Hot iron mending a plastic water-bag

[Robert Wilson]

Would the edge of a hot clothes iron "seal" a plastic water bag - or would it melt? How hot - very, medium or cool?
Failing this DIY attempt any suggestions for a commercial "hot sealer" company/outfit.

My bow water-bag is too large for the space in the fore-peak and being squeezed in has created a split at a doubled-up corner. They are expensive to replace and if I could reduce the size (at the widest end) this would allow it to sit neatly without creases and bends.

 

[Lon nan Gruagach]

Use brown paper as a buffer between the iron and the plastic.
The plastic must melt for the job to work, but if it is in contact with the iron you will get a mess that usually puts you in the dog house for a week or so.

If you can find some spare material to practice on, so much the better, failing that start cool and build up.

 

[sarabande]

The original bag will have been joined by radio diathermy, but you can weld using a hair dryer carefully.



The technique is shown here

https://www.youtube.com/watch?v=LXlCv3HJViE

and here

https://www.youtube.com/watch?v=sAhrUK0ud8Q

but can be done by hand with hair dryer with some practice.

You will need to identify the material precisely so that you get the optimum temp, and probably use their little wooden roller to squeeze the hot new edges together. A wallpaper roller will do the job.

 

[earlybird]

I wouldn't be too optimistic about sealing a water bag with a hot iron, although someone else might know differently.
An edge joint would be weak and a lap joint has the problem of melting the joining surfaces by heating through the thickness of the material.
If the bag is, say, PVC you could consider adhesive as per inflatable repair. Polymarine sells the glue, although not particularly cheap, and have good guidance on their website.
I think that the chances of DIY size reduction of the bag are very slim.

 

[VicMallows]

I agree that adhesive if more likely to be successful. I have had good success repairing PVC dinghies ..... and waterbeds.

 

[Dockyard Doris]

Can sailing boots be repaired as mine have got a 2 inch split in them, or are they now to be consigned to the skip ?

 

[Tranona]

Would the edge of a hot clothes iron "seal" a plastic water bag - or would it melt? How hot - very, medium or cool?
Failing this DIY attempt any suggestions for a commercial "hot sealer" company/outfit.

My bow water-bag is too large for the space in the fore-peak and being squeezed in has created a split at a doubled-up corner. They are expensive to replace and if I could reduce the size (at the widest end) this would allow it to sit neatly without creases and bends.

I have a brand new Plastimo triangular bow tank still in its box and surplus to requirements at a modest price if you are interested.

 

[Robert Wilson]

I have a brand new Plastimo triangular bow tank still in its box and surplus to requirements at a modest price if you are interested.

Thank you for the offer. I'll experiment with ideas from above before I take you up on it. My bag is also brand new and only used for a few months last year.

If using a glue system to reduce the size I must first cut the bag which is an "all on nothing" scenario. My thoughts on sealing it prior to reducing were to maintain a watertight seam before cutting/trimming.

Thank you one and all, I'll experiment on some of the outside edges (outside the existing seams) with the various suggestions.

 

[Robert Wilson]

Update:

Using a hot iron with brown paper did not work. Full stop
It sort of stuck the two sides together, but pulled apart when gentle force applied.

Shall find a way to make the bag fit the space available, even if it's just folding it over and securing with copious duct-tape.

 

[sailaboutvic]

Update:

Using a hot iron with brown paper did not work. Full stop
It sort of stuck the two sides together, but pulled apart when gentle force applied.

Shall find a way to make the bag fit the space available, even if it's just folding it over and securing with copious duct-tape.

I would had tho that folding it over to the size you want then use some kind of glue , would be your best bet , better then cutting it to size .

 

[NickRobinson]

I successfully patched a Plastimo inner bag which had rubbed a small hole by using part of the spare material outside the welded seam as a patch which I superglued on and clamped overnight after cleaning with meths.

 

[MoodySabre]

With soft PVC can you use the PVC Weld stuff that they use for fixing drainpipe etc?

 

[Robert Wilson]

I would had tho that folding it over to the size you want then use some kind of glue , would be your best bet , better then cutting it to size .

I shall definitely NOT cut it to size - don't ask me how I know. Cost me a new bag last year!

I successfully patched a Plastimo inner bag which had rubbed a small hole by using part of the spare material outside the welded seam as a patch which I superglued on and clamped overnight after cleaning with meths.

That sounds encouraging. Probably best to fold over (to size) then apply superglue and weight.
I tried a bit of duct-tape as a temporary fix, outside in the yard, but the pressure of water in a full bag was too much for the short lengths of tape.

 

[sarabande]

Soft PVC needs a welding temperature of 350C. That is temp of the material, not temp of an iron.

The only real way is use a regulated hot air torch and a roller .


PM me for more details.

 

[skyflyer]

years ago i used a soldering iron through thick greaseproof paper to seal small plastic bags as a get you by for sealing freezer bags - took a bit of practice to work out how quickly to draw the iron across the seam