Tourmaster Posted April 12, 2018 Share Posted April 12, 2018 I was doing some spring maintenance, specifically changing the air filter, and I managed to crack the mounting flange on the snorkel...yea it was cold in the garage. The locking sliders were not pulled entirely clear of the air box, and when I pulled the stud out of the grommet it released rather quickly (again it was cold) and the flange went snap. It has broken the factory glue joint about half way around the flange / tube joint and the flange itself has 2 cracks as well. Does anybody know what kind of plastic its made from, or better yet, what glue will repair it. I have tried J-B Weld Steel (2 part epoxy), J-B Weld PlasticWeld putty, and ABS pipe glue, all just sit on top and do not penetrate / dissolve the surface. Acetone also has no effect on it. The factory joint doesn't have a fillet of glue, it seems their glue just fused the parts together. Thanks in advance. Rick Link to comment
6speedTi Posted April 12, 2018 Share Posted April 12, 2018 Mine cracked as well at the flange area. I probably wasn't paying full attention when removing it. I used JB weld Quick. I did not want to wait a full 24 hours for it to set. Its all good now. Just a dab in the seams of the cracks is all you need. Make sure you don't get any on the mating surface that butts up with the filter. It's no big deal unless you totally ripped it apart. I priced a new one from BMW. Expensive. JB Weld was much cheaper. 😆 Link to comment
Tourmaster Posted April 12, 2018 Author Share Posted April 12, 2018 Hi 6speedTi, I just tried the J-B Weld Kwik with the same results as the other 2 J-B Weld products, it simply sits on the surface. I am hoping to find something that will interact chemically with the plastic. Link to comment
Skywagon Posted April 12, 2018 Share Posted April 12, 2018 (edited) Greetings TM...I've not had to repair the tube you are referring to, but have repaired several plastic things on boats, cars, etc. As long as you don't care about the look too much here is what I do. I get a 30 minute epoxy from a model airplane shop and mix it with microballoons. It makes it very spreadable and holds like a charm Here is a web link to show you what those are, but you should be able to source locally. https://www.towerhobbies.com/cgi-bin/wti0095p?FVSEARCH=micro+balloons The other thing Ive had success with is zap CA +1 glue. Put a small bead on. Cover the bead with baking soda. It won't be pretty but it has worked for me many times. Edited April 12, 2018 by Skywagon Link to comment
Pappy35 Posted April 13, 2018 Share Posted April 13, 2018 Also from a model airplane shop you can find the cement that's used on plastic model planes (and cars and boats, etc.). It works by dissolving the plastic at the joint to allow them to fuse together (think of it as room-temperature plastic welding). I would try that. Epoxy is not going to do squat to hold plastic parts like that. Those adhesives (the plastic cements I mean) may or may not work as it's possible that the type of plastic that BMW uses won't chemically react with cements I'm thinking of. YMMV. I'm a mechanical engineer and don't really know much about polymer chemistry beyond having built plastic models all my life. Good luck Link to comment
MichiganBob Posted April 13, 2018 Share Posted April 13, 2018 Never heard of micro-balloons before so read up on it. Really interesting. Wish I knew about it years ago. Thanks for the information. Link to comment
Tourmaster Posted April 13, 2018 Author Share Posted April 13, 2018 Hi Skywagen, The 30 minute epoxy mixed with micro-balloons (filler) is still epoxy, so I can't see it working (as in chemically reacting) on this plastic. As for the Zap CA+1, it's a cyanoacrylate glue (Super glue, Krazy glue), again I don't believe it will fuse the plastic. What does covering it with baking soda do...should I have paid a little more attention back in Chemistry class? I personally haven't had much luck with this type of glue ON PLASTIC, it holds for a week or two then fails. Any other thoughts? Link to comment
Tourmaster Posted April 13, 2018 Author Share Posted April 13, 2018 Hi Pappy35, I forgot to mention in my OP that I had also tried 'Testors Cement for Plastic Models', the card says its for joining polystyrene and ABS. It had no effect on the snorkel plastic. I recall reading somewhere that certain plastics cannot be glued, Acetal (Delrin) I think is one. The snorkel is molded in 2 parts that are glued / fused together so there must be something available. Link to comment
Pappy35 Posted April 13, 2018 Share Posted April 13, 2018 Hi Pappy35, I forgot to mention in my OP that I had also tried 'Testors Cement for Plastic Models', the card says its for joining polystyrene and ABS. It had no effect on the snorkel plastic. I recall reading somewhere that certain plastics cannot be glued, Acetal (Delrin) I think is one. The snorkel is molded in 2 parts that are glued / fused together so there must be something available. Yeah. That's what I feared. Can you post a picture of the crack? FYI. Micro balloons are a filler used with epoxy to make it more sandable and build it up to create radii at junctions between right angle joints, fill cracks. Makes the epoxy kinda like bondo. It will actually make any joint weaker. Epoxies are very strong but need surface area to work (the needed area depends on how strong a bond you need and the porosity of the materials begin joined). CA is basically same principle though using totally different chemistry. It relies much more on porosity as it's very brittle when cured. Link to comment
