Anderzander Posted February 7, 2015 Share Posted February 7, 2015 I have a damaged airbox and wondered if there is something that I could use to repair it ? It's sort of a broad crack - like a split with a piece missing. So if there is something suitable it could be filled and sanded back. Would a glue gun work ? Or is there something else ? I'm just mindful it needs to bond well to seal properly and stay that way to be waterproof. Quote Link to comment Share on other sites More sharing options...
jackmac Posted February 7, 2015 Share Posted February 7, 2015 Fibreglassing kit? Worked nicely for me on a snorkel, doesn't cost much either Quote Link to comment Share on other sites More sharing options...
Boydie Posted February 7, 2015 Share Posted February 7, 2015 As above, rough up the inside of the airbox to make a surface the fibreglass cloth will bond to, mix the resin, paint the inside surface with it then lay the cloth (not mat) on it and brush in more resin, allow it to dry and trim off. You will find the cloth is easier to use than the loose matting as you can easily cut it to shape with scissors, if you don't have any fibreglass cloth you can use a piece of old terry towelling, it works just as well and in many instances is easier to mould to the required shape, for example repairing damaged plastic bumpers. Quote Link to comment Share on other sites More sharing options...
Anderzander Posted February 7, 2015 Author Share Posted February 7, 2015 I must admit to being a fibreglass virgin - and a bit irrationally unconfident of using it .... But that said, I think the damage may be too small and awkward for laying something up on it ? It's along an edge where two sides / surfaces join - and if it was on a skirting board you'd use a thick bead of caulk or polyfilla .... Thus my thought of something like a gluegun ? Quote Link to comment Share on other sites More sharing options...
Boydie Posted February 8, 2015 Share Posted February 8, 2015 Hot glue or araldite will only break away after time, fibre glass will be more permanent Quote Link to comment Share on other sites More sharing options...
mmgemini Posted February 8, 2015 Share Posted February 8, 2015 Check out your local model shop. There's quite a number, confusing. of plastic glues available for glue plastics. Check first that the glue will work and not melt the plastic. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted February 8, 2015 Share Posted February 8, 2015 There are folk about who weld plastic fuel tanks so maybe they could fix this? There is a high chance it is the same plastic vacuum formed material. Quote Link to comment Share on other sites More sharing options...
muddy Posted February 8, 2015 Share Posted February 8, 2015 I'd probably use sikaflex it's my favourite method of fixing stuff to other stuff. You can use thin plastic like a juice carton or even cling film as shuttering. Will. Quote Link to comment Share on other sites More sharing options...
GW8IZR Posted February 8, 2015 Share Posted February 8, 2015 Hot air gun and filler rod made from off cuts of similar plastic. Quote Link to comment Share on other sites More sharing options...
ejparrott Posted February 8, 2015 Share Posted February 8, 2015 If there's a piece missing you can't very well just glue it back together. I'd use a fibregalss mat on the inside to build it up, but I've also never used it....where's that post on fitting a double DIN in a TD5 dash... Quote Link to comment Share on other sites More sharing options...
studmuffin Posted February 8, 2015 Share Posted February 8, 2015 Sugru will fill and bond in one go. SimonR said you can make your own with silicon and corn flour or talcum powder. I tried it and it works. Barry Quote Link to comment Share on other sites More sharing options...
Shackleton Posted February 8, 2015 Share Posted February 8, 2015 I'd probably use sikaflex it's my favourite method of fixing stuff to other stuff. You can use thin plastic like a juice carton or even cling film as shuttering. Will. +1 5200 is "never come off" grade Sika and a good option. It'll have gone off enough to be strong in hours to a day depending on temp but it's not fully cured for about a week so don't go wooling out of it. Personally I'd go the glass fibre route though. Don't be afraid of it, it's really easy and rewarding and once you've cut your teeth you realise there are so many things you can fix and make. Get a good quality kit, some cheap paint brushes a sharp scissors, and measure well. It's all about the prep, there's no need to rush. Lay up the job, have everything out and to hand and literally run through how it will go before getting into actual glassing. Once you ad your catalyst you're on the clock and you don't want to be rushing because it's not working out or something's missing. Cut the cloth and offer it up dry first (for a job like yours thinner cloth will give you more strength so something like 6oz or thinner). Could be overkill but if it were mine Id' get some fumed silica like "Aerosil", it's a powder you make a thick paste out of and makes resin structural by itself. Chopping cloth into your resin to achieve the same thing works too but it can be more difficult to gauge a mix and if wrong, difficult to work. Use the Aerosil mix to fill the gaps and before it goes off paint some straight resin onto the surrounding area that your cloth will cover, add your sheets of cloth and wet them up with more resin. The trick is not to work the cloth too much so you keep the weave straight. At the end, if you put a piece of acetate over your glass job when you're done (or use it for form work from the get go) it'll peel away once everything has gone off and leave a glossy smooth finish. Also - small mixes, a little goes a long way. Good kit is expensive and there's no point in wasting it. If you want a more in depth run through gimmie a shout and I'll do a step by step for you. It sounds like a small job so a little kit will do, although they don't tend to come with enough cloth. Quote Link to comment Share on other sites More sharing options...
simonr Posted February 8, 2015 Share Posted February 8, 2015 What about friction welding? There is some infor here: http://makezine.com/projects/make-34/skill-builder-finishing-and-post-processing-your-3d-printed-objects/ Although this is about 3D Printing - the technique works for any plastic which will melt. You can even weld two dissimilar plastics together as they are being stirred / mixed up at the interface. Just use a dremmel and a bit of plastic rod (ABS 3D Printer filament is ideal but you can just cut a strip of any old plastic). You'll be surprised at how strong the joint is - better than any glue! I used it to weld my dash back together (long story!) the weld is on the inside and on the outside, the gap is invisible. It's invaluable! Si Quote Link to comment Share on other sites More sharing options...
Snagger Posted February 8, 2015 Share Posted February 8, 2015 Sorry for hijacking the thread, but it's related. The plastic retaining ring on my Defender indicator stalk has snapped where it meets the main body of the switch unit (it's an open sided semi-circle with a screw through the open end to clamp on to the steering column). I have tried Tiger Seal and then JB Weld with a steel strip around the outer circumference, but neither seems to stick well tot he plastic (degreased before glueing). I was thinking of trying the same again, but with a small screw through each end of the strip into the plastic... Any other ideas? The joint is under tension when the screw is tightened. Quote Link to comment Share on other sites More sharing options...
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