Plastic welding. What's the drill?

[Ixion]

These days I seem to be accumulating quite a lot of broken, cracked and generally munted plastic bits . No, I've not broken them myself, I've gotten them like that.

Now, in the good old days, when all bike parts were made of decent honest cast iron, fixing broken bits was easy. You welded, or brazed them up. With the trusty oxy torch. Which I can still do tolerably well.

Unfortunately, (and IMHO very ill advisedly) manufacturers seem determined to use more and more plastic and less and less cast iron nowadays.

Which leaves the question, what does one do when it gets broken ?

I know that broken plastic CAN be welded up. But I doubt that it involves an oxy torch.

I see plastic welding kits on Tardme for around 500 - 600 bucks.

But I have no idea of whether they are any good or not (it's rather a lot to pay for an experiment). And where do you get filler rods (I presume some sort of filler is required). And such like questions.

And ,and , and , generally.

Anyone know the gubbins on it.

Oh, and is it hard to do? And are the results worth it, or does it just look like crap anyway, and it would be just as well to stick with fibreglass repair kits and Araldite?

[Subike]

Plastic welding. What's the drill?

Its that thing that makes holes in everything you point it at.

Plastic welding? Only some types of plastic can be welded, you are probably better off using the fiberglass as you discribe for most repairs.

[madboy]

When my green 636 went black I got a couple cracks fixed up. Crazefox did the whole job. Might be worth having a yarn to him.

[hayd3n]

a cheap welder will be sufficent for little jobs easy with a bit of practice you can buy all the welding rod look on guards etc for product code

[hayd3n]

most fairings abs most huggers etc polyprop

[MIZXR]

Soldering iron, some spare fairings or even some form of plastic, melt the two together with a bead at the back and fairing repaired and in a lot of cases better than the crud "professional job". easy

careful not to burn the plastic or something ..forget tooo drunkkkk

[MIZXR]

Crome too hard to weld witha soldering iron, much better with plastic
yet too make a larger hole too.

[hayd3n]

Plastic welding. What's the drill?

Its that thing that makes holes in everything you point it at.

Plastic welding? Only some types of plastic can be welded, you are probably better off using the fiberglass as you discribe for most repairs.

almost all plastic fairings can be welded as long as they are actually plastic.
i should know i am a plastics fabricator, andi try to fix ppls bikes when required , fibreglass will only bond to some plastics (it will bond to abs/pvc/styrene etc) ,for small abs repairs (cracks) i make my own glue, i use abs (can use scrap as long as its clean) and mek( methyl ethyol ketone) eventually it will break down the polymer chains and become a liquid this will form a very good paintable glue , with a brush!! also you can just use the mek in small cracks just brush on the inside of the fairing and eventually it will soak in about 3-5 minutes ,and will form a permanent bond in 12-24 hrs but totaly ridable in a hr


i can do a video of the welding this week if you would like and you will see its quite simple with a bit of practice

[hayd3n]

Soldering iron, some spare fairings or even some form of plastic, melt the two together with a bead at the back and fairing repaired and in a lot of cases better than the crud "professional job". easy

careful not to burn the plastic or something ..forget tooo drunkkkk

you have to determine which plastic it is first! a soldering iron will not allow the new (welding rod) to penetrate properly and will do a temporary fix so when you do your respray it looks all pretty for about 6 months then one day your riding along and it falls off lol
all surface most be clean form dirt and paint the welding rod will not bond to it if you dont

[erik]

I've just used a soldering iron (40W I think) and made a flathead screwdriver shaped tip with one corner rounded, to make it easier to mash the plastic together and smooth it etc. We had some ABS at work that I used as filler.
There's some photos of what I've done here:
http://s38.photobucket.com/albums/e118/edorp/sv650s/

When I was looking for info on it, I found this 'how to' which is basically what I did:
http://www.sportbikes.net/forums/how-tos-section/338068-how-plastic-weld.html

I had a bit of a problem with painting it, I think the lacquer reacted with the plastic or one of the previous coats. it's not too noticeable though, so I haven't fixed it yet.

