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Creative Advice Needed


Chaharly

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Hey guys! Got a little more plastic welding to do, and I think the best way to go about this is to have a fine powder made of ABS to do the welding. I tried running small pieces of plastic through an old blender, but I dont see them gettign to be the powder I was hoping for. You guys have any suggestions to work this ABS down into a fine powder?

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If the pieces you have are large enough to sand and you have a sander with a dust collector, clean the dust collector bag to remove dust you do not want and then sand the parts and use the dust in the collection bag.

 

Not sure what exactly you are fixing, but you can also try Super Glue gel and then sprinkle the glue joint with baking soda, is makes the gel set up almost instantly and is super hard and strong.

Experiment with the super glue and baking soda first to get the hang of it.

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Always could take a piece of plastic over to the grinder, make a mess, and sweep it up.

 

I just used some of this JB plastic glue on a cracked / broken front car plastic bumper (gotta love my college girl). Anyways, the stuff is awesome. I had a nasty fix, holding like a charm.

https://www.amazon.com/J-B-Weld-8237-PlasticWeld-Plastic/dp/B003S2E4UE/ref=asc_df_B003S2E4UE/?tag=hyprod-20&linkCode=df0&hvadid=241975700326&hvpos=1o2&hvnetw=g&hvrand=3934157096004971059&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9016155&hvtargid=pla-526005054381&psc=1

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I use Q-Bond for most of my repairs. It dries fast and is the strongest thing I have used. I get it at Advanced Auto and not expensive as others out there. I have used it on the handles of the wife's electric skillets and it holds like it was never broken. If you try it you will keep it on hand for a lot of repairs.

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Instead of trying to make the ABS into a powder, just dissolve it in Acetone and now you have liquid ABS that can be flowed into a crack to weld it back together. You can add more ABS to get the consistency you want. when you use it in the repair the acetone in the mix will melt into the surfaces of the crack and the dissolved ABS will fill small gaps. when it dries it is back to one homogeneous part.

 

If you tell us what specifically you are working on we may have more and better ideas.

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Instead of trying to make the ABS into a powder, just dissolve it in Acetone and now you have liquid ABS that can be flowed into a crack to weld it back together.
Methyl Ethyl Ketone Peroxide solvent is a better choice than Acetone because it does not dissolve the paint used on the Ventures. Cracks can be masked using a cello tape like Scotch Tape which prevents or at least reduces the need for much cleanup.

 

I use a small glass jar with a metal lid that seals to hold the MEK and small bits of ABS water pipe while they dissolve. It can take a day or two to dissolve small chunks which is the biggest con to this method. Collecting the saw cuttings from cutting leftover pipe or fittings can be used to fairly quickly alter the thickness of the mix.

 

It seems to be about as strong as the original ABS once you learn how to apply it without getting any air pockets.

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If you have any bits and pieces laying around fill a glass jar with acetone and toss them in and put the lid back on. Keep doing it and eventually you'll end up with a dandy slurry for ABS repair. If it get's too thick, add acetone. We can all thank Fred Vogt for this one.... The old timers know who he is.. How's that for creativity??

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Well I got the trunk off the bike to work on the CLASS system and found a few cracks to fix while i had everything off. Ive done the acetone dissolving method as mentioned above, but I have a difficult time finding the right consistency of plasti-puddy. I've also heard of people using the MEKP solvent, but I don't think Bomgaars has it on hand. Either way, I have a tendency to have a porous plastic weld that, while its pretty strong, could be stronger. Ive seen a plastic repair kit online that has a solvent and a powder, which I can only assume is powdered abs. What they do is get the plastic that is getting fixed damp with their solvent and drizzle a fine dust on it. It dries quickly and molds right into the plastic. Then after a bit of drying dampen it up with the solvent and add more powder. I really cant see how this isn't ABS plastic and MEKP or even Acetone. The kit is 30 dollars and it seems they go through the powder pretty quick so that would get super expensive when I can just grind my own.

 

I read on a forum about a guy grinding ABS pellets down with a coffee grinder and I really think that sounds like a chief idea! For now I dissolved up some plastic and have started putting it all back together, but I'll be grinding a few of the deeper ones down to make sure that there isn't too much porosity.

 

Thanks for the help guys!

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Always could take a piece of plastic over to the grinder, make a mess, and sweep it up.

