I welded polycarbonate sheets

[cwah]

Hello there,

Yesterday I realized my plastic box felt apart again. It is a battery protection box made of 5 mm polycarbonate sheet:

I used the plastic cement provided by the seller but it wasn't strong enough and felt apart multiple times already. I already tried industrial super glue and it wasn't strong enough neither...


I was thinking that glue wasn't maybe not the best idea... and I've seen a video on youtube showing guys welding plastic with a soldering iron.


So I thought I could do the same!

I cleaned the sheets and tried first with my heat gun (at 400 C). The sheets were indeed welded together!! But for some reason, there were bubble everywhere. It didn't feel solid enough.

I tried to do the same with my soldering iron (480C) and there wasn't anymore bubble and I was able to meld the sheets. But the colour became yellowish and very ugly.


At the end, I was able to weld my box. It's now quite strong and doesn't seem to fall apart easily. But it's so ugly and doesn't look like the clean box I had before. All join are not yellowish and looks like an old rotten box...


But at least it's strong!!

Have any of you welded yourself plastic to create your custom part?

 

[cwah]

Here is what the pack now look like when it's finished:

You can see the yellowish stuff on the corner, and some of the hot glue I added to make sure the welded area won't move, even under the food plastic wrap I used to make it waterproof.

 

[electric_avenue]

well, that sure is one ugly box.

 

[Tinker]

You can get plastic angle trim that could be glued on to smarten the appearance.
I often use black 'food-grade' poly' sheet to construct boxes, welding is very easy I find a small flame torch easier for neater joints.

 

[cwah]

Yeah, very ugly for sure lol.

At least people won't want to steal it from me. And few that've seen this battery told me it's a car battery

This is an 66V20AH A123 battery at worth 500£ or more if purchased in Europe


Tinker, I was looking for food box but they were all the wrong dimension. So I decided to have custom cut polycarbonate sheet to be sure to have the right size.

 

[wurly]

What you could do is, buy a roll of sticky back plastic sheet(fablon) and cover your battery box. You can get
it in several colours from b&q. It's. A cheap way of getting a finished look.

 

[Hugh]

What you could do is, buy a roll of sticky back plastic sheet(fablon) and cover your battery box. You can get
it in several colours from b&q. It's. A cheap way of getting a finished look.

Bring back Valerie Singleton

 

[wurly]

Someone giving away their age Hugh?
yeah me too.

'Now boys and girls, today we are going to make a battery box for your new ebike project, all you need is some glue, old fairy liquid washing up liquid bottles (ask your mum for these) and some sticky back plastic.
Here is one i made earlier..........'

These days i Tig weld my battery boxes together.

 

[Mussels]

I've used a solvent to weld ABS before, not as strong as a heat weld but pretty good. Anyone thinking of trying it should look in modelling shops, another useful product from those places is threadlock.

 

[cwah]

What you could do is, buy a roll of sticky back plastic sheet(fablon) and cover your battery box. You can get
it in several colours from b&q. It's. A cheap way of getting a finished look.

Thanks Wurly. That seems to be a good idea.

I've seen that on ebay:
Matt Kitchen Units Cupboard Doors Draws Self Adhesive Vinyl Cover Up Fablon | eBay

Would that be waterproof? I need something that would protect from water.


An alternative would to paint the box:
- Get the spray:Plasti-kote 9439 400ml Stone Touch Alabaster: Amazon.co.uk: DIY & Tools
- Use it with primer: http://www.amazon.co.uk/Rust-Oleum-AE0030003E8-400ml-Plastic-Primer/dp/B001W03PQI/ref=sr_1_1?ie=UTF8&qid=1345721049&sr=8-1
- Protect myself with a mask: TRIXES 2pc Spray Paint Twin Cartridge Respirator Mask/Goggles: Amazon.co.uk: Garden & Outdoors
- And sand it for nice finish: http://www.amazon.co.uk/Waterproof-Abrasive-Paper-Sanding-Sandpaper/dp/B003S8JZSE/ref=sr_1_1?s=diy&ie=UTF8&qid=1345721255&sr=1-1


What would be the best option for nice touch, solidity and waterproofing?

 

[cwah]

A bit on the expensive side, but I've maybe found exactly what I need in term of cover:

1000D PVC Waterproof fabric caravan campervan motorhome awning cover material 5M | eBay

Heavy duty waterproof and fire retardant fabric. I can even use that to store my lipo pack on it.

 

[cwah]

Finally used fablon to cover my battery:

It's ok. But there are bubble and it's also not as clean as paint I suppose?

But at least it's better and waterproof

 

[wurly]

Shame about the bubbles, there is a knack to applying it.Try pulling it back and start again from one corner spreading the sheet with the palm off your hand.
Its possible to get good results. I dont bother painting the battery boxes any more, i use the fablon sheet.

 

[cwah]

Yeah I tried for the bubble. I should cut the sheet to the right size before sticking it to the box. And try your technique to avoid bubbles

But the finish isn't as nice as some nice paint. Maybe I'll try some carbon fiber sheet that are bubble free. Would maybe have a better finish.

 

[cwah]

I finally decided to bolt the sheet together rather than welding them. I also added some angle bracket to protect it from the drop. It already felt many times on the floors and the polycarbonate box has cracked holes there and there

Surrounded with so much steel, I called my box "the terminator" lol

 

[OldBob1]

In the past I have stuck broken plastic together using a soldering Iron and melted into it paper clips to stich and strengthen the break.
We also used a solvent to put together Electrical plastic conduit and fittings, seem to weld every think together OK.

 

[cwah]

The thing with welding plastic is that it's not as strong as bolting them together.

Also, bolting them allow me to repair easily. If a part get broken, I can easily change it.

I tried plastic glue, heat gun glue, soldering iron and it doesn't seem that strong for my need.