[hayd3n]

Crome too hard to weld witha soldering iron, much better with plastic
yet too make a larger hole too.

whats this large hole your talking about i just vee out the crack/break if needed, you can drill a small hole at the end of the crack to stop it goin any further tho!!!!!!!!!

[Blackbird]

Hi Les,

This is an extract from my mate's website in the UK. I know it works because I've seen a photo of the repair he did to the front of his Blackbird after a pheasant hit it!

Cheers,

Geoff

You have two options here. Either send it to somebody who specialises in repairing bodywork, or do it yourself. It is surprisingly straightforward to weld plastic panels, although it does take a modicum of skill and practice - so start in an area that isn't obvious, if at all possible, or practice on unwanted bits that you may have around the shed. For cracks that are clean, undamaged and undistorted, you can actually achieve invisible mends, good enough not to require re-spraying. However, anything less than perfect mating edges will mean that there'll be a visible scar. Be careful around mounting lugs, and anywhere that's intended to take strain, pressure or tension. Repairs at these points need to be as strong as possible, but without altering the dimensions of the effected parts. It's no good having an invisible repair that perfectly mates two previously separated parts of a fairing if the headlight can no longer be re-mounted!

This option is an excellent one for short-term remedial action that'll put you on until a replacement part is found, as you're not as concerned about the final finish. You can even add-in alien sheets of plastic to fill-in for missing sections to achieve that necessary weather-proofing, and the like. Sheets of suitable plastic can often be found in those plastic boxes that you have around the place, the stuff the Autoglym product comes in, or the Muck-Off kit you have. But, beware, there are as many types of plastic as there are plastic objects ... almost. Some will mate perfectly happily, but many will reject each other by curling up at the opposite ends of the job from each other! Test it out first, and be sure that they will weld successfully well after they have cooled.

The welding technique is pretty straightforward. Start by getting hold of some plastic coat hangers - preferably black ones. The plastic that they use for almost all hangers is near identical to that used in the manufacture of fairing panels - convenient, eh? You'll need a soldering iron with a large bit, something about 5mm across its flat end - don't use a pointed one. Get the iron nicely hot, and up to working temperature. If you have a variable iron, then set it to a moderate heat - this is better than very hot as you reduce the risk of burning the plastic.

Bring the two edges of the panel into close contact. If the split or crack doesn't hold itself, then temporarily secure them together as best as you can. Keep checking the finished side of the work to judge alignment and fit. Gentle pressure bringing the two pieces together during the cooling process works well, but don't overdo it and end up distorting the job!

With the pieces in close contact, and working from the non-finished, or inner side, place the iron a mm or so to one side of the join, with the flat of the bit facing it. Feed some of the plastic coat hanger into the point of the iron, where you're holding it against the panel plastic. Use a small blob of the hanger plastic, severing it from the hanger using the iron tip. Apply gentle pressure until both the plastics soften, and as they does so guide the iron tip slightly down into the panel plastic and towards the join. Pass through the join and hold the tip on the opposite side until you're happy that the opposite side of the join's plastic is also softened, and has merged with the blob that you have now transported across the weld area. You are, in effect, pushing bow-waves of melted hanger & panel plastic from one side of the split to the other. Do this slowly, and with due care that you don't dig too deep into the plastic and end up going through! Although you're pushing plastic across the join, on each pass try to leave some at the join itself for optimum strength.

Repeat this process as though you were sewing the two sides of the join together, working alternately one way and then the other. Take your time, but try to be fluid and smooth. Get a feel for how malleable and viscous the melted plastic is, and hence how fast you need to work to ensure that you don't tear strands away, or leave the bit too long in one place and risk going through.

