through the barrel. Keep applying some heat, across the whole area, and use the flat blade of the craft knife to knead and press the now âdoughyâ donor plastic into the original. This is the crucial bit â unless the whole area and the donor plastic is welded into a coherent mass, the repair wonât work. You can also use your fingers to force it together, but wear gloves.
What you should have now is the area of the hole and slightly surrounding it as malleable plastic, almost transparent. Your donor plastic should have fully melted into the original and you shouldnât be able to see where the hole was. The area may be slightly raised due to the added plastic. This is OK.
Stop the heating. The plastic will return to white. Make sure it is back to room temperature, then test the barrel for leaks.
If it still leaks, drain the barrel again, reheat the area back to transparent and do some more kneading of the plastic to try to seal the hole. You may have to do this 1 or 2 times.
If you doubt this can be done, I can tell you I have repaired 3 leaks in barrels with this method. It can be done, but it takes patience, persistence and care. My repaired barrels will take enough pressure to blow the safety valve, without leaking a drop. So I've saved myself quite a few £.
You will need:
A heat source to melt the plastic. This shouldnât be too powerful or it will melt too much plastic, too fast. You need to be able to control whatâs happening and do the job gradually. I used a little hand-held gas soldering iron, with a hot air attachment. Iâll refer to this as the heat gun. Also, donât use a naked flame, like a blowtorch, or youâll set the plastic afire and wreck it.
Some âdonorâ plastic. This must be a similar plastic to the barrel, as dissimilar plastics wonât mix together. It needs to have the approximately same melting point as well or itâs never going to weld together. Fortunately HDPE is used for a lot of containers. The best stuff Iâve found is washing liquid bottles (EG Surf, Persil) but make sure there's no trace of detergent left on it.
A small knife. A craft knife type thing, with a small blade.
Gloves. Iâd recommend gloves, as the molten plastic burns like **** if you get it on your fingers.
Wash the barrel and rinse to make sure any soap is gone. Leave the tap open or the top off.
Clean out the hole or crack with the knife to get any debris out (EG beer residue). Itâs good to cut away some surrounding plastic to get a bevel or cone effect so your repair will start on the far surface (the inside) of the barrel. Just like preparing metal for welding.
Clean the area with some ethyl alcohol (or maybe cheap nail varnish remover at a push â good stuff has additives to make it âskin friendlyâ!). This will get any grease or other muck out of the area.
Cut a small piece of donor plastic that approximately covers the area to be repaired. It will shrink a bit when it gets hot.
Use the heat gun on the area to be repaired to start melting the plastic in and around the hole. BE CAREFUL â donât heat it too fast or heat too much in one go. As the plastic gets to its malleable state, it will change from white to almost transparent â once it is transparent be careful not to heat it much further or will become a liquid and the hole will become a whole lot bigger! When the original plastic is softened, put on the hole your piece of donor plastic and apply heat to that as well as the surrounding area to get the whole area and the donor plastic just molten.
Now the tricky bit: you have to get the damaged area just molten enough to weld it all together, without melting a hole through the barrel. Keep applying some heat, across the whole area, and use the flat blade of the craft knife to knead and press the now âdoughyâ donor plastic into the original. This is the crucial bit â unless the whole area and the donor plastic is welded into a coherent mass, the repair wonât work. You can also use your fingers to force it together, but wear gloves.
What you should have now is the area of the hole and slightly surrounding it as malleable plastic, almost transparent. Your donor plastic should have fully melted into the original and you shouldnât be able to see where the hole was. The area may be slightly raised due to the added plastic. This is OK.
Stop the heating. The plastic will return to white. Make sure it is back to room temperature, then test the barrel for leaks.
If it still leaks, drain the barrel again, reheat the area back to transparent and do some more kneading of the plastic to try to seal the hole. You may have to do this 1 or 2 times.
If you doubt this can be done, I can tell you I have repaired 3 leaks in barrels with this method. It can be done, but it takes patience, persistence and care. My repaired barrels will take enough pressure to blow the safety valve, without leaking a drop. So I've saved myself quite a few £.