 

I just used some of this JB plastic glue on a cracked / broken front car plastic bumper (gotta love my college girl). Anyways, the stuff is awesome. I had a nasty fix, holding like a charm.

https://www.amazon.com/J-B-Weld-8237-PlasticWeld-Plastic/dp/B003S2E4UE/ref=asc_df_B003S2E4UE/?tag=hyprod-20&linkCode=df0&hvadid=241975700326&hvpos=1o2&hvnetw=g&hvrand=3934157096004971059&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9016155&hvtargid=pla-526005054381&psc=1

 

I used a JB weld "Plasticweld" recently, a lot like the one in the link. Damn good stuff!

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Since it is a structural repair that you are doing. My recommendation changes.

For structural repairs, I use fiberglass cloth cut to cover about an inch all the way around the damage. I then coat the area with ABS pipe cement (available at any hardware store or other place that sells plumbing supplies) and and flex the joint to work some of the cement into the crack, while it is still wet I press in the glass cloth and then coat the glass cloth with more cement to be sure that it is fully saturated. This makes a repair that is much stronger than the original plastic.

 

The pipe cement is dissolving the surface of your ABS part so the glass cloth will now be a permanent part of the plastic. It broke there once so it was obviously not strong enough, now it is stronger.

 

Even if you already did the liquid ABS repair you can still use this method to reinforce the area.

 

Earlier it was mentioned to use super glue. There are a few plastic safe versions of super glue, they are expensive and hard to find. Most "Superglue" will dramatically weaken the plastic. Super glue is known as a cyanoacrylate adhesive. Cyanoacrylate it the ingredient in Loctite that destroys ABS. It causes the ABS to crystallize.

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Ive done the acetone dissolving method as mentioned above, but I have a difficult time finding the right consistency of plasti-puddy. I've also heard of people using the MEKP solvent, but I don't think Bomgaars has it on hand. Either way, I have a tendency to have a porous plastic weld that, while its pretty strong, could be stronger.
When I do a repair, a few days before I put some fresh MEK Solvent in my mix jar so it has time to dissolve the left-over plastic and add a little more ABS so there is enough to do the repair. It is easiest to get the mix a bit on the runny side and then add more ABS until it gets to a reasonable thickness. The process is just guesswork as to how much of each will be required.

 

The consistency should be something like the natural peanut butter rather than Kraft or Jiffy... so a little runnier. Scoop a little out, about a half inch around. Put the lid on your jar and let what has been removed dry for a minute or two. When it stops being really sticky it is ready to roll around in your fingers. Kneed it a bit to get any air out. Work from the back side of the crack so the mess is not on the visible part. Put a squirt of MEKS on the area to be repaired then press the putty into the crack. Give the area another little squirt to help activate the putty.

 

Two years ago I had to repair the front corner of the trunk bottom which had a spiderweb of cracks around the hinge. Nothing was missing but the cracks went all the way through. After removing the hinge and the metal brace I covered the outside painted surface with cello tape to contain the plastic repair then pushed the putty through until I could see it coming through to the tape.

 

After scraping the inside to clean it up as much as possible I put the hinge and brace back to help keep the corner in the proper position and to make sure it wasn't deformed and the lid would close properly. These major repairs will set up in a few hours but will need several days to cure and will take a few months to get to full strength depending on temperature. The cracks can still be seen, from close up, but the repaired area is strong and would only need a light sanding to paint if I wanted to go that far.

 

Just a point of information, MEKP most likely refers to Methyl Ethyl Keytone Peroxide which is the chemical that is used as a catalyst for the polyester resin used in common fiberglass products. It is not the same thing as MEK Solvent. MEK Solvent is fairly inexpensive, I bought a liter of it about 8 years ago for under $10 CAD and still have almost 1/3 of it left after doing a lot of repairs. The ABS cost me nothing because they were scraps from plumbing repairs.

 

FF mentioned using a fiberglass cloth to strengthen specific areas. This should work very well when liquid ABS is worked into the strands in a similar way to laying up polyester resin. The mix would need to be liquid enough to be absorbed by the glass fibers, so not a putty.

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I used Plastex also known as PlastiFix to repair any of my cracks. I even used it to join a bottom and top half of two different side fairings to make one good one. I embed a couple of layers of Fiberglass drywall tape as I build it up to improve strength (I add fiberglass drywall tape to JB weld sometimes for the same reason). Any way the repair was strong enough that when the bike dropped of the work table this summer, 10 years later there was absolutely no indication of failure and to this day no buddy has been able to tell were the joint is (I'm not even sure I can tell exactly anymore and I did the job).

Edited by saddlebum
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I used a soldering pencil and welded small pieces of ABS to the area along the crack...melting both the plastic and the crack. Think using the small ABS piece like solder....melting it as I went along the crack. Finished with epoxy and fiberglass cloth a few inches on either side of repair. Stronger than factory and easy, peasy to do. Only downside is the smell of the melting plastic....