[hayd3n]

I've just used a soldering iron (40W I think) and made a flathead screwdriver shaped tip with one corner rounded, to make it easier to mash the plastic together and smooth it etc. We had some ABS at work that I used as filler.
There's some photos of what I've done here:
http://s38.photobucket.com/albums/e118/edorp/sv650s/

When I was looking for info on it, I found this 'how to' which is basically what I did:
http://www.sportbikes.net/forums/how-tos-section/338068-how-plastic-weld.html

I had a bit of a problem with painting it, I think the lacquer reacted with the plastic or one of the previous coats. it's not too noticeable though, so I haven't fixed it yet.
those assumable professional plastic welds didint hold as it was welded to paint not actual plastic

[Dan Mapp]

I have a hot air plastic welder and I'm b***ed if I can get it to work proper it just makes a mess. But every so offen i have another go so must get the hang of it soon.

[erik]

those assumable professional plastic welds didint hold as it was welded to paint not actual plastic
They had made a small v in the back of the crack, so it was welded to the plastic, but it seemed like they didn't get the fairing hot enough to actually melt with the weld bead. They must have been trying to limit the heat so as not to damage the paint on the outside.

[hayd3n]

I have a hot air plastic welder and I'm b***ed if I can get it to work proper it just makes a mess. But every so offen i have another go so must get the hang of it soon.

are you getting it too hot???
for abs it shouldent bubble
are you using a welding tip?
2/3/4mm welding rod?
if you arnet using a tip you will need much more practice ill try and get a video this week so you all can see
free hand and with a tip

[hayd3n]

blackbird

that not a bad home effort!!!

[Racey Rider]

So the 'Mek' brakes down the abs to a pliable state? then in a hour or so it re-sets again?

Where would one buy this mek( methyl ethyol ketone) from?

[hayd3n]

So the 'Mek' brakes down the abs to a pliable state? then in a hour or so it re-sets again?

Where would one buy this mek( methyl ethyol ketone) from?

try repco
yes its just like glue but better coz you are using the same plastic, use a little bit at a time and it will bond great !!!
u can thin it out or keep it thick

[Blackbird]

Where would one buy this mek( methyl ethyol ketone) from?

You need to be BLOODY careful with MEK. Get it in your eye and your sight is gone for good. Look at the MSDS sheet here: http://www.jtbaker.com/msds/englishhtml/m4628.htm and then take the proper precautions if you still plan to go ahead. MEKP (the peroxide derivative) is even more harmful.

[birdhandler]

Some plastic model glues are actually a solvent not sure if its MEK
they are handy if you only want a small amount o9r can be liberated from yorr brother or sons stuff
Cheers

[Ixion]

Coat hangers. And MEK. This is looking promising. Coat hangers I can get (may have to sleep on the couch for a week, but what is life without sacrifice). And once upon a time I practically bathed in MEK every day. Completely harmless. Comparatively.So, these $500 hot air kits? Do they do anything better than a soldering iron (I have a soldering gun with some funny flat tips, maybe that';s what they're for).?

I think this may be a starter, time I learned some new skills.

And , on reflection, it occurs to me that a wander along the ditches on SH22 should provide more than sufficient scrap plastic for filler purposes. One afternoon after Boomer's been out and one could garner enough for a lifetime.

[Bonez]

Go for it Ixion.

I've used super glue and black shoe polish to repair cracked plack plastic instrument consols.

[Dan Mapp]

are you getting it too hot???
for abs it shouldent bubble
are you using a welding tip?
2/3/4mm welding rod?
if you arnet using a tip you will need much more practice ill try and get a video this week so you all can see
free hand and with a tip

Cheers for that will buy you a beer or six when I get down south. :drinknsin

[imdying]

So the 'Mek' brakes down the abs to a pliable state? then in a hour or so it re-sets again?

Where would one buy this mek( methyl ethyol ketone) from?What out for MEK, it's very aggressive, keep it away from your body, especially the eyes or any wounds you may have.

[Ixion]

Oh, by the way it's also insanely inflammable. And the vapour will travel for an amazing distance to find an ignition source. Good stuff.

[NinjaNanna]

Mark_M Plastics repair - Glenfield, Auckland 09-443 4063

http://yellow.co.nz/whitepages/Glenfield/Mark-M-Plastic-Repairs/101894514_BUS.html

Had 2 jobs done there and been very happy with job and price.