Tourmaster Posted April 13, 2018 Author Share Posted April 13, 2018 Making headway - sort of. I had a visit from a buddy today, showed him the part and he immediately recognized a set of characters under the molded in part # & Germany C of O identification. >PP/PP - GF 30< He says its polypropylene and a quick internet search says PP-GF 30 is 30% long strand glass fiber reinforced polypropylene. So now I know what I'm dealing with. Solvents are ineffective on polypropylene. The joining method is heat, and usually some sort of tooling / fixture to align and control the pressing together of the near molten plastic is required. Since I have to maintain a relatively flat surface where the flange meets the filter / air box, and I have nothing in the fixture department, all I can do is try some epoxy with lots of surface prep. My previous epoxy tests were on the smooth exterior surface of the snorkel, abrading the joint and surrounding area should help with its adhesion. Crossing my fingers... I'll post some pics if I can find a free on-line 3rd party hosting site (damn Photo-bucket). Link to comment
Richard_D Posted April 13, 2018 Share Posted April 13, 2018 https://www.freemansupply.com/products/adhesives-repair-materials/methacrylate-adhesives/plexus-ma-300-methacrylate-adhesive This repaired a crack in my hot tub and held forever. It's also used in the boat repair business. I found the Devcon Plastic welder at True Value which is the same thing according to the mother company : Plexus. Link to comment
Tourmaster Posted April 14, 2018 Author Share Posted April 14, 2018 some pics... I used the end of a hacksaw blade to roughen the surfaces inside the flange groove, 80 grit sandpaper elsewhere. For the break along the flange side, I used a Dremel with a ball burr to cut a groove on both sides, then scrapped the epoxy flat to the adjacent surfaces. I went with J-B Kwik epoxy, it's easy to work with, fast setting and a close colour match. Thanks to all for their suggestions. Link to comment
6speedTi Posted April 14, 2018 Share Posted April 14, 2018 Glad it worked out for you. JB Weld fixes anything except a broken heart. 😆 Link to comment
AZgman Posted April 14, 2018 Share Posted April 14, 2018 You might try Beemerboneyard to see if they have a used part. They will also put you on a waiting list if they don't have one today but get one in down the road. Link to comment
beemer chuck Posted April 16, 2018 Share Posted April 16, 2018 Many of these on e-bay for less than $40. Link to comment
Tourmaster Posted April 16, 2018 Author Share Posted April 16, 2018 I had checked E-Bay and they are certainly available, the shipping + duty + exchange kills us north of the border. Repairing was my first option. Link to comment
poodad Posted April 17, 2018 Share Posted April 17, 2018 Making headway - sort of. I had a visit from a buddy today, showed him the part and he immediately recognized a set of characters under the molded in part # & Germany C of O identification. >PP/PP - GF 30< He says its polypropylene and a quick internet search says PP-GF 30 is 30% long strand glass fiber reinforced polypropylene. So now I know what I'm dealing with. Solvents are ineffective on polypropylene. The joining method is heat, and usually some sort of tooling / fixture to align and control the pressing together of the near molten plastic is required. Since I have to maintain a relatively flat surface where the flange meets the filter / air box, and I have nothing in the fixture department, all I can do is try some epoxy with lots of surface prep. My previous epoxy tests were on the smooth exterior surface of the snorkel, abrading the joint and surrounding area should help with its adhesion. Crossing my fingers... I'll post some pics if I can find a free on-line 3rd party hosting site (damn Photo-bucket). Well, the good news is that polypropylene is supposed to be easy to weld according to this: http://www.kingplastic.com/tips-for-welding-thermoplastics/ There's a bunch of youtube videos on welding plastic - including some folks that use a small torch or soldering gun for heat instead of dedicated plastic welding tools. Link to comment
MichiganBob Posted April 17, 2018 Share Posted April 17, 2018 Interesting read poodad ... thanks. Link to comment
MotoMichael Posted May 13, 2018 Share Posted May 13, 2018 My other money gobbling past time is kayaking. To repair that polyethylene people use something like this: https://www.austinkayak.com/products/15512/Wilderness-Systems-Weld-Rod-Stock-10-Pack.html not sure if that would work here but it might be worth looking into. Link to comment
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