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I embed a couple of layers of drywall tape as I build it up to improve strength (I add drywall tape to JB weld sometimes for the same reason).
The drywall tape you refer to is made from glass fiber and is a very good choice because the open weave makes it easier to embed it in whatever repair compound is being used. The firmness of the tape way easier to work with than glass fiber cloth. Also being easy to find in convenient amounts is a big plus.
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The drywall tape you refer to is made from glass fiber and is a very good choice because the open weave makes it easier to embed it in whatever repair compound is being used. The firmness of the tape way easier to work with than glass fiber cloth. Also being easy to find in convenient amounts is a big plus.
Yes it is. Sorry :confused24: I did leave that part out :doh:. and because of the open weave I prefer it to regular fiberglass cloth. For more strength you just build it up in alternating layers.

Just like adding rebar to concrete :detective:

Edited by saddlebum
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See the plastifix stuff is what I'm talking about. The only issue is that I'm not spending 30 bucks on powdered ABS and acetone no thanks! I've had good luck just layering on ABS pipe glue, which I'm pretty sure is just a dissolver and abs plastic. As far as using heat and donor ABS to "solder" the plastic, I've done it, but with mixed results. I end up getting the plastic too hot and make it weak or even warp the other side of the plastic with the heat!

 

I've heard of using fiberglass to help add rigidity and strength, but I've also read that the fiberglass wont flex while the ABS around it will flex which could cause more cracking?

 

Either way, I'm doing a 63 hour work week this week so I'm not gonna get super far on the old girl. I appreciate the advice as its always interesting to see what everyone else is using.

 

A question when using the fiberglass. I would probably have to sand down a large area of paint to the bare plastic to get the fiberglass to stick. Some of the cracks are visible on the bike, and I'd like to save myself from doing a full repaint if at all possible

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When applying the glass cloth you do not need to sand it down first, just clean it with some alcohol to remove any grease or oil. The solvents in the ABS cement will dissolve the surface of the part anyhow so the sanding will not matter. IF you are using an epoxy glue then you do need to sand to give some tooth for the glue to try to hold on to.

 

As far as flexibility, because the glass cloth is fully embedded in ABS it will remain just as flexible as the rest of the ABS. It is when glass is embedded in something hard like epoxy or polyester resin which cures hard that the result will be brittle. When I did my front bumper using the glass cloth and ABS cement it was loaded with cracks, it was like putting a jigsaw puzzle back together the entire inside of that fender was coated with glass cloth and ABS cement. after the repair the fender was still just as flexible and you could not see any of the cracks in the paint unless you looked really close. It never did crack again either.

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As I stated before I used a mix of plastifix and fiberglass drywall tape to make one good fairing out of two good halfs. the repair remained flexible enough that ten years later when my bike fell off my fully elevated bike table it sustained absolutely no damage. If that is not flexible enough for you then I don't know. As far as cost goes I spent a total of about $200.00 for 2 large plastifix kits and considering the results, was money well spent. Secondly follow these steps I posted for slow roll and you should see minimal paint damage almost to the point of nothing more than a slight almost invisible fill mark to the original crack:

 

{{ Put a layer of putty or clear packing tape over the crack on the outside I use clear packing tape and rub it in real good to eliminate air pockets. Then gouge/bevel the crack out on the inside about 3/4s of the way through the plastic and so it opens about 1/4 inch wide at the surface, take care not to penetrate completely to the outside surface (I use a 1/4 inch round ball burr on a Dremel tool for this). Fill the crack with plastex/plastifix using the stitch method which is explained in the instructions that come with the kit. Once it is built up flush with the inside surface cover with a piece of fiberglass dry wall tape. Wet the area down with the liquid solution then sprinkle powder on it and then wet the powder. keep alternating until the tape is covered. At this point you can either let it cure or add additional layers of tape and plastex to build it up until you feel satisfied. Once the curing is complete peel of the tape from the outside. If the tape was sealed down well their should be no trespassing on the paint job. At best you might notice an extra fine black web line }}

 

Regarding the cost I feel it well worth it and if you use it correctly it actually does go a long why. Consider my scoot was a total wright off and I totally restored the bike to like new condition. The plastex even sands baby butt smooth and you can touch up and sand as often as needed to pull off a perfect surface for painting (no spot putty required what so ever).