[Shaun]

Just send all your plastic welding to me in New Plymouth mate, I employ a man here to do it, WHO IS VERY VERY GOOD and fussy, Brilliant work man ship

There are more tricks to plastic welding proffessionaly, than most NON plasticwelders know about.

Gauranteed quality work man ship, fo the price of a Courier:Police:

[Ixion]

Perhaps I should (re)emphasise that my present interest is not fostered by any actual need.

I do not have any plastics that NEED to be welded or replaced.

I have however inherited some "came along with" plastic bits that "would be OK to use if that big crack was welded up". Keeping a spare unusable panel on the wall is somewhat pointless. Keeping a welded up and usable at need panel is more sensible.

Since I have no actual need, I cannot justify paying someone.

If I were actually attempting to repair a damaged bike I would consider farming the task out.

[Shaun]

Perhaps I should (re)emphasise that my present interest is not fostered by any actual need.

I do not have any plastics that NEED to be welded or replaced.

I have however inherited some "came along with" plastic bits that "would be OK to use if that big crack was welded up". Keeping a spare unusable panel on the wall is somewhat pointless. Keeping a welded up and usable at need panel is more sensible.

Since I have no actual need, I cannot justify paying someone.

If I were actually attempting to repair a damaged bike I would consider farming the task out.


Good on ya, I am just a Parasite looking for a way to make a customer happy, and me some money if possible.

[Morcs]

I used a lighter and a plastic coat hanger last time I attempted to weld something...

It failed.

[Ixion]

Well, that was easier thna I expected.

I decided to give it a try , using the Virago side cover , which badly cracked from one of the mounting lugs when it went for a little ride on its own.

Used my solder gun with the funny spade shaped bit thing that I always wondered what it was for. And a plastic coat hanger.

I'd call it more plastic stitching that welding.

Basically I just melted each side of the break to about half thickness, on the 'inside' (the side you don't see) , then smoodged them together and added coathanger filler to make the plastic thicker than it was (compensating for the fact that I hadnt gone full thickness).

Then turned it over and did somewhat similar on the 'good' side, but more lightly and no filler rod. And smoodged it nicely so it was smooth and even. Then sanded it down.

Looks OK, and some flexing and prying suggests it is at least as strong as the original

Then tried the same thing on an RZ side panel that had the same problem. Also a good result.

Admittedly these were cracks rather than broken off pieces, so I had no need to jig the pieces together.

But, all in all, I'm quite chuffed for a first attempt.

I still haven't been able to find any MEK though, neither Ripco nor Supacrap stock it here. I'll try one of the specialist paint places , failing that see if I can get some nail polish remover. That's about 20% MEK , and the rest mainly acetone, which is Methyl methy ketone (ie one less CH2 unit). And a bit of methyl butyl ketone. Or was when I used to mix it up.

[Hawkeye]

failing that see if I can get some nail polish remover. That's about 20% MEK , and the rest mainly acetone, which is Methyl methy ketone (ie one less CH2 unit). And a bit of methyl butyl ketone. Or was when I used to mix it up.

Having done quite a bit of research over the last few day's on the best way to approach this, the general concensus was to basically create liquid plastic to use for the underside of the joint. :scratch: Not having a clue how to achieve this has been bugging me. Where 'do' you get MEK from! :confused:
Never gave nail polish remover a thought. Cheers Ixion. I'm going to have an experiment with that.:niceone:

[imdying]

Nuplex has MEK and lots of it, and also MEKP too. Best of all, it's dead cheap, about $30 a litre or something iirc.

[vifferman]

H
Never gave nail polish remover a thought. Cheers Ixion. I'm going to have an experiment with that.:niceone:
Just don't buy the stuff that has other crap in it, like "nail conditioner" or whatever, as it's oily and will "bugger things up" (technical term).

[yomikey]

Where can I get the plastic filler rod?????

[Ixion]

Just don't buy the stuff that has other crap in it, like "nail conditioner" or whatever, as it's oily and will "bugger things up" (technical term).

No oil in the brand I used to mix, can't speak for others though. Only Acetone, MEK and MIBK.