 

Here are some before and after pics. The hard part was spending a season rebuilding and painting the bike instead of riding it.

bike accident 001.jpg

IMG_20130804_133055_057.jpg

IMG_20130804_133321_181.jpg

Edited by saddlebum
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[h=3]ABS Glue[/h]ABS glue is great for welding two ABS parts together, and is better than using other adhesives, even super glue. ABS glue melts the two pieces, fusing them together into one strong piece instead of two glued pieces.

ABS Glue Instructions:

 

  1. Pour 50mL of acetone into your container.
  2. Measure out 100cm of 3.00mm ABS filament or 8g of ABS scrap. Keep in mind your juice will be the same color as the material you put in. Natural ABS won't affect the color of the mixture, making it an ideal choice to be used when printing with any other filament.
  3. Snip the filament into small bits to open more surface area to the acetone and allow it to dissolve quicker. If you're using scraps, try and chop it up as small as you can get it.
  4. Drop the ABS into the acetone and mix it in, this can either be done with a mixing stick or closing the lid and occasionally loosening the lid and burping the fumes it gives off.
  5. Let the ABS sit in the acetone overnight to ensure all of it dissolves.
  6. When fully mixed, your ABS glue should look like and have the consistency of white school glue.

[h=3]ABS Slurry[/h]ABS slurry should be used to blend the seam between the two ABS pieces that were glued together. Use it like a filler putty to fill in any gaps between the glued parts or even use it to add more material in places that need to be built up.

 

ABS Slurry Instructions:

 

  1. Pour 50mL of acetone into your container.
  2. Measure out 250cm of 3.00mm ABS filament or 20g of ABS scrap. Keep in mind your juice will be the same color as the material you put in. Natural ABS won't affect the color of the mixture, making it an ideal choice to be used when printing with any other filament.
  3. Snip the filament into small bits to open more surface area to the acetone and allow it to dissolve quicker. If you're using scraps, try and chop it up as small as you can get it.
  4. Drop the ABS into the acetone and mix it in, this can either be done with a mixing stick or closing the lid and occasionally loosening the lid and burping the fumes it gives off.
  5. Let the ABS sit in the acetone overnight to ensure all of it dissolves.
  6. When fully mixed, your ABS slurry should look like and have the consistency of putty. It should be very goopy.

 

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When applying the glass cloth you do not need to sand it down first, just clean it with some alcohol to remove any grease or oil. The solvents in the ABS cement will dissolve the surface of the part anyhow so the sanding will not matter. IF you are using an epoxy glue then you do need to sand to give some tooth for the glue to try to hold on to.

 

As far as flexibility, because the glass cloth is fully embedded in ABS it will remain just as flexible as the rest of the ABS. It is when glass is embedded in something hard like epoxy or polyester resin which cures hard that the result will be brittle. When I did my front bumper using the glass cloth and ABS cement it was loaded with cracks, it was like putting a jigsaw puzzle back together the entire inside of that fender was coated with glass cloth and ABS cement. after the repair the fender was still just as flexible and you could not see any of the cracks in the paint unless you looked really close. It never did crack again either.

 

 

Okay I see what yer saying. If i were to use the fiberglass epoxy then it has the possibility of not flexing the same as the ABS but if its melded directly into the ABS it'll flex with it just fine.

 

By the way, Jeff I got that Stator and R&R in. Looks great! Thanks bud!

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As I stated before I used a mix of plastifix and fiberglass drywall tape to make one good fairing out of two good halfs. the repair remained flexible enough that ten years later when my bike fell off my fully elevated bike table it sustained absolutely no damage. If that is not flexible enough for you then I don't know. As far as cost goes I spent a total of about $200.00 for 2 large plastifix kits and considering the results, was money well spent. Secondly follow these steps I posted for slow roll and you should see minimal paint damage almost to the point of nothing more than a slight almost invisible fill mark to the original crack:

 

{{ Put a layer of putty or clear packing tape over the crack on the outside I use clear packing tape and rub it in real good to eliminate air pockets. Then gouge/bevel the crack out on the inside about 3/4s of the way through the plastic and so it opens about 1/4 inch wide at the surface, take care not to penetrate completely to the outside surface (I use a 1/4 inch round ball burr on a Dremel tool for this). Fill the crack with plastex/plastifix using the stitch method which is explained in the instructions that come with the kit. Once it is built up flush with the inside surface cover with a piece of fiberglass dry wall tape. Wet the area down with the liquid solution then sprinkle powder on it and then wet the powder. keep alternating until the tape is covered. At this point you can either let it cure or add additional layers of tape and plastex to build it up until you feel satisfied. Once the curing is complete peel of the tape from the outside. If the tape was sealed down well their should be no trespassing on the paint job. At best you might notice an extra fine black web line }}

 

Regarding the cost I feel it well worth it and if you use it correctly it actually does go a long why. Consider my scoot was a total wright off and I totally restored the bike to like new condition. The plastex even sands baby butt smooth and you can touch up and sand as often as needed to pull off a perfect surface for painting (no spot putty required what so ever).