[Ixion]

Where can I get the plastic filler rod?????

Plastic coat hangers. try the wardrobe. They breed in there.

[Hawkeye]

Found an absolutely brilliant glue for the plastics. It's the 'cement' stuff that plummer's use for gluing the plastic waste pipe joints together. Used it on my broken bits and they are great. Snapped the lugs that hold the fairing together. The glue has them as strong as the rest of the plastic. I also glued 3 pieces together that had broken around a fixing hole. Again, the joint is strong and also flexible. The cracks are almost invisible.

[Ixion]

An estimable discovery. Cheap, and readily avilable.

And, by induction, that means that the plastic fittings themselves are a source of compatible plastic for repairs.

[hayd3n]

Found an absolutely brilliant glue for the plastics. It's the 'cement' stuff that plummer's use for gluing the plastic waste pipe joints together. Used it on my broken bits and they are great. Snapped the lugs that hold the fairing together. The glue has them as strong as the rest of the plastic. I also glued 3 pieces together that had broken around a fixing hole. Again, the joint is strong and also flexible. The cracks are almost invisible.

pvc glue?
there is also abs pipe so you can buy abs solvent glue say at micos or plumbing world

[Ixion]

Doesn't work with those sticky out phalluses that go into grommets to hold panels on. Y'know the ones that look like a tiny little dick (some of you should be fairly familiar with what that looks like, I'm sure).

Not even with a bit of 16# wire up the inside . Tried welding and glue, still pulls apart.

Any ideas?

[hayd3n]

Doesn't work with those sticky out phalluses that go into grommets to hold panels on. Y'know the ones that look like a tiny little dick (some of you should be fairly familiar with what that looks like, I'm sure).

Not even with a bit of 16# wire up the inside . Tried welding and glue, still pulls apart.

Any ideas?

maybe weld it properly !@!
and if you have too
get someone to machine a new grommet for ya!!
then weld it on

[pete376403]

Supercheap do a two-pack plastic adhesive/filler. Dynatech Plastic Steel, IIRC. Comes in a double barrel syringe type dispenser. From the smell of it there are some fairly healthy chemicals in there. Not as cheap as old coathangers but it did a superb job of repairing the broken ABS radiator shroud of my KLR, and the $30 is a shitload cheaper than the $249 ex Japan cost of a bare panel (plus $180 for decals).

Stays usable for about 5 minutes after mixing and very good strength after an hour. After 24 hours I think it is stronger then the original plastic

[riffer]

Sounds really good Pete.

My tail light needs fixing before warrant time (broken bits mean it flops around a bit. I've tried plastic welding it but the welding keeps cracking again. This stuff might be the go.

[hayd3n]

took forever for me to make a video
so i goggled one instead
I2pQKPxZMd0

[specter]

hey i have some lugs that hold the main faring and bottom faring together, snap off... how would i go about plastic welding these back to have a strong bond as my bike rattles like f#$k
cheers

[nallac]

hey i have some lugs that hold the main faring and bottom faring together, snap off... how would i go about plastic welding these back to have a strong bond as my bike rattles like f#$k
cheers


You could try the stuff from Supercheap pete376403 mentioned above,
or use super glue and baking Soda for a cheap pretty strong fix.

Google it ,it does work pretty good...

[specter]

You could try the stuff from Supercheap pete376403 mentioned above,
or use super glue and baking Soda for a cheap pretty strong fix.

Google it ,it does work pretty good...

true that
didnt read most of last page which really helps..... :msn-wink:

[Grubber]

These days I seem to be accumulating quite a lot of broken, cracked and generally munted plastic bits . No, I've not broken them myself, I've gotten them like that.

Now, in the good old days, when all bike parts were made of decent honest cast iron, fixing broken bits was easy. You welded, or brazed them up. With the trusty oxy torch. Which I can still do tolerably well.

Unfortunately, (and IMHO very ill advisedly) manufacturers seem determined to use more and more plastic and less and less cast iron nowadays.

Which leaves the question, what does one do when it gets broken ?

I know that broken plastic CAN be welded up. But I doubt that it involves an oxy torch.

I see plastic welding kits on Tardme for around 500 - 600 bucks.

But I have no idea of whether they are any good or not (it's rather a lot to pay for an experiment). And where do you get filler rods (I presume some sort of filler is required). And such like questions.

And ,and , and , generally.

Anyone know the gubbins on it.

Oh, and is it hard to do? And are the results worth it, or does it just look like crap anyway, and it would be just as well to stick with fibreglass repair kits and Araldite?

Not sure what area you are in but i use a guy out in Waiuku and he does a superb job at reasonable price. Can get his number if ya like...

[specter]

just tried some sealeys aradite from repco on my fairing lugs..... seem to be holding strong but will keep you posted

[hayd3n]

any glue that has been used on repairs i refuse to fix
the fumes they give off when heated are very toxic

[specter]

ARADITE WORKS VERY VERY WELL.... strong bond and dries clear give 24hrs to set fully though

[PlasticDoc]

Hi, I spotted this thread on the net and decided I should join to help out and of course, to promote my services! I am a specialist plastic repairer based in Levin and I repair anything & everything but, I especially enjoy sport, road bike semi rigid plastic repairs. See my website www.plasticweldingrepairs.co.nz or www.falconplastics.co.nz I advise anyone; NEVER attempt to glue or attack ANY plastic with a soldering iron, it will not work, well, maybe, till just after the bike is sold---- All Thermoplastics, as against ThermoSET plastics, are temperature sensitive and have a narrow weld temp range, a non adjustable soldering iron will burn & destroy the weld area. An adjustable soldering iron will only 'MELD', it cannot perform a proper weld but, if good technique is used may do a quick, just acceptable job - not the ideal.
There is a confusion re 'gluing' and solvent or chemical welding - a glue will simply sit on top of the substrate and maybe, lock around some rough or edged areas, one nudge and it will separate. Polyethylene >PE< and Polypropylene >PP< plastics are completely impervious to Solvents/chemicals and therefore ALL & any glues. Here's a clue; PP & PE are used to contain chemicals.
There are some expensive two part adhesives that with special preparation can do a reasonable job on some plastics but I rarely use them.
The majority of road bikes utilize >ABS< type plastics which can be hot-air or solvent welded. The problem with using hot-air on ABS is, it warps, can crack while being welded even when pre-heated and, thin areas will just blow away. This explains why many hot air welds fail - the welder is afraid of blowing through so he limits the temperature which causes a poor weld, he also wont weld both sides as a welder should. These welds need a lot of FGlass filler which makes the fairing more rigid, less able to flex and is likely to crack quite easily. Also, Urethane FG & most other fillers I have encountered do not adhere to semi rigid plastics that well.

A good weld is where the substrate and the rod/weld material melt at the correct temp or liquidity and adjoining molecules start holding hands! It takes some knowledge/experience and excellent equipment to be able do this on every weld.

On the other hand, Solvent welding ABS type plastics produces no warping or cracks & therefore a minimum of refinishing. Extra reinforcing material can be easily added where needed, tight areas can be accessed, small lugs can be repaired & re attached, decals can be better preserved. The only negatives for solvent welding are; there is a curing time which increases with the thickness of added material. Incorrect procedure can make repainting a problem. Aeration of the added material has to be avoided to effect a strong weld, this can be critical.
I have developed, through experience, the technology required to provide guaranteed repairs to ABS plastics.

Performance bikes may have front fairings made of nylon >PA< (which has to be hot air welded only), others may be ABS or some alloy mix like >PA/PBT<. All plastics have their own unique properties and repair techniques, you cannot weld one plastic with another.
I hope I have helped those interested here and cleared the air some. I am willing to answer questions (without giving away trade secrets of course!) re your particular plastic problem.
All KiwiBiker members will receive a 10% discount on labour should they require my services.
Brian plastic.welding.repairs@vodafone.co.nz

[hayd3n]

thanks for the reply
good to hear of other ppl in the trade