 

Here are some before and after pics. The hard part was spending a season rebuilding and painting the bike instead of riding it.

 

 

That looks great Saddlebum! So you're actually laying the fiberglass flush or even on top of the ABS after you've layered on some of the plastifix?

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ABS Glue

 

ABS glue is great for welding two ABS parts together, and is better than using other adhesives, even super glue. ABS glue melts the two pieces, fusing them together into one strong piece instead of two glued pieces.

ABS Glue Instructions:

 

  1. Pour 50mL of acetone into your container.
  2. Measure out 100cm of 3.00mm ABS filament or 8g of ABS scrap. Keep in mind your juice will be the same color as the material you put in. Natural ABS won't affect the color of the mixture, making it an ideal choice to be used when printing with any other filament.
  3. Snip the filament into small bits to open more surface area to the acetone and allow it to dissolve quicker. If you're using scraps, try and chop it up as small as you can get it.
  4. Drop the ABS into the acetone and mix it in, this can either be done with a mixing stick or closing the lid and occasionally loosening the lid and burping the fumes it gives off.
  5. Let the ABS sit in the acetone overnight to ensure all of it dissolves.
  6. When fully mixed, your ABS glue should look like and have the consistency of white school glue.

ABS Slurry

 

ABS slurry should be used to blend the seam between the two ABS pieces that were glued together. Use it like a filler putty to fill in any gaps between the glued parts or even use it to add more material in places that need to be built up.

 

ABS Slurry Instructions:

 

  1. Pour 50mL of acetone into your container.
  2. Measure out 250cm of 3.00mm ABS filament or 20g of ABS scrap. Keep in mind your juice will be the same color as the material you put in. Natural ABS won't affect the color of the mixture, making it an ideal choice to be used when printing with any other filament.
  3. Snip the filament into small bits to open more surface area to the acetone and allow it to dissolve quicker. If you're using scraps, try and chop it up as small as you can get it.
  4. Drop the ABS into the acetone and mix it in, this can either be done with a mixing stick or closing the lid and occasionally loosening the lid and burping the fumes it gives off.
  5. Let the ABS sit in the acetone overnight to ensure all of it dissolves.
  6. When fully mixed, your ABS slurry should look like and have the consistency of putty. It should be very goopy.

 

 

Yessir that's how I've fixed previous cracks!

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See the plastifix stuff is what I'm talking about. The only issue is that I'm not spending 30 bucks on powdered ABS and acetone no thanks!
I tried it before I came up with the MEKS method. Way too expensive and not that adaptable to different requirements.

 

I've heard of using fiberglass to help add rigidity and strength, but I've also read that the fiberglass wont flex while the ABS around it will flex which could cause more cracking?
Probably some confusion here. Most people who say fiberglass mean the combination of glass fiber and polyester resin. I don't think polyester resin chemically bonds very well, if at all, with ABS plastic. The way it sticks is by physically gripping the tiny indentations in the surface, mostly provided by sanding. Applying fiberglass to wood works fairly well because the resin will soak into the wood fibers before setting up. On ABS or metal surfaces that does not work so well.

 

The other thing to be aware of is that polyester resin has a different bending coefficient from ABS which can lead to separation of the two surfaces, particularly when exposed to direct heating and cooling such as HOT Arizona sun.

 

Unless I'm off base here, Saddlebum and Flyinfool both refer to using glass fibers embedded in ABS. In any case, that is what I would use when trying to achieve a strengthening repair. Fiberglass cloth has a fairly close weave which makes it more difficult to soak up liquid with fillers while the fiberglass tape used on wallboard has an open weave and comes in a much more convenient form for these types of repairs. As Saddlebum said the tape is like laying down rebar and is also similar to embedding copper wire in the ABS to strengthen a repair.

 

A question when using the fiberglass. I would probably have to sand down a large area of paint to the bare plastic to get the fiberglass to stick. Some of the cracks are visible on the bike, and I'd like to save myself from doing a full repaint if at all possible
When doing any repair but particularly when using fiberglass, it is far better to do it from the back unseen side. It's a real chore to feather the line between ABS and Fiberglass because they have a different hardness